The prognostic value in threatened abortion of plasma progesterone values and the cornification index of vaginal smears.

The predictive values of plasma progesterone levels in 70 patients threatening to abort was investigated. It was found that no patient aborted whosed plasma progesterone level remanined above 35 nmol/l between 7 and 16 weeks of pregnancy, whereas if the plasma progesterone level was less than this, subsequent abortion always occurred. The predictive value of cornification index in vaginal smears was also examined: many smears were unsatisfactory for assessment and in patients with threatened abortion there was a 14 per cent incidence of falsely optimistic and 29 per cent of falsely pessimistic predictions.