Background/Purpose: Fertility is reduced in patients with Rheumatoid Arthritis (RA) due to unknown cause. Few studies mostly involving single center cohorts have addressed pregnancy outcomes in RA. This study was undertaken to determine the frequency of complications occurring during pregnancy for women with RA and to compare these outcomes with the general obstetric population by using the largest inpatient care database.

Methods: By using the 2003-2011 Nationwide Inpatient Sample of Healthcare Cost and Utilization Project, we estimated the number of obstetric hospitalization, deliveries and caesarean deliveries in women between the age group 18-50 years. Patients hospitalized with RA as one of the top three diagnoses were identified. Demographic characteristics and in-hospital outcomes were recorded for both RA and control group. Then we compared maternal and pregnancy complications for all pregnancy-related admissions for women with and without RA. Multivariate logistic regression analysis was used to obtain adjusted odds ratio (OR).

Results: The total number of obstetric hospitalization was 42.32 million of which 31439 were women with diagnosis of RA. The maternal age of RA population was higher (30.5 years) than that in the control group (27 years) (p < 0.001). After adjusting for potential confounders, maternal RA population had a significantly higher prevalence of hypertensive diseases, premature rupture of membranes, antepartum hemorrhage, preterm delivery, intrauterine growth retardation and cesarean delivery. However, the prevalence of postpartum hemorrhage and the risk of inpatient mortality were not different between two groups. The frequencies of the above outcomes along with Odds Ratio are provided in Table 1.

Conclusion: Based on our study of national cohort, we conclude that women with RA have a higher risk of adverse outcomes of pregnancy than do pregnant women without RA and thus close antenatal and post delivery monitoring need to be performed in order to reduce complications. The mean maternal age of RA population is higher likely secondary to infertility. Further studies are needed to examine these findings in relation to severity of disease, medications used and the presence of other comorbidities.

References:

1. Chakravarty EF et al. Arthritis Rheum. 2006 Mar;54(3):899-907.

2. Healthcare cost and utilization project: overview of the Nationwide Inpatient Sample (NIS). URL: http://www.hcup-us.ahrq.gov/nisoverview.jsp.