The correct answer is No safe level has been established because any amount of alcohol during pregnancy carries a risk of fetal harm, including fetal alcohol spectrum disorders (FASD). Alcohol crosses the placenta and affects fetal brain development at all stages of pregnancy. No amount or type of alcohol is proven safe, and the safest recommendation is complete abstinence to prevent potential lifelong physical, behavioral, and cognitive impairments. This principle applies throughout all trimesters.

Reference: Williams Obstetrics, Cunningham FA et al., 26th Edition.