Obstetric risk factors: can they predict fetal mortality and morbidity?

An antepartum fetal risk score was developed and applied to 29,101 pregnancies which delivered at National Women's Hospital between January 1983 and April 1988. Twenty-one past and current obstetric and medical factors available at the onset of pregnancy or labour were weighed to obtain a risk score. The scoring system developed compared favourably with international systems. An antepartum fetal risk score of three or more was chosen to select a high risk group. These 10,859 women, 37% of the total population, identified 90% of those who had a fetal or neonatal loss. The perinatal mortality rate was 34.7/1000. Twenty-eight percent of this group had a caesarean section and 23% gave birth to a low birth weight infant. Women who had an antepartum risk score of seven or more had a perinatal mortality rate of 200/1000. The remaining women, a low risk group of 18,242 (63%), had a perinatal mortality rate of 4.1/1000. However 60% had a complicated pregnancy including 8.2% who required a caesarean section and 2.7% who gave birth to a low birth weight infant. The antepartum fetal risk score clearly identified the population at risk of fetal or neonatal loss. In addition significantly more medical intervention was provided to the high risk group. It is important to note that 60% of the low risk group had a complicated pregnancy leaving only 24% of the total population whose pregnancy was normal.