In1 J Gynecol Obstet, 1992, 38: 281-286
281
International Federation of Gynecology and Obstetrics
The impact of maternal age on pregnancy and its outcome M. Milnera,
C. Barry-Kinsella”,
A. Unwinb and R.F. Harrisona
aRoyal College of Surgeons in Ireland, Department of Obstetrics and Gynaecology, Rotunda Hospital, Dublin 1 and bDepartment of Statistics, Trinity College Dublin (Republic of Ireland)
(Received December 16th, 1991) (Revised and accepted February 2Oth, 1992)
Abstract There were 28 600 deliveries of 500 g or more to women at the Rotunda Hospital between January 1st 1985 and December 1st 1989. Of these, 595 were to women aged 40 years and over. Thirty-five variables of clinical significance were analyzed, comparing those of 40 years of age and more with those under 40. The older group had sign$cant increases in gestational diabetes, ante-partum hemorrhage, fetal distress, prematurity, low birth weight and perinatal mortality. Chromosome congenital abnormalities were significantly higher, particularly Down syndrome. There were sign@ cantly increased rates of induction and cesarean section in the older women. Some evidence of interaction of age with other factors wasfound, however these were difficult to separate out in the clinical setting. We therefore recommend it wiser to manage all elderly gravidas in a high risk manner dealing with cases individually within this framework. Intervention should, however, need to be justified in the older as in the younger woman.
Keywords: Pregnancy; Maternal age.
in particular, to the known increased incidence of maternal intercurrent illness and fetal congenital abnormalities as age advances [ 19,211. The reaction has been to treat all such pregnancies as high risk. This has frequently resulted in higher levels of obstetrical interference which may not have occurred with a younger patient [14]. Pregnancy is however, a multivariant situation and age may be only one of a number of factors deserving of consideration [ 17,181. Indeed, recent studies on pregnancy in the older woman have indicated no excess risk with advancing age when other features are taken into account [1,4,10,20]. These reports have predominantly considered women of low parity and high social class (the middle class postponers). In common with other countries, Ireland has such patients. However, because of sociocultural factors related to the age of marriage and family size, there is still a sizable group of women (Irish Perinatal Statistics) [9] who have carried on reproducing from their youth thrgugh into their middle years. These offer an ideal opportunity to examine whether all elderly pregnant women (40 years and over) justify special handling, or whether this can be safely reserved for those where age is accompanied by other factors of risk.
Introduction Materials and methods Traditionally there is concern about the effect of advancing maternal age on pregnancy and its outcome [7]. This has been due, 0020-7292/92/605.00 0 1992 International Federation of Gynecology and Obstetrics Printed and Published in Ireland
Patients
This study concerns the 28 600 deliveries of Article
282
hfillner et al.
infants weighing 500 g or more to women who delivered at the Rotunda Hospital, Dublin between January 1st 1985 and December 1st 1989. Of these 595 (2.1%) occurred in the over 40 age group and within this group 23 women (0.08%) were aged 45 or over. Data collection
An in-depth analysis was carried out on each case record of the women aged 40 years and over. Thirty-five variables were studied retrospectively (Table 1). For comparative purposes, data for the under 40 age group was primarily obtained from the Rotunda Hospital Annual Reports (1985-1989), with further reference to the Labor Ward Record book, the Rotunda Hospital Computerised Data collection system and research projects carried out during that time on items such as antepartum hemorrhage [2]. Statistics
All the information gathered was stored on a database (DBase 3). Statistical tests in studies of this kind can only be used as guidelines to identify differences of interest. Most of the comparisons between the over and under 40s were made using chi-square tests. For comparisons in which the rates were small the under 40s rate was used as the parameter of a Poisson distribution in assessing the likelihood of the over 40s result. RlEWltS No significant differences were found between the over and under 40 age groups in many of the parameters. Results are therefore only presented where variations have been found, where there were relevant interacting variables, or where results illustrate specific points of interest in the over 40s. Epidemiological factors
Ninety-five percent studied were married, the younger women. occupational prestige Int J Gynecol Obstet 38
of all women over 40 compared with 82% of Classified by scales of [ 131 the whole spectrum
Table 1. Variables examined. Personal status Marital status Age Socioeconomic group Gravidity Parity History of infertility Medical disease Smoking Weight Antenatal problems Gestation Induction Mode of induction Indication for Induction Oxytocin Epidural Fetal distress: 1. Meconium 2. Late decelerations 3. Scalp/cord pH < 7.20 First stage Second stage Normal delivery Operative delivery/type Indications for op/del Stage 3 problems 1 min Apgar 5 min Apgar Fetal weight Fetal abnormality NICU admission Fetal problems Type feeding Contraception Postnatal problems
of social classes was represented. Women in social Class 2, 4 and 7 predominated and there were no significant differences in the distribution of the social classes between the two age groups. Of women over 40,5 1.7% had a parity of four or more, compared with 9.8% of those under 40 years. In the over 40 group advancing parity was found to be associated with an increased incidence of placenta previa, shorter labors and a lower incidence of epidural anesthesia.
Impact of maternal age on pregnancy and outcome
Antenatal While the incidence of overt diabetes in the over 40 group (0.12%) was similar to that of those under 40 (0.13%), gestational diabetes was significantly more common in the older women - 0.97% compared with 0.26% (P < 0.01 Poisson model). Maternal weights and the proportion of babies weighing in excess of 4 kg at delivery during the relevant period were similar: 15% for the over 40s compared with 16% for women under 40. Antepartum hemorrhage was more frequent in the over 40 group (8.23% compared with 2.8% for women under 40). This was due to increased incidences of both placenta previa (3% compared with 0.92%) and clinically diagnosed abruptio placenta (2.03% compared with 0.13%). These differences were statistically significant (P < 0.01 x2). Within the older group there appeared to be no relationship with advancing age, social class and parity in respect of abruptio placenta but hemorrhage due to placenta previa was significantly associated with advancing parity (P < 0.01 x2). The incidence of pre-eclampsia (defined as a rise of 20 mmHg in the diastolic blood pressure from the booking visit together with proteinuria greater than a trace) was 6.3% for primigravidae over 40. No direct comparison with those under 40 was possible, nor was it possible to compare the incidences found in the over 40s of essential hypertension 5.9%, psychiatric illness 3% or preceding infertility of at least 2 years duration of 2.9%. Labor Induction of labor at 28% for the over 40s was more than double the rate for the younger women 12.5% (P < 0.01 x2). Maternal age alone was cited as the indication for this in 37% of the over 40 group. Only in the primigravidas (7.2 h:5.7 h) and in those of parity of six or more (4.3 h:3.34 h) was there any difference in total length of labor (including 1st and 2nd stages) of more than 0.5 h. These figures did not reach statistical significance and in the latter group are a likely
283
reflection of the greater proportion of very highly parous women over 40. Fetal distress, as defined by a minimum of two separate occurrences of late decelerations on CTG and/or a scalp pH reading of less than 7.20, was more frequent in the over 40 group (16.1%) compared with 8.6% in those under 40 (P < 0.01 x2). However, vaginal operative delivery (Table 2) was significantly less common in the patient over 40 (18.3%) versus 25.2% (P < 0.01 x2) and cesarean section in the over 40 group was increased by a factor of two - 24.3%:11.74%, (P < 0.01 x2). In the over 40s group 70 cesarean sections were electively performed and 74 were deemed emergencies. It was not however possible to make this distinction in the under 40 group. Looking at the indications overall, while a number in the two age groups (Table 2) were Table 2.
Operative delivery % comparisons of the two groups. 40
years (%I n = 451 16.1 13.3 2.9 2.1 n = 144 24.3 13.2
16.1 10.8 3.9 3.8
7.6 4.9 12.5 6.9
1.8 1.5
4.9 1.6
0.8
1.2 0.2 2.0
2.8 3.5 0.7 3.5
18.4
21.3
15.4
10.6
Article
284 Mliner et al.
cesarean sections for fetal comparable, distress, failure to advance and breech were more common in the under 40 group, whereas parity-related conditions such as malpresentation and placenta previa were more common in the over 40s group. These women also had a higher incidence of two or more previous cesarean sections. The incidence of vaginal breech delivery and indeed the outcome was similar in the two groups. The incidence of multiple pregnancy in the over 40s was however double that of the under 40s (2.5%:1.2%). Outcomes
The incidence of prematurity in the older group at 12.6% was significantly greater than in the younger group (7.1%) (P < 0.01 x2). The low birth weight rate (< 2.5 kg) was also greatly increased at 10.15% versus 5.92% (P < 0.01 x2). The former figure fell to 8.6% when corrected for twins. The overall admission rates to the Neonatal Intensive Care Unit of the two groups were, respectively, 16.2% and 12.5%, the former becoming 10.6% when due allowance was made for admission associated with congenital abnormality, the overall percentage incidence of which was increased significantly in the over 40s (4.5%:1.5%, P c 0.01 x2). In this regard it must also be noted that the rate of nonchromosomal abnormalities in the study was similar in the two groups at 1.65% v 1.3% and overall the increase is due to the higher level of chromosomal abnormalities, in particular the percentage with Down syndrome (2.5%:0.15%). The perinatal mortality rate (500 g and over, to include only stillbirths and deaths in the first week of life) was 28.6 per 1000 in the over 40s group compared with ¶0.8/1000 for the younger women (P < 0.01 x2). The causes of death are listed in Table 3. This threefold increase persists even when corrected for congenital malformation (18.7:7.5). For women delivered by cesarean section the perinatal mortality rate in the women over 40 was 34.7/1000 compared with 7.2/1000 in the Int J Gynecol Obstet 38
Table3. Causes of perinatal death in women aged 40 years and over 1985-1989. Causes
Total
Normally formed Abruptio Unexplained ? cord Unexplained Antepartum asphyxia PET Previable Abnormal Edwards Anencephaly Nonimmune hydrops Meckel gruber Congenital heart lesion n=
18
younger women. However the five deaths that give this figure were all due to antenatally undiagnosed lethal congenital abnormalities (anencephaly, Edwards Syndrome, multiple congenital anomalies, severe spina bitida/ hydrocephalus and severe hydrops fetalis). There were no maternal deaths in the patients over 40. Three occurred in the younger age group. The causes were, respectively subarachnoid hemorrhage, cardiac failure and AIDS. This is the equivalent to a maternal mortality rate of 9.53/100 000 deliveries. Discussion Increased maternal age has been of interest to obstetricians ever since childbirth has become safer. Two distinct groups present, the middle class postponers of low parity who increasingly form the majority of older pregnant women in some developed countries [8,1 l] and the woman who carries on reproducing into her middle years. She is more likely found in developing countries and in societies with certain sociocultural characteristics such as Ireland. In this study 51.7% had a parity of 4 or more.
Impact of maternal age on pregnancy and outcome
It has been suggested that it is this latter group that has gained for the older woman the reputation for increased maternal and fetal morbidity and mortality [ 121. While the small number (6”/) of primigravid patients over 40 years of age in this study makes it impossible to confirm or refute such a suggestion, the study certainly confirms that pregnancy over the age of 40 years is at high risk for maternal and fetal complications and thus deserving of high risk status and management. We found highly significantly increased incidences of antepartum hemorrhage, fetal distress, low birth weight and perinatal mortality. The rate of gestational diabetes in the older women, while increased compared with the younger group was considerably lower than expected. There is a clear relation between impaired glucose tolerance in pregnancy and advancing age and rates of as high as 8-9% [lo] may be found in this age group when women are appropriately screened. Some of our study group may have remained undiagnosed as there was no formal screening policy over this period in the Rotunda Hospital. In agreement with figures for the rest of Ireland (Eurocat, 1991) [5] there was a particularly high incidence of congenital abnormality with Down syndrome a special feature. In agreement with Baird et al. [3] there was no increased incidence of birth defects of unknown etiology. The data however also confirm that while the status of age with concomitant parity led to shorter labors and less uptake of epidurals it also conferred on these patients a significantly increased risk of induction and having cesarean section with the attendant potential maternal morbidity. Whether these actions prevent what is already a significantly increased perinatal mortality rate in such women from being even worse is unclear and should be questioned [ 14,161. It is debatable whether the outcome in cases of congenital abnormality is influenced by such handling. In-depth analysis of the perinatal mortality and in particular from those delivered by cesarean section in the over 40s group shows
285
that in these cases of undiagnosed lethal congenital abnormalities matters would obviously not have been any different had vaginal delivery been allowed to proceed. To date the recommendation in the Rotunda Hospital has been to manage all elderly gravidas with the special care afforded the high risk patient. Our findings suggest that in a heterogeneous population such as ours this is indeed correct, differing from recent other studies (albeit concerned mostly with the middle class postponer and using a cut off age of 35) [ 1,4,10,20] but also from the Irish study of Turner and MacDonald (1984) who suggest such management based on age grounds alone is not justifiable if other risk factors are eliminated. However, advanced age, parity and other possible risk factors such as socioeconomic group [17], are inevitably inextricably linked. To attempt to separate them out for even a scientific exercise would be extremely difficult in the majority of cases and in the pragmatic clinical situation or when formulating policy surely not plausible. Cases could however be managed individually within the high risk framework mindful of the need to justify intervention in the same way as in the younger age groups. In addition, targeting this population [6,15] for prepregnancy counselling and health care and intensive antenatal assessment including prenatal diagnosis could go some way to reducing the morbidity and mortality associated with the older woman. This would enable her, when contemplating pregnancy, to be assured that although she is at a higher risk for complications, intervention and fetal chromosomal congenital malformation than her younger sisters, prior good health plus proper management during pregnancy and labor can put her well on the way to a favorable outcome. References 1
Ales KL, Druzin ML, Santini DL: Impact of advanced maternal age on the outcome of pregnancy. Surg Gynecol Obstet 171(3): 209, 1990. Article
286
2
3
4
5
6
I
8 9
10
11 12
13
Miher
et al.
Al-Sharida H, Holohan M: Pregnancy outcome following vaginal bleeding in late pregnancy. Irish J Med Sci 159: 255, 1990. Baird PA, Sadovnick AD, Yee IM: Maternal age and birth defects: a population study. Lancet 337(8740): 527, 1991. Berkowitz GS, Skovron ML, Lapinski RH, Berkowitz RL: Delayed childbearing and the outcome of pregnancy. N Engl J Med 322(10): 659, 1990. Eurocat Surveillance of Congenital Anomalies in the Eastern Health Board Region, 1980-1987: Health Research Board, Ireland, 1991. Fonteyn VJ, Isada NB: Nongenetic implications of childbearing after age thirty-five. Obstet Gynecol Surv 43 (12): 709, 1988. Hansen JP: Older maternal age and pregnancy outcome. A review of the literature. Obstet Gynecol Surv 41: 726, 1986. Hollander D, Breen JL: Pregnancy in the older gravida: How old is old? Obstet Gynecol Surv 45(2): 106, 1990. Irish Perinatal Statistics. Magee H: Department of Health Planning Unit. Perinatal Statistics 1984, 1985, 1986 and 1987. The Stationery Office Dublin. Kirz DS, Dorchester W, Freeman RK: Advanced maternal age: the mature gravida. Am J Obstet Gynecol 1.52: 7, 1985. Leyland AH, Boddy FA: Maternal Age and Outcome of Pregnancy. New Engl J Med 323(6): 412, 1990. Mansfield PK, McCool W: Toward a better understanding of the “advancing maternal age” factor. Health Care Women Int lO(4): 395, 1989. Oppenheim AM: Questionnaire Design and Attitude Measurement. Heinemann, London, p 263, 1966.
Int J Gynecol Obstet 38
14 Popov I, Motov IU: The effect of maternal age on the incidence of and indications for caesarean section in primiparae. Akuskerstvo I Ginekol 29(2): 23, 1990. 15 Rosenfeld JA: Pregnancy in women over 35. Risks for mother and baby. Postgrad Med 87(2): 167, 1990. 16 Shapiro H, Lyons E: Late maternal age and postdate pregnancy. Am J Obstet Gynecol 160(4): 909, 1989. 17 Seidman DS, Samueloff A, Mor-Yosef S, Sahenker JG: The effect of maternal age and so&economical background on neonatal outcome. Int J Gynecol Obstet 33: 7, 1990. 18 Turner MJ, MacDonald D: Pregnancy after the age of 40 years: are the risks increased. J Obstet Gynecol5: 1, 1984. 19 Tuck SM, Yudkin PL, Tumbull AC: Pregnancy Outcome in elderly primigravidae with and without a history of infertility. Br J Obstet Gynaecol 95: 230, 1988. 20 Utian WH, Kiwi R: Obstetrical risk of pregnancy and childbirth after age 35. Maturitas Suppl. I: 63, 1988. 21 van Noord-Zaadstra BM, Looman CWN, Alsbach H, Habbema JDF, te Velde ER, Karbaat J: Delaying childbearing: effect of age on fecundity and outcome of pregnancy. Br Med J 302: 1361, 1991.
Address for reprints:
R.F. Harrison Royal CoUege of Surgeons in Ireland Department of Obetetrics and Cynaecology Rotmda Hospital Dublin 1, Republic of IreImd
281
International Federation of Gynecology and Obstetrics
The impact of maternal age on pregnancy and its outcome M. Milnera,
C. Barry-Kinsella”,
A. Unwinb and R.F. Harrisona
aRoyal College of Surgeons in Ireland, Department of Obstetrics and Gynaecology, Rotunda Hospital, Dublin 1 and bDepartment of Statistics, Trinity College Dublin (Republic of Ireland)
(Received December 16th, 1991) (Revised and accepted February 2Oth, 1992)
Abstract There were 28 600 deliveries of 500 g or more to women at the Rotunda Hospital between January 1st 1985 and December 1st 1989. Of these, 595 were to women aged 40 years and over. Thirty-five variables of clinical significance were analyzed, comparing those of 40 years of age and more with those under 40. The older group had sign$cant increases in gestational diabetes, ante-partum hemorrhage, fetal distress, prematurity, low birth weight and perinatal mortality. Chromosome congenital abnormalities were significantly higher, particularly Down syndrome. There were sign@ cantly increased rates of induction and cesarean section in the older women. Some evidence of interaction of age with other factors wasfound, however these were difficult to separate out in the clinical setting. We therefore recommend it wiser to manage all elderly gravidas in a high risk manner dealing with cases individually within this framework. Intervention should, however, need to be justified in the older as in the younger woman.
Keywords: Pregnancy; Maternal age.
in particular, to the known increased incidence of maternal intercurrent illness and fetal congenital abnormalities as age advances [ 19,211. The reaction has been to treat all such pregnancies as high risk. This has frequently resulted in higher levels of obstetrical interference which may not have occurred with a younger patient [14]. Pregnancy is however, a multivariant situation and age may be only one of a number of factors deserving of consideration [ 17,181. Indeed, recent studies on pregnancy in the older woman have indicated no excess risk with advancing age when other features are taken into account [1,4,10,20]. These reports have predominantly considered women of low parity and high social class (the middle class postponers). In common with other countries, Ireland has such patients. However, because of sociocultural factors related to the age of marriage and family size, there is still a sizable group of women (Irish Perinatal Statistics) [9] who have carried on reproducing from their youth thrgugh into their middle years. These offer an ideal opportunity to examine whether all elderly pregnant women (40 years and over) justify special handling, or whether this can be safely reserved for those where age is accompanied by other factors of risk.
Introduction Materials and methods Traditionally there is concern about the effect of advancing maternal age on pregnancy and its outcome [7]. This has been due, 0020-7292/92/605.00 0 1992 International Federation of Gynecology and Obstetrics Printed and Published in Ireland
Patients
This study concerns the 28 600 deliveries of Article
282
hfillner et al.
infants weighing 500 g or more to women who delivered at the Rotunda Hospital, Dublin between January 1st 1985 and December 1st 1989. Of these 595 (2.1%) occurred in the over 40 age group and within this group 23 women (0.08%) were aged 45 or over. Data collection
An in-depth analysis was carried out on each case record of the women aged 40 years and over. Thirty-five variables were studied retrospectively (Table 1). For comparative purposes, data for the under 40 age group was primarily obtained from the Rotunda Hospital Annual Reports (1985-1989), with further reference to the Labor Ward Record book, the Rotunda Hospital Computerised Data collection system and research projects carried out during that time on items such as antepartum hemorrhage [2]. Statistics
All the information gathered was stored on a database (DBase 3). Statistical tests in studies of this kind can only be used as guidelines to identify differences of interest. Most of the comparisons between the over and under 40s were made using chi-square tests. For comparisons in which the rates were small the under 40s rate was used as the parameter of a Poisson distribution in assessing the likelihood of the over 40s result. RlEWltS No significant differences were found between the over and under 40 age groups in many of the parameters. Results are therefore only presented where variations have been found, where there were relevant interacting variables, or where results illustrate specific points of interest in the over 40s. Epidemiological factors
Ninety-five percent studied were married, the younger women. occupational prestige Int J Gynecol Obstet 38
of all women over 40 compared with 82% of Classified by scales of [ 131 the whole spectrum
Table 1. Variables examined. Personal status Marital status Age Socioeconomic group Gravidity Parity History of infertility Medical disease Smoking Weight Antenatal problems Gestation Induction Mode of induction Indication for Induction Oxytocin Epidural Fetal distress: 1. Meconium 2. Late decelerations 3. Scalp/cord pH < 7.20 First stage Second stage Normal delivery Operative delivery/type Indications for op/del Stage 3 problems 1 min Apgar 5 min Apgar Fetal weight Fetal abnormality NICU admission Fetal problems Type feeding Contraception Postnatal problems
of social classes was represented. Women in social Class 2, 4 and 7 predominated and there were no significant differences in the distribution of the social classes between the two age groups. Of women over 40,5 1.7% had a parity of four or more, compared with 9.8% of those under 40 years. In the over 40 group advancing parity was found to be associated with an increased incidence of placenta previa, shorter labors and a lower incidence of epidural anesthesia.
Impact of maternal age on pregnancy and outcome
Antenatal While the incidence of overt diabetes in the over 40 group (0.12%) was similar to that of those under 40 (0.13%), gestational diabetes was significantly more common in the older women - 0.97% compared with 0.26% (P < 0.01 Poisson model). Maternal weights and the proportion of babies weighing in excess of 4 kg at delivery during the relevant period were similar: 15% for the over 40s compared with 16% for women under 40. Antepartum hemorrhage was more frequent in the over 40 group (8.23% compared with 2.8% for women under 40). This was due to increased incidences of both placenta previa (3% compared with 0.92%) and clinically diagnosed abruptio placenta (2.03% compared with 0.13%). These differences were statistically significant (P < 0.01 x2). Within the older group there appeared to be no relationship with advancing age, social class and parity in respect of abruptio placenta but hemorrhage due to placenta previa was significantly associated with advancing parity (P < 0.01 x2). The incidence of pre-eclampsia (defined as a rise of 20 mmHg in the diastolic blood pressure from the booking visit together with proteinuria greater than a trace) was 6.3% for primigravidae over 40. No direct comparison with those under 40 was possible, nor was it possible to compare the incidences found in the over 40s of essential hypertension 5.9%, psychiatric illness 3% or preceding infertility of at least 2 years duration of 2.9%. Labor Induction of labor at 28% for the over 40s was more than double the rate for the younger women 12.5% (P < 0.01 x2). Maternal age alone was cited as the indication for this in 37% of the over 40 group. Only in the primigravidas (7.2 h:5.7 h) and in those of parity of six or more (4.3 h:3.34 h) was there any difference in total length of labor (including 1st and 2nd stages) of more than 0.5 h. These figures did not reach statistical significance and in the latter group are a likely
283
reflection of the greater proportion of very highly parous women over 40. Fetal distress, as defined by a minimum of two separate occurrences of late decelerations on CTG and/or a scalp pH reading of less than 7.20, was more frequent in the over 40 group (16.1%) compared with 8.6% in those under 40 (P < 0.01 x2). However, vaginal operative delivery (Table 2) was significantly less common in the patient over 40 (18.3%) versus 25.2% (P < 0.01 x2) and cesarean section in the over 40 group was increased by a factor of two - 24.3%:11.74%, (P < 0.01 x2). In the over 40s group 70 cesarean sections were electively performed and 74 were deemed emergencies. It was not however possible to make this distinction in the under 40 group. Looking at the indications overall, while a number in the two age groups (Table 2) were Table 2.
Operative delivery % comparisons of the two groups. 40
years (%I n = 451 16.1 13.3 2.9 2.1 n = 144 24.3 13.2
16.1 10.8 3.9 3.8
7.6 4.9 12.5 6.9
1.8 1.5
4.9 1.6
0.8
1.2 0.2 2.0
2.8 3.5 0.7 3.5
18.4
21.3
15.4
10.6
Article
284 Mliner et al.
cesarean sections for fetal comparable, distress, failure to advance and breech were more common in the under 40 group, whereas parity-related conditions such as malpresentation and placenta previa were more common in the over 40s group. These women also had a higher incidence of two or more previous cesarean sections. The incidence of vaginal breech delivery and indeed the outcome was similar in the two groups. The incidence of multiple pregnancy in the over 40s was however double that of the under 40s (2.5%:1.2%). Outcomes
The incidence of prematurity in the older group at 12.6% was significantly greater than in the younger group (7.1%) (P < 0.01 x2). The low birth weight rate (< 2.5 kg) was also greatly increased at 10.15% versus 5.92% (P < 0.01 x2). The former figure fell to 8.6% when corrected for twins. The overall admission rates to the Neonatal Intensive Care Unit of the two groups were, respectively, 16.2% and 12.5%, the former becoming 10.6% when due allowance was made for admission associated with congenital abnormality, the overall percentage incidence of which was increased significantly in the over 40s (4.5%:1.5%, P c 0.01 x2). In this regard it must also be noted that the rate of nonchromosomal abnormalities in the study was similar in the two groups at 1.65% v 1.3% and overall the increase is due to the higher level of chromosomal abnormalities, in particular the percentage with Down syndrome (2.5%:0.15%). The perinatal mortality rate (500 g and over, to include only stillbirths and deaths in the first week of life) was 28.6 per 1000 in the over 40s group compared with ¶0.8/1000 for the younger women (P < 0.01 x2). The causes of death are listed in Table 3. This threefold increase persists even when corrected for congenital malformation (18.7:7.5). For women delivered by cesarean section the perinatal mortality rate in the women over 40 was 34.7/1000 compared with 7.2/1000 in the Int J Gynecol Obstet 38
Table3. Causes of perinatal death in women aged 40 years and over 1985-1989. Causes
Total
Normally formed Abruptio Unexplained ? cord Unexplained Antepartum asphyxia PET Previable Abnormal Edwards Anencephaly Nonimmune hydrops Meckel gruber Congenital heart lesion n=
18
younger women. However the five deaths that give this figure were all due to antenatally undiagnosed lethal congenital abnormalities (anencephaly, Edwards Syndrome, multiple congenital anomalies, severe spina bitida/ hydrocephalus and severe hydrops fetalis). There were no maternal deaths in the patients over 40. Three occurred in the younger age group. The causes were, respectively subarachnoid hemorrhage, cardiac failure and AIDS. This is the equivalent to a maternal mortality rate of 9.53/100 000 deliveries. Discussion Increased maternal age has been of interest to obstetricians ever since childbirth has become safer. Two distinct groups present, the middle class postponers of low parity who increasingly form the majority of older pregnant women in some developed countries [8,1 l] and the woman who carries on reproducing into her middle years. She is more likely found in developing countries and in societies with certain sociocultural characteristics such as Ireland. In this study 51.7% had a parity of 4 or more.
Impact of maternal age on pregnancy and outcome
It has been suggested that it is this latter group that has gained for the older woman the reputation for increased maternal and fetal morbidity and mortality [ 121. While the small number (6”/) of primigravid patients over 40 years of age in this study makes it impossible to confirm or refute such a suggestion, the study certainly confirms that pregnancy over the age of 40 years is at high risk for maternal and fetal complications and thus deserving of high risk status and management. We found highly significantly increased incidences of antepartum hemorrhage, fetal distress, low birth weight and perinatal mortality. The rate of gestational diabetes in the older women, while increased compared with the younger group was considerably lower than expected. There is a clear relation between impaired glucose tolerance in pregnancy and advancing age and rates of as high as 8-9% [lo] may be found in this age group when women are appropriately screened. Some of our study group may have remained undiagnosed as there was no formal screening policy over this period in the Rotunda Hospital. In agreement with figures for the rest of Ireland (Eurocat, 1991) [5] there was a particularly high incidence of congenital abnormality with Down syndrome a special feature. In agreement with Baird et al. [3] there was no increased incidence of birth defects of unknown etiology. The data however also confirm that while the status of age with concomitant parity led to shorter labors and less uptake of epidurals it also conferred on these patients a significantly increased risk of induction and having cesarean section with the attendant potential maternal morbidity. Whether these actions prevent what is already a significantly increased perinatal mortality rate in such women from being even worse is unclear and should be questioned [ 14,161. It is debatable whether the outcome in cases of congenital abnormality is influenced by such handling. In-depth analysis of the perinatal mortality and in particular from those delivered by cesarean section in the over 40s group shows
285
that in these cases of undiagnosed lethal congenital abnormalities matters would obviously not have been any different had vaginal delivery been allowed to proceed. To date the recommendation in the Rotunda Hospital has been to manage all elderly gravidas with the special care afforded the high risk patient. Our findings suggest that in a heterogeneous population such as ours this is indeed correct, differing from recent other studies (albeit concerned mostly with the middle class postponer and using a cut off age of 35) [ 1,4,10,20] but also from the Irish study of Turner and MacDonald (1984) who suggest such management based on age grounds alone is not justifiable if other risk factors are eliminated. However, advanced age, parity and other possible risk factors such as socioeconomic group [17], are inevitably inextricably linked. To attempt to separate them out for even a scientific exercise would be extremely difficult in the majority of cases and in the pragmatic clinical situation or when formulating policy surely not plausible. Cases could however be managed individually within the high risk framework mindful of the need to justify intervention in the same way as in the younger age groups. In addition, targeting this population [6,15] for prepregnancy counselling and health care and intensive antenatal assessment including prenatal diagnosis could go some way to reducing the morbidity and mortality associated with the older woman. This would enable her, when contemplating pregnancy, to be assured that although she is at a higher risk for complications, intervention and fetal chromosomal congenital malformation than her younger sisters, prior good health plus proper management during pregnancy and labor can put her well on the way to a favorable outcome. References 1
Ales KL, Druzin ML, Santini DL: Impact of advanced maternal age on the outcome of pregnancy. Surg Gynecol Obstet 171(3): 209, 1990. Article
286
2
3
4
5
6
I
8 9
10
11 12
13
Miher
et al.
Al-Sharida H, Holohan M: Pregnancy outcome following vaginal bleeding in late pregnancy. Irish J Med Sci 159: 255, 1990. Baird PA, Sadovnick AD, Yee IM: Maternal age and birth defects: a population study. Lancet 337(8740): 527, 1991. Berkowitz GS, Skovron ML, Lapinski RH, Berkowitz RL: Delayed childbearing and the outcome of pregnancy. N Engl J Med 322(10): 659, 1990. Eurocat Surveillance of Congenital Anomalies in the Eastern Health Board Region, 1980-1987: Health Research Board, Ireland, 1991. Fonteyn VJ, Isada NB: Nongenetic implications of childbearing after age thirty-five. Obstet Gynecol Surv 43 (12): 709, 1988. Hansen JP: Older maternal age and pregnancy outcome. A review of the literature. Obstet Gynecol Surv 41: 726, 1986. Hollander D, Breen JL: Pregnancy in the older gravida: How old is old? Obstet Gynecol Surv 45(2): 106, 1990. Irish Perinatal Statistics. Magee H: Department of Health Planning Unit. Perinatal Statistics 1984, 1985, 1986 and 1987. The Stationery Office Dublin. Kirz DS, Dorchester W, Freeman RK: Advanced maternal age: the mature gravida. Am J Obstet Gynecol 1.52: 7, 1985. Leyland AH, Boddy FA: Maternal Age and Outcome of Pregnancy. New Engl J Med 323(6): 412, 1990. Mansfield PK, McCool W: Toward a better understanding of the “advancing maternal age” factor. Health Care Women Int lO(4): 395, 1989. Oppenheim AM: Questionnaire Design and Attitude Measurement. Heinemann, London, p 263, 1966.
Int J Gynecol Obstet 38
14 Popov I, Motov IU: The effect of maternal age on the incidence of and indications for caesarean section in primiparae. Akuskerstvo I Ginekol 29(2): 23, 1990. 15 Rosenfeld JA: Pregnancy in women over 35. Risks for mother and baby. Postgrad Med 87(2): 167, 1990. 16 Shapiro H, Lyons E: Late maternal age and postdate pregnancy. Am J Obstet Gynecol 160(4): 909, 1989. 17 Seidman DS, Samueloff A, Mor-Yosef S, Sahenker JG: The effect of maternal age and so&economical background on neonatal outcome. Int J Gynecol Obstet 33: 7, 1990. 18 Turner MJ, MacDonald D: Pregnancy after the age of 40 years: are the risks increased. J Obstet Gynecol5: 1, 1984. 19 Tuck SM, Yudkin PL, Tumbull AC: Pregnancy Outcome in elderly primigravidae with and without a history of infertility. Br J Obstet Gynaecol 95: 230, 1988. 20 Utian WH, Kiwi R: Obstetrical risk of pregnancy and childbirth after age 35. Maturitas Suppl. I: 63, 1988. 21 van Noord-Zaadstra BM, Looman CWN, Alsbach H, Habbema JDF, te Velde ER, Karbaat J: Delaying childbearing: effect of age on fecundity and outcome of pregnancy. Br Med J 302: 1361, 1991.
Address for reprints:
R.F. Harrison Royal CoUege of Surgeons in Ireland Department of Obetetrics and Cynaecology Rotmda Hospital Dublin 1, Republic of IreImd
