Pregnancy after idiopathic granulomatous mastitis does not increase the rate of disease recurrence: a retrospective cohort study on 54 pregnancies.

Idiopathic granulomatous mastitis (IGM) is a recurrent, morbid breast disease. Pregnancy and breastfeeding are important risk factors for both the occurrence of IGM and its recurrence. However, safety of post-IGM pregnancy has not been investigated; we examined it regarding recurrence, obstetrics complications, and breastfeeding capability via a retrospective cohort study among patients of a national IGM registry. Overall, 54 pregnancies had occurred in 42 participants after IGM. The mean maternal age at post-IGM pregnancy was 32.6 ± 4.4 years, and the median IGM-pregnancy interval was 27.5 ± 29.5 months. Live birth occurred in 40(74.1%), spontaneous abortion in 7 (13.0%), induced abortion in 6 (11.1%), and ectopic pregnancy in 1 (1.9%). Gestational diabetes, gestational hypertension, preeclampsia, and intra-uterine growth restriction occurred in 14.8%, 5.6%, 1.9%, and 5.6% of pregnancies; respectively. All participants breastfed successfully except one, but 15.4% did not use the affected side. IGM recurrence occurred in 1 (1.9%) during pregnancy, 2(3.7%) during BF, and 6 (11.1%) after BF cessation. The overall rate of recurrence during post-IGM pregnancy (1.9%) and breastfeeding (3.7%) in this study was lower than the general IGM recurrence rate of 13-25%, and obstetrics complications were close to the rates in the general population. Post-IGM pregnancy can be safe in terms of disease recurrence, obstetrical complications, and breastfeeding.