From: https://kidshealth.org/en/parents/high-risk.html
A "high-risk" pregnancy means a woman has one or more things that raise her — or her baby's — chances for health problems or preterm (early) delivery.

A woman's pregnancy might be considered high risk if she:

• is age 17 or younger
• is age 35 or older
• was underweight or overweight before becoming pregnant
• is pregnant with twins, triplets, or other multiples
• has high blood pressure, diabetes, depression, or another health problem
• had problems with a previous pregnancy, including premature labor or having a child with a genetic problem or birth defect

Not to be confused with:

• impregnation_risk - For scenarios where impregnation is an imminent threat or risk of sexual contact.