Chorioamnionitis and mid-trimester pregnancy loss

Mid-trimester pregnancy loss defined as miscarriage at 14-23 weeks' gestation and preterm birth between 24 and 28 weeks are in essence clinical manifestations of the same disease process. The pathogenic and socio-biologic risk factors are the same, but the timing of onset of uterine activity and cervical dilatation may be delayed in the case of preterm birth. The overwhelming majority of cases are associated with ascending infection from the lower genital tract. Women with a prior history of late miscarriage are at increased risk of preterm delivery and vice versa. The risk of preterm delivery in women with prior mid-trimester pregnancy loss approximates the same recurrence risk documented for women with a previous history of preterm delivery, suggesting that mid-trimester miscarriage represents the lower end of the spectrum of preterm birth. There are many causes of mid-trimester pregnancy loss including abnormal placentation, immunological interactions, thrombophilias, cervical insufficiency and upper genital tract anomalies to name a few. This paper, however, will focus on the role of chorioamnionitis in the pathogenesis of mid-trimester pregnancy loss and the value of current interventions to reduce recurrence.