Background: Mixed connective tissue disease (MCTD), systemic sclerosis (SS) and inflammatory idiopathic myopathies (IIM) are uncommon conditions that can occur in women of childbearing age. Pregnancies in these patients seem to be associated with an increased risk of adverse pregnancy outcomes (APO), however, data remain scarce.

Objectives: To describe maternal and perinatal outcomes in women with rare connective tissue diseases (CTD) and to identify possible risk factors for APO.

Methods: Retrospective observational study including pregnant women with CTD followed at our rheumatology-obstetric clinic from 01/2009 to 12/2023.

Results: We identified 31 pregnancies in 23 women: 9 with MCTD, 5 with IIM and 9 with SS. Table 1 summarizes clinical data.

The mean age at conception was 32.4±4.9 years, with a median disease duration of 8.3 years (IQR 29–37.5). Most patients (19/29, 66%) had their disease stable at the time of conception. Major-organ involvement was present in 5 (22%) patients, all of whom exhibited interstitial pulmonary disease.

We documented 23 live births, 6 early miscarriages and 2 stillbirths [one at 37 weeks of gestation (WG) and one at 23WG]. No congenital abnormalities were found. There was one neonatal infection reported in a baby of a mother with MCTD born at 32 WG.

The mean gestational age at delivery was 38.2 ± 2.1 WG. Six (26%) viable pregnancies resulted in preterm births (only one before 34WG), 5 in women diagnosed with MCTD and 1 with SS. Fetal growth restriction was detected in 3 (15%) pregnancies - 2 in one woman with MCDT with active disease at conception on both occasions; and 1 in a mother with SS. Two (9.5%) newborns were small for gestational age (SGA), all from mothers with MCDT. Cesarean section (CS) was performed in 9 (38%) patients, mostly for obstetric reasons.

All patients were ANA positive. SSA/B antibodies were detected in 10 (44%) women. No cases of neonatal lupus were recorded. Antiphospholipid antibodies were negative in all women.

Regarding disease activity 8 (28%) patients relapsed during pregnancy (4 MCTD, 1 IIM and 3 SS) - 50% exhibited pulmonary involvement, 37.5% had muscular involvement and all had vasculopathy. In the postpartum period, 5 (22%) women had flares: 3 MCDT, 1 IIM and 2 SS.

Concerning treatment, 19 (61%) patients received glucocorticoids (GC) during pregnancy, most of them (63%) at low doses (≤5mg/day of prednisolone or equivalent). Twenty-two (71%) pregnancies were managed with cDMARDs: hydroxychloroquine (20), azathioprine (5), cyclosporine (2), tacrolimus (1) and immunoglobulin (1). Only 1 patient with IIM received a bDMARD (Rituximab) in the first trimester.

Disease activity before conception increased the risk for APO (p=0.017). No association was found concerning maternal age, use of DMARDs/GC or flares during pregnancy, and the risk of APO (p>0.05).

Conclusion: Pregnant women with rare CTD, including those with multiorgan involvement, can achieve successful pregnancies. However, they are more likely to experience APO, particularly if disease activity is present before conception. Multidisciplinary management is of utmost importance.

REFERENCES: NIL.

Acknowledgements: NIL.

Disclosure of Interests: None declared.