Background: Serum progesterone has been advocated as a tool in the diagnosis of early pregnancy failure. We conducted this prospective study in order to investigate the potential value of early (14 days after oocyte recovery) serum progesterone measurement, in women undergoing IVF/ICSI and receiving rectal progesterone supplements, in relation to pregnancy outcome.
Methods: 442 women consecutively treated by IVF or ICSI had serum progesterone and bhCG levels prospectively measured 14 days after oocyte retrieval (day 0). All women received natural progesterone 400 mg rectally until the pregnancy test on day 14. Pregnant women were followed up by serial transvaginal ultrasound scans to 8 weeks gestation.
Results: 115 women (26%) had a viable intra-uterine pregnancy at 8 weeks gestation, 80 (18.1%) had an abnormal pregnancy (biochemical, ectopic, miscarriage) and 247 (55.9%) failed to conceive. Women with on-going pregnancies had significantly higher serum progesterone levels (median: 430, 95%CI: 390-500 nmol/l) compared to those who had either an abnormal pregnancy (72, 48-96 nmol/l; P < 0.001) or failed to conceive (33, 28-37 nmol/l; P < 0.001). Receiver-operator curve analysis demonstrated that a single serum progesterone on day 14 post-oocyte retrieval, could highly differentiate between normal and abnormal pregnancies (area under the curve = 0.927, 95%CI = 0.89-0.96; P < 0.0001).
Conclusions: In spite of exogenous progesterone supplementation, serum progesterone levels, from as early as 4 weeks gestation (day 14 post-oocyte retrieval) were significantly elevated and predicted women destined to have viable intra-uterine pregnancies. These high levels are suggestive that endogenous progesterone is already sufficient in viable pregnancies and that exogenous progesterone administration will not rescue a pregnancy destined to result in a miscarriage. Single serum progesterone measurement could be a useful indicator of pregnancy outcome in women undergoing IVF or ICSI treatment.