Eating Habits and Eating Disorders During Pregnancy CHRISTOPHER G. FAIRBURN, DM, ROSEMARY JONES, BSC
ALAN STEIN, MRCPSYCH, AND
A general population sample of 100 primigravid women was studied prospectively to describe the changes in eating that occur in pregnancy with particular reference to cravings and aversions and the behavior and attitudes characteristic of clinical eating disorders. Assessment was by standardized interview. Dietary cravings and aversions were found to be common and largely confined to early pregnancy. Eating disorder features decreased in severity early in pregnancy but increased later on. Dietary cravings rarely resulted in episodes of overeating like those seen in patients with eating disorders. In this study of a general population sample, no evidence was found of a relationship between pregnancy outcome and the severity of eating disorder features prior to pregnancy. Key words: pregnancy; eating disorders; cravings; aversions.
INTRODUCTION
There have been a succession of case reports on the pregnancies of women with either anorexia nervosa or bulimia nervosa and more recently several case series (1-5). No consistent findings have emerged. In some instances there is a dramatic improvement in the eating disorder and this may be lasting or shortlived. In others, the disturbance continues unchanged or it worsens. There has been concern that fetal well-being may be compromised; both low birth weight and low APGAR scores have been reported, and there may be an increased risk of spontaneous abortion (6). Much more common than clinical eating disorders are the so-called "normative
From the University Department of Psychiatry, Warneford Hospital, Oxford, United Kingdom Address reprint requests to- Christopher G. Fairburn, D.M., University Department of Psychiatry, Warneford Hospital, Oxford 0X3 7JX, United Kingdom. Received for publication February 21, 1992; revision received July 8, 1992
Psychosomatic Medicine 54:665-672 (1992) 0033-3174/92/5406-0665$03.00/0 Copyright © 1992 by the American Psycho
concerns" about shape and weight seen in young women today (7). Many women are dissatisfied with their appearance and weight and attempt to modify them either by dieting and exercising or, in a minority, by using more extreme methods, including inducing vomiting and misusing laxatives or diuretics (8). Most of these women are of childbearing age. How they adjust to being pregnant is not known. This subject is not only of clinical importance: it is of theoretical interest. It can be informative observing how psychopathology responds to provocations, be they artificial as in the case of therapeutic interventions or natural as in the case of pregnancy. Indeed, pregnancy is a particularly interesting event in the context of eating disorders. Most women wish to eat healthily when pregnant, yet problems controlling eating are common amongst those who are not pregnant (8). Certain characteristics of pregnancy may also complicate the matter. It might be predicted that the so-called dietary "cravings" of pregnancy would encourage overeating, although they have not been sufficiently well characterized to be clear 665
C. G. FAIRBURN et al.
that they would promote the types of using a prospective design and a standardovereating seen amongst patients with ized assessment interview. clinical eating disorders. The increase in weight in pregnancy and the alterations in shape might also be expected to have METHODS an influence on eating behavior since these changes are of the type that would Design typically provoke many women to diet. The study was confined to primigravid women There have been few studies of eating since they have no prior experience of the changes in pregnancy. The most systematic study in eating, shape, and weight that occur in pregnancy. of pregnancy-related cravings and aver- The subjects were interviewed on two occasions, sions was by Dickens and Trethowan once in early-to-middle pregnancy and once in the (9). They interviewed 100 primigravid third trimester. women a few days after delivery. In addition, there have been two attempts to describe the effects of pregnancy on the Recruitment behavior and attitudes characteristic of The names of potential subjects, aged 18 years or patients with clinical eating disorders. As over, were obtained from consecutive letters of rein the Dickens and Trethowan study, both ferral to the Maternity Department of the John Radused a retrospective design in which sub- cliffe Hospital in Oxford. This is the only maternity hospital in the Oxford area and it is where the great jects were asked some days after giving majority of births take place. Primigravid women birth about the changes that had occurred estimated to be less than 12 weeks pregnant were over the preceding 9 months. In the first identified and their family doctors contacted to destudy, assessment was by a self-report termine whether there were any medical or social questionnaire (10), whereas in our pre- reasons not to invite them to take part. It was exthat we wished to exclude those with physvious study we used a semi-structured plained ical illnesses (e.g., diabetes mellitus) or treatments interview (11). The two studies came to (e.g., steroids) known to influence eating, shape, or similar conclusions, namely that a signif- weight. We also did not want to contact subjects icant subgroup of primigravid women eat whose pregnancy was unwanted since participation might have distressed them. Potentially suitable in a highly disturbed fashion and that this subjects were contacted by letter asking if they might possibly affect fetal development. would be willing to help with a study of the effects However, the research methods used of pregnancy on eating and weight. Those who did were not sufficiently precise to determine not reply were sent a second letter. Subjects who to take part were subsequently interviewed, either the prevalence or precise character agreed in almost all cases at their home. Recruitment conof the behavioral abnormalities encoun- tinued until 100 subjects had been entered into the study. tered. The aim of the present study was to describe, using a community sample, the changes in eating that occur in pregnancy Assessment Measures with particular reference to cravings and The measure of the clinical features of eating aversions and those features characteriswas the Eating Disorder Examination tic of clinical eating disorders. The study disorders (EDE) (12, 13). This standardized investigator-based was intended to overcome the principal interview assesses in detail the full range of the limitations of the two earlier studies by characteristic psychopathology of eating disorders. 666
Psychosomatic Medicine 54:665-672 (1992)
EATING HABITS AND DISORDERS DURING PREGNANCY It measures the key behavioral and attitudinal features including overeating; dieting; self-induced vomiting; laxative misuse; and concerns about eating, shape, and weight. A global EDE score may be generated which is the average of the five EDE subscales (restraint, overeating, eating concern, shape concern, and weight concern). The EDE also generates operationally defined DSM-III-R eating disorder diagnoses. With the exception of the diagnostic items, the EDE is exclusively concerned with the subject's state over the preceding 28 days. Studies of its reliability and discriminant validity support its use (14-17). For the purpose of this study the EDE was modified in three ways. First, the initial interview addressed two time periods: the usual one of the preceding 28 days, and in addition the 3-month period prior to conception. Second, certain items were adapted to distinguish behavior motivated by being pregnant from that attributable to an eating disorder. For example, when assessing food avoidance, careful note was taken of the reasons for the avoidance to distinguish the desire to eat healthily from the wish to lose weight. Third, questions were added concerning nausea, dietary aversions and cravings, and pica. Data on the course and outcome of each pregnancy were obtained from the computer records of the Oxford Obstetric Data System.
RESULTS The Sample and Interviews To recruit the 100 primigravid women, 128 eligible subjects were identified from the letters of referral. This represents a response rate of 78%. All 100 subjects completed both interviews. The first interview took place at the beginning of the second trimester (i.e., early-to-middle pregnancy; mean number of weeks pregnant = 15) and the second midway through the third trimester (i.e., late pregnancy; mean = 32 weeks). The mean age of the sample was 25.9 years (SD = 3.8). Ninety-four percent were married or cohabiting. Social class was assigned on the basis of occupation using the customary Psychosomatic Medicine 54:665-672 (1992)
UK classificatory scheme (18). The distribution was as follows: I (professional) 13%, II (intermediate) 29%, IIINM (skilled nonmanual occupation) 13%, HIM (skilled manual occupation) 41%, IV (partly skilled occupation) 2%, and V (unskilled occupation) 2%.
Nausea and Vomiting Both nausea and vomiting were common in the early stages of pregnancy, being reported by 91% an 52%, respectively. The nausea began on average at 6.1 weeks (range = 3-14) and lasted on average 8,5 weeks (range = 2-23). The comparable figures for vomiting were 8,0 weeks (range = 4-12) and 7.4 weeks (range = 1-19).
Aversions Strong aversions to specific foods, drinks, or smells were reported by 80 subjects (i.e., 80%). They began early in pregnancy (mean = 7.1 weeks, range = 2-12) and lasted on average 11.4 weeks (SD = 5.2, range = 3-25). The two most common aversions were to coffee and tea, reported by 34% and 18%, respectively. Next most common were the smell of fried or fatty foods (15%), the taste of highly spiced foods like curries (10%), and the presence of cigarette smoke (8%). In the case of coffee and tea, it seemed to be their taste rather than their smell that was aversive. However, an altered sense of smell appeared to underlie the majority of the aversions including the more unusual ones such as aversion to the smell of previously liked perfume or to household detergent. Many of the subjects with aversions were surprised at their intensity,
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and few had expected them. Rarely was the aversion an exaggeration of a previous dislike.
Dietary Cravings Specific dietary cravings were defined as "A definite urge to eat specific foods, drink particular drinks, or smell particular smells." They were described by 53 subjects. On average, they started at 9.2 weeks (range = 4-20) and lasted 10.3 weeks (range = 1-27). They were more varied in character than the aversions. The most common substances craved were chocolate (14%), citrus fruits (11%), savory foods such as pickles (9%), potato crisps (7%), and ice cream (7%). Most subjects had expected cravings of some sort, but some reported amazement at the intensity of their desire for these foods. Several subjects expressed disappointment at having had no cravings. The cravings were often exaggerations of previous likes.
Pica There was a single instance of pica. When pregnant for 32 weeks, one subject ate coal: she reported that it was "irresistibly inviting." Two subjects ate vegetables when they were still frozen saying that they preferred their taste: this was not their normal practice.
Psychopathology of Eating Disorders Eating Disorder Diagnoses Prior to Con-
ception. Over the 3 months prior to conception, three subjects (i.e., 3%) had met strict operational diagnostic criteria for a 668
clinical eating disorder based on the DSMIII-R scheme (13). All three were cases of "eating disorder not otherwise specified" (EDNOS): there were no cases of anorexia nervosa or bulimia nervosa. These prevalence rates are comparable with those for young nonpregnant women from the same geographical area (4.5%, 0%, and 0.8%, respectively (19)). A further five women had a history of bulimia nervosa, three of whom had also met diagnostic criteria for anorexia nervosa. The three subjects who met criteria for EDNOS varied in their clinical characteristics. The first subject dieted to an extreme degree despite being underweight (88% average weight for her age and height). She had the attitudes to shape and weight characteristic of anorexia nervosa and bulimia nervosa. The second subject was of average weight. She too dieted to an extreme degree and had the attitudes characteristic of anorexia nervosa and bulimia nervosa. She had been significantly overweight in the past. The third subject had recurrent objective bulimic episodes as defined by the EDE (i.e., episodes of eating objectively large amounts of food associated with loss of control at the time) (13). These episodes occurred on average twice a week. However, she was not eligible for a diagnosis of bulimia nervosa since she did not practice extreme weight control behavior nor did she have the characteristic attitudes to shape or weight. Her weight was unremarkable. Changes in the Features of Clinical Eating Disorders. Few subjects reported that they had experienced over the 4 weeks prior to conception any of the characteristic behavioral features of clinical eating disorders. Seven (7%) reported objective bulimic episodes, three (3%) had practiced self-induced vomiting, but none had Psychosomatic Medicine 54:665-672 (1992)
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EATING HABITS AND DISORDERS DURING PREGNANCY
taken laxatives to control their shape or weight. Comparable figures for nonpregnant women in this region are 8.6%, 3.3%, and 1.2%, respectively (19). Table 1 shows the rates of these behaviors at the three time points. In addition, scores on the three key EDE subscales are given. There was a change in the level of dietary restraint (F(2,95) = 5.7, p < 0.01]: between the 4 weeks prior to conception and the first interview, there was a decline in the level of restraint (F(l,96) = 9.4, p < 0.01), and an increase between early-to-middle and late pregnancy (F(l,96) = 6.3, p < 0.02). The degree of concern about body shape also changed (F(2,95) = 3.1, p < 0.05), there being an increase between early-to-middle and late pregnancy (F(l,96) = 5.8, p < 0.02). Concerns about weight changed significantly (F(2,95) = 8.2, p < 0.01): there was
a decline in the early stages of pregnancy (F(l,96) = 16.1, p < 0.01) and an increase later on (F(l,96) = 4.5, p < 0.05). This overall pattern of change was also reflected in the global EDE (F(2,95) = 5.0, p < 0.01) with there being a decrease between the 4 weeks prior to conception and interview one (F(l,96) = 7.4, p < 0.01) followed by an increase in late pregnancy (F(l,96) = 6.7, p < 0.02). Changes in Eating Disorder Diagnoses. The number of subjects who met diagnostic criteria for a clinical eating disorder remained stable from prior to conception through to late pregnancy (three prior to pregnancy, three in early-to-middle pregnancy and four in late pregnancy). The stability in the number of cases is misleading, however, since there was considerable flux. None of the three subjects who met case criteria prior to pregnancy
TABLE 1. Changes in Eating Disorder Psychopathology during Pregnancy (N = 100) Prior to Conception" Objective bulimic episodes (number of subjects)6 Self-induced vomiting (number of subjects)6 Laxative misuse (number of subjects)6 Dietary restraint (mean and SD)C Overeating (mean and SD)C Concern about eating (mean and SD)C Concern about shape (mean and SD)C Concern about weight (mean and SD)C Global EDE score (mean and SD)d
Early Pregnancy3
Late Pregnancy"
7
3
5
3
3
1
0
0
0
0.9 (1.4)
0.5 (1.0)
0.9 (1.3)
0.04 (0.3)
0.06 (0.4)
0.00
0.1 (0.5)
0.08 (0.6)
0.04 (0.3)
0.9 (0.8)
0.9 (0.7)
1.1 (0.9)
1.0 (1.0)
0.7 (0.6)
0.8 (0.6)
0.6 (0.6)
0.4 (0.4)
0.6 (0.5)
" Immediately prior to pregnancy, and at 15 and 32 weeks. 6 Number of subjects who had shown this behavior over the previous 28 days. c Eating Disorder Examination subscale (13). d Average score on the five Eating Disorder Examination subscales (13).
Psychosomatic Medicine 54:665-672 (1992)
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was a case during pregnancy. Instead, all the cases at each time point irose de novo, although two had a history of bulimia nervosa. (Thus two of the five subjects with a history of bulimia nervosa (40%) developed a clinically significant eating disorder during pregnancy.) All the cases that arose during pregnancy were of EDNOS. They were characterized by significant attitudinal disturbance and extreme dietary restraint, but they varied in terms of both the use of other weight control behaviors and the presence of clinically significant overeating.
Relationship of Eating Disorder Psychopathology to Other Changes in Eating and Pregnancy Outcome To determine whether there were relationships between the occurrence of nausea, vomiting, aversions, and cravings, and the degree of eating disorder psychopathology, the sample was divided into quartiles on the basis of their preconception global EDE score. The highest and lowest quartiles were compared. No significant differences emerged. A similar comparison was made with respect to perinatal state (gestation, birth weight, APGAR score, birth complications, referral for intensive care) and labor complications. No significant differences were found. DISCUSSION
This study has two significant advantages over its predecessors. The first is its prospective design. On the basis of our previous experience (11), we doubt whether the practice of assessing women shortly after birth allows subtle distinc670
tions to be made, for example, between various forms of overeating. We also doubt whether events during pregnancy can be accurately timed from this vantage point. The second methodological strength is the use of a standardized interview to characterize subjects' eating habits and attitudes and to make eating disorder diagnoses. Self-report questionnaires have serious limitations in this regard and it is generally accepted that a research clinical interview (such as the EDE) is to be preferred (20). The use of the EDE had two other advantages in this context: first, the availability of comparison data on young women from the same geographical area; and second, the possibility of adjusting the instrument to distinguish behavior motivated by being pregnant from that attributable to an eating disorder. We have used an equivalent adaptation of the EDE in a controlled study of eating disorders amongst young women with diabetes and have shown that in this context self-report questionnaires yield spuriously high estimates of the level of eating disorder features (21). We believe that the same is likely to be true when evaluating women who are pregnant. Another strength of the study is its use of a general population sample, thereby avoiding the biases that often result from studying volunteers. The response rate was high at 78% but even this response rate may have resulted in bias since there is evidence that past and present eating disorders may be over-represented amongst those who choose not to respond to surveys on eating disorders (22). The rates of eating disorder features reported here may be underestimates, although there seems no reason to question the rates of other features or the relationships found between them. There is no Psychosomatic Medicine 54:665-672 (1992)
EATING HABITS AND DISORDERS DURING PREGNANCY
obvious solution to the response rate problem if one wants to study a general population sample from early in pregnancy. We considered recruiting subjects when they first attended the clinic since this method worked well when recruiting subjects with diabetes but we found that on average this appointment occurred too late in pregnancy for our purposes. The findings with respect to cravings and aversions were remarkably similar to those of the retrospective study by Dickens and Trethowan (9). Our observation that aversions were more common than cravings mirrors theirs, although more of our subjects reported aversions (80% versus 62%). The focus of the aversions was similar with coffee, tea, and fatty foods being most common. Given our prospective design we were able to time the occurrence of the aversions and cravings: both started in the first trimester and lasted about 10 weeks with aversions tending to start earlier than cravings (9.2 weeks versus 7.1 weeks]. The focus of the cravings also resembled that found by Dickens and Trethowan with fruit, sweet and savory foods being most common. Like Dickens and Trethowan we believe that, as in the case of aversions, the cravings are likely to be a response to pregnancy-induced alterations in taste and smell. The findings with respect to the behavior and attitudes characteristic of clinical eating disorders were complex. There was a general tendency for there to be a decrease in severity early in pregnancy followed by an increase later on. The early decrease in dietary restraint appeared to result from a desire to eat healthily but the decrease was temporary. Concerns about weight lessened in early pregnancy
Psychosomatic Medicine 54:665-672 (1992)
possibly because subjects felt less accountable for their weight (11). However, there was an increase in late pregnancy which may have been related to the common fear of not being able to lose the weight being gained. The increase in concerns about shape that occurred in late pregnancy probably had a similar origin. There was no evidence that tendencies to overeat worsened, and the dietary cravings rarely resulted in episodes of overeating like those seen in patients with eating disorders: while the amounts eaten were sometimes objectively large, this was often not the case and it was uncommon for there to be a loss of control at the time. In this study of a general population sample, we found no evidence of a relationship between pregnancy outcome and the severity of eating disorder features prior to pregnancy. This finding should not be taken to imply that clinical eating disorders (particularly anorexia nervosa and bulimia nervosa) are not associated with adverse pregnancy outcomes. To answer this question with any certainty, data on the pregnancies of a large number of women with clinical eating disorders would need to be compiled. This study was supported by a project grant from the Health Promotion Research Trust. CGF, AS, and RJ were supported by grants from the WeJJcome Trust. We are grateful to Adrienne Garrod, Elizabeth GaskeJJ, Angela Tremayne, Barbara Chambers, Marianne O'Connor, and Jenny Burton for their help with the study and to Pat Yudkin for providing the data on pregnancy outcome. Joan Fagg helped with the data analysis. Helen Doll gave helpful comments on a draft of the paper.
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REFERENCES 1. Lacey JH, Smith G: Bulimia nervosa: The impact of pregnancy on mother and baby. Br J Psychiatry 150:777-781, 1987 2. Stewart DE, Raskin J, Garfinkel PE, et al: Anorexia nervosa, bulimia, and pregnancy. Am J Obstet Gynecol 157:1194-1198, 1987 3. Brinch M, Isager T, Tolstrup K: Anorexia nervosa and motherhood: Reproductional pattern and mothering behavior of 50 women. Acta Psychiatr Scand 77:98-104, 1988 4. Treasure JL, Russell GFM: Intrauterine growth and neonatal weight gain in babies of women with anorexia nervosa. Br Med ] 296:1038-1039, 1988 5. Lemberg R, Phillips J: The impact of pregnancy on anorexia nervosa and bulimia. Int J Eating Disord 8:285-295,1989 6. Mitchell JE, Seim HC, Glotter D, et al: A retrospective study of pregnancy in bulimia nervosa. Int J Eating Disord 10:209-214, 1991 7. Rodin J, Silberstein L, Striegel-Moore RH: Women and weight: A normative discontent. In Sonderegger TB [ed], Psychology and Gender: Nebraska Symposium on Motivation. Lincoln, University of Nebraska Press, 1984 8. Fairburn CG, Beglin SJ: Studies of the epidemiology of bulimia nervosa. Am J Psychiatry 147:401-408, 1990 9. Dickens G, Trethowan WH: Cravings and aversions during pregnancy. J Psychosom Res 15:259-268, 1971 10. King W, Abraham S: Attitudes to body weight, weight gain and eating behaviour in pregnancy. In Abraham S, Llewellyn-Jones D (eds), Eating Disorders and Disordered Eating. Sydney, Ashwood House, 1988 11. Fairburn CG, Welch SL: The impact of pregnancy on eating habits and attitudes to shape and weight. Int J Eating Disord 9:153-160, 1990 12. Cooper Z, Fairburn CG: The Eating Disorder Examination: A semi-structured interview for the assessment of the specific psychopathology of eating disorders. Int J Eating Disord 6:1-8, 1987 13. Fairburn CG, Cooper Z: The interview schedule of the Eating Disorder Examination. In Fairburn CG and Wilson GT (eds), Binge Eating: Nature, Assessment and Treatment. New York, Guilford Press, in press 14. Cooper Z, Cooper PJ, Fairburn CG: The validity of the Eating Disorder Examination and its subscales. Br J Psychiatry 154:807-812, 1989 15. Wilson GT, Smith D: Assessment of bulimia nervosa: An evaluation of the Eating Disorder Examination. Int J Eating Disord 8:173-179, 1989 16. Rosen JC, Vara L, Wendt S, Leitenberg H: Validity studies of the Eating Disorder Examination. Int J Eating Disord 9:519-528, 1990 17. Beglin SJ, Fairburn CG: The reliability of the Eating Disorder Examination. Submitted for publication. 18. Office of Population Censuses and Surveys: Classification of Occupations 1980. London, HMSO, 1980 19. Fairburn CG, Beglin SJ, Davies B: Eating habits and disorders amongst young adult women: an interviewbased study. In preparation. 20. Rosen JC, Srebnik D: The assessment of eating disorders. In McReynolds P, Rosen JC, Chelune G (eds), Advances in Psychological Assessment. New York, Plenum, 1991 21. Fairburn CG, Peveler RC, Davies BA, et al: Eating disorders in young adults with insulin dependent diabetes: A controlled study. Br Med J 303:17-20, 1991 22. Beglin SJ. Fairburn CG: Women who choose not to participate in surveys on eating disorders. Int J Eating Disorders 12:113-116, 1992
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Psychosomatic Medicine 54:665-672 (1992)
ALAN STEIN, MRCPSYCH, AND
A general population sample of 100 primigravid women was studied prospectively to describe the changes in eating that occur in pregnancy with particular reference to cravings and aversions and the behavior and attitudes characteristic of clinical eating disorders. Assessment was by standardized interview. Dietary cravings and aversions were found to be common and largely confined to early pregnancy. Eating disorder features decreased in severity early in pregnancy but increased later on. Dietary cravings rarely resulted in episodes of overeating like those seen in patients with eating disorders. In this study of a general population sample, no evidence was found of a relationship between pregnancy outcome and the severity of eating disorder features prior to pregnancy. Key words: pregnancy; eating disorders; cravings; aversions.
INTRODUCTION
There have been a succession of case reports on the pregnancies of women with either anorexia nervosa or bulimia nervosa and more recently several case series (1-5). No consistent findings have emerged. In some instances there is a dramatic improvement in the eating disorder and this may be lasting or shortlived. In others, the disturbance continues unchanged or it worsens. There has been concern that fetal well-being may be compromised; both low birth weight and low APGAR scores have been reported, and there may be an increased risk of spontaneous abortion (6). Much more common than clinical eating disorders are the so-called "normative
From the University Department of Psychiatry, Warneford Hospital, Oxford, United Kingdom Address reprint requests to- Christopher G. Fairburn, D.M., University Department of Psychiatry, Warneford Hospital, Oxford 0X3 7JX, United Kingdom. Received for publication February 21, 1992; revision received July 8, 1992
Psychosomatic Medicine 54:665-672 (1992) 0033-3174/92/5406-0665$03.00/0 Copyright © 1992 by the American Psycho
concerns" about shape and weight seen in young women today (7). Many women are dissatisfied with their appearance and weight and attempt to modify them either by dieting and exercising or, in a minority, by using more extreme methods, including inducing vomiting and misusing laxatives or diuretics (8). Most of these women are of childbearing age. How they adjust to being pregnant is not known. This subject is not only of clinical importance: it is of theoretical interest. It can be informative observing how psychopathology responds to provocations, be they artificial as in the case of therapeutic interventions or natural as in the case of pregnancy. Indeed, pregnancy is a particularly interesting event in the context of eating disorders. Most women wish to eat healthily when pregnant, yet problems controlling eating are common amongst those who are not pregnant (8). Certain characteristics of pregnancy may also complicate the matter. It might be predicted that the so-called dietary "cravings" of pregnancy would encourage overeating, although they have not been sufficiently well characterized to be clear 665
C. G. FAIRBURN et al.
that they would promote the types of using a prospective design and a standardovereating seen amongst patients with ized assessment interview. clinical eating disorders. The increase in weight in pregnancy and the alterations in shape might also be expected to have METHODS an influence on eating behavior since these changes are of the type that would Design typically provoke many women to diet. The study was confined to primigravid women There have been few studies of eating since they have no prior experience of the changes in pregnancy. The most systematic study in eating, shape, and weight that occur in pregnancy. of pregnancy-related cravings and aver- The subjects were interviewed on two occasions, sions was by Dickens and Trethowan once in early-to-middle pregnancy and once in the (9). They interviewed 100 primigravid third trimester. women a few days after delivery. In addition, there have been two attempts to describe the effects of pregnancy on the Recruitment behavior and attitudes characteristic of The names of potential subjects, aged 18 years or patients with clinical eating disorders. As over, were obtained from consecutive letters of rein the Dickens and Trethowan study, both ferral to the Maternity Department of the John Radused a retrospective design in which sub- cliffe Hospital in Oxford. This is the only maternity hospital in the Oxford area and it is where the great jects were asked some days after giving majority of births take place. Primigravid women birth about the changes that had occurred estimated to be less than 12 weeks pregnant were over the preceding 9 months. In the first identified and their family doctors contacted to destudy, assessment was by a self-report termine whether there were any medical or social questionnaire (10), whereas in our pre- reasons not to invite them to take part. It was exthat we wished to exclude those with physvious study we used a semi-structured plained ical illnesses (e.g., diabetes mellitus) or treatments interview (11). The two studies came to (e.g., steroids) known to influence eating, shape, or similar conclusions, namely that a signif- weight. We also did not want to contact subjects icant subgroup of primigravid women eat whose pregnancy was unwanted since participation might have distressed them. Potentially suitable in a highly disturbed fashion and that this subjects were contacted by letter asking if they might possibly affect fetal development. would be willing to help with a study of the effects However, the research methods used of pregnancy on eating and weight. Those who did were not sufficiently precise to determine not reply were sent a second letter. Subjects who to take part were subsequently interviewed, either the prevalence or precise character agreed in almost all cases at their home. Recruitment conof the behavioral abnormalities encoun- tinued until 100 subjects had been entered into the study. tered. The aim of the present study was to describe, using a community sample, the changes in eating that occur in pregnancy Assessment Measures with particular reference to cravings and The measure of the clinical features of eating aversions and those features characteriswas the Eating Disorder Examination tic of clinical eating disorders. The study disorders (EDE) (12, 13). This standardized investigator-based was intended to overcome the principal interview assesses in detail the full range of the limitations of the two earlier studies by characteristic psychopathology of eating disorders. 666
Psychosomatic Medicine 54:665-672 (1992)
EATING HABITS AND DISORDERS DURING PREGNANCY It measures the key behavioral and attitudinal features including overeating; dieting; self-induced vomiting; laxative misuse; and concerns about eating, shape, and weight. A global EDE score may be generated which is the average of the five EDE subscales (restraint, overeating, eating concern, shape concern, and weight concern). The EDE also generates operationally defined DSM-III-R eating disorder diagnoses. With the exception of the diagnostic items, the EDE is exclusively concerned with the subject's state over the preceding 28 days. Studies of its reliability and discriminant validity support its use (14-17). For the purpose of this study the EDE was modified in three ways. First, the initial interview addressed two time periods: the usual one of the preceding 28 days, and in addition the 3-month period prior to conception. Second, certain items were adapted to distinguish behavior motivated by being pregnant from that attributable to an eating disorder. For example, when assessing food avoidance, careful note was taken of the reasons for the avoidance to distinguish the desire to eat healthily from the wish to lose weight. Third, questions were added concerning nausea, dietary aversions and cravings, and pica. Data on the course and outcome of each pregnancy were obtained from the computer records of the Oxford Obstetric Data System.
RESULTS The Sample and Interviews To recruit the 100 primigravid women, 128 eligible subjects were identified from the letters of referral. This represents a response rate of 78%. All 100 subjects completed both interviews. The first interview took place at the beginning of the second trimester (i.e., early-to-middle pregnancy; mean number of weeks pregnant = 15) and the second midway through the third trimester (i.e., late pregnancy; mean = 32 weeks). The mean age of the sample was 25.9 years (SD = 3.8). Ninety-four percent were married or cohabiting. Social class was assigned on the basis of occupation using the customary Psychosomatic Medicine 54:665-672 (1992)
UK classificatory scheme (18). The distribution was as follows: I (professional) 13%, II (intermediate) 29%, IIINM (skilled nonmanual occupation) 13%, HIM (skilled manual occupation) 41%, IV (partly skilled occupation) 2%, and V (unskilled occupation) 2%.
Nausea and Vomiting Both nausea and vomiting were common in the early stages of pregnancy, being reported by 91% an 52%, respectively. The nausea began on average at 6.1 weeks (range = 3-14) and lasted on average 8,5 weeks (range = 2-23). The comparable figures for vomiting were 8,0 weeks (range = 4-12) and 7.4 weeks (range = 1-19).
Aversions Strong aversions to specific foods, drinks, or smells were reported by 80 subjects (i.e., 80%). They began early in pregnancy (mean = 7.1 weeks, range = 2-12) and lasted on average 11.4 weeks (SD = 5.2, range = 3-25). The two most common aversions were to coffee and tea, reported by 34% and 18%, respectively. Next most common were the smell of fried or fatty foods (15%), the taste of highly spiced foods like curries (10%), and the presence of cigarette smoke (8%). In the case of coffee and tea, it seemed to be their taste rather than their smell that was aversive. However, an altered sense of smell appeared to underlie the majority of the aversions including the more unusual ones such as aversion to the smell of previously liked perfume or to household detergent. Many of the subjects with aversions were surprised at their intensity,
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and few had expected them. Rarely was the aversion an exaggeration of a previous dislike.
Dietary Cravings Specific dietary cravings were defined as "A definite urge to eat specific foods, drink particular drinks, or smell particular smells." They were described by 53 subjects. On average, they started at 9.2 weeks (range = 4-20) and lasted 10.3 weeks (range = 1-27). They were more varied in character than the aversions. The most common substances craved were chocolate (14%), citrus fruits (11%), savory foods such as pickles (9%), potato crisps (7%), and ice cream (7%). Most subjects had expected cravings of some sort, but some reported amazement at the intensity of their desire for these foods. Several subjects expressed disappointment at having had no cravings. The cravings were often exaggerations of previous likes.
Pica There was a single instance of pica. When pregnant for 32 weeks, one subject ate coal: she reported that it was "irresistibly inviting." Two subjects ate vegetables when they were still frozen saying that they preferred their taste: this was not their normal practice.
Psychopathology of Eating Disorders Eating Disorder Diagnoses Prior to Con-
ception. Over the 3 months prior to conception, three subjects (i.e., 3%) had met strict operational diagnostic criteria for a 668
clinical eating disorder based on the DSMIII-R scheme (13). All three were cases of "eating disorder not otherwise specified" (EDNOS): there were no cases of anorexia nervosa or bulimia nervosa. These prevalence rates are comparable with those for young nonpregnant women from the same geographical area (4.5%, 0%, and 0.8%, respectively (19)). A further five women had a history of bulimia nervosa, three of whom had also met diagnostic criteria for anorexia nervosa. The three subjects who met criteria for EDNOS varied in their clinical characteristics. The first subject dieted to an extreme degree despite being underweight (88% average weight for her age and height). She had the attitudes to shape and weight characteristic of anorexia nervosa and bulimia nervosa. The second subject was of average weight. She too dieted to an extreme degree and had the attitudes characteristic of anorexia nervosa and bulimia nervosa. She had been significantly overweight in the past. The third subject had recurrent objective bulimic episodes as defined by the EDE (i.e., episodes of eating objectively large amounts of food associated with loss of control at the time) (13). These episodes occurred on average twice a week. However, she was not eligible for a diagnosis of bulimia nervosa since she did not practice extreme weight control behavior nor did she have the characteristic attitudes to shape or weight. Her weight was unremarkable. Changes in the Features of Clinical Eating Disorders. Few subjects reported that they had experienced over the 4 weeks prior to conception any of the characteristic behavioral features of clinical eating disorders. Seven (7%) reported objective bulimic episodes, three (3%) had practiced self-induced vomiting, but none had Psychosomatic Medicine 54:665-672 (1992)
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EATING HABITS AND DISORDERS DURING PREGNANCY
taken laxatives to control their shape or weight. Comparable figures for nonpregnant women in this region are 8.6%, 3.3%, and 1.2%, respectively (19). Table 1 shows the rates of these behaviors at the three time points. In addition, scores on the three key EDE subscales are given. There was a change in the level of dietary restraint (F(2,95) = 5.7, p < 0.01]: between the 4 weeks prior to conception and the first interview, there was a decline in the level of restraint (F(l,96) = 9.4, p < 0.01), and an increase between early-to-middle and late pregnancy (F(l,96) = 6.3, p < 0.02). The degree of concern about body shape also changed (F(2,95) = 3.1, p < 0.05), there being an increase between early-to-middle and late pregnancy (F(l,96) = 5.8, p < 0.02). Concerns about weight changed significantly (F(2,95) = 8.2, p < 0.01): there was
a decline in the early stages of pregnancy (F(l,96) = 16.1, p < 0.01) and an increase later on (F(l,96) = 4.5, p < 0.05). This overall pattern of change was also reflected in the global EDE (F(2,95) = 5.0, p < 0.01) with there being a decrease between the 4 weeks prior to conception and interview one (F(l,96) = 7.4, p < 0.01) followed by an increase in late pregnancy (F(l,96) = 6.7, p < 0.02). Changes in Eating Disorder Diagnoses. The number of subjects who met diagnostic criteria for a clinical eating disorder remained stable from prior to conception through to late pregnancy (three prior to pregnancy, three in early-to-middle pregnancy and four in late pregnancy). The stability in the number of cases is misleading, however, since there was considerable flux. None of the three subjects who met case criteria prior to pregnancy
TABLE 1. Changes in Eating Disorder Psychopathology during Pregnancy (N = 100) Prior to Conception" Objective bulimic episodes (number of subjects)6 Self-induced vomiting (number of subjects)6 Laxative misuse (number of subjects)6 Dietary restraint (mean and SD)C Overeating (mean and SD)C Concern about eating (mean and SD)C Concern about shape (mean and SD)C Concern about weight (mean and SD)C Global EDE score (mean and SD)d
Early Pregnancy3
Late Pregnancy"
7
3
5
3
3
1
0
0
0
0.9 (1.4)
0.5 (1.0)
0.9 (1.3)
0.04 (0.3)
0.06 (0.4)
0.00
0.1 (0.5)
0.08 (0.6)
0.04 (0.3)
0.9 (0.8)
0.9 (0.7)
1.1 (0.9)
1.0 (1.0)
0.7 (0.6)
0.8 (0.6)
0.6 (0.6)
0.4 (0.4)
0.6 (0.5)
" Immediately prior to pregnancy, and at 15 and 32 weeks. 6 Number of subjects who had shown this behavior over the previous 28 days. c Eating Disorder Examination subscale (13). d Average score on the five Eating Disorder Examination subscales (13).
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was a case during pregnancy. Instead, all the cases at each time point irose de novo, although two had a history of bulimia nervosa. (Thus two of the five subjects with a history of bulimia nervosa (40%) developed a clinically significant eating disorder during pregnancy.) All the cases that arose during pregnancy were of EDNOS. They were characterized by significant attitudinal disturbance and extreme dietary restraint, but they varied in terms of both the use of other weight control behaviors and the presence of clinically significant overeating.
Relationship of Eating Disorder Psychopathology to Other Changes in Eating and Pregnancy Outcome To determine whether there were relationships between the occurrence of nausea, vomiting, aversions, and cravings, and the degree of eating disorder psychopathology, the sample was divided into quartiles on the basis of their preconception global EDE score. The highest and lowest quartiles were compared. No significant differences emerged. A similar comparison was made with respect to perinatal state (gestation, birth weight, APGAR score, birth complications, referral for intensive care) and labor complications. No significant differences were found. DISCUSSION
This study has two significant advantages over its predecessors. The first is its prospective design. On the basis of our previous experience (11), we doubt whether the practice of assessing women shortly after birth allows subtle distinc670
tions to be made, for example, between various forms of overeating. We also doubt whether events during pregnancy can be accurately timed from this vantage point. The second methodological strength is the use of a standardized interview to characterize subjects' eating habits and attitudes and to make eating disorder diagnoses. Self-report questionnaires have serious limitations in this regard and it is generally accepted that a research clinical interview (such as the EDE) is to be preferred (20). The use of the EDE had two other advantages in this context: first, the availability of comparison data on young women from the same geographical area; and second, the possibility of adjusting the instrument to distinguish behavior motivated by being pregnant from that attributable to an eating disorder. We have used an equivalent adaptation of the EDE in a controlled study of eating disorders amongst young women with diabetes and have shown that in this context self-report questionnaires yield spuriously high estimates of the level of eating disorder features (21). We believe that the same is likely to be true when evaluating women who are pregnant. Another strength of the study is its use of a general population sample, thereby avoiding the biases that often result from studying volunteers. The response rate was high at 78% but even this response rate may have resulted in bias since there is evidence that past and present eating disorders may be over-represented amongst those who choose not to respond to surveys on eating disorders (22). The rates of eating disorder features reported here may be underestimates, although there seems no reason to question the rates of other features or the relationships found between them. There is no Psychosomatic Medicine 54:665-672 (1992)
EATING HABITS AND DISORDERS DURING PREGNANCY
obvious solution to the response rate problem if one wants to study a general population sample from early in pregnancy. We considered recruiting subjects when they first attended the clinic since this method worked well when recruiting subjects with diabetes but we found that on average this appointment occurred too late in pregnancy for our purposes. The findings with respect to cravings and aversions were remarkably similar to those of the retrospective study by Dickens and Trethowan (9). Our observation that aversions were more common than cravings mirrors theirs, although more of our subjects reported aversions (80% versus 62%). The focus of the aversions was similar with coffee, tea, and fatty foods being most common. Given our prospective design we were able to time the occurrence of the aversions and cravings: both started in the first trimester and lasted about 10 weeks with aversions tending to start earlier than cravings (9.2 weeks versus 7.1 weeks]. The focus of the cravings also resembled that found by Dickens and Trethowan with fruit, sweet and savory foods being most common. Like Dickens and Trethowan we believe that, as in the case of aversions, the cravings are likely to be a response to pregnancy-induced alterations in taste and smell. The findings with respect to the behavior and attitudes characteristic of clinical eating disorders were complex. There was a general tendency for there to be a decrease in severity early in pregnancy followed by an increase later on. The early decrease in dietary restraint appeared to result from a desire to eat healthily but the decrease was temporary. Concerns about weight lessened in early pregnancy
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possibly because subjects felt less accountable for their weight (11). However, there was an increase in late pregnancy which may have been related to the common fear of not being able to lose the weight being gained. The increase in concerns about shape that occurred in late pregnancy probably had a similar origin. There was no evidence that tendencies to overeat worsened, and the dietary cravings rarely resulted in episodes of overeating like those seen in patients with eating disorders: while the amounts eaten were sometimes objectively large, this was often not the case and it was uncommon for there to be a loss of control at the time. In this study of a general population sample, we found no evidence of a relationship between pregnancy outcome and the severity of eating disorder features prior to pregnancy. This finding should not be taken to imply that clinical eating disorders (particularly anorexia nervosa and bulimia nervosa) are not associated with adverse pregnancy outcomes. To answer this question with any certainty, data on the pregnancies of a large number of women with clinical eating disorders would need to be compiled. This study was supported by a project grant from the Health Promotion Research Trust. CGF, AS, and RJ were supported by grants from the WeJJcome Trust. We are grateful to Adrienne Garrod, Elizabeth GaskeJJ, Angela Tremayne, Barbara Chambers, Marianne O'Connor, and Jenny Burton for their help with the study and to Pat Yudkin for providing the data on pregnancy outcome. Joan Fagg helped with the data analysis. Helen Doll gave helpful comments on a draft of the paper.
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