Aims-To compare the outcome in in vitro fertilisation (IVF) children (
after fresh embryo transfer) from multiple and singleton births with o
ne another, and with normally conceived control children. Methods-A co
hort of 278 children (150 singletons, 100 twins, 24 triplets and four
quadruplets), conceived by IVF after three fresh embryos had been tran
sferred, born between October 1984 and December 1991, and 278 normally
conceived control children (all singletons), were followed up for fou
r years after birth. They were assessed for neonatal conditions, minor
congenital anomalies, major congenital malformations, cerebral palsy
and other disabilities. Control children, all born at term, were match
ed for age, sex and social class. Results-The ratio of male:female bir
ths was 1.03. Forty six per cent of IVF children were from multiple bi
rths; 34.9% were from preterm deliveries; and 43.2% weighed less than
2500 g at birth. The IVF singletons were on average born one week earl
ier than the controls, weighed 400 g less, and had a threefold greater
chance of being born by caesarean section. The higher percentage of p
reterm deliveries was largely due to multiple births and they contribu
ted to neonatal conditions in 45.0% of all IVF children. The types of
congenital abnormalities varied: 3.6% of IVF children and 2.5% of cont
rols had minor congenital anomalies, and 2.5% of NF children and none
of the controls had major congenital malformations. The numbers of eac
h specific type of congenital abnormality were small and were not sign
ificantly related to multiple births. IVF children (2.1%) and 0.4% of
the controls had mild/moderate disabilities. They were all from multip
le births, including two children with cerebral palsy who were triplet
s. Conclusions-The outcome of NF treatment leading to multiple births
is less satisfactory than that in singletons because of neonatal condi
tions associated with preterm delivery and disabilities in later child
hood. A reduction of multiple pregnancies by limiting the transfer of
embryos to two instead of three remains a high priority.