Introduction: historical aspects

Perinatal mortality

Perhaps no other medical subspecialty has achieved such a dramatic improvement in survival as that documented in neonatal medicine over the last 40 years. Since the 1960s the survival rate for infants born weighing less than 1500 g (very low birthweight, VLBW) has increased from 45% to over 80%. For the small group born weighing less than 1 kg (extremely low birthweight, ELBW) the increase in survival has been from 20% to almost 70%. These changes have occurred against a background of improving perinatal, infant and childhood mortality in the United Kingdom and elsewhere, although it remains true that a VLBW infant is 100 times more likely to be stillborn or die during the first month of life than an infant born weighing 3000 g or more (Table 4.1). The UK definition of a stillbirth was changed to include all fetuses delivered dead after 24 complete weeks of pregnancy in October 1992. This caused a step up of about 1 per 1000 in the UK perinatal mortality rate, which at 8.0 per 1000 total births remains similar to that in other European countries and the USA (Fig. 4.1). Whilst prematurity remains the leading cause of perinatal and neonatal death, significant contributions continue to be made from perinatal asphyxia, sepsis and congenital malformations. Group B streptococcal infection and chorioamnionitis, where the organism is rarely isolated, are important causes of fetal and neonatal deaths.