Table 4.

Risk classification of preterm birth using the simplified prediction score (n=1260)

Score* (risk category)	Prediction model based on maternal characteristics
	Number of mothers	Incidence of preterm birth
<3 (low)	982 (77.9%)	72 (7.9%)
≥3 (high)	278 (14.36%)	97 (53.59%)
Total	1260 (100%)	169 (13.4%)

*Score = (2*PIH) + (3*PROM) + (HGB <11 mg/dL) + 2*residence + (2*APH) + gravidity.

APH, antepartum haemorrhage; HGB, haemoglobin; PIH, pregnancy-induced hypertension; PROM, premature rupture of membranes.