Is amniotic fluid quantitation of value in the diagnosis and conservative management of prelabour membrane rupture at term?

This study examined the hypothesis that ultrasound quantitation of amniotic fluid depth is of value in the diagnosis and management of prelabour rupture of the membranes (PROM) at term. The deepest vertical pool was measured in 151 consecutive patients with a history of suspected PROM for at least 10 h before labour. In 100 patients the diagnosis of PROM was confirmed by the collection of amniotic fluid at the vulva. There was no difference in mean depth of amniotic fluid in 100 patients with confirmed PROM, compared with 51 in whom PROM was not confirmed (48.5 mm SD 16.4 vs. 60.1 mm SD 16.5); the frequency of oligohydramnios (fluid depth less than 30 mm) was 5% and 5.8% respectively. There was no relation between ultrasound amniotic fluid quantitation and the onset of labour, the duration of labour nor the frequency of oxytocin augmentation in labour. The results show that ultrasound quantitation of amniotic fluid is of no value in the diagnosis and conservative management of PROM at term.