We thank Drs Quintero, Chmait, and Kontopoulos for their interest in our Society for Maternal-Fetal Medicine clinical guideline on twin-twin transfusion syndrome (TTTS). They are concerned that the Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD)-sponsored randomized controlled trial (RCT) by Crombleholme et al was included in the Society for Maternal-Fetal Medicine clinical guideline, as they believe that it is “flawed” and that “even centers that participated in the National Institutes of Health study doubt the validity of the study.” This RCT was a prospective, multicenter study that followed Consolidation of Standards for Reporting Trials guidelines and was a result of the work of several leaders in the field. The trial was indeed stopped early, as was the other referenced RCT. Both RCTs were considered to be of adequate quality to be included in the Cochrane metaanalysis on this issue; and this analysis was referenced in our guideline. We are not in a position to judge whether the participants of the NICHD-sponsored RCT believe their results or not. We do concur with the Cochrane Library that these 2 studies represent the current best level-I evidence regarding this issue and encourage further prospective controlled studies to evaluate the effectiveness of laser for TTTS.

We recognize the published experience regarding laser therapy of TTTS at the 2 centers of the USFetus group. This represents a large cohort followed by Drs Quintero, Chmait, Kontopoulos, and others. However, this report does not include a control group and thus represents level-III data, which should not supersede published level-I data.

Society for Maternal-Fetal Medicine Publications Committee

409 12th St. S.W.

Washington, DC 20024

Contact: Beth Steele ( esteele@smfm.org )

Each member of the Society for Maternal-Fetal Medicine Publications Committee has submitted a conflict of interest disclosure delineating personal, professional, and/or business interest that might be perceived as a real or potential conflict of interest in relation to this publication and none have a conflict.