This study seeks to establish
progesterone and
progesterone-induced
blocking factor (PIBF) levels as predictors of subsequent completed
miscarriage among women presenting with
threatened miscarriage between 6 and 10 weeks of gestation. Our secondary objective was to assess the known maternal risk factors, toward development of a parsimonious and clinician-friendly risk assessment model for predicting completed
miscarriage. In this article, we present a prospective cohort study of 119 patients presenting with
threatened miscarriage from gestation weeks 6 to 10 at a tertiary women's hospital emergency unit in Singapore. Thirty (25.2%) women had a spontaneous
miscarriage. Low
progesterone and PIBF levels are similarly predictive of subsequent completed
miscarriage. Study results (OR, 95% CI) showed that higher levels of
progesterone (0.91, 95% CI 0.88-0.94) and PIBF (0.99, 95% CI 0.98-0.99) were associated with lower risk of
miscarriage. Low
progesterone level was a very strong predictor of
miscarriage risk in our study despite previous concerns about its pulsatile secretion. Low serum
progesterone and PIBF levels predicted spontaneous
miscarriage among women presenting with
threatened miscarriage between gestation weeks 6 to 10. Predictive models to calculate probability of spontaneous
miscarriage based on serum
progesterone, together with maternal BMI and fetal heart are proposed.