Third Trimester Screening of Fetal Growth Restriction

Inclusion Criteria: * Eligible cases are nulliparous pregnant women, with first trimester ultrasound assessment of gestational age, who conceived singleton fetuses. If the crown-rump-length (CRL) differs of more than ± 3-5 days from the last menstrual period, gestational age is calculated on the CRL. Exclusion Criteria: * major medical disease * high risk for preeclampsia on history or detected in those centres that perform pre-eclampsia screening at first trimester * women older than 40 years on ASA low dose prophylaxis * known immune disorders or clinical thrombophilic conditions; * twin pregnancies; * IVF * suspected fetal anomalies at any gestational age * Papp-A at Combined-Test\<0.2