Impact of Enoxaparin on Maternal and Fetal Outcomes in In Vitro Fertilization (IVF) Pregnancies With Thyroid Autoimmunity: A Real-World, Single-Center, Retrospective, Observational Study

Aim Thyroid autoimmunity (TAI) in women undergoing in vitro fertilization (IVF) is linked to adverse pregnancy outcomes, despite euthyroid status. This study aims to evaluate the efficacy of enoxaparin in improving maternal and fetal outcomes in anti-thyroid antibody (ATA)-positive euthyroid IVF pregnancies. Methods This observational study included 80 ATA-positive women undergoing IVF. Levothyroxine was administered in hypothyroid women to achieve euthyroid status prior to embryo transfer, and enoxaparin therapy was initiated post-transfer and continued throughout pregnancy. The primary outcome was live birth rate. Secondary outcomes included obstetric complications - pregnancy-induced hypertension (PIH), gestational diabetes mellitus (GDM), intrauterine growth restriction (IUGR), miscarriage, and preterm delivery. Results The live birth rate was 78 (97.5%). Among single pregnancies, 44 (95.7%) reached full term, with only two (4.4%) resulting in preterm births. Twin pregnancies had a higher preterm birth rate of 11 (39.3%). The incidence of PIH was 11 (34.2%), with higher rates in twin pregnancies, seven (25.9%), compared to single pregnancies, four (8.3%). GDM was equally prevalent in both single and twin pregnancies (13 (26%) vs. 6 (21.4%)). A miscarriage was observed in two of the total cases. IUGR affected two (4.2%) of singleton and two (7.4%) of twin pregnancies. First-trimester bleeding occurred in five (10%) of singleton and three (10.7%) of twin pregnancies, while only one (3.6%) case of placental abruption was observed in twin pregnancies. No major safety concerns were observed. Conclusion Enoxaparin was associated with improved maternal and fetal outcomes, notably reducing the rates of miscarriage, preterm birth, and IUGR. These findings suggest that enoxaparin can be a valuable addition for improving pregnancy outcomes in ATA-positive patients undergoing IVF.