Study population and recruitment

We recruited pregnant women in their second trimester from the Women’s Options Center (WOC) at San Francisco General Hospital (SFGH) in San Francisco, California. The WOC is an academic-based outpatient clinic that performs pregnancy terminations and serves communities from Northern and Central California. We recruited pregnant women, 18 to 45 years of age, English- or Spanish-speaking, and pregnancy gestation between 13 and 24 weeks. Because our study objectives were to understand BPA exposure and exposure sources in healthy pregnancies, patients seeking a pregnancy termination due to fetal anomalies were excluded. We identified eligible study participants by reviewing the patient’s medical record only after she had 1) consulted with a trained counselor for an elective second trimester pregnancy termination procedure and 2) consented to the procedure as documentation of her intent to proceed with the elective pregnancy termination. Study protocols were approved by the University of California, San Francisco Committee on Human Research. We recruited a total of 185 participants between 2009 and 2011 and collected urine samples from 171. The integrity of 54 urine samples was potentially compromised due to a freezer malfunction, so they were not analyzed for BPA. Creatinine measurements were unavailable for 5 participants who were thus excluded, leaving a total of 112 pregnant women in the final study sample.