501: Incidence of ischemic placental disease in women with a history of spontaneous preterm birth

Abstract

OBJECTIVE: Placental insufficiency is described to play a role in the pathophysiology of spontaneous preterm birth (SPTB). Placental insufficiency is also known to play a key role in hypertensive disorders of pregnancy (HD), small for gestational age (SGA) or placental abruption; together referred to as 'ischemic placental disease' (IPD). Therefore, we hypothesized that women with a history of SPTB have an increased risk of ischemic placental disease in a subsequent pregnancy. STUDY DESIGN: A prospective national cohort study in the period 1999 - 2009 within the Dutch Perinatal Registry. We studied 349.291 women with a 1st and 2nd singleton pregnancy within the study period. Women with an indicated preterm birth, a preexisting hypertension, fetal congenital abnormalities or antenatal fetal death were excluded. Women were stratified into 2 groups: women with a SPTB (19.991) or with a term birth (329.300) in their 1st pregnancy. The main outcome measure is prevalence of ischemic placental disease in the 2nd pregnancy. RESULT(S): 3.253 women (16.3%) with SPTB in their 1st pregnancy had ischemic placental disease in their 2nd pregnancy compared to 43.954 women (13.3%) with a previous term birth (OR 1.26 (CI 1.21 - 1.31)). Among the 3.253 women with SPTB in their 1st pregnancy, 15.1% had also ischemic placental disease. These women were at high risk of recurrence of ischemic placental disease in their 2nd pregnancy (38.9%). Women with a history of SPTB without any signs of ischemic placental disease, still had a higher risk of ischemic placental disease in their second pregnancy compared to women with a previous term birth without ischemic placental disease (10.4% versus 6.9%, OR 1.49 (CI1.42- 1.56), table 1). All described differences were statistically significant (P<0.05). CONCLUSION(S): A history of SPTB results in a 1.5 higher risk of ischemic placental disease in the subsequent pregnancy, especially if women reach the term period. Caregivers should be aware of the elevated risk of (other) ischemic placental disease in a pregnancy after SPTB.