Study population
There were 91 pregnancies in 73 women with adenomyosis during the study period of 11 years. Among these 91 pregnancies, 12 pregnancies (11 women) (13.2%) presented with pain at the adenomyosis site during pregnancy, and were given oral acetaminophen. None of the 12 pregnancies had coexisting fibroids. Maternal background and perinatal outcomes of the 12 pregnancies are shown in Table 1. In total, 5 pregnancies (41.7%) developed PE, which resulted in preterm delivery, and only 3 out of 12 pregnancies (25.0%) achieved term delivery. To quantitatively assess inflammation, CRP level was measured in each of the 12 pregnancies who developed pain during the onset of pain, and the maximum CRP level is shown in Table 1. The median value of the maximum CRP level in the 12 pregnancies was 1.67 mg/dL (interquartile range [IQR]: 0.11-4.89 mg/dL). Among the 12 pregnancies with pain, the median gestational week at which the pain started was 19 weeks (IQR: 14-23 weeks), and the median duration of the pain was 42 days (IQR: 28-148 days) (Fig. 1).