Page 69 - Fertility in Women with Rheumatoid Arthritis Vruchtbaarheid van vrouwen met reumatoïde artritis

DISCUSSION
In this study, 17% of pregnancies in RA patients ended in a miscarriage. Women with
RA who miscarried were older and tended to be more often ACPA positive, to have
higher disease activity, and to more often have been treated with MTX in the past.
After miscarriage, one-third of women experienced a disease flare. In total, 75% of
women with a previous miscarriage conceived again and delivered a live-born baby.
The miscarriage rate of 17% in the PARA cohort, which is comparable to that in the
general population (11-22%),15 is probably an underestimation of the true miscarriage
rate in female RA patients. All pregnancies in our analysis were planned pregnancies,
in contrast to those in prior retrospective studies, many of which often also included
unplanned pregnancies, which were generally associated with a less healthy lifestyle. 4 Moreover, unplanned pregnancies in RA may be associated with postconception use
of teratogenic medications such as MTX, and therefore these patients have a higher risk of miscarriage.16 In the PARA cohort, there is a known healthy cohort effect,17 since the cohort contains fewer smokers and the education level is higher than that in the general population. Furthermore, a considerable number of women in this study had already had already had a previous pregnancy, most of which were ongoing. Therefore, the a priori chance of establishing a subsequent ongoing pregnancy was probably already higher in this selected group.
This is the rst study that measured disease activity during the preconception period in women with a subsequent miscarriage. The association between an increasing DAS28 and the occurrence of miscarriage was not signi cant. However, since both ACPA positivity and previous MTX treatment, both of which are markers of more active disease, showed an association with the occurrence of miscarriage, it is likely that disease severity increases the risk of miscarriage in RA patients. This is also in concordance with current ndings in the literature on embryo implantation and pregnancy loss, which describes physiological inflammatory reactions within the endometrium, a nding that seems important in attempting to achieve successful embryo implantation and decidualization.9,18 Active RA may increase the risk of pregnancy loss through disturbance of decidualization. Moreover, repeated implantation failures due to immune imbalances may explain the association of active RA with subfertility.2 Furthermore, the inflammatory reactions in the endometrium may also be altered by antirheumatic medications, although we did not nd any statistically signi cant associations with antirheumatic treatments in this study.
Miscarriages in RA
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