Comparative study of perinatal outcome of dichorionic and trichorionic iatrogenic triplets.

OBJECTIVE: The purpose of this study was to compare the perinatal outcome of dichorionic and trichorionic triplets who were conceived by assisted reproductive techniques. STUDY DESIGN: In this retrospective study, the maternal, neonatal, and chorionicity data were collected from 106 sets of trichorionic triamniotic and 34 sets of dichorionic triamniotic triplet pregnancies who were conceived by assisted reproductive techniques between January 1986 and December 2000. Perinatal and neonatal data were evaluated in relation to chorionicity and intertriplet birth weight discordance. RESULTS: The dichorionic triamniotic triplets have an 8-fold higher risk of perinatal death than trichorionic triamniotic gestations (odds ratio, 7.9; 95% CI, 4.4-14.0; P < .001). This is attributed to a higher risk of very low birth weight (P < .01), delivery at < 30 weeks of gestation (P < .001), and premature rupture of membrane (P < .001) in dichorionic triamniotic triplets compared with trichorionic triamniotic pregnancies. Twin-twin transfusion syndrome (odds ratio, 11.5; 95% CI, 4.8-27.7; P < .001), delivery at < 30 weeks of gestation (odds ratio, 40.5; 95% CI, 16.9-97; P < .01), premature rupture of membrane (odds ratio, 6.7; 95% CI, 3.8-11.9; P < .01), and nulliparity (odds ratio, 3.1; 95% CI, 1.6-6.1; P < .05) had independent effects on perinatal loss rate. CONCLUSION: The dichorionic triplets have an 8 times higher perinatal mortality rate than trichorionic triamniotic pregnancies.

Perinatal outcome of spontaneously conceived triplet pregnancies in relation to chorionicity.

OBJECTIVE: The purpose of this study was to determine the perinatal outcome of spontaneously conceived triplet pregnancies in relation to chorionicity. STUDY DESIGN: In this retrospective study, maternal, neonatal, and chorionicity data were collected from 88 sets of triplet pregnancies that were delivered at >20 weeks of gestation from 3 tertiary referral centers in the United Kingdom. The data were collected between January 1986 and December 2000. There were 49 sets of trichorionic triamniotic triplet pregnancies and 39 sets of triplet pregnancies with a monochorionic pair (ie, dichorionic triamniotic triplets). The outcome of each pregnancy was assessed in relation to chorionicity. RESULTS: The overall perinatal mortality rate was 151.5 per 1000 total births, with dichorionic triamniotic triplets having a 5.5-fold higher risk than trichorionic triamniotic gestations (odds ratio, 5.5; 95% CI, 2.5-12.2). The dichorionic triamniotic triplets have a higher risk of delivery at < 30 weeks of gestation (odds ratio, 4.6; 95% CI, 1.6-11.8; P < .05) and birth weight of < 1000 g (odds ratio, 53.6; 95% CI, 17.5-164; P < .05) than those of trichorionic triamniotic pregnancies. The neonatal morbidity in terms of respiratory distress syndrome (P < .001), anemia (P < .01), and intraventricular hemorrhage (P < .001) were higher in dichorionic triamniotic compared with trichorionic triamniotic triplets. The premature rupture of membrane (odds ratio, 7.5; 95% CI, 3.5-15.7) and twin-twin transfusion syndrome (odds ratio, 14.9; 95% CI, 6.6-4) were independent risk factors for perinatal death. CONCLUSION: In spontaneously conceived triplets, the incidence of dichorionicity was 44%. The dichorionic triamniotic triplets have a 5.5-fold higher risk of adverse perinatal outcome predominantly because of twin-twin transfusion syndrome and premature rupture of membranes.

Perinatal outcome following amniotic septostomy in chronic TTTS is independent of placental angioarchitecture.

OBJECTIVES: To determine whether the vascular anatomy of monochorial placenta influences the success of amniotic septostomy for the treatment of chronic mid-trimester twin-twin transfusion syndrome, we report placental anastomoses and perinatal data of 13 pregnancies treated by amniotic septostomy in combination with amnioreduction (AR). The placental anastomoses were delineated postnatally by perfusion studies. Perinatal outcome was also evaluated in relation to umbilical artery Doppler waveform of the donor twin. RESULTS: The median gestational age at septostomy was 21 weeks (range 18 to 25.5 weeks). Amniotic septostomy in combination with single AR procedure successfully resolved polyhydramnios in all cases. The median gestational age at delivery and the septostomy to delivery interval were 27 weeks (range 20 to 34 weeks) and 4 weeks (range 0.3 to 13.6 weeks), respectively. Of the 26 fetuses, 10 died in utero and four died within a week of life, with a combined survival rate of 46%. There was no relation between the clinical outcome and angioarchitecture of the placenta. However, pregnancy loss was higher in the donor twin with absent end-diastolic flow umbilical artery Doppler waveform than those with end-diastolic flow (85 vs 17%; p < 0.001). CONCLUSION: This study suggests that although amniotic septostomy is a promising method for the correction of oligohydramnios and/or polyhydramnios, perinatal survival rate does not depend on angioarchitecture of the placenta. Instead, umbilical artery Doppler waveform of the donor twin may be a better marker for survival rate.