Association of syndromes predisposing to low birthweight.

In a geographically-defined sample of low birthweight deliveries, the incidence was measured of ante-partum haemorrhage, hypertension, placental insufficiency and premature rupture of the membranes. When more than one of these syndromes was present, a clear pattern of segregation into pairs was noted, ante-partum haemorrhage tending to occur with premature rupture of the membranes, and hypertension with placental insufficiency.