Optimisation of the Management of Placental Delivery in Second Trimester Pregnancy Interruption

Interruption of a pregnancy after 14 weeks gestation may be required when the fetus is dead, severely malformed or in cases of maternal illness. This process is usually conducted medically in Australia, using the prostaglandin E1 analogue misoprostol. This prostaglandin, although not specifically licensed for use in pregnancy termination, is now a common abortifacient with a lot of accumulated experience both within Australia and internationally.

Since 1996, misoprostol, a synthetic prostaglandin, has been used at King Edward Memorial Hospital as the principal agent for second trimester pregnancy termination. This agent is administered vaginally, and in its current form and dosage regimen results in 75-80% of women delivering within 24 hours. As experience with this agent has grown, it has been observed that in approximately 40% of women the placenta is either completely retained or incompletely delivered, necessitating operative removal and an increased potential for maternal blood loss. In this study, it is planned, in a randomized controlled clinical trial, to evaluate three regimens for the management of placental delivery in women undergoing second trimester pregnancy interruption. The primary intention of this study is to develop a third stage management protocol to reduce the incidence of placental retention in second trimester medical pregnancy termination.

The secondary aim of this study is to assess the ultrasound appearance of the uterus and its cavity within 24 hours of second trimester pregnancy termination. The ultrasound appearances of the uterus following second trimester pregnancy loss have not been previously investigated in detail. Previous ultrasound studies of the term postpartum uterus have demonstrated a high incidence of echogenic material within the uterine cavity soon after an uncomplicated vaginal delivery. These findings have been of concern as the ultrasound appearances may erroneously imply a need for operative intervention. The investigators wish to ascertain if this high incidence of echogenic tissue presence is also true in the second trimester. Ultrasound is frequently used by clinicians to define placental completeness and the potential requirement for surgical curettage. The data from this single sonographic examination of the uterus will provide baseline data for a planned longitudinal study of uterine appearances following second trimester pregnancy loss and their correlation with clinical symptoms.