Rheumatoid Arthritis Effects On Pregnancy

It has long been appreciated, since the observations of Hench in 1938 [16], that pregnancy is associated with improvement in the clinical signs and symptoms of  rheumatoid arthritis in more than 70% of patients [17–19]. However, disease recurs postpartum for the majority of women by 8 weeks after delivery. Sex hormones, particularly estrogen, were considered likely candidates for pregnancy-induced remission.

Yet it has been disappointing that studies aimed at improving RA by means of treatment with exogenous estrogens have not shown benefit [20]. Furthermore, the rise of cortisol during pregnancy does not appear to explain  the amelioration of rheumatoid arthritis [21].

Because an immune response to paternally inherited fetal HLA occurs during normal pregnancy, Nelson and her colleagues examined the relationship of maternal-fetal HLA in pregnancies characterized by remission or improvement compared to pregnancies in which disease was active [22]. Maternalfetal disparity in alleles of HLA-DRb1, DQa, and DQb occurred in 26 of 34 pregnancies characterized by remission or improvement (76%) but in only 3 of 12 pregnancies characterized by continuing active arthritis (25%).

The strongest association with improvement in arthritis was with maternal-fetal disparity for DQa. In contrast, disparities for HLA-A, HLA-B, and HLA-C antigens were not significantly different in the two groups. Recent investigations of others have shown that HLA molecules, in addition to presenting foreign antigens, also present peptides derived from other self-HLA molecules [23].

This raises the possibility that HLA self-peptides presented by other HLA molecules are involved in the pathogenesis of autoimmunity. Based on these observations it was suggested that presentation of fetal DQa peptides might correct autoimmunity in patients with RA either by induction of maternal regulatory T cells or by affecting the maternal T cell receptor repertoire.

Apart from a beneficial effect of pregnancy on existing rheumatoid arthritis, there is also evidence suggesting that pregnancy may decrease the risk of developing RA or at least postpone it. A twofold increased risk of RA in nulliparous women has been reported [24, 25].

However, no increase in the incidence of RA was 282 Journal of Leukocyte Biology Volume 63, March 1998 found among 220 nuns [26]. The majority of studies indicate there is no increase in adverse pregnancy outcomes, either spontaneous abortion or stillbirths, in women who are currently or subsequently diagnosed with RA [27].

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