The goal of this observational study is to identify a novel biomarker for stillbirth.

Specifically the aim is to predict perinatal hypoxia using quantitative ultrasound from the placenta (QUS-P) between 35 and 37 weeks gestation.

Funding: Wellcome Leap, In Utero Program

Primary outcome: Perinatal hypoxia

Background: Perinatal hypoxia is an inadequate supply to or utilization of oxygen by the fetus. It is typically diagnosed at delivery and can lead to serious medical complications, including encephalopathy, and ultimately stillbirth. Fetal hypoxia represents 23% of neonatal deaths worldwide.

Aim: To predict perinatal hypoxia using quantitative ultrasound from the placenta (QUS-P) between 35 weeks gestation and delivery.

Methods: Raw radio frequency data is collected during ultrasounds between 35 and 37 weeks gestation using ClariusTM (handheld ultrasound). All scans take place at BC Women's Hospital. QUS-P parameters are derived from the raw radio frequency data and analyzed using linear regression.

Impact: The ability to identify perinatal hypoxia as early as 35 weeks gestation will allow for additional monitoring as well as efforts to prepare for immediate intervention if necessary (e.g. c-section, resuscitation, neonatal cooling), prevent progression to encephalopathy, and ultimately stillbirth.

Inclusion Criteria:

1. Pregnant with singleton
2. Age 19 years or older
3. Provision of informed consent
4. Planning to deliver at BC Women's Hospital
5. 38 weeks gestation or less

Exclusion Criteria:

1. Pregnant with multiples
2. Not planning to deliver at BC Women's Hospital
3. Less than 19 years of age
4. Greater than 38 weeks gestation

Potential participants are recruited from the following sources:

1. South Community Birth Program
2. Maternal Fetal Medicine Clinics at BC Women's Hospital (EMMA and Fetal Monitoring)