A prospective study of placental growth factor in twin pregnancy and development of a dichorionic twin pregnancy specific reference range.

OBJECTIVE The aim of this study was twofold; to develop a dichorionic twin pregnancy specific reference range for placental growth factor, and to compare gestational specific placental growth factor levels in twin pregnancies later complicated by preeclampsia, hypertensive disorder of pregnancy or fetal growth restriction to controls DESIGN: Prospective observational study. SETTING Single large tertiary maternity unit in Ireland . POPULATION OR SAMPLE Women with a twin pregnancy. METHODS Consenting pregnant women, across a variety of gestations, had a single blood sample taken at one time point only during their pregnancy. The plasma was initially biobanked and PlGF was measured later in batches using the point of care Triage® PlGF test. MAIN OUTCOME MEASURES Development of preeclampsia, hypertensive disorder of pregnancy or fetal growth restriction. RESULTS PlGF levels in uncomplicated dichorionic twin pregnancies were significantly lower in the women who later developed preeclampsia than in the controls at all gestational intervals. In those that later developed any hypertensive disorder of pregnancy median PlGF was lower only in those recruited before 24 weeks' gestation while in infants with a customised birthweight below the 3rd centile, PlGF was lower only in those sampled after 24 weeks' gestation. CONCLUSIONS PlGF levels in twin pregnancy differ significantly between those women with a pregnancy that will later be complicated by preeclampsia and those that will not. This difference is present many weeks before clinical signs or symptoms of disease are present. Using cross sectional values from uncomplicated twin pregnancies, we have developed a dichorionic twin pregnancy specific reference range for PlGF.