Binge drinking in the three months before conception is associated with unintended pregnancy, but the relationship appears to vary by race.1 In a population-based case-control study of women with pregnancies resulting in a live birth, one in seven women reported bingeing (consuming at least five alcoholic drinks on one occasion) in the preconception period; nearly half of pregnancies were unintended. In analyses accounting for other risk factors, white women who reported preconception binge drinking had 60% higher odds of unintended pregnancy than women who had not binged. In contrast, among black women, those reporting binge drinking did not have increased odds. Women who reported preconception binge drinking had a higher prevalence of other factors posing a risk to their own health and the health of their fetus, including smoking and physical abuse during the preconception period, and consuming alcohol, binge drinking and smoking during pregnancy.
To assess the relationship between preconception binge drinking and unintended pregnancy, and to identify characteristics of women who binge drink in the preconception period, researchers analyzed data from 15 states participating in the Pregnancy Risk Assessment Monitoring System for the years 1996-1999. Within six months of delivering a live infant, women were contacted by mail or telephone and questioned about their pregnancy intention and about binge drinking, as well as other possible risk factors, during the preconception period and the last trimester of pregnancy. Women who reported that they had wanted to get pregnant later or had not wanted to get pregnant at all were classified as having had an unintended pregnancy.
Analyses were based on 72,907 women. Half of the women were aged 26 or older. Most were white (80%) and married (70%). Nearly half (47%) had an education beyond the high school level. For 42%, the birth was their first.
Pregnancy was unintended in 45% of women. Compared with women whose pregnancy was intended, women with an unintended pregnancy had a significantly higher prevalence of reported binge drinking during the preconception period (16% vs. 12%). This difference corresponded to a roughly 40% increase in the odds of reporting preconception binge drinking among women with an unintended pregnancy (unadjusted odds ratio, 1.4). Other factors related to having an unintended pregnancy were being aged 13-20, black or unmarried; having no more than a high school education; lacking health insurance, being covered by Medicaid, smoking, experiencing physical abuse or using birth control during the preconception period; delaying pregnancy recognition or the start of prenatal care; and binge drinking or smoking during pregnancy.
Fourteen percent of women reported that they binged on alcohol in the preconception period. Binge drinkers were significantly older than non-binge drinkers (15% and 18%, respectively, were aged 13-20), and larger proportions were white (89% vs. 78%), were unmarried (37% vs. 31%) and had given birth for the first time (49% vs. 41%). Binge drinkers had significantly higher prevalences of a variety of other risk factors when compared with non-binge drinkers, both during the preconception period and during pregnancy. They more frequently reported having smoked (50% vs. 20%) and been physically abused (10% vs. 6%) during the preconception period. Similarly, they more often said that they had smoked (27% vs. 11%), consumed alcohol (13% vs. 4%) and binged on alcohol (3% vs. 0%) during pregnancy.
The more preconception episodes of binge drinking women reported, the greater the proportion of pregnancies that were unintended. Among women reporting any preconception alcohol consumption, the proportion of pregnancies that were unintended increased significantly from 40% among those reporting no binge drinking episodes to 60% among those reporting four or more episodes. The odds of unintended pregnancy were more than doubled among women reporting four or more episodes relative to women reporting none (unadjusted odds ratio, 2.3).
In adjusted analysis, the odds of unintended pregnancy were 60% higher for white women reporting preconception binge drinking than for those not reporting this behavior (odds ratio, 1.6); no association between binge drinking and unintended pregnancy was found for black women. Both white women and black women had significantly elevated odds of unintended pregnancy if they were 20 or younger (2.6 and 2.1, respectively), were unmarried (2.5 and 2.9), had given birth at least twice (1.5 for each), had no health insurance before conception (1.5 and 1.4) and were using birth control at the time of conception (7.0 and 3.2). Two additional factors were significantly associated with increased odds of unintended pregnancy only among white women: preconception smoking and preconception physical abuse (1.5 for each).
Commenting on the findings, the researchers note that the observed association between preconception binge drinking and unintended pregnancy is likely an underestimate because the study did not include pregnancies ending in abortion or miscarriage. They further observe that women who binged in the preconception period often had other risk factors for poor health and pregnancy-related outcomes. "Therefore, effectively addressing binge drinking and other risk factors in community and clinical settings might not only reduce rates of unintended pregnancy but . . . also improve the overall health and well-being of mothers and their children," the researchers conclude.--S. London
1. Naimi TS et al., Binge drinking in the preconception period and the risk of unintended pregnancy: implications for women and their children, Pediatrics, 2003, 111(5):1136-1141.