Pregnancy outcomes in women with idiopathic inflammatory myopathy, before and after diagnosis—a population-based study

Abstract

Objectives To examine pregnancy outcomes among births to women with idiopathic inflammatory myopathy (IIM) in relation to time of IIM diagnosis using population-based data. Methods This study used Swedish nationwide registers to identify all singleton births that occurred between 1973 and 2016 among women diagnosed with IIM between 1998 and 2016 and among women unexposed to IIM. We classified births according to the IIM status of the mother at time of delivery: post-IIM (n = 68), 1–3 years pre-IIM (n = 23), >3 years pre-IIM (n = 710) and unexposed to IIM (n = 4101). Multivariate regression models were used to estimate relative risks of adverse pregnancy outcomes in post-IIM births and pre-IIM births separately, in comparison with their non-IIM comparators. Results We found that post-IIM births had increased risks of caesarean section [adjusted relative risk (aRR) = 1.98; 95% CI: 1.08, 3.64], preterm birth (aRR = 3.35; 95% CI: 1.28, 8.73) and low birth weight (aRR = 5.69; 95% CI: 1.84, 17.55) compared with non-IIM comparators. We also noticed higher frequencies of caesarean section and instrumental delivery in 1–3 years pre-IIM births than in the non-IIM comparators. Conclusion Women who gave birth after IIM diagnosis had higher risks of caesarean section, preterm birth and low birth weight. These results further underline the importance of special care and close monitoring of women with IIM. Higher frequencies of caesarean section and instrumental delivery in pre-IIM births highlight the need for future research on the influence of subclinical features of IIM on pregnancy outcomes.

Pregnancy in adult‐onset dermatomyositis/polymyositis: A systematic review

“…The incidence of gestational hypertension was 20.4% in a cohort of 853 patients with DM/PM. 4 Only 2 of 68 pregnancies (2.94%) after DM/PM onset were complicated by hypertension 6 . The most frequently mentioned complication of DM/PM was interstitial lung disease 19–23 .…”

“…On the basis of a nationwide sample of 853 pregnancies in patients with DM/PM in the United States, pregnant women with myositis were found to be at an increased risk of pregnancy‐associated hypertensive disorders compared with matched controls from a general obstetric population (20.9% vs. 7.4%, P < .001) 4 . According to the national patient register datasets of Australia and Sweden, the incidence of pregnancy hypertension in women with DM/PM is 23.5% 7 and 2.94%, 6 respectively.…”

“…The As for complications of pregnancy, the incidence of pregnancyassociated hypertension was different among case series (2.94%-66.7%). 6,18 The incidence of gestational hypertension was 20.4% in a cohort of 853 patients with DM/PM. 4 Only 2 of 68 pregnancies…”

“…IIM can be diagnosed before, during, and after gestation. Several studies have reported that IIM during pregnancy poses a potential risk for both mother and child and is associated with increased incidence of pregnancy‐related hypertension, antepartum hemorrhage, cesarean delivery, intrauterine growth retardation, spontaneous abortion, preterm birth, stillbirth, and other poor maternal and fetal outcomes 4–7 …”

Neuromuscular disorders in pregnancy

“…Patients with controlled disease or remission have low risk of complications and generally good outcomes for both mother and child. In contrast, active disease is associated with increased fetal mortality, low birth weight, and prematurity ( Silva et al, 2003 ; Váncsa et al, 2007 ; Nagy-Vincze et al, 2014 ; Zhong et al, 2017 ; Che et al, 2020 ). A large and recent retrospective series from India reviewed 24 pregnancies resulting in only 6 live births, though some were voluntarily terminated ( Gupta et al, 2019 ).…”