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

Objective: To develop a dichorionic twin pregnancy specific reference range for placental growth factor (PlGF), and to compare gestation‐specific placental growth factor levels in twin pregnancies later complicated by pre‐eclampsia, hypertensive disorder of pregnancy or fetal growth restriction with control pregnancies. 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 pre‐eclampsia, hypertensive disorder of pregnancy or fetal growth restriction. Results: Placental growth factor levels in uncomplicated dichorionic twin pregnancies were significantly lower in the women who later developed pre‐eclampsia 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 of gestation, whereas in infants with a customised birthweight below the third centile, PlGF was lower only in those sampled after 24 weeks of gestation. Conclusions: Placental growth factor levels in twin pregnancy differ significantly between those women with a pregnancy that will later be complicated by pre‐eclampsia 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