September 11, 2008

Alcohol Use among Pregnant Women and Recent Mothers: 2002 to 2007

Prenatal alcohol exposure increases the risk of birth defects, including physical, cognitive, and behavioral disorders.¹ Research also shows a link between alcohol use during pregnancy and increased risk of preterm birth.² In 2005-2006, an estimated 11.8 percent of pregnant women aged 15 to 44 reported using alcohol in the past month.³ A recent paper based on data from the National Survey on Drug Use and Health (NSDUH) found that illicit drug, alcohol, and cigarette use was lower among pregnant women, particularly during their second and third trimesters, than among their parenting or nonpregnant counterparts.⁴ The study also found indirect evidence of resumption of substance use after pregnancy.

To guide the development of public health interventions regarding alcohol use during pregnancy, data from population-based studies such as NSDUH are needed to show the scope of the problem and to identify subgroups that may be at significant risk. NSDUH asks female respondents aged 12 to 44 whether they are currently pregnant, and it also asks persons aged 12 or older to report on their alcohol use during the month prior to the survey. Respondents who drank alcohol in the past 30 days (i.e., current drinkers) also are asked the number of days they consumed alcohol in the past month and the average number of drinks they consumed per day on the days they drank.⁵

This report concentrates on alcohol use among women of childbearing age (i.e., those aged 15 to 44). Comparisons are made between the alcohol use of pregnant women, recent mothers, and women who were not pregnant and not recent mothers. Pregnant women are defined as women who were pregnant at the time of the survey. Recent mothers are defined as women who were not pregnant at the time of the survey, but who gave birth during the prior 12 months. Nonpregnant women who were not recent mothers are defined as women who were not pregnant at the time of the interview and who did not have a biological child under 1 year old in the household. Analyses include trends and patterns based on data from 2002 to 2007. Additional findings are based on annual averages for the combined 2006 and 2007 NSDUH data.

Past month alcohol use among pregnant and nonpregnant women and recent mothers aged 15 to 44 did not change significantly between 2002-2003 and 2006-2007, with 9.8 percent of pregnant women reporting past month alcohol use in 2002-2003, 12.1 percent in 2004-2005, and 11.6 percent in 2006-2007 (Figure 1). A stable pattern also was found for both recent mothers and nonpregnant women who were not recent mothers from 2002-2003 to 2006-2007.

Figure 1. Trends in Past Month Alcohol Use among Women Aged 15 to 44, by Pregnancy Status*: Percentages, 2002-2007

Combined 2006 and 2007 data indicate that the rate of past month alcohol use among women aged 15 to 44 was lower for those who were pregnant (11.6 percent) than for recent mothers (42.1 percent), who in turn had a lower rate than women who were not pregnant and not recent mothers (54.0 percent) (Figure 1).

Among pregnant women aged 15 to 44, those aged 15 to 17 had the highest rate of past month alcohol use (15.8 percent), followed by those aged 26 to 44 (12.5 percent), and those aged 18 to 25 (9.8 percent); however, these rates did not differ significantly (Table 1). Conversely, among recent mothers and nonpregnant women who were not recent mothers, those aged 15 to 17 had lower rates of past month alcohol use than women in the older age groups. White women were more likely than Hispanic women to have drunk alcohol in the past month regardless of their pregnancy status.

Generally, higher education status and higher family income were associated with higher rates of past month alcohol use among all women of childbearing age regardless of their pregnancy status. Among women aged 18 to 44, those with a college education were nearly twice as likely as their counterparts with less than a high school education to have used alcohol in the past month in each pregnancy status category. Similarly, women aged 15 to 44 with annual family incomes of $75,000 or higher had the highest rates of alcohol use in the prior month compared with those with lower family incomes in all three pregnancy status categories.

Among past month female alcohol users aged 15 to 44, pregnant women and recent mothers drank on fewer days in the past month than nonpregnant women who were not recent mothers—an average of 4.9, 4.4, and 6.1 days, respectively. Among pregnant past month alcohol users, there was no difference by race/ethnicity in the average number of days they drank in the past month, with white pregnant women drinking on an average of 4.8 days, black pregnant women on an average of 4.9 days, and Hispanic pregnant women on an average of 5.2 days.

Among women aged 15 to 44 who used alcohol in the past month, those who were pregnant consumed an average of 2.4 drinks per day on the days they drank in the past month, while those who were recent mothers drank an average of 2.5 drinks, and those who were not pregnant and not recent mothers consumed an average of 3.0 drinks. Among past month alcohol users, pregnant women aged 15 to 17 and those aged 18 to 25 drank an average of 3.6 drinks per day on the days they drank compared with pregnant women aged 26 to 44, who drank an average of 1.7 drinks per day on the days they drank (Table 2). The average number of drinks consumed per day generally declined with higher education status and higher income.

Alcohol use during pregnancy can cause physical and mental birth defects, preterm births, and miscarriages. Because a safe level of alcohol intake during pregnancy cannot be determined, both the U.S. Surgeon General and the March of Dimes Foundation recommend that pregnant women not consume any alcohol.^1,6 Additionally, because small amounts of alcohol can be transmitted in breast milk, they recommend alcohol abstinence for women who are breast-feeding. Findings in this report indicate that many women may not be getting this message.

Identifying specific subgroups of women who are at risk for drinking during pregnancy is especially critical, given the need for careful allocation of scarce resources for prevention, intervention, and treatment activities. Pregnant women aged 15 to 17 may be in particular need of alcohol prevention services tailored for their age group because nearly 16.0 percent of them used alcohol in the past month. Pregnant women in this age group consumed an average of 24 drinks in the past month (i.e., they drank on an average of 6 days during the past month and an average of about four drinks on the days that they drank).