Pregnancy and delivery in women with chronic inflammatory arthritides with a specific focus on first birth

Objective: To examine possible associations between chronic inflammatory arthritides and pregnancy outcomes with separate analyses of first and subsequent births before and after diagnosis.

Methods: Linkage of data from a registry of patients with chronic inflammatory arthritides and the Medical Birth Registry of Norway enabled a comparison of pregnancy outcomes in women with chronic inflammatory arthritides and pregnancy outcomes in reference subjects. Outcomes of first birth and subsequent births before and after diagnosis were analyzed separately. Associations between chronic inflammatory arthritides and the women's health during pregnancy and delivery as well as perinatal outcomes were assessed in logistic regression analyses with adjustments for maternal age at delivery and gestational age.

Results: We analyzed 128 first births and 151 subsequent births after diagnosis and 286 first births and 262 subsequent births before diagnosis in patients and compared them with first and subsequent births in reference subjects. Firstborn children of women diagnosed as having chronic inflammatory arthritides were more often preterm (odds ratio [OR] 1.85 [95% confidence interval (95% CI) 1.09-3.13]) and small for gestational age (OR 1.60 [95% CI 1.00-2.56]). They also had lower mean birth weight (P=0.01) and higher perinatal mortality (OR 3.26 [95% CI 1.04-10.24]). Birth by caesarean section (all classifications) was more frequent in patients than in reference subjects, and elective caesarean section was 2-fold more frequent in patients, both in first birth (OR 2.60 [95% CI 1.43-4.75]) and in subsequent births (OR 2.18 [95% CI 1.33-3.58]). No excess risks of clinical importance were observed prior to diagnosis of chronic inflammatory arthritides.

Conclusion: Excess risks were related to first birth in women diagnosed as having chronic inflammatory arthritides, including a higher rate of perinatal mortality. A higher caesarean section rate was related to all patient deliveries. Mainly, pregnancy outcomes before diagnosis did not differ from those in reference subjects.