Maternal and foetal placental vascular malperfusion in pregnancies with anti-phospholipid antibodies

Abstract Objective The objective of the study was to evaluate the rates of pathological placental lesions among pregnant subjects positive for aPL antibodies. Methods We performed a longitudinal case–control study including 27 subjects with primary APS, 51 with non-criteria APS, 24 with aPL antibodies associated with other well-known CTDs enrolled at the end of the first trimester of pregnancy and 107 healthy controls. Results Compared with controls and after correction for multiple comparisons, primary, non-criteria APS and aPL associated to CTD, subjects had lower placental weight, volume and area. After penalized logistic regression analysis to correct for potential confounders, placental lesions suggesting severe maternal vascular malperfusion (MVM) were more common among primary [odds ratio (OR) 11.7 (95% CI 1.3, 108)] and non-criteria APS [OR 8.5 (95% CI 1.6, 45.9)] compared with controls. The risk of foetal vascular malperfusion (FVM) was higher in primary APS [OR 4.5 (95% CI 1.2, 16.4)], aPL associated with CTDs [OR 3.1 (95% CI 1.5, 6.7)] and non-criteria APS [OR 5.9 (95% CI 1.7, 20.1)] compared with controls. Among clinical and laboratory criteria of APS, first trimester aCL IgG >40 UI/ml [OR 4.4 (95% CI 1.3, 14.4)], LA positivity [OR 6.5 (95% CI 1.3, 33.3)] and a history of pre-eclampsia at <34 weeks [OR 32.4 (95% CI 6.5, 161)] were the best independent first trimester predictors of severe MVM [area under the curve 0.74 (95% CI 0.6, 0.87)]. Conclusion Compared with healthy controls, pregnant subjects with aPL antibodies have an increased risk of placental lesions, suggesting MVM and FVM. First-trimester variables such as aCL IgG >40 UI/ml and a history of pre-eclampsia were significant predictors of both severe MVM and FVM.