Antiphospholipid antibodies in stillbirth

Abstract

Objective: To compare antiphospholipid antibodies in deliveries with and without stillbirth using a multicenter, population-based case-control study of stillbirths and live births.

Methods: Maternal sera were assayed for immunoglobulin (Ig)G and IgM anticardiolipin and anti-β2-glycoprotein-I antibodies. Assays were performed in 582 stillbirth deliveries and 1,547 live birth deliveries.

Results: Elevated levels of IgG anticardiolipin and IgG anti-β2-glycoprotein-I antibodies were associated with an approximate threefold increased odds of stillbirth (crude odds ratio [OR] 3.43, 95% confidence interval [CI] 1.79-6.60, 3.8% compared with 1.1% and OR 3.17, 95% CI 1.30-7.72, (1.9% compared with 0.6%, respectively) when all deliveries with stillbirth were compared with all deliveries with live birth. When the subset of stillbirths not associated with fetal anomalies or obstetric complications was compared with term live births, elevated IgG anticardiolipin antibodies were associated with stillbirth (5.0% compared with 1.0%; OR 5.30, 95% CI, 2.39-11.76; IgG anti-β2-glycoprotein-I antibodies (1.9% compared with 0.6%) had an OR of 3.00 (95% CI 1.01-8.90) and IgM anticardiolipin antibodies (6.0% compared with 3.0%) had an OR of 2.03 (95% CI 1.09-3.76). Elevated levels of anticardiolipin and anti-β2-glycoprotein-I antibodies were associated with a threefold to fivefold increased odds of stillbirth.

Conclusions: Our data support consideration of testing for antiphospholipid antibodies in cases of otherwise unexplained stillbirth.

Level of evidence: II.

Figure 1

Study enrollment and inclusion in antiphospholipid antibody analysis for A. stillbirth deliveries, B. live birth deliveries. A pregnancy was categorized as a stillbirth pregnancy if there were any stillbirths delivered and as a live birth pregnancy if all live births were delivered. A fetal death was defined by Apgar scores of 0 at 1 and 5 minutes and no signs of life by direct observation. Fetal deaths were classified as stillbirths if the best clinical estimate of gestational age at death was 20 weeks or more. Fetal deaths at 18 weeks and 19 weeks without good dating were also included as stillbirths. The analysis includes comparison of all stillbirths to all live births, all stillbirths to term live births, nonanomalous stillbirths to term live births, and nonanomalous stillbirths without obstetric complications to term live births.