Bull N Y Acad Med. 1990 Nov-Dec;66(6):618-37.
The epidemiology of perinatal mortality in multiple births.
Kiely JL.
Department of Community Health and Social Medicine, Sophie Davis School of
Biomedical Education, City University of New York, New York.
The epidemiology of perinatal mortality in multiple pregnancies was
investigated from data on 16,831 multiple births from New York City's
computerized vital records for 1978-1984. Twins had a sixfold higher rate of
neonatal death and a threefold higher rate of fetal death during labor than
had singleton infants. Much of this excess mortality can be explained by the
lower birthweight distribution in twins: between 1,001 and 2,500 grams twins
had birthweight-specific death rates equivalent to or substantially less
than singletons. However, in infants of normal birthweights, twins had more
than three times the mortality risk of singletons. For twins in vertex
presentation between 1,001 and 3,000 grams, cesarean section did not
appreciably reduce neonatal mortality risk. For twins in vertex presentation
who weighted more than 3,000 grams the neonatal mortality rate was more than
four times higher in vaginal deliveries than in cesarean sections (exact p =
0.034). Efforts to prevent intrapartum and neonatal mortality in multiple
births should aim at reducing the incidence of low birthweight twins. More
research is needed on the etiology of perinatal problems in normal
birthweight twins (greater than or equal to 2,501 grams), especially on the
effects of different modes of delivery.
