"Among pregnant women aged 15 to 44 in 2012-2013, an annual average of 9.4 percent reported current alcohol use, 2.3 percent reported binge drinking, and 0.4 percent reported heavy drinking. These rates were lower than the rates for nonpregnant women in the same age group (55.4, 24.6, and 5.3 percent, respectively). Current alcohol use in 2012-2013 was lower among pregnant women aged 15 to 44 during the second and third trimesters than during the first trimester (5.0 and 4.4 percent vs. 19.0 percent)."
Substance Abuse and Mental Health Services Administration, Results from the 2013 National Survey on Drug Use and Health: Summary of National Findings, NSDUH Series H-48, HHS Publication No. (SMA) 14-4863. Rockville, MD: Substance Abuse and Mental Health Services Administration, 2014.