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We thank Dr Averbach et al for their interest in our study. As we have highlighted in our article1Saccone G. Perriera L. Berghella V. Prior uterine evacuation of pregnancy as independent risk factor for preterm birth: a systematic review and metaanalysis.Am J Obstet Gynecol. 2016; 214: 572-591Abstract Full Text Full Text PDF PubMed Scopus (53) Google Scholar and in prior letters,2Saccone G. Perriera L. Berghella V. Reply.Am J Obstet Gynecol. 2016 Jul 16; https://doi.org/10.1016/j.ajog.2016.07.018Abstract Full Text Full Text PDF Scopus (1) Google Scholar, 3Berghella V. Saccone G. Perriera L. Reply.Am J Obstet Gynecol. 2016 Jul 26; https://doi.org/10.1016/j.ajog.2016.07.046Abstract Full Text Full Text PDF Scopus (1) Google Scholar we completely agree that we have found a weak association (odds ratio <2) between abortion and preterm birth and acknowledge the high risk of bias of the included studies. Most of the included studies did not control appropriately for confounders, and only 6 included parity, an important determinant of preterm delivery,4Suhag A. Saccone G. Bisulli M. Seligman N. Berghella V. Trends in cerclage use.Acta Obstet Gynecol Scand. 2015; 94: 1188-1194Crossref PubMed Scopus (11) Google Scholar as a potential confounder. Moreover, because women face stigma when reporting an induced abortion, patients in the case or control group could have omitted abortion from their medical history, which would lead to a high risk of recall bias.1Saccone G. Perriera L. Berghella V. Prior uterine evacuation of pregnancy as independent risk factor for preterm birth: a systematic review and metaanalysis.Am J Obstet Gynecol. 2016; 214: 572-591Abstract Full Text Full Text PDF PubMed Scopus (53) Google Scholar Dr Averbach et al also cited a possible association between unintended pregnancies and preterm birth.5Shah P.S. Balkhair T. Ohlsson A. Beyene J. Scott F. Frick C. Intention to become pregnant and low birth weight and preterm birth: a systematic review.Matern Child Health J. 2011; 15: 205-216Crossref PubMed Scopus (218) Google Scholar They stated that “when women gained access to safe abortion…a decrease in preterm birth and neonatal mortality were observed.” We agree with this statement, as the social risk factors associated with preterm birth are the same risk factors associated with unintended pregnancies. In our article, we did not conclude that abortion is a risk factor for preterm delivery, but that prior surgical uterine evacuation could be.1Saccone G. Perriera L. Berghella V. Prior uterine evacuation of pregnancy as independent risk factor for preterm birth: a systematic review and metaanalysis.Am J Obstet Gynecol. 2016; 214: 572-591Abstract Full Text Full Text PDF PubMed Scopus (53) Google Scholar Indeed, we also found that women with prior medical abortion had a similar risk of spontaneous preterm birth compared with controls (28.2% vs 29.5%).1Saccone G. Perriera L. Berghella V. Prior uterine evacuation of pregnancy as independent risk factor for preterm birth: a systematic review and metaanalysis.Am J Obstet Gynecol. 2016; 214: 572-591Abstract Full Text Full Text PDF PubMed Scopus (53) Google Scholar Counseling women that, based on the available evidence, however poor, surgical uterine evacuation either for miscarriage or abortion may be an independent risk factor for preterm birth, may give women additional information when making a decision regarding medical or surgical management of unintended pregnancy or early pregnancy loss. Perhaps most importantly, the description of cervical preparation before uterine evacuation was limited, but cervical ripening (eg, with misoprostol) may indeed prevent any small increase in preterm birth associated with these procedures.1Saccone G. Perriera L. Berghella V. Prior uterine evacuation of pregnancy as independent risk factor for preterm birth: a systematic review and metaanalysis.Am J Obstet Gynecol. 2016; 214: 572-591Abstract Full Text Full Text PDF PubMed Scopus (53) Google Scholar Moreover, as there were no randomized controlled trials (RCTs) included in our meta-analysis, and no studies comparing prior medical with prior surgical abortion, we still call for future large clinical RCTs with long-term follow-up comparing surgical versus medical evacuation of the uterus. We strongly believe that physicians and researchers should always be encouraged to practice based on the highest level of evidence, which comes from RCTs and meta-analyses of RCTs.6Burns P.B. Rohrich R.J. Chung K.C. The levels of evidence and their role in evidence-based medicine.Plast Reconstr Surg. 2011; 128: 305-310Crossref PubMed Scopus (1005) Google Scholar Re: Prior uterine evacuation of pregnancy as independent risk factor for preterm birth: a systematic review and metaanalysisAmerican Journal of Obstetrics & GynecologyVol. 216Issue 1PreviewThe meta-analysis by Dr Saccone and colleagues1 concludes that surgical abortion “is an independent risk factor” for subsequent preterm birth. The authors found a weak association (odds ratios [OR], 1.44; 95% confidence interval, 1.09–1.90) between abortion and preterm birth, but we question whether this association is causal. We agree with the discussion of study limitations and will highlight several key points. First, the reported associations all had OR <2. Not only do bias and confounding often account for weak associations, but OR exaggerate true relative risk. Full-Text PDF