Any woman keeping a prenatal appointment at one of our study clinics during a pre-established recruitment times was a Potential Subject. We tried to contact all Potential Subjects to determine their eligibility and interest in participation.  

To be eligible the pregnancy had to be conceived naturally and be less than 36 weeks gestation when the woman was contacted. Both partners had to be literate in English or Spanish, at least 18 years old and living together. Two-thirds of Potential Subjects were eligible.