Outcomes of IVF treatments in women with antiphospholipid antibodies or antiphospholipid syndrome

Background: Ovulation induction for in vitro fertilization (IVF) may increase intravascular thromboses among patients with antiphospholipid autoantibodies (aPLs) or antiphospholipid syndrome (APS) due to the high estrogen levels. While natural or modified natural IVF treatment cycles (MNC) are sometimes used instead of stimulated cycles with empiric anticoagulant treatment among these infertile patients, their efficacy is unclear. Materials and methods: A retrospective cohort study including all IVF cycles of patients diagnosed with aPLs or APS in a tertiary, university-affiliated hospital between 2012 and 2022. The outcomes of stimulated cycles with anticoagulants and MNC and natural IVF cycle attempts were compared. Results: 121 oocyte retrievals from 38 women were analyzed: 93 stimulated and 28 MNC or natural IVF cycles. The rates of cycle cancellation (0 % vs. 17.9 %, p < 0.001) and cycles in which no oocytes were retrieved (0 % vs. 43.5 %, p < 0.001) were significantly lower following stimulated cycles vs. natural and MNC. In parallel, positive β-hCG (31.9 % vs. 10.9 %, p = 0.03), clinical pregnancy rate (23.6 % and 3.6 %, p < 0.001) and live birth rates (18.1 % vs. 3.6 %, p = 0.01) were significantly higher following stimulated cycles. No thrombotic events or bleeding occurred in any cycle. Conclusion: Ovarian stimulation for IVF is more effective for successful pregnancy and delivery than natural cycles and MNC and can be safely undertaken in aPLs or APS women undergoing IVF. Rates of complication from hormonal treatment are not increased when treated with LMWH during ovarian stimulation.