Human Chorionic Gonadotropin Levels are Predictive of Pregnancy Outcomes: 248 Blastocyst Transfers

Abstract

Objective: To determine the predictive value of β-hCG serum levels at days 14 and 16 post-retrieval for pregnancy outcome following blastocyst transfer. Design: Cohort analysis of 248 blastocyst transfers in 248 patients at a university-based assisted reproductive science center from January 1998 to December 1999. Materials and Methods: 248 Blastocyst transfers were consecutively studied. β-hCG serum samples were analyzed at day 14 and day 16 after retrieval. Pregnancy outcomes were followed through 12 weeks of gestation. Differences were evaluated using the Student t-test and Fisher’s exact test where appropriate. A p value of <0.05 was considered significant. Results: A total of 248 patients received 522 blastocysts transfers for an overall clinical pregnancy rate per transfer of 64.5% and an implantation rate (IR) of 46.2% per transfer. The average number of blastocysts transferred was 2.01. Twenty-six (10.5%) of the 248 transfers ended in spontaneous abortions (SABs), and one in an ectopic pregnancy (0.4%). The mean age of patients with SABs was statistically higher than ongoing pregnancies (p<0.05). Of the clinical pregnancies (n=160) 40% were singletons, 39.4% were twins, and 3.75% were triplets. β-hCG serum levels of SABs were lower than ongoing pregnancies for day 14 and for day 16 (p<0.05) respectively. Also, there were significant differences in β-hCG serum levels on day 16 between twin and singleton gestations (p<0.05). The rate of change of β-hCG between d14 and d16 was also analyzed. We found that this rate of change was significantly different between twins and singletons (p<0.05) and between SAB’s and ongoing pregnancies (p<0.05). For Serum values >100 mIU/mL on day 14 and >250 mIU/mL on d16 the sensitivity was 94% to detect ongoing pregnancies. At day 14 the sensitivity to detect for multiple pregnancies for a β-hCG ≥200 was >80%. Tabled 1Pregnancy outcomeNo. of patientsAge (±SEM)Day 14 (±SEM)Day 16 (±SEM)SABs2634.4 ± 0.769.3 ± 10.4176.5 ± 26.3Singleton6433.0 ± 0.597.7 ± 7.5147.3 ± 32.2Twins6331.8 ± 0.4167.7 ± 11.8494.1 ± 41.1Ongoing13332.4 ± 0.3135.7 ± 7.9403.6 ± 28.8 Open table in a new tab Conclusion: This is the first report of β-hCG values and their ability to predict pregnancy outcomes following blastocyst transfer. Serum β-hCG levels at day 14 and day 16 following retrieval were strongly predictive for ongoing and multiple pregnancy outcomes in patients undergoing blastocyst transfer.