Psoriasis and pregnancy outcomes: A nationwide population-based study

Background: Previous research regarding pregnancy outcomes in women with psoriasis either used selective hospital-based data, or analyzed obstetric, but not infant-specific, outcomes. Objective: We sought to investigate whether maternal psoriasis was associated with increased risk of adverse pregnancy outcomes, compared with unaffected mothers, in an unselected nationwide population-based data set. Methods: In total, 1463 mothers with psoriasis and 11,704 randomly selected mothers without psoriasis were included. Of the 1463 mothers with psoriasis, 645 (44.1%) who had received photochemotherapy or systemic therapy within 2 years before their index deliveries were put in the severe psoriasis group. Conditional logistic regression analyses were conducted to calculate the risk of low birth weight (LBW), preterm birth, cesarean section, small for gestational age, and preeclampsia or eclampsia for these two groups, after adjusting for characteristics of the mother, father, and infant. Results: The odds of LBW for women with severe psoriasis were 1.40 times those of mothers without psoriasis (95% confidence interval = 1.04-1.89) after adjusting for characteristics of the mother, father, and infant. However, mothers with mild psoriasis had no significantly higher odds of LBW, preterm birth, cesarean section, infants small for gestational age, and preeclampsia or eclampsia compared with those without psoriasis. Limitations: Patients with psoriasis were identified by diagnostic code in database, resulting in the possibility of misclassification bias. In addition, lack of information regarding maternal risk behaviors and previous adverse pregnancy outcomes may leave residual confounding. Conclusion: We found that pregnant women with severe psoriasis had an increased risk of LBW infants, whereas mild psoriasis was not associated with excess risk of adverse birth outcomes.