The impact of hydroxychloroquine on obstetric outcomes in refractory obstetric antiphospholipid syndrome

The use of low-dose aspirin (LDA) and heparin has improved pregnancy outcomes in women with antiphospholipid syndrome (APS). However, 20-30% still have adverse outcomes despite treatment. Recent retrospective studies showed a beneficial effect of hydroxychloroquine (HCQ) in APS due to its anti-inflammatory, immunomodulatory and antithrombotic properties. Data in refractory obstetric APS (OAPS) remain scarce and include heterogeneous populations with various concomitant treatments.

The objective of this study was to assess the impact on the obstetric outcomes of adding HCQ to classical treatments for women with refractory primary obstetric APS.

In a retrospective single-centre cohort study, we compared pregnancy outcomes in women with refractory primary OAPS (2004-2019) who received two different treatments in subsequent pregnancies. Group A received 400 mg HCQ + 60 mg enoxaparin + LDA, while Group B received 60 mg enoxaparin + LDA. The main outcome was live birth rates, while pregnancy complications (early and late pregnancy losses and placental-mediated complications) were the secondary outcome.

A total of 101 pregnancies in 87 refractory primary OAPS patients were included. The rate of live-born babies in Group A (HCQ) was 97.1% (67/69) vs. 62.5% (20/32) in Group B (RR: 1.55 [95% CI, 1.19-2.1]; p < 0.001). Pregnancy complications in Group A were 8.7% (6/69) vs. 37.5% (12/32) in Group B (RR 0.22 [95% CI, 0.15-0.30]; p < 0.001).

Hydroxychloroquine was associated with a higher rate of live births and a lower prevalence of pregnancy complications in refractory primary obstetric APS. The addition of HCQ to classical treatment may present a promising approach that needs to be confirmed with prospective studies.