Twin gestation: fetal presentation as a function of gestational age.

Abstract

Our objective in this study was to evaluate the rate of spontaneous version in twin gestation throughout the third trimester. Serial ultrasonographic examinations were performed on 119 consecutive patients with twin gestation. The incidence of spontaneous version as a function of gestational age was calculated. The mean birth weight and gestational age at delivery were 2640 gm and 37 weeks, respectively. Nineteen percent had birth weight discordancy, and 37% were delivered by cesarean section. The incidence of spontaneous version decreased from 60% at 28 to 30 weeks' gestation to 25% to 30% at term. The lowest incidence of spontaneous version was observed in pregnancies with a cephalic-cephalic presentation (7%). All other presentations were relatively unstable. Neither the patients' parity nor the presence of birth weight discordancy, the placental location, or the amniotic fluid volume had a significant association with the incidence of spontaneous version. These data should be incorporated into the routine antepartum counseling of patients with twin gestation. Their use in this capacity may result in a decreased cesarean delivery rate if clinicians realize that malpresentations may spontaneously resolve before the onset of labor.