First trimester serum angiogenic/anti-angiogenic status in twin pregnancies: relationship with assisted reproduction technology

BACKGROUND: The risk of pre-eclampsia (PE) increases in twin pregnancies, especially when assisted reproduction technologies (ART) are used. The aim of this study was to assess angiogenic/anti-angiogenic factors in maternal serum in the first trimester of twin pregnancies and establish if the mode of conception influences angiogenic status. METHODS: This prospective study enrolled women with twin (n = 61) and singleton (n = 50) pregnancies. Dichorionic twin pregnancies were divided into two groups according to their mode of conception. Singleton pregnancies were used as the control group. Soluble fms-like tyrosine kinase (sFlt-1), free placental growth factor (PlGF) and soluble endoglin (sEng) concentrations were measured in the first trimester maternal serum. RESULTS: In the first trimester, women with twin pregnancies had higher serum concentrations of the anti-angiogenic factor sFlt-1 than that with singleton pregnancies (3924 +/- 250 versus 2426 +/- 162 pg/ml, respectively; P < 0.001). Maternal serum PlGF concentrations were lower in singleton pregnancies than those in twin pregnancies (37 +/- 3.7 versus 59 +/- 5.6, respectively; P < 0.001). Serum concentrations of sFlt-1 were higher in twin pregnancies conceived by ART than those in spontaneous twin pregnancies (4313 +/- 389 versus 3522 +/- 300 pg/ml, respectively; P < 0.05). No differences between groups were observed for sEng. CONCLUSIONS: In the first trimester, twin pregnancies conceived using ART showed a heightened anti-angiogenic status that could explain the increased risk of PE in these cases.