OBJECTIVE To examine whether a history of hysteroscopic adhesiolysis (HA)-treated intrauterine adhesions (IUAs) was associated with an increased risk of adverse obstetrical outcomes in subsequent pregnancies. METHODS Retrospective cohort study. METHODS A tertiary-care hospital in Shanghai, China. METHODS A cohort of 114 142 pregnant women who were issued an antenatal card and received routine antenatal care in Shanghai First Maternity and Infant Hospital, between January 2016 and October 2021. METHODS From the cohort of 114 142 pregnant women, each woman with a history of HA-treated IUA prior to the current pregnancy (n = 780) was matched with four women without a history of IUAs (n = 3010) using propensity score matching. The matching variables were maternal age and parity, mode of conception, pre-pregnancy body mass index and prior history of abortion. METHODS Pregnancy complications, placental abnormalities, postpartum haemorrhage and adverse birth outcomes. RESULTS Compared with women with no history of IUAs, women with a history of HA-treated IUAs were at higher risk of pre-eclampsia (RR 1.69, 95% CI 1.23-2.33), placenta accreta spectrum (RR 4.72, 95% CI 3.9-5.73), placenta praevia (RR 4.23, 95% CI 2.85-6.30), postpartum haemorrhage (RR 2.86, 95% CI 1.94-4.23), preterm premature rupture of membranes (RR 3.02, 95% CI 1.97-4.64) and iatrogenic preterm birth (RR 2.86, 95% CI 2.14-3.81). Those women were also more likely to receive cervical cerclage (RR 5.63, 95% CI 3.95-8.02) during pregnancy and haemostatic therapies after delivery (RR 2.17, 95% CI 1.75-2.69). Moreover, we observed that the RRs of those adverse obstetrical outcomes increased with the increasing number of hysteroscopic surgeries. CONCLUSIONS This study found that a history of HA-treated IUAs, especially a history of repeated HAs, was associated with an increased risk of adverse obstetrical outcomes.