Do pregnant women with a low-situated placenta in the 16th week constitute a risk group?

The object of this investigation was to elucidate whether pregnant women with low-placed placentae in the 16th week of pregnancy had more frequent haemorrhagic complications during pregnancy or during delivery and to demonstrate how many had placenta praevia at the time of delivery. In addition, the frequency of Caesarean section, the perinatal mortality, birthweights under 2,500 g in the infants delivered and placental anomalies were registered. A total of 1,572 pregnancies were investigated sonographically at about the 16th week of pregnancy and in 166 (10.6%) the placenta was found in the lower uterine segment. 40% of the 15 women with complete placenta praevia at the 16th week of pregnancy developed haemorrhage necessitating hospitalization, 27% were delivered by Caesarean section and 20% had placenta praevia at delivery. Out of 99 women with partial placenta praevia at the 16th week of pregnancy, one was found to have placenta praevia at the time of delivery but no significantly increased risk of haemorrhage necessitating hospitalization, abortion or Caesarean section. In 52 women with "deep insertion" of the placenta at the 16th week of pregnancy, one was subsequently found to have complete placenta praevia but the frequency of complications was not increased as compared with that in women with a free orifice. This investigation reveals a basis for control sonography of women with complete placenta praevia at the 16th week of pregnancy.