The timing of placental competence in pregnancy after oocyte donation

Abstract

To test the timing of placental support of pregnancy. Steroid levels in blood and urine were determined in pregnancy after ET into women with ovarian failure. The study was carried out in a private IVF clinic and a university endocrine department. Four patients with ovarian failure were treated by IVF using donor oocytes. Estrogen and P were given, up to the point of ET, to achieve the hormonal levels in the ranges for normal menstrual cycles. Pregnancy was supported in the first trimester by exogenous steroids. The four pregnancies went to term, and each resulted in singleton livebirths. Increases in plasma P concentrations and in urinary pregnanediol excretion rates were indications for a placental contribution to the hormone pool. One hundred mg of P were probably a supraphysiological dose to support pregnancy 6 to 8 weeks after conception. The fetoplacental unit was competent from 10 to 12 weeks' gestation.