Risk of placenta accreta spectrum following myomectomy: a nationwide cohort study

BACKGROUND: Whether myomectomy increases the risk of placenta accreta spectrum in the following pregnancies remains controversial. OBJECTIVE: This study aimed to investigate the effect of myomectomy on the risk of placenta accreta spectrum in the following pregnancies. Moreover, different methods of myomectomy on the risk of placenta accreta spectrum were explored. STUDY DESIGN: A nationwide cohort study was conducted using data from the Taiwan National Health Insurance Research Database, including all pregnant patients in Taiwan who gave birth between January 2008 and December 2017. A 1:1 propensity score estimation matching was performed for the analysis of myomectomy on the risk of placenta accreta spectrum. Among pregnant patients who received myomectomy, different methods of myomectomy on the risk of placenta accreta spectrum were compared with the control group. RESULTS: Among the 1,371,458 pregnant patients in this study, 11,255 pregnant patients had a history of myomectomy. The risk of placenta accreta spectrum was higher in pregnant patients with a history of myomectomy than in pregnant patients without a history of myomectomy (incidence: 0.96% vs 0.20%; adjusted odds ratio, 2.28; 95% confidence interval, 1.85-2.81; P<.01). Among pregnant patients with a history of myomectomy, 5045 (46.87%) received laparotomic myomectomy, 3973 (36.93%) received laparoscopic myomectomy, and 1742 (16.20%) received hysteroscopic myomectomy. The incidence of placenta accreta spectrum was higher in the hysteroscopic group than in the laparotomic group or the laparoscopic group (1.89% [hysteroscopic group] vs 0.71% [laparotomic group] and 0.81% [laparoscopic group]; P<.05). Compared with patients without a history of myomectomy, the adjusted odds ratio for placenta accreta spectrum was 3.88 (95% confidence interval, 2.68-5.63; P<.05) in the hysteroscopic group. CONCLUSION: Myomectomy, especially hysteroscopic myomectomy, is associated with an increased risk of placenta accreta spectrum in the subsequent pregnancy.