Characteristics of hypertensive disorders in twin versus singleton pregnancies

ObjectiveTo determine the characteristics of hypertensive disorders of pregnancy in twin compared with singleton pregnancies.Study designAnalysis of a prospectively recorded database of 4976 hypertensive pregnancies.Main outcome measuresComparison of progression to pre-eclampsia and maternal and neonatal outcomes.ResultsThere were 3942 singleton and 214 twin pregnancies. De novo hypertension in twin pregnancy was diagnosed earlier (p < 0.001). In singleton pregnancies with de novo hypertension (n = 3161), 60% had an initial diagnosis of gestational hypertension (GH) and 40% had pre-eclampsia (PE). In twin pregnancies with de novo hypertension (n = 199), 35% of women were initially diagnosed with GH and 65% with PE (p < 0.001). At delivery, 46% of the singletons had GH and 54% had PE, compared with twin pregnancies where 23% had GH and 77 % had PE (p < 0.001). The progression from GH to PE for twins was twice that of singleton pregnancies (p < 0.001).There were 781 singleton and 15 twin pregnancies with chronic hypertension (CH). Twin pregnancies complicated by CH were more likely to progress to PE than singletons (p < 0.01). The gestation at delivery was earlier for twin pregnancies (p < 0.001) and there were more twins that were smaller for gestational age (p < 0.001). There were no differences in maternal outcomes.ConclusionWomen carrying twins with de novo hypertension are more likely to present earlier, have initial PE and to subsequently progress from GH to PE. Neonatal outcomes are worse in such pregnancies.