Conception after early IVF pregnancy loss: should we wait?

Research question: Is the interval length between an early pregnancy loss and the following treatment cycle a predictor for achieving clinical pregnancy among IVF patients? Design: This retrospective cohort study of 257 women who reinitiated treatment after first-trimester IVF pregnancy loss was conducted at a tertiary, university-affiliated medical centre between 1 January 2014 to 1 January 2018. Women aged 18–40 years, with normal uterine cavity, who experienced first-trimester pregnancy loss at less than 14 weeks after IVF, were included. Miscarriages were classified as spontaneous, biochemical, medical or surgical. Results: Among 257 women, interval to subsequent IVF treatment was not associated with achieving pregnancy. Patients after biochemical pregnancy (72.7 ± 56.4, median 60 days) or spontaneous miscarriage (97.7 ± 93.1, median 66 days) had shorter intervals to next cycle, compared with medical (111.9 ± 103.2, median 65 days) or surgical (123.4 ± 111.1, median 84 days) (Kaplan–Meier, P = 0.03) miscarriages. Logistic regression analysis showed that the chance of subsequent pregnancy was affected by the number of embryos transferred (P = 0.009) and the type of miscarriage. Medical (P = 0.005) and surgical (P = 0.017) miscarriages were related to lower likelihood of pregnancy compared with biochemical pregnancy (reference group). When pregnancy was achieved in the first post-miscarriage cycle, the chance of live birth increased with shorter intervals (median 57.5 days), whereas second miscarriage was related to longer intervals (median 82.5 days) between miscarriage and subsequent IVF cycle (P = 0.03). Conclusion: On the basis of this cohort, IVF should not be postponed after pregnancy loss, as shorter intervals were associated with greater likelihood of live birth.