Pregnancy in Autoimmune Disease
Abstract 1319: Disease Activity and Prednisone Use Influences Birth Weight in Rheumatoid Arthritis Pregnancies
Authors: Y. A. de Man1, H. van der Heide2, R. J. E. M. Dolhain2, C. J. M. de Groot3, E. A. P. Steegers2, J. M. W. Hazes2. 1Erasmus MC, Dept. of Rheumatology, Rotterdam, The Netherlands; 2Erasmus Medical Center, Rotterdam, The Netherlands; 3Medical Center Haaglanden, The Hague, The Netherlands
In this portion of the same PARA study, the authors compared the gestational age at delivery and birth weight of babies born to the women with RA to the general population in The Netherlands. They report that the mean gestational age was 39.4 weeks, and was not different from the rest of the population. Women with RA were more likely to have an instrumented vaginal birth (i.e. forceps) (20% vs 10%), but had a similar rate of caesarean section (14.7% vs 13.7%). The average birth weight for all babies born to women with RA was similar to the general population (3391g vs 3403g).
The authors did note differences in birth weight, however, when they stratified by disease activity and prednisone use early in pregnancy. They found that women with high activity and on prednisone had the lowest birth weight babies (3166g), and women with lower activity and no prednisone use had the highest birth weight babies (3613g).
|
DAS-28 <3.9 (low activity) |
DAS-28 >3.9 (high activity) |
|
| No Prednisone in 1st trimester |
3613g n=28 |
3307g n=18 |
| Prednisone in 1st trimester |
3228g n=7 |
3166g n=18 |
Using a multiple regression model to determine the strongest risk factors for low birth weight, the authors identified that having a shorter pregnancy and high activity arthritis where more important than prednisone use. The authors did not find an association between sulfasalazine use and birth weight.
Editorial: This study demonstrates that having increased rheumatoid arthritis activity decreases birth weight. Prednisone use may play a role, but this is overshadowed by the disease activity. Lower birth weight can be caused by an early delivery, and it would be interesting to see the gestational age at birth for these groups of women, as well. Having a smaller or damaged placenta can also cause a baby to be smaller.
Recent research has demonstrated the importance of birth weight latter in life. Babies that are small at birth may have increased risk for diabetes and heart disease, though the evidence for this is not currently concrete. The difference in 500g seen between the largest and smallest babies in this study, equivalent to about one pound, may indeed have an impact on these children. This study demonstrates the importance of treating active RA during pregnancy – perhaps with low dose steroids or other safe DMARD’s.