There are many things that can make a pregnancy high risk. An underlying medical condition such as hypertension, diabetes, seizure disorder, and a blood clotting disorder are all examples of conditions that can make you high risk. Advanced maternal age is another high risk condition. Some pregnancies can become high risk even if they started low risk. Conditions such as gestational diabetes, preeclampsia, or persistent placenta previa are examples of conditions that arise mid pregnancy that can turn a low risk pregnancy high risk.
The term ‘high risk” is really just a label and is somewhat arbitrary. There are some things that almost everyone would consider high risk, others can depend on the individual doctor. Do not let the term high risk frighten you, most high risk pregnancies do just fine. The importance of knowing that you are high risk is mostly so you can choose who you will see for your pregnancy. It is important that the doctor has experience with high risk patients and the training to keep you safe. It is my opinion that women who are high risk should see people with the most training; this means an obstetrician. Family doctors and midwifes are great for low risk pregnancies, but I feel in a truly high risk situation an obstetrician will have the most training. High risk pregnant women often see a perinatologist or maternal fetal medicine specialist. This is a doctor that did 4 years of residency to become an obstetrician/gynecologist as well as additional training in a fellowship to learn about high risk pregnancies specifically. They will follow along with your obstetrician providing detailed ultrasounds as well as advice to your obstetrician.
Women with high risk pregnancies will usually be seen more often than their low risk counterparts. They may require increased monitoring for fetal well being as well as more frequent ultrasounds. All of this monitoring is designed to make your high risk pregnancy as low risk as possible.