Medication in early pregnancy: Prevalence of use and relationship to maternal characteristics Simone Buitendijk, MD, MPH,. and Michael B. Bracken, PhD, MPH"
b
New Haven, Connecticut Medication use was assessed in a population of 4186 women who were delivered of infants at Yale-New Haven Hospital, New Haven, Connecticut, between 1980 and 1982. The frequency of over-the-counter and prescription drug use, and the association of such use with maternal characteristics was studied. Of all women, 66% used at least one drug. The mean number of drugs used by all subjects was 1.3 and, among drug users, 2.9. Of all drugs used, 68% were over-the-counter and 32% were prescription preparations. Internal analgesics, autonomic drugs, antiinfective agents, and antacids were most frequently used. Women who used prescription drugs were also more likely to use over-the-counter medications. Maternal characteristics that were associated with an increase in both over-the-counter and prescription drug use were being white, smoking more than 20 cigarettes a day, using alcohol, using caffeine, and smoking marijuana. These findings suggest that women who engage in "risk-taking behavior" during pregnancy are also more likely to use medications while pregnant. (AM J OBSTET GYNECOL 1991 ;165:33-40.)
Key words: Drugs, medications, risk-taking behavior, pregnancy
During the past 25 years there has been increasing awareness of the potentially harmful effects of drugs and chemicals on the developing fetus. However, the mechanism of most teratogenic compounds is still poorly understood and very little information exists concerning the absolute safety of the use of specific medications during pregnancy. Knowledge of the potential danger of medication use during pregnancy and recognition of the fact that important information is still lacking should warrant conservative use of medications. Unfortunately, medication use during pregnancy is quite prevalent and does not appear to be decreasing. During the past 25 years, several studies of the prevalence of drug use during pregnancy have been carried out. \-0 Although the studies differ in several aspects (patient population, year of study, type of drugs studied, size of study), they all report a large number of drugs being used by pregnant women: 44% to 92% of women using at least one medication, with an average of 3 to 5.5 medications per woman among users. There also does not appear to be a downward trend in frequency of use in more recent studies. No previous research, to our knowledge, has assessed From the Yale Perinatal Epidemiology Unit and the Departments of Epidemiology and Public Health" and Obstetrics and Gynecology,' Yale Universit~ Medical School. Funded byawdrds HD11357 andDA05484 toM.B.B. and Training Grant No. T32 HD0730 to S.B., all from the National Institutes of Health. Received for publication November 27, 1990; accepted January 28, 1991. Reprint requests: Michael B. Bracken, 60 College St., New Haven, CT 06510. 611128311
Table I. Prevalence of prescription and nonprescription drug use in pregnancy among women delivered of infants at Yale-New Haven Hospital, 1980 to 1982 No. of drugs
I
o 1
2
3 4 5 6 7 8 9 10 12
Frequency 1425 1351 793 348 156 58 28 15 6 3 1 1
I
% 34.1 32.3 18.9 8.3 3.7 1.4 0.7 0.4 0.1 0.1
Total number of drugs used: 5265. Mean number of drugs used by all subjects: 1.3. Mean number of drugs used by women taking at least one medication: 2.9.
the relationship of medication use with maternal characteristics other than age and race, or to exposures other than smoking. We are also unaware of prior research into either the relationship of maternal characteristics and drug use for over-the-counter and prescription drugs separately, or studies looking at the relationship between over-the-counter and prescription drug use. This study addresses these questions m a relatively large population of pregnant women. Material and methods All women who made their first prenatal visit to a private obstetric or midwifery practice, a health main-
33
34
Buitendijk and Bracken
July 1991 Am J Obstet Gynecol
Table II. Prevalence of over-the-counter and prescription drug use, Yale-New Haven Hospital, 1980 to 1982 Over-tke-counter drugs* No.
Frequency
0 1 2 or 3 2::4
1887 1444 768
I
4186
I
%
Frequency
45.1 34.5 18.4
3043 802 302
72.7 19.2 7.2
~
~
---.tl
~
TOTALt
Prescription drugst
100.1
4186
%
100.0
*Total number of over-the-counter drugs used = 3542; ave~age number of over-the-counter drugs for all subjects = 0.9. tTotal number of prescription drugs used = 1638; average number of prescription drugs for all subjects = 0.4. tTotal number of drugs = 5180. Eighty-five drugs could not be labeled over-the-counter or prescription and are not used in those frequency tables or analyses that look at over-the-counter and prescription drugs separately.
Table III. Cross-tabulation of over-the-counter and prescription drug use, Yale-New Haven Hospital, 1980 to 1982 Prescription drug use Over-tke-counter drug use
0
0 1 or 2 3 or 4 >5
1440 1423 155 13
X'
=
60.66;
P
5 411 554 68 10
28 46 13 4
0 7 1 0
0.0001.
tenance organization, or a hospital clinic, and who were scheduled for delivery at Yale-New Haven Hospital, New Haven, Connecticut, were invited to participate in the study. Subjects were recruited between May 12, 1980, and March 12,1982. Of6219 women identified at the start of the study, 4926 were willing to be contacted and met the eligibility criteria. Valid interviews were completed for 4186 (85%) of the eligible subjects. The interview was conducted by trained interviewers and contained questions concerning pregnancy history, demographic characteristics, and exposure to other possible risk factors. Most interviews took place in the woman's home, the majority a few weeks after the first prenatal visit. Of all subjects, 80% were interviewed before week 22 of the pregnancy. A more detailed description of subject selection and data collecting procedures has been provided elsewhere. 7 To ascertain their exposure during the critical period of organogenesis, women were asked whether they had taken any medication in each of the 12 weeks since their pregnancy started (i.e., since the estimated day of conception) for any specific indication. A list of 23 different indications such as fluid retention, nausea, constipation, and epilepsy was read to the respondent. For every affirmative answer the name of the specific drug or
medication was asked. Where possible, women were asked to show the interviewer the package with the name of the medication. Over-the-counter drugs were coded in accordance with the listing from the Handbook of Nonprescription Drugs." The prescription drug listing was coded according to the American Hospital Formulary Service. 9 Vitamins, iron supplements, and food supplements were excluded from the drug listings. Respondents were asked whether and how often since their pregnancy started they had consumed different types of alcohol and how many drinks, on average, they had at one time. They were asked whether and how often they had used marijuana or hashish since their pregnancy started. Information on smoking was obtained by asking whether a woman had smoked during each of the months of the pregnancy and, if she had, how many cigarettes, on average, per day. First we displayed the frequency of overall and individual use. Next, a X2 analysis was carried out to assess the relationship between frequency of over-the-counter and prescription drug use. Further, to study whether maternal characteristics influence the extent of drug use, analyses were carried out to assess frequency of medication use by a number of maternal variables, both for all drugs and for prescription and over-the-counter drugs separately. Finally, we carried out logistic regression analyses with the use of the Statistical Analysis System (SAS)lO to assess the independent relationship of maternal characteristics to prescription, over-thecounter, and total use of drugs. Results
Of the 4186 study subjects, 67.0% were younger than 30 years of age, 78.1 % were white, 78.2% were married, 58.7% had more than 12 years of education, and 46.0% were nulliparous. During the first trimester of pregnancy, 34.1 % of women abstained from medication use, 32.3% used one drug, 27.3% used two or three, and
Medication in early pregnancy 35
Volume 165 Number I
Table IV. Frequency of over-the-counter drug use by indication category, Yale-New Haven Hospital, 1980 to 1982 Indication category*
Frequency
Internal analgesics Antacids Cold, allergy Laxatives Antitussives Skin products Antidiarrheals Weight-control medication Topical decongestants Appetite suppressants Antiemetics Menstrual products Throat lozenge Sleep aid Asthma medication Stimulants
2181 361 313 150 130 127 72 54 50 43 18 14 13 8 6 5
% All aTC uses
61.6 10.2 8.8 4.2 3.7 3.6 2.0 1.5 1.4 1.2 0.5 0.4 0.4 0.2 0.2 0.1
% All drug uses
% All women
42.1 7.0 6.0 2.9 2.6 2.5 1.4 1.0 1.0 0.8 0.3 0.3 0.3 0.2 0.1 0.1
52.1 8.7 7.5 3.6 3.1 3.0 1.7 1.3 1.2 l.l 0.3 0.3 0.3 0.2 0.2 0.1
aTC, Over-the-counter.
*Indications co20 cigs/day Alcohol use Caffeine use 1-150 mg/day Caffeine use> 150 mg/day
0.58 1.03 0.92 1.92 1.39 1.23 1.23
0.46-0.71 0.83-1.28 0.71-1.\9 1.11-3.23 1.19-1.62 1.04-1.46 1.01-1.85
Cigs, Cigarettes. Reference categories are being nonwhite, nonsmoking, and not using alcohol or caffeine. Calculated by: el~ , l.
b
New Haven, Connecticut Medication use was assessed in a population of 4186 women who were delivered of infants at Yale-New Haven Hospital, New Haven, Connecticut, between 1980 and 1982. The frequency of over-the-counter and prescription drug use, and the association of such use with maternal characteristics was studied. Of all women, 66% used at least one drug. The mean number of drugs used by all subjects was 1.3 and, among drug users, 2.9. Of all drugs used, 68% were over-the-counter and 32% were prescription preparations. Internal analgesics, autonomic drugs, antiinfective agents, and antacids were most frequently used. Women who used prescription drugs were also more likely to use over-the-counter medications. Maternal characteristics that were associated with an increase in both over-the-counter and prescription drug use were being white, smoking more than 20 cigarettes a day, using alcohol, using caffeine, and smoking marijuana. These findings suggest that women who engage in "risk-taking behavior" during pregnancy are also more likely to use medications while pregnant. (AM J OBSTET GYNECOL 1991 ;165:33-40.)
Key words: Drugs, medications, risk-taking behavior, pregnancy
During the past 25 years there has been increasing awareness of the potentially harmful effects of drugs and chemicals on the developing fetus. However, the mechanism of most teratogenic compounds is still poorly understood and very little information exists concerning the absolute safety of the use of specific medications during pregnancy. Knowledge of the potential danger of medication use during pregnancy and recognition of the fact that important information is still lacking should warrant conservative use of medications. Unfortunately, medication use during pregnancy is quite prevalent and does not appear to be decreasing. During the past 25 years, several studies of the prevalence of drug use during pregnancy have been carried out. \-0 Although the studies differ in several aspects (patient population, year of study, type of drugs studied, size of study), they all report a large number of drugs being used by pregnant women: 44% to 92% of women using at least one medication, with an average of 3 to 5.5 medications per woman among users. There also does not appear to be a downward trend in frequency of use in more recent studies. No previous research, to our knowledge, has assessed From the Yale Perinatal Epidemiology Unit and the Departments of Epidemiology and Public Health" and Obstetrics and Gynecology,' Yale Universit~ Medical School. Funded byawdrds HD11357 andDA05484 toM.B.B. and Training Grant No. T32 HD0730 to S.B., all from the National Institutes of Health. Received for publication November 27, 1990; accepted January 28, 1991. Reprint requests: Michael B. Bracken, 60 College St., New Haven, CT 06510. 611128311
Table I. Prevalence of prescription and nonprescription drug use in pregnancy among women delivered of infants at Yale-New Haven Hospital, 1980 to 1982 No. of drugs
I
o 1
2
3 4 5 6 7 8 9 10 12
Frequency 1425 1351 793 348 156 58 28 15 6 3 1 1
I
% 34.1 32.3 18.9 8.3 3.7 1.4 0.7 0.4 0.1 0.1
Total number of drugs used: 5265. Mean number of drugs used by all subjects: 1.3. Mean number of drugs used by women taking at least one medication: 2.9.
the relationship of medication use with maternal characteristics other than age and race, or to exposures other than smoking. We are also unaware of prior research into either the relationship of maternal characteristics and drug use for over-the-counter and prescription drugs separately, or studies looking at the relationship between over-the-counter and prescription drug use. This study addresses these questions m a relatively large population of pregnant women. Material and methods All women who made their first prenatal visit to a private obstetric or midwifery practice, a health main-
33
34
Buitendijk and Bracken
July 1991 Am J Obstet Gynecol
Table II. Prevalence of over-the-counter and prescription drug use, Yale-New Haven Hospital, 1980 to 1982 Over-tke-counter drugs* No.
Frequency
0 1 2 or 3 2::4
1887 1444 768
I
4186
I
%
Frequency
45.1 34.5 18.4
3043 802 302
72.7 19.2 7.2
~
~
---.tl
~
TOTALt
Prescription drugst
100.1
4186
%
100.0
*Total number of over-the-counter drugs used = 3542; ave~age number of over-the-counter drugs for all subjects = 0.9. tTotal number of prescription drugs used = 1638; average number of prescription drugs for all subjects = 0.4. tTotal number of drugs = 5180. Eighty-five drugs could not be labeled over-the-counter or prescription and are not used in those frequency tables or analyses that look at over-the-counter and prescription drugs separately.
Table III. Cross-tabulation of over-the-counter and prescription drug use, Yale-New Haven Hospital, 1980 to 1982 Prescription drug use Over-tke-counter drug use
0
0 1 or 2 3 or 4 >5
1440 1423 155 13
X'
=
60.66;
P
5 411 554 68 10
28 46 13 4
0 7 1 0
0.0001.
tenance organization, or a hospital clinic, and who were scheduled for delivery at Yale-New Haven Hospital, New Haven, Connecticut, were invited to participate in the study. Subjects were recruited between May 12, 1980, and March 12,1982. Of6219 women identified at the start of the study, 4926 were willing to be contacted and met the eligibility criteria. Valid interviews were completed for 4186 (85%) of the eligible subjects. The interview was conducted by trained interviewers and contained questions concerning pregnancy history, demographic characteristics, and exposure to other possible risk factors. Most interviews took place in the woman's home, the majority a few weeks after the first prenatal visit. Of all subjects, 80% were interviewed before week 22 of the pregnancy. A more detailed description of subject selection and data collecting procedures has been provided elsewhere. 7 To ascertain their exposure during the critical period of organogenesis, women were asked whether they had taken any medication in each of the 12 weeks since their pregnancy started (i.e., since the estimated day of conception) for any specific indication. A list of 23 different indications such as fluid retention, nausea, constipation, and epilepsy was read to the respondent. For every affirmative answer the name of the specific drug or
medication was asked. Where possible, women were asked to show the interviewer the package with the name of the medication. Over-the-counter drugs were coded in accordance with the listing from the Handbook of Nonprescription Drugs." The prescription drug listing was coded according to the American Hospital Formulary Service. 9 Vitamins, iron supplements, and food supplements were excluded from the drug listings. Respondents were asked whether and how often since their pregnancy started they had consumed different types of alcohol and how many drinks, on average, they had at one time. They were asked whether and how often they had used marijuana or hashish since their pregnancy started. Information on smoking was obtained by asking whether a woman had smoked during each of the months of the pregnancy and, if she had, how many cigarettes, on average, per day. First we displayed the frequency of overall and individual use. Next, a X2 analysis was carried out to assess the relationship between frequency of over-the-counter and prescription drug use. Further, to study whether maternal characteristics influence the extent of drug use, analyses were carried out to assess frequency of medication use by a number of maternal variables, both for all drugs and for prescription and over-the-counter drugs separately. Finally, we carried out logistic regression analyses with the use of the Statistical Analysis System (SAS)lO to assess the independent relationship of maternal characteristics to prescription, over-thecounter, and total use of drugs. Results
Of the 4186 study subjects, 67.0% were younger than 30 years of age, 78.1 % were white, 78.2% were married, 58.7% had more than 12 years of education, and 46.0% were nulliparous. During the first trimester of pregnancy, 34.1 % of women abstained from medication use, 32.3% used one drug, 27.3% used two or three, and
Medication in early pregnancy 35
Volume 165 Number I
Table IV. Frequency of over-the-counter drug use by indication category, Yale-New Haven Hospital, 1980 to 1982 Indication category*
Frequency
Internal analgesics Antacids Cold, allergy Laxatives Antitussives Skin products Antidiarrheals Weight-control medication Topical decongestants Appetite suppressants Antiemetics Menstrual products Throat lozenge Sleep aid Asthma medication Stimulants
2181 361 313 150 130 127 72 54 50 43 18 14 13 8 6 5
% All aTC uses
61.6 10.2 8.8 4.2 3.7 3.6 2.0 1.5 1.4 1.2 0.5 0.4 0.4 0.2 0.2 0.1
% All drug uses
% All women
42.1 7.0 6.0 2.9 2.6 2.5 1.4 1.0 1.0 0.8 0.3 0.3 0.3 0.2 0.1 0.1
52.1 8.7 7.5 3.6 3.1 3.0 1.7 1.3 1.2 l.l 0.3 0.3 0.3 0.2 0.2 0.1
aTC, Over-the-counter.
*Indications co20 cigs/day Alcohol use Caffeine use 1-150 mg/day Caffeine use> 150 mg/day
0.58 1.03 0.92 1.92 1.39 1.23 1.23
0.46-0.71 0.83-1.28 0.71-1.\9 1.11-3.23 1.19-1.62 1.04-1.46 1.01-1.85
Cigs, Cigarettes. Reference categories are being nonwhite, nonsmoking, and not using alcohol or caffeine. Calculated by: el~ , l.
