As detailed in Nordstrom-Bailey, et al (2004), mothers were screened extensively at each prenatal visit to estimate pattern, quantity and frequency of current and peri-conceptional alcohol consumption using a semi-structured interview developed specifically to assess alcohol use during pregnancy (Sokol, et al., 1985) and conducted by trained researchers. At each visit to our prenatal clinic (mean visits = 5.9; SD = 3.2; range = 1–14), a previous 2-week recall by beverage type was obtained; questions linked to specific drinking habits, alcohol use, defined as the number of standard drinks, at particular times of the day and days of week, and binge drinking. From these data, alcohol exposure variables were calculated as average ounces of absolute alcohol per day (AAD) and average ounces of absolute alcohol per drinking day (AADD). Because a standard drink contains approximately one half ounce (or ~15 ml) of absolute alcohol, an AAD of 1 is equivalent to 2 drinks. Both average AAD and AADD were calculated without including an estimate of peri-conceptional drinking. In addition, at the first prenatal visit, the 25-item Michigan Alcoholism Screening Test
