Interpregnancy interval and the risk for recurrence of placental mediated pregnancy complications

The aim of this study was to investigate the effect of short or long interpregnancy interval (IPI) with placental mediated pregnancy complications after already complicated first delivery. We performed a retrospective cohort analysis of all women with singleton pregnancies who delivered their first three consecutive deliveries in one university-affiliated medical center (1994-2013). Placental mediated complications included placental abruption, small for gestational age, preeclampsia, gestational hypertension, or preterm delivery. Following first complicated delivery, IPI was compared stratified by second delivery outcome. Following two complicated deliveries, IPI was compared stratified by third delivery outcome. IPI was evaluated as continuous or categorical variable (>18, 18-60, >60 months). Related samples Cochrans' Q test and Mann-Whitney analysis were used as appropriate. Overall, 4310 women entered analysis. Of them, 18.3%, 10.5%, and 9.3% had complicated first, second, and third delivery, consecutively. Evaluated continuously, longer IPI, but not short IPI, was associated with higher rates of complicated second delivery. Stratified to categories, IPI had no effect on recurrent complications evaluated separately or as composite. Our results suggest that long IPI may increase risk for placental mediated pregnancy complications. Further studies are needed to evaluate this effect.