A study evaluating the various tests in the diagnosis of membrane rupture examined 100 consecutive women in labour with either intact or ruptured membranes.15The best results were obtained with the Nitrazine and ferning tests,with a sensitivityof 90%.The false-positiverate was 17% for the Nitrazine test,owing to contamination with urine,blood or semen,and 6% for the ferning test,owing to contamination with cervical mucus.A similar sensitivity and false-positive rate was achieved by obtaining a history of rapid passage of fluid from the vagina.Ultrasound examination demonstrating oligohydramnios is also used to help confirm the diagnosis of spontaneous rupture of the membranes.16–19AmniSure® (AmniSure® International LLC,Boston, MA,USA),a rapid immunoassay,has been shown to be accurate in the diagnosis of ruptured membranes with a sensitivity and specificity of 98.9% and 100%,respectively.20