The significance of plasma progesterone levels during early pregnancies achieved after in vitro fertilization (IVF) treatment

Objective: Corpus luteum steroidogenesis is lower for in vivo ectopic pregnancy than for intrauterine pregnancy. There is a progesterone hallmark level distinguishing between viable intrauterine pregnancy and nonviable or ectopic pregnancy. This study attempts to answer whether this is also true for in vitro fertilization-treated patients. Study Design: Using information retrieved from a computerized database, we compared the plasma 17Β-estradiol (E₂) and progesterone during the luteal phase and for every 2 to 3 days for several weeks during early pregnancy between those patients with proven ectopic pregnancies and those with singleton and multiple intrauterine pregnancies. Vaginal ultrasonography to detect an intrauterine gestational sac was performed from day 19. A total of 73 pregnancies resulted from the replacement of fresh embryos in our in vitro fertilization-embryo transfer program. Results: Only at day 10 post embryo transfer did those patients with ectopic pregnancy show statistically lower mean (SD) serum levels of E₂ [2257 (SD, 2351) pmol/L] and plasma progesterone [PP; 221 (SD, 283) nmol/L] compared with patients with intrauterine pregnancy, whose mean E₂ was 8846 (SD, 5871) pmol/L and mean PP was 805 (SD, 582) nmol/L (P=0.008). For the rest of the follow-up until surgery was performed in ectopic pregnancy, there were no differences of statistical significance between extrauterine pregnancy and the intrauterine pregnancy groups. Furthermore, only on day 10 post embryo transfer, did we find a discriminatory zone (confidence interval, 95%) for E₂ levels (903 to 3502 pmol/L for EP vs 6116 to 9493 pmol/L for a singleton and 4875 to 9493 pmol/L for multiple pregnancies). PP levels were 26 to 283 nmol/L for ectopic pregnancy versus 496 to 1096 nmol/L for both singleton and multiple pregnancies. An intrauterine gestational sac was visualized at a mean of 23.2 (SD, 4) days after embryo transfer. On this day, the mean P levels were 982.6 (SD, 286.2) nmol/L for intrauterine and 804.5 (SD, 502.4) nmol/L for ectopic pregnancies (P=NS. Conclusions: Except for day 10 post embryo transfer, the steroidogenesis in ectopic pregnancy after in vitro fertilization treatment does not differ from successful intrauterine pregnancy. This observation negates an impaired steroidogenesis for ectopic pregnancy after in vitro fertilization and makes the PP level irrelevant in the diagnosis of pregnancy implantation.