Evidence for benefited newborns following delayed cord clamping (DCC), including increasing hemoglobin and hematocrit levels, improving iron stores, and decreasing need for blood transfusion and incidence of intraventricular hemorrhage, in term or preterm infants led the American College of Obstetricians and Gynecologists (ACOG) to recommend a delayed cord clamping at least 30-60 seconds in vigorous term and preterm infants at birth. Although DCC has been found to be beneficial to infants, the additional blood provided by DCC could increase the incidence of jaundice that requires phototherapy and the hyperbilirubinemia, and the time prolonged by DCC might jeopardize timely resuscitation efforts, if needed. The acid-base status in umbilical cord blood at birth reflects the newborn's aerobic and anaerobic intrauterine metabolisms and is an objective measure of the fetal exposure and response to hypoxia during labour.

Gestational diabetes mellitus (GDM) is a condition in which glucose intolerance develops during pregnancy. It has been estimated in 2009 that nearly 7% of pregnancies are complicated by diabetes and approximately 86% of these cases represented women with GDM. The Hyperglycemia and Adverse Pregnancy Outcome study (HAPO) revealed that the infants of diabetic mothers (IDMs) are at increased risk of neonatal hypoglycemia, hyperbilirubinemia, shoulder dystocia, and birth trauma. And newborns to diabetic mothers are at increased risk of neonatal respiratory distress syndrome (RDS) and hypoxia, a major cause of admission in neonatal intensive care units. There is little direct evidence on the implementation of delayed umbilical cord clamping in the risk group of IDMs. Therefore, it no clear that the effectiveness and impairment of DCC in IDMs.

Therefore, the investigators conducted a prospective study in performing DCC in the infants of diabetic mothers versus the newborns with early cord clamping (ECC) to assess the effect of DCC on neonatal bilirubin levels, hyperbilirubinemia incidence, acid-base status and hypoxia in IDMs.

Inclusion Criteria:

People in the study should meet the following inclusion criteria:

• Must be a singleton pregnancy
• Clinical diagnosis of gestational diabetes mellitus according to ACOG Practice Bulletin

Exclusion Criteria:

• Pregnant women and neonates were excluded if they met the exclusion criteria (not included in if meeting one of following items )
• Maternal clinical diseases (hypertension disorders, abnormal liver function, Rhesus negative blood group or other blood system disease)
• Maternal other pregnancy complications (polyhydramnios, oligohydramnios, placenta praevia, and abruptio placentae).
• Delivery before 37 weeks or after 42 weeks
• Neonatal weight was < 2.5 kg or>4.0 kg
• Neonates had major congenital malformations (congenital anal atresia, congenital biliary atresia, congenital heart disease and so on, whether prenatal suspicion or diagnosis postpartum)
• Neonatal septicemia, hemolytic disease or other diseases affecting bilirubin metabolism.

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