A retrospective population-based study of primigravid women on the potential effect of threatened miscarriage on obstetric outcome.

The aim of this study was to ascertain any potential link between threatened miscarriage and obstetric outcome. Threatened miscarriage was associated independently with an increased incidence of abruption (OR 2.8, 2.0-3.7), unexplained antepartum haemorrhage (APH) (OR 2.3, 1.1-5.1) and preterm delivery (OR 2.0, 1.3-3.3). The incidence of low and very low birth weight deliveries, although significantly higher compared with the control population, was not affected independently by this early pregnancy complication on logistic regression (OR 1.3, 0.8-1.9). The early neonatal mortality rates were significantly higher in the threatened miscarriage group, which on logistic regression was due independently to preterm delivery, placental abruption and low birth weight deliveries. All forms of APH were significantly higher in term deliveries complicated by threatened miscarriage. Pregnancies presenting with threatened miscarriage should be highlighted as 'high risk' for a suboptimal obstetric outcome and a prospective observational trial followed by a randomised-controlled trial may be needed to establish whether the need exists for increased feto-maternal surveillance in this cohort of women.