Background: The aim was to study whether prolongation of luteal support during early pregnancy influences the delivery rate after IVF.
Methods: Dual centre study including 303 women who achieved pregnancy after IVF or ICSI was used. All were treated with the long protocol using GnRH agonists and given luteal support with 200 mg vaginal progesterone three times daily during 14 days from the day of transfer until the day of a positive HCG test. The study group (n = 150) withdrew vaginal progesterone from the day of positive HCG. The control group (n = 153) continued administration of vaginal progesterone during the next 3 weeks of pregnancy.
Results: The number of miscarriages prior to and after week 7 of gestation was seven (4.6%) and 15 (10.0%) in the study group and five (3.3%) and 13 (8.5%) in the control group respectively. The number of deliveries was 118 (78.7 %) in the study group and 126 (82.4 %) in the control group. The differences were not significant.
Conclusions: Prolongation of progesterone supplementation in early pregnancy has no influence on the miscarriage rate, and thus no effect on the delivery rate. Progesterone supplementation can safely be withdrawn at the time of a positive HCG test.