Systemic lupus erythematosus and outcomes in first and subsequent births based on data from a national birth registry

To examine the associations between systemic lupus erythematosus (SLE) and outcomes in first and subsequent births.

Data from the Medical Birth Registry of Norway during the period December 1, 1998 to December 31, 2009 were used to assess maternal and perinatal outcomes in women diagnosed with SLE compared with the general population. Outcomes of first and subsequent births were analyzed separately. Associations between SLE and pregnancy outcomes were assessed in logistic regression analyses and are shown as adjusted odds ratios (aORs) after adjustment for maternal age, gestational age, smoking habits, and previous cesarean section (CS), when relevant.

We analyzed 95 first and 145 subsequent births in patients and compared them with references. The risk of CS was two-fold higher in SLE patients in first and subsequent births. More newborns of patients had a birth weight <2,500 gm (aOR 5.00 [95 % confidence interval (95% CI) 3.02, 8.27] in first births and aOR 4.33 [95% CI 2.64, 7.10] in subsequent births). Additionally, preterm birth was more frequent among SLE patients (aOR 4.04 [95% CI 2.45, 6.56] in first births and aOR 3.13 [95% CI 1.97, 4.98] in subsequent births). Congenital malformations were more prevalent among children of patients than references (aOR 2.71 [95% CI 1.25, 5.86] in first births and aOR 3.13 [95% CI 1.69, 5.79] in subsequent births). Perinatal death was more frequent in first births among patients (aOR 7.34 [95% CI 2.69, 20.03]), but no difference was observed in subsequent births.

Pregnancy complications were more frequent in SLE patients than references, and the greatest differences between groups were observed in first births.