An observational cohort study to assess the clinical utility of the OxNNet Toolkit for the prediction of adverse pregnancy outcomes.

The First PLUS study is a single centre, prospective, observational study recruiting 4000 women from The Harris Birthright Centre, which provides ultrasound scanning for all women who would attend King's College Hospital NHS Foundation Trust for their pregnancy care.

This study aims to develop a tool to provide reliable measurements of placental size and estimate the blood flow within the placenta during the first trimester of pregnancy. These metrics hope to develop a screening tool for fetal growth restriction (FGR), which is a condition in which a baby fails to grow to its full potential and can cause adverse pregnancy outcomes and is the single most common cause of stillbirth. This devastating outcome could potentially be reduced by stratifying pregnancies into high risk, allowing women to undergo additional monitoring and limiting clinician resource to those in need of it most. Stillbirth is also a serious adverse pregnancy outcome that NHS England is looking to reduce the rate of as part of their long-term plan.

Women 18 years of age or older, attending their first trimester scan during 11-14 weeks of pregnancy, who has a viable pregnancy with no more than one baby with no major defects identified during the scan will be eligible to take part.

The study will take place over 24 months and participants will undergo a single study visit in which their demographics and routine medical history will be recorded, an additional research ultrasound scan will be conducted alongside their routine scan, and blood from a sample taken as part of routine care will be used to assess the level of Placental Growth Factor (PlGF). Participants will then be followed up until the completion of their pregnancy via their pregnancy records (remote follow up) and the outcome of their pregnancy will be recorded.

Inclusion Criteria:

• Pregnant
• 18 years of age, or older
• Presenting for first-trimester combined test screening between 11+0 and 13+6 weeks of pregnancy
• Participant is willing and able to give informed consent for participation in the investigation.
• Able to understand written or verbal English and able to access methods of translation.
• In the opinion of the investigator, the participant is not at risk or under stress or limited in their ability to participate in the study activities.

Exclusion Criteria:

• Participant with a multiple pregnancy (more than one viable fetus) discovered at the scan
• Participant with a non-viable pregnancy discovered at the scan (no detectable heartbeat)
• Pregnancies with major defects identified during 11+0 to13+6 week scan
• Any pregnancy subsequently found to be chromosomally abnormal as a result of either prenatal or postnatal testing

Pregnant women attending the Fetal Medicine Foundation for their first-trimester screening scan