Prospective risk of intrauterine death of monochorionic-diamniotic twins

Abstract

Simoes et al retrospectively evaluated 193 monochorionic diamniotic twin pregnancies that were monitored with intense fetal surveillance (biweekly assessment between 24 and 30 weeks’ gestation and weekly nonstress testing and biophysical profile testing after 30 weeks’ gestation with biweekly growth scans) and delivered after 24 weeks’ gestation.1Simoes T. Amaral N. Lerman R. Ribeiro F. Dias E. Blickstein I. Prospective risk of intrauterine death of monochorionic-diamniotic twins.Am J Obstet Gynecol. 2006; 195: 134-139Abstract Full Text Full Text PDF PubMed Scopus (59) Google Scholar They did not exclude gestations complicated by malformations, growth problems, and twin-to-twin transfusion syndrome. The prospective risk of fetal death was calculated, and the prospective risk of stillbirth per pregnancy after 32 weeks’ gestation was found to be 1.2% (95% CI, 0.3% to 4.2%). The authors concluded that their findings do not support elective preterm delivery for monochorionic diamniotic twin pregnancies that are progressing well. These conclusions are in contrast to those of Barigye et al2Barigye O. Pasquini L. Galea P. Chambers H. Chapell L. Fisk N.M. High risk of unexpected late fetal death in monochorionic twins despite intensive ultrasound surveillance: a cohort study.PLoS Med. 2005; 2: e172Crossref PubMed Scopus (117) Google Scholar who retrospectively evaluated 151 “uncomplicated” monochorionic twin pregnancies. They excluded all cases with malformations, growth abnormalities, and twin-to-twin transfusion syndrome. Fetal surveillance included biweekly ultrasound for growth, amniotic fluid, and Doppler studies. The prospective risk of unexpected antepartum death after 32 weeks was 1 of 23 (95% confidence interval 1/11 to 1/63). These authors suggested that elective preterm delivery may mitigate the risk for stillbirth. Although the findings of the study by Simoes et al are better than those of Barigye et al, a prospective risk of still birth of 1.2% after 32 weeks is substantial especially because there is the real potential for significant impact on the surviving co-twin specifically a risk for long-term adverse neurologic outcomes.3Pharoah P.O. Adi Y. Consequences of in-utero death in a twin pregnancy.Lancet. 2000; 355: 1597-1602Abstract Full Text Full Text PDF PubMed Scopus (181) Google Scholar Thus, this study by Simoes et al2Barigye O. Pasquini L. Galea P. Chambers H. Chapell L. Fisk N.M. High risk of unexpected late fetal death in monochorionic twins despite intensive ultrasound surveillance: a cohort study.PLoS Med. 2005; 2: e172Crossref PubMed Scopus (117) Google Scholar further confirms our belief that there is a great need for a large prospective and likely multicenter study with long-term pediatric follow-up to definitively answer the question when is the ideal time to deliver monochorionic twins.4Cleary-Goldman J. D’Alton M.E. Uncomplicated monochorionic diamniotic twins and timing of delivery.PLoS Med. 2005; 2: e180Crossref PubMed Scopus (27) Google Scholar Until the question is answered, delivering apparently “uncomplicated” monochorionic diamniotic twins at 34-35 weeks’ gestation after administration of antenatal steroids, although by no means standard of care, in our opinion, is reasonable provided that the patients have been counseled about the risks and benefits.4Cleary-Goldman J. D’Alton M.E. Uncomplicated monochorionic diamniotic twins and timing of delivery.PLoS Med. 2005; 2: e180Crossref PubMed Scopus (27) Google Scholar ReplyAmerican Journal of Obstetrics & GynecologyVol. 196Issue 3PreviewWe are thankful for the comments of Cleary-Goldman and D’Alton that summarize their enlightening and invaluable editorial on this topic.1 At present, the available estimations of the prospective risk of fetal demise in monochorionic-diamniotic (MC-DA) twins after 32 weeks suggest 2 distinct numbers: a high risk of 1.2% and a significantly higher risk of 4.3%.2,3 The discrepancy between these figures is, in fact, even larger, given the different exclusion criteria in the 2 studies. Full-Text PDF