Page 37 - Fertility in Women with Rheumatoid Arthritis Vruchtbaarheid van vrouwen met reumatoïde artritis

our study is consistent with a recent study that reported subfertility in 36% of women withRAdiagnosedbeforefamilycompletion.2 ADanishbirthregistrystudyfounda
TTP exceeding 12 months in 25% of pregnant RA women.3 Since they did not include
miscarriages or women who failed to conceive at all, these data are compatible with 2 our study.
We identi ed various risk factors for a longer TTP in women with RA, including older age and nulliparity, which were already known to prolong the TTP. As in the general population, higher age negatively affects fertility.17 The mean age in our patient group was 31.3±3.9 years, which is slightly older than the mean maternal age at child birth in the Netherlands (31.0 years in 2000–2010).18 Therefore, we cannot explain the higher subfertility in this patient group by age alone.
Concerning nulliparity, it has been shown that a previous pregnancy increases the chance of a subsequent pregnancy, at least in subfertile couples.19 In our study, 58% of patients were nulliparous compared to 47% in the general Dutch population.4 Having a chronic disease may influence the time at which a woman starts having a family, or the choice to have fewer children, thereby explaining the higher number of nulliparous patients.20 It seems unlikely that the higher number of nulliparous patients would reflect a selection bias, with relatively more subfertile women enrolling in our study, since the subfertility rate in this study is comparable with that reported in the literature.2,3 Furthermore, it is not expected that this influenced the proper identi cation of RA-associated risk factors for a prolonged TTP in this study.
RA related factors that were associated with TTP in our cohort were DAS28, and preconception use of NSAIDs and prednisone >7.5 mg. To our knowledge, RA disease activity has not previously been related to reduced fertility, probably because of the retrospective design of previous studies. In inflammatory bowel disease, disease activity has been related to subfertility, but this is mainly attributed to tubal and ovarian dysfunction due to local inflammation or as a result of previous surgery.21 The impact of high RA disease activity on fertility could be mediated via inflammatory mediators, since many cytokines, chemokines and growth factors play an important role in the preimplantation blastocyst-endometrial interactions.22 We have previously shown that high IL-6 serum levels are associated with lower birth weight in children born to women with RA.23
Fertility in RA – clinical factors
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