DOES A HISTORY OF UNEXPLAINED INFERTILITY INCREASE THE RISK OF COMPLICATIONS IN SUBSEQUENT PREGNANCIES? A FOLLOW-UP STUDY OF FAST TRACK AND STANDARD TREATMENT TRIAL (FASTT) PARTICIPANTS

To compare pregnancy complications and birth outcomes of live births conceived by couples with a history of unexplained infertility. Long-term follow-up of randomized controlled trial (RCT) participants. In FASTT, from 2001-2006, 503 couples with women aged 21-39 years and unexplained infertility were randomized to 3 cycles of clomiphene citrate (CC)/IUI, 3 cycles of gonadotropin/IUI, then IVF or 3 cycles of CC/IUI prior to IVF. Between March 2019-February 2020 a 22-question telephone survey with branching logic was administered to couples who were enrolled in FASTT. Analysis was performed using SAS v9.2. Categorical variables were analyzed using chi-square and Fisher’s exact tests while continuous variables were analyzed with two-sample t-tests with P<0.05 considered significant. Of the 503 women enrolled in FASTT, 311 (61.8%) were contacted during the current study and 286 (56.9%) consented to participate with an average age of 49.5 ±3.4 years. Participants reported a total of 251 live births conceived after participation in FASTT. Of the 251 live births, 129 (51.4%) were conceived spontaneously, 8 (3.2%) via COH without IUI, 13 (5.2%) via COH with IUI, 90 (35.9%) via IVF with fresh or frozen embryos, and 11 (4.4%) via IVF with donor eggs. Among these methods of conception, there were no statistically significant differences in incidence of preterm delivery, low birth weight, gestational hypertension, preeclampsia, gestational diabetes, placental abruption, abnormal placentation, fetal growth restriction, or postpartum hemorrhage. Pregnancies conceived via IVF with fresh or frozen embryos were more likely to result in twins (22.2%) compared with spontaneous conception (2.3%), COH without IUI (0%), COH with IUI (15.4%), and IVF with donor eggs (9.1%), overall P<0.0001. However, the number of embryos transferred in pregnancies conceived via IVF is unknown. Survey respondents reported that 27/251 (10.8%) live births conceived after FASTT resulted in a child that is not alive and well today. 18/27 respondents provided diagnoses and although the numbers are small, the most common abnormalities included asthma (n=6), allergies (n=5), autism (n=3), ADHD (n=3), and trisomy 21 (n=2). Women with a history of infertility treated with ovarian stimulation with or without IVF are not at increased risk of developing gestational hypertension, preeclampsia, gestational diabetes, abnormal placentation, fetal growth restriction, postpartum hemorrhage, or having a preterm delivery in subsequent pregnancies.