The timing of placental competence in pregnancy after oocyte donation.

OBJECTIVE

To test the timing of placental support of pregnancy.

DESIGN

Steroid levels in blood and urine were determined in pregnancy after ET into women with ovarian failure.

SETTING

The study was carried out in a private IVF clinic and a university endocrine department.

PATIENTS

Four patients with ovarian failure were treated by IVF using donor oocytes.

INTERVENTIONS

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.

OUTCOME

The four pregnancies went to term, and each resulted in singleton livebirths.

RESULTS

Increases in plasma P concentrations and in urinary pregnanediol excretion rates were indications for a placental contribution to the hormone pool.

CONCLUSIONS

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.