If you like your gynecologist, and he or she is also an obstetrician, stay put. Unless you object to the hospital where your doctor delivers, there's no reason not to stay with a doctor who knows you well for your pregnancy and delivery.
But if you need an obstetrician:
1. Seek recommendations from mothers and pregnant women. Or get the inside scoop -- call a local hospital where you'd like to deliver, ask to speak to a labor-and-delivery nurse, and ask that nurse for recommendations. For a general list of board-certified obstetricians in your area, you can call the American College of Obstetricians and Gynecologists at (202) 638-5577. And, of course, if you belong to an HMO, that company will have a list of ob-gyns they work with.
2. Visit ob-gyns in your area to learn about their policies, preferences, and specialties. Pick one whose views most closely parallel your own (especially if you want a drug-free birth). Or if you have hormonal issues, urinary tract disorders, or other special needs, seek a specialist with related training.
3. Consider your own preferences. If you want a close doctor-patient relationship, you might want a solo practice rather than a large group practice where you see different doctors. On the other hand, if you want to be sure that you can run in and see a doctor at any time, a group practice may be better. In a solo practice the lone docotor often has to leave to deliver other patients. Finally, if you want to deliver in a particular hospital, look for affiliated doctors.