No increased risk of adverse pregnancy outcomes for women with myasthenia gravis: a nationwide population-based study.

BACKGROUND This study aims to examine the risk of adverse pregnancy outcomes [low birthweight (LBW), preterm birth, cesarean sections (CS) and babies born small for gestational age (SGA)] in pregnant women with myasthenia gravis (MG), using a 3-year population-based database, taking characteristics of infant and mother into consideration. METHODS This study used two nationwide population-based datasets: the Taiwan National Health Insurance Research Dataset and the Taiwan birth certificate registry. We identified 163 pregnant women with MG during 2001-2003 as the study cohort and 815 randomly selected pregnant women as a comparison cohort. Conditional logistic regression analyses were performed. RESULTS The results showed that, although these patterns did not reach a statistically significant level, mothers with MG had higher percentages of LBW (6.8%, vs. 5.6%), SGA (17.8%, vs. 14.1%) and cesarean deliveries (44.8%, vs. 37.4%), except for preterm births (8.1%, vs. 8.1%). After adjusting for highest maternal education level, marital status, family monthly income and infant gender and parity, the odds ratios (OR) of LBW, preterm birth, SGA infants, and cesarean delivery for mothers with MG were 1.19 (95% CI = 0.60-2.38), 1.00 (95% CI = 0.54-1.87), 1.30 (95% CI = 0.83-2.04), and 1.33 (95% CI = 0.94-1.88), respectively, as compared to unaffected mothers. CONCLUSIONS We conclude that there were no statistically significant differences in the risk of having preterm, LBW, SGA infants and cesarean deliveries between women with and without MG.