Biochemical pregnancy and spontaneous abortion in first IVF cycles are negative predictors for subsequent cycles: an over 10,000 cases cohort study

To identify whether biochemical pregnancy (BP) and spontaneous abortion (SA) cases have the same clinical characteristics in assisted reproductive therapy (ART), and to assess its predictive value for the subsequent cycles.

Retrospectively reviewed 12,174 cycles in the first in vitro fertilization and embryo transfer (IVF-ET) cycle from January 2009 to December 2012 of Peking University Third Hospital Reproductive Medical Center. Besides those patients who reached ongoing pregnancy stage, 7,598 cases were divided into three groups: group 1, lack of pregnancy (n = 6,651); group 2, BP (n = 520); and group 3, SA (n = 427). We compared the basic status of patients of the three groups, including ages, body mass index, basic hormone levels, controlled ovarian hyperstimulation protocols, amount of gonadotropin use, and endometrium thickness. The reproductive outcome of the next embryo transfer cycles of the three groups was analyzed.

520 patients ended as BP, and 427 patients ended as SA. The age, primary infertility proportion, body mass index, basic FSH level and basic E2 level were similar among groups. Endometrial thickness, controlled ovarian hyperstimulation protocol, Gn dosage, average oocyte retrieval and ET numbers were also similar. Multivariate analysis showed that only the age (P = 0.037, OR 1.060, 95 % CI 1.001–1.120) and endometrium thickness on hCG administration day (P = 0.029, OR 1.136, 95 % CI 1.013–1.275) may result in the differences between BP and SA groups. In the subsequent ET cycles, the total BP rate was 4.37 %, clinical pregnancy rate was 37.28 %, and miscarriage rate was 8.18 %. The clinical pregnancy rates were similar among groups. However, BP group still had the highest BP rate (P < 0.05, 7.97 vs. 4.01 % and 5.28 %), BP and SA group had higher miscarriage rate (P < 0.05, 11.76 % and 14.75 vs. 7.41 %).

BP and SA in first IVF cycles had negative predictive value for subsequent ART outcomes.