Twin gestation: Fetal presentation as a function of gestational age

OBJECTIVE: Our objective in this study was to evaluate the rate of spontaneous version in twin gestation throughout the third trimester. STUDY DESIGN: 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. RESULTS: 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. {bd}CONCLUSION: 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.