Chance of live birth in the first pregnancy after referral among patients with recurrent pregnancy loss is not influenced by their relatives' reproductive history.

Recurrent pregnancy loss (RPL) is defined as three or more consecutive pregnancy losses and affects 1-3% of couples trying to conceive. Pregnancy loss is more common among RPL patients' siblings than in the general population. Our objective was to investigate whether first-degree relatives with pregnancy losses influenced the chance of live birth in the first pregnancy after referral among women with RPL. This is a cohort study of 2138 women with RPL seen at the Danish RPL Unit at Copenhagen University Hospital, Rigshospitalet between January 1st 2000 and December 31st 2017 with follow-up until December 2018. Pregnancies among first-degree relatives were reported by patients at their first consultation. Chance of live birth after referral was compared by logistic regression analysis. Overall, 76% of the referred women achieved a pregnancy after referral and of these, 58% delivered a live born child. Women whose mother had experienced pregnancy loss were referred at a younger age than women with no pregnancy losses among first-degree relatives (mean age 33.6 (SD 4.6) versus 34.3 (SD 4.5),  = 0.002). Pregnancy losses among first-degree relatives did not influence chance of live birth. Our results indicate that pregnancy losses among first-degree family members is not an important risk factor for outcome of the first pregnancy after referral among women with RPL.