Can third trimester ultrasound predict the presentation of the first twin at delivery?

Abstract

Objective: To determine the ability of early sonogram to predict the presentation of twin A at birth. Methods: A retrospective cohort study was conducted on all twin pregnancies evaluated at our Fetal Evaluation Unit from 2007 to 2009. Sonogram records were reviewed for the presentation of twin A at seven gestational age intervals and inpatient medical records were reviewed for the presentation of twin A at delivery. The positive predictive value, sensitivity, and specificity of presentation as determined by ultrasound, at each gestational age interval, for the same presentation at delivery were calculated. Results: Two hundred and thirty-eight twin pregnancies met inclusion criteria. A total of 896 ultrasounds were reviewed. The positive predictive value of cephalic presentation of twin A as determined by ultrasound for the persistence of cephalic presentation at delivery reached 95% after 28 weeks gestation. The positive predictive value for noncephalic presentation as established by sonogram for noncephalic at delivery was >90% after 32 weeks gestation. Conclusions: The presentation of the first twin at delivery can be determined by sonogram by the 32nd week of gestation in over 90% of twin pregnancies.

Keywords::

• Antenatal
• breech
• cephalic
• multifetal
• multiple gestation
• sonogram

Declaration of Interest: The authors report no conflicts of interest.