Pregnancy and fetal outcome in women with primary Sjogren's syndrome compared with women in the general population: a nested case-control study.

OBJECTIVE To study pregnancy and fetal outcome in women with primary SS (pSS) compared with women in the general population. METHODS In a nested case-control setting, variables related to pregnancy and fetal outcomes were compared. Cases (n = 16) were identified through registry linkage (Malmö pSS registry and a database entailing information of all pregnancies and deliveries in Malmö from 1990 through 2006). For each pregnancy with pSS, the following five deliveries from the same registry were chosen as controls (n = 80). RESULTS All cases fulfilled the American European Consensus Criteria for pSS and were positive for ANA and anti-SSA antibodies. Date of diagnosis was before pregnancy in 10 women and after delivery in 6. Mean age at delivery was significantly higher in women with pSS (33.6 years) vs controls (29.8 years). While pregnancy duration did not differ, mean birthweight was significantly lower in offspring of pSS mothers (3010 g) vs babies of control mothers (3458 g). Normal partus in contrast to vacuum extraction or Caesarean section was significantly more frequent in healthy women than in pSS women (83 vs 56%). Other pregnancy outcomes such as parity, miscarriages and Apgar score did not differ. There were no significant differences between women with a pSS diagnosis before or after the index pregnancy. Only one of the included pregnancies was complicated by intrauterine AV block. CONCLUSION Pregnancy occurs later in life in pSS women. Mothers with pSS give birth to offspring with lower birthweight and less commonly have normal partus.