The Effect of Time Window for Umbilical Cord Clamping During Cesareans on Offspring Hemoglobin and Maternal Blood Loss

Inclusion Criteria: * local resident in Liuyang city, Huantai county and their surrounding areas * Singleton pregnancy * Elective caesarean, or cesarean section after the start of labor but the cervix is less than 3 cm * Term pregnancy (≥37 weeks of gestation), and the fetal weight was estimated ≥2500g by intrauterine ultrasound * Written informed consent is obtained Exclusion Criteria: * Pregnant women with the following risk factors: severe hypertension (systolic blood pressure ≥160 mmHg and/or diastolic blood pressure ≥110mmHg), preeclampsia, chronic hypertension with preeclampsia, diabetes mellitus with severe microangiopathy, placenta previa, placenta implantation, placental abruption, intrauterine distress, prenatal infection, severe anemia (hemoglobin\<7g/dL), coagulation disorders, thrombosis disease * Plan to retain cord blood * Rh-negative pregnant women * Prenatal diagnosis of fetal abnormalities which may lead to difficulties in cesareans or adverse pregnancy outcomes, such as abnormal heart monitoring, fetal distress, malformation, anemia, and intrauterine growth restrictions * Other conditions not suitable for intervention as judged by obstetricians