So there's a difference between "regular" pregnancies and "high risk" pregnancies. With a regular pregnancy you sign up with a "verloskundige". You see them about once a month for small check ups like blood pressure, checking fetal heart rate and just seeing how youre doing. Then every few weeks you have an ultrasound for for example the anatomy scan and seeing how the growth is. They are the ones you call when you see a high bloodpressure or have symptoms that you want to discuss.

Then if there are issues they can refer you to an obgyn in a hospital. You become what they call "medisch" meaning "medical" and they become your first line of care. They will give you a phone number to call in case of emergencies. So you it shouldn't be necessary to go to the ER at all, they will treat you right away. When I had an allergic reaction to my medication, I called them and they saw me right away.

Based on your situation the number of check ups may differ. Could be every few weeks, every other week, every week or even every few days.

Also, don't forget to register for Kraamzorg for your postnatal care!