Current Concepts of Immature Birth

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 　Preterm births accounts for a major proportion of perinatal deaths. It is important however, that 8 per cent of deliveries that occured prematurely accounted for 75 per cent of perinatal deaths. An Oxford study reported that 85 per cent of neonatal deaths, not due to a lethal abnormality occured in infants with gestational ages between 22 and 37 weeks of gestation. In Singaore last year 400 infants weighing less than 2270 g were dead by the 4th week of life. The true incidence of preterm labour (<37 weeks) is not known because of variations in reporting. The British Perinatal Mortality Survey reported that 3.4 per cent of births occured at gestations less than 251 days. A United States Medical Centre reported a preterm delivery rate of 7.6 per cent over the previous eleven years. We have also to consider the contribution of preterm birth in relation to perinatal morbidity. Although there has been a significant increase in neonatal survival rate of preterm babies, morbidity is still high. The incidence of late neurological handicap in the group below 34 week (750-1500g) has improved in parallel with modern neonatal intensive care. Major handicaps are present in 10-30 per cent of very small survivors. This group can be decreased considerably with good neontal care. For the present, we realise that the incidence of handicap runs parallel with perinatal mortality and is dependent on the adequacy of neonatal care.

 Generally, gross fetal abnormalities are accompanied by an increased likelihood of preterm labour and so are obstetrical complications which lead to early fetal death or delivery. I do not intend to become entangled in the confusion perpetuated in the English literature by including all such cases as prematurity but propose to describe preterm birth of unknown aetiology.

 The following table 1 summarizes the various factors which are known associates with risk for prematurity.