TERM AND POSTTERM TWIN GESTATIONS - PLACENTAL CAUSE OF PERINATAL-MORTALITY

OBJECTIVE: To compare perinatal mortality in twins and singletons and to study the influence of fetal sex, placentation and maternal parity on perinatal mortality in term and postterm twin gestations. STUDY DES IGN: The subjects of the study were 1,511 twin pairs and 3,022 singlet ons. All were born at a gestational age of 27 weeks or more in two cli nics in Amsterdam between 1931 and 1975. RESULTS: Perinatal mortality was lower in twins than in singletons until 37-38 weeks and higher aft erwards. In twins, perinatal mortality was higher in boys than in girl s, in monochorial than in dichorial twins, and in primiparae than in m ultiparae, especially in the last trimester. CONCLUSION: The developme nt of the twin placenta may set limits in term and postterm twin gesta tions and may be responsible, to some extent, for the increase in peri natal mortality.