Clinical Features and Outcomes of Twin Pregnancies with Antiphospholipid Antibodies Positivity: A Retrospective Study

Objective: This study aimed to evaluate the impact of twin pregnancies with antiphospholipid antibody (aPL) positivity, a rare and complex clinical condition that remains a huge challenge for management.

Methods: This study enrolled twin-pregnant women at our hospital between January 2018 and August 2023. Women with and without aPL positivity were selected using propensity score matching (PSM). Clinical features and pregnancy outcomes were compared between the two groups in the PSM cohort. To analyze the effect of aPL positivity on pregnancy outcomes, multivariate logistic models were used to obtain adjusted odds ratios (aOR) with 95% confidence intervals (CI).

Results: Among the 773 women with twin pregnancies, aPL positivity was found in 26 women (3.36%). In the PSM cohort, there were 24 twin-pregnant women with positive aPL, and 48 women without aPL were selected as controls. Twin-pregnant women with aPL positivity had a higher proportion of abortion (8.33% vs 0, P = 0.043), preterm birth < 34 weeks (33.33% vs 8.33%, P = 0.007) and very low birthweight (<1500 g) (20.83% vs 4.17%, P = 0.016) than the control group. In addition, stillbirth of one fetus was observed in one twin-pregnant woman with positive aPL. Multivariate logistic regression analysis revealed that twin pregnancy with aPL positivity was associated with preterm birth < 34 weeks (aOR = 2.76, 95% CI: 0.83-4.70, P = 0.005), very low birthweight (<1500 g) (OR = 2.40, 95% CI: 0.18-4.67, P = 0.034) and small for gestational age (SGA) (aOR = 1.66, 95% CI: 0.22-3.10, P =0.024).

Conclusion: Twin pregnancies with aPL positivity were correlated with obstetric complications, including abortion, preterm birth < 34 weeks and very low birthweight (<1500 g). The detection of aPL may be of clinical significance for women with twin pregnancies and should be considered in future studies.