Study question: Does Dilatation and Curettage (D&C) for a miscarriage or induced abortion increase the risk of preterm birth in subsequent pregnancy?
Summary answer: This meta-analysis shows that D&C is associated with increased risk of subsequent preterm birth.
What is known already: D&C is a frequently used procedure in obstetrics and gynecology. The procedure is generally considered to be safe and easy to perform, but serious adverse effects, e.g. cervical tears, bleeding, infection, perforation of the uterus, bowel or bladder and Asherman syndrome, may occur. As suggested by some, preterm birth in subsequent pregnancies might also be an adverse effect of D&C.
Study design, size, duration: We conducted a systematic review and meta-analysis of cohort and case-control studies.
Participants/materials, setting, methods: We searched OVID MEDLINE and OVID EMBASE form inception until May 2014. We selected cohort studies comparing subsequent preterm birth in women who had a D&C for miscarriage or IA and a control group, and case control studies assessing a history of D&C among women with and without D&C.
Main results and the role of chance: We included 21 studies reporting on 1,853,017 women. In women with a history of D&C, the odds ratio (OR) for preterm birth (<37 weeks) was 1.29 (95% CI: 1.17; 1.42), while for very preterm birth ORs were 1.69 (95% CI: 1.20; 2.38, <32 weeks) and 1.68 (95% CI: 1.47; 1.92, <28 weeks). The risk remained increased for D&C when the control group was limited to women with a medically managed miscarriage or induced abortion: OR 1.19 (95%CI: 1.10; 1.28). For women with a history of multiple D&Cs, the OR for preterm birth (<37 weeks) was 1.74 (95% CI: 1.10; 2.76). When the analysis was limited to spontaneous preterm birth subsequent to D&C the OR was 1.44 (95% CI: 1.22; 1.69).
Limitations, reason for caution: There were no randomized controlled trials comparing women with and without a history of D&C and subsequent preterm birth. Furthermore confounding influence the results since included studies were either cohort or case control studies and not all studies corrected their results for possible confounding factors.
Wider implications of the findings: This meta-analysis shows that D&C is associated with increased risk of subsequent preterm birth. Although confounding cannot be excluded, these data warrant caution in the use of D&C for miscarriage and induced abortion. This conclusion should contribute to the implementation of misoprostol as a non-invasive treatment option for both miscarriage and induced abortion.
Study funding/competing interest(s): Funding by national/international organization(s) – This study was funded by ZonMw, a Dutch governmental organization for Health Research and Development. Project number 80-82310-97-12066.
Trial registration number: Not applicable