Brief report: does medication use or disease activity during pregnancy in patients with rheumatoid arthritis affect...

Prednisone use and active disease are associated with reduced bone mineral density (BMD) in patients with rheumatoid arthritis (RA). Either or both of these factors may be inevitable during pregnancy in women with RA, but it is unknown whether they variables influence the BMD of the offspring. This study was undertaken to investigate whether medication use or disease activity during pregnancy in RA patients influences the BMD of their prepubertal offspring.

Mothers (n = 255) participated in a prospective cohort study of RA and pregnancy, and 108 children of these mothers (ages 5-10 years) were included in this followup study. Information on features known to influence BMD in children, i.e., calcium intake, physical activity, serum 25-hydroxyvitamin D level, sex, height, and weight, was collected. In addition, pre- and postnatal variables known to influence BMD, i.e., gestational age, maternal smoking, birth weight, postnatal rate of growth, and type of feeding, were recorded. Independent variables were prednisone use, sulfasalazine use, and RA disease activity during pregnancy.

We found no association of BMD in the children with either prednisone use or RA disease activity during pregnancy, even after correcting for all known associated variables. Sulfasalazine use during pregnancy had a positive effect on the total-body BMD of the offspring (difference in standard deviation score 0.53, P = 0.005).

Our findings indicate that neither medication use nor high RA disease activity during pregnancy is associated with decreased BMD in offspring at age ∼7 years. The maternal benefit of medication use for RA during pregnancy outweighs the effect on BMD in the offspring.