Winn et al. profiled gene expression at the human maternal–fetal interface during five gestational age intervals: 14–16, 18–19, 21, 23–24, and 37–40 weeks. Basal plate biopsy specimens were obtained from placentas after second trimester elective terminations of singleton pregnancies or normal nonlabored singleton pregnancies. Pregnancies complicated by fetal anomalies, hypertension, diabetes, or other significant maternal health issues were excluded.
||basal plate at 21 weeks
||basal plate at 18–19 weeks