Pregnancy Health Interview Study (Birth Defects Study)

PHISThis was a study of factors in pregnancy that may be related to the health of newborns focusing on the safety and risks of a wide range of environmental exposures (primarily medications) in pregnancy. The outcomes of primary interest included birth defects and complications of pregnancy such as prematurity and pregnancy-induced hypertension.

This multicenter case-control study was conducted in the areas surrounding Philadelphia, Nashville, and San Diego; the states of Massachusetts and Rhode Island, Southern New Hampshire; and portions of New York State. Infants with birth defects and a sample of healthy infants without birth defects were identified through special arrangements with either state birth defect registries or through regular contact with approximately 28 participating institutions. Mothers of these infants were invited to take part in a telephone interview conducted by trained nurse-interviewers. The interview included questions on medical history, previous pregnancies, nutrition, occupation, health behaviors, and smoking, as well as detailed questions on medication use and vaccines received in the period prior to conception through the entire pregnancy. Over 51,000 women were interviewed, making this one of the largest studies of its kind.