You can still renew your F1 visa if you want to continue your study. It is the same procedure as before. Nothing will change no matter whether you have babies or not.

If you want to stop your study now, you have to leave USA right away since it will be illegal if you are not a full time student any more. Or you could register for zero credit to keep your as a full time student. I know some schools have this policy for PhD student. Check with OIA or your department.