Caesarean myomectomy in pregnant women with uterine fibroids.

Abstract

Rationale: Postpartum haemorrhage, defined as a blood loss of 500 mL or more within 24 hours of birth, is the leading global cause of maternal morbidity and mortality. Uterine fibroids are non-cancerous growths that develop in or around the uterus, and affect an increasing number of women. Caesarean myomectomy is the surgical removal of fibroids during a caesarean section. Traditionally, obstetricians have avoided this procedure given the risk of uncontrollable haemorrhage. There is also the risk of longer operating time and more days in the hospital. However, there could be potential benefits in removing uterine fibroids for improved fertility, and caesarean section may provide an effective and efficient opportunity to perform this procedure. Given the link between removal of uterine fibroids and postpartum haemorrhage, it is prudent to evaluate current literature and assess the benefits and harms of caesarean myomectomy in pregnant women with uterine fibroids.

Objectives: To assess the benefits and harms of caesarean myomectomy in pregnant women with uterine fibroids undergoing caesarean section.

Search methods: We searched CENTRAL, MEDLINE, Embase, Global Index Medicus, ICTRP portal, and ClinicalTrials.gov; performed supplementary searches of references and citations; and contacted study authors on 2 February 2024.

Eligibility criteria: We included published randomised and quasi-randomised controlled trials, and observational controlled studies that assessed the impact of myomectomy on maternal health outcomes in pregnant women with fibroids undergoing caesarean birth. We excluded qualitative studies, case reports or series, conference abstracts, opinion papers, letters, and book chapters. There were no restrictions on ethnicity, race, socioeconomic status, education level, or place of residence.

Outcomes: Critical outcomes were requirement for blood transfusion, risk of haemorrhage, change in haemoglobin, length of hospitalisation, length of operation, major surgery at time of procedure, fertility outcome, and postpartum fever.

Risk of bias: We assessed risk of bias for non-randomised controlled studies using the Risk Of Bias In Non-randomised Studies of Interventions (ROBINS-I) tool.

Synthesis methods: We conducted a meta-analysis for each outcome when more than one study provided data. If it was not possible to analyse data via meta-analysis, we synthesised results narratively using Synthesis Without Meta-analysis (SWiM) guidance. We used GRADE to assess certainty of evidence for each critical and important outcome.

Included studies: We included 23 non-randomised studies with 7504 women. Most studies were conducted in high-income or upper-middle-income countries. Five studies enrolled women with singleton pregnancies and one study was restricted to women with a twin pregnancy. Most studies did not report whether the caesarean section was elective or emergent. Thirteen studies diagnosed fibroids prior to operation.

Synthesis of results: Blood transfusion The evidence is very uncertain about whether caesarean myomectomy affects the risk of requiring blood transfusion compared to caesarean section alone (risk ratio (RR) 1.34, 95% confidence interval (CI) 1.01 to 1.79; I² = 33%; 18 non-randomised studies, 6897 women; very low-certainty evidence). Haemorrhage The evidence is very uncertain about the effect of caesarean myomectomy on the risk of haemorrhage (RR 1.12, 95% CI 0.84 to 1.50; I² = 0%; 9 non-randomised studies, 1729 women; very low-certainty evidence). Change in haemoglobin Sixteen studies reported change in postpartum haemoglobin. Meta-analysis was not possible due to statistical heterogeneity, and the evidence for this outcome was very low certainty. Length of hospitalisation The evidence is very uncertain about the effect of caesarean myomectomy on length of hospitalisation (mean difference (MD) 0.30 days, 95% CI 0.10 to 0.51; I² = 93%; 15 non-randomised studies, 2955 women; very low-certainty evidence). The significant heterogeneity was explained by two outlying studies; once we removed these studies, the effect size remained consistent but heterogeneity reduced (MD 0.24 days, 95% CI 0.15 to 0.33; I² = 40%; 2760 women). Length of operation The evidence is very uncertain about the effect of caesarean myomectomy on length of operation (MD 11.17 minutes, 95% CI 8.78 to 13.56; I² = 91%; 19 non-randomised studies, 4289 women; very low-certainty evidence). Major surgery at time of procedure The evidence is very uncertain about the effect of caesarean myomectomy on risk of major surgery at the time of procedure (RR 1.94, 95% CI 0.67 to 5.63; I² = 0%; 5 non-randomised studies, 1165 women; very low-certainty evidence). Four of the studies followed the pooled direction of effect. Fertility outcome No studies reported data on future fertility outcomes. Postpartum fever The evidence is very uncertain about the effect of caesarean myomectomy on risk of postpartum fever (RR 1.13, 95% CI 0.88 to 1.44; I² = 0%; 13 non-randomised studies, 2735 women; very low-certainty evidence). It was possible to assess the certainty of evidence for seven of the eight priority outcomes using GRADE; the evidence for all outcomes was very low certainty.

Authors' conclusions: The available evidence for all critical outcomes is very low certainty. As such, it is not possible to draw conclusions about the effects of caesarean myomectomy on the risk of requiring blood transfusion, risk of haemorrhage, length of hospitalisation, length of operation, risk of major surgery at time of procedure, and risk of postpartum fever. Data retrieved on mean change in haemoglobin were too heterogenous to be pooled. There were no data on fertility outcomes.

Funding: This Cochrane review had no dedicated funding.

Registration: The review was registered with PROSPERO (CRD42024554215) and available from: https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42024554215.