OP11.03: Pregnancy outcomes of uterine heterotopic pregnancies after <i>in vitro</i> fertilization‐embryo transfer

To analyse the pregnancy outcome of uterine heterotopic pregnancies (UHPs) following in vitro fertilization-embryo transfer (IVF-ET). A retrospective, single-centre matched-cohort study was conducted. Infertile women who obtained UHPs via IVF-ET between June 2006 and December 2022 were selected as the study group. For each UHP, 4 control patient conceived with a solely eutopic pregnancy matched for predefined criteria was selected randomly. The matching criteria were: maternal age ±1 year, infertility type (primary or secondary), time of the first B-ultrasound after transfer ±2 days and insemination method. The pregnancy outcomes of the study group and the control group were compared. Fifty-nine cases of UHPs (25 with expectant management and 34 with surgical treatment) were included. In expectant management, UEP was associated with increased risk of preterm birth (P = 0.006), and low birthweight (P = 0.006). Compared with the control group, the birthweight (2,743 ± 804 vs 3,307 ± 514 g; P = 0.004) was significantly lower in the study group; In surgical treatment, UEP was associated with increased risks of early miscarriage (P < 0.001), preterm birth (< 37 weeks) (P < 0.001), low birthweight (< 2500 g) (P < 0.001), and decreased risks of live birth (P < 0.001) and term delivery (P < 0.001). Regarding different implantation positions of UEPs, except for live birth rate are different (75.0% vs 15.4% vs 44.7% for accompanied by intramural pregnancy, Caesarean scar pregnancy and cervical pregnancy group respectively; P = 0.033), other pregnancy and obstetric outcomes were all similar between these three implantation positions. UHP was associated with higher rates of miscarriage, preterm birth, low birthweight, and low live birth in both expectant and surgical treatments. The effect of intramural pregnancy on live delivery of intrauterine pregnancy is minimal, while the effect of cervical pregnancy is greatest.