The predictive value of the sFlt-1/PlGF ratio on short-term absence of preeclampsia and maternal and fetal or neonatal complications in twin pregnancies

Objective: A sFlt-1/PlGF ratio of ≤38 has been reported to predict the absence of preeclampsia (PE) in singleton pregnancies. We evaluated whether a sFlt-1/PlGF ratio of ≤38 could be used to predict the absence of PE in twin pregnancies and maternal and fetal/neonatal complications.
Methods: This is a secondary analysis of a prospective multicenter cohort study that enrolled women with suspected or confirmed PE with the aim of evaluating the use of the sFlt-1, PlGF and their ratio to predict maternal and fetal/neonatal complications. Twin and singleton pregnancies with clinically suspected or confirmed PE were matched for gestational age and parity. Blood samples were drawn at time of study entry, but serum values of sFlt-1 and PlGF and their ratio were determined postpartum.
Results: Twenty-one women with twin and 21 with singleton gestations were included at a median gestational age of 30 weeks. At inclusion PE was diagnosed in 13 twin and 15 singleton pregnancies. In comparison to singleton control pregnancies, twin controls had a significantly higher sFlt-1 (6377 vs. 1732 pg/ml, p = 0.008), a higher sFlt-1/PlGF ratio 26 vs. 3 p = 0.361) and a lower PlGF (228 vs. 440 pg/ml p = 0.479). Compared to singleton preeclamptic pregnancies values of sFlt-1 (9134 vs. 8625 pg/ml) did not differ, whereas values of PlGF (185 vs. 33 pg/ml, p < 0.001) were higher and values of the ratio (49 vs. 158, p = 0.002) were lower in preeclamptic twin pregnancies. All preeclamptic patients with a singleton pregnancy had a ratio >38, but only 5 of the 13 patients with a preeclamptic twin pregnancy. Conversely, the ratio was ≤38 in 5 of the 6 control singleton, but in only 4 of the 8 control twin pregnancies. When classified according to a ratio ≤38 or >38 at inclusion, maternal complications occurred more frequently in patients with a ratio >38 both in singleton and twin pregnancies. In singleton pregnancies fetal/neonatal complications, except one admission to NICU, only occurred in patients with a ratio >38. In twin pregnancies fetal/neonatal complications occurred equally frequent in women with a ratio ≤38 or >38.
Conclusion: Serum sFlt-1 levels are considerably higher in twin than in singleton control gestations. A sFlt-1/PlGF ratio of ≤38 to predict short-term absence of PE is not applicable to twin pregnancies in predicting either the absence of PE or the absence of adverse pregnancy outcomes.