We read with interest the meta-analysis by Saccone et al regarding the risk of preterm birth in women with a history of uterine evacuation. While the authors used rigorous methodology to conduct their meta-analysis, the outcomes are only as good as the original data from which they are derived. Since most of the original studies did not include a number of known confounders for preterm birth, including prior preterm birth, multiple gestations, and short interpregnancy interval to name a few, it is important to highlight the potential for bias and false assumptions based on the meta-analysis.

The vast majority of the reported odds ratios (OR) in this article were <2, most with a confidence interval (CI) approaching 1.0. Because of the large sample sizes, small differences in the outcomes can provide significant P values and narrow CI, which may yield statistically significant results but do not reflect meaningful clinical differences. Additionally, we were surprised by the significantly higher OR provided by the Zhou et al article in Figures 4, A; 5, A; 6, A; 10; and 12 (OR, 19.51; CI, 17.61–21.61) and were unable to verify those results in the original article.

The authors suggest that perhaps women should be encouraged to use medical methods for uterine evacuation or to consider surgical methods with cervical preparation. We believe it is premature to make these recommendations because: (1) the overall association is weak; and (2) none of the studies included controlled for the variety of surgical techniques that may be used to evacuate a uterus, such as cervical preparation. Until we have more detailed information about the impact of various procedures and cervical preparation by gestational age, it is difficult to fully inform patients on the potential risk for preterm birth as a result of uterine evacuation.

We would encourage the authors to reconsider their recommendations in light of the weak association between surgical uterine evacuation and subsequent preterm birth given that this is based on observational studies and the inherent limitations of this approach. Given the already hostile environment and stigma surrounding abortion care, we need to ensure that we avoid placing premature blame on surgical evacuation as a risk factor for preterm birth.