UAB - Center for Clinical and Translational Science

are listed below and will be confirmed prior to randomization: 1. Fetal diagnosis of congenital heart disease (CHD) by prenatal ultrasound / echocardiography from local fetal ECHO, conducted between 18 - 36 weeks of gestation. The study fetal diagnosis of CHD must be rated as 3 - 6 on the Fetal Cardiovascular Disease Severity Score (FCDSS), as determined by independent evaluators at the CORD-CHD trial ECHO Core at the Children's Hospital of Philadelphia (to determine final FCDSS eligibility for randomization). For each potential participant that has provided consent, the most relevant diagnostic prenatal ultrasound will be uploaded (shared) between 32 and 36 weeks of gestation for review by the ECHO Core. The ECHO Core will make the final FCDSS determination for eligibility status and stratification assignment.] [NOTE: A fetal diagnosis of CHD rated as 3 - 6 FCDSS per local review, including borderline cases, will be used to determine preliminary eligibility for consent. Among borderline cases, eligible patients will be included if there is a reasonable expectation of the need for surgery or cardiac catheterization during the birth hospitalization.] 2. Singleton gestation. 3. Gestational age at labor and delivery admission (randomization) between 37 0/7 - 41 6/7 weeks of gestation inclusive based on clinical information and evaluation of the earliest ultrasound determined using criteria proposed by the American Congress of Obstetricians and Gynecologists (ACOG), the American Institute of Ultrasound in Medicine and the Society for Maternal-Fetal Medicine. [NOTE: Pregnant individuals who were admitted to the delivery hospital prior to 37 0/7 weeks of gestation remain eligible, provided they deliver within the 37 0/7 and 41 6/7 weeks "eligibility window".] 4. Informed consent to participate for both the pregnant individual and their infant

are listed below and will be confirmed prior to randomization: Exclusion Criteria for Pregnant Individuals: 1. Pregnant individual is a gestational carrier or surrogate. 2. Compromise of the pregnant individual (e.g., vasa previa, placental accreta with hypotension, placental abruption, amniotic fluid embolism, uterine rupture, uterine inversion, disseminated intravascular coagulation), as determined by local care team [NOTE: There is no limitation on pregnant individual's age] Fetal Exclusion Criteria: 1. Fetal demise or planned termination of pregnancy prior to randomization 2. Tachyarrhythmia requiring transplacental therapy 3. Fetal hydrops, severe 4. Autoimmune myocardial disease 5. Planned fetal surgery 6. Diaphragmatic hernia, omphalocele, gastroschisis, intestinal atresia 7. Major chromosomal defects (e.g., Trisomy 13, 18) identified prenatally; Trisomy 21 is allowed 8. Neuromuscular disorders (e.g., holoprosencephaly) 9. Parents choosing to limit treatment Pregnancy Exclusion Criteria: 1. Delivery planned at an institution not affiliated with or does not refer to a CORD-CHD participating site 2. Participation in another prenatal interventional study that influences cord clamping or perinatal morbidity or mortality