Where I live, a gynecologist is treated as more of a specialist than someone you'd go to on a yearly basis as a regular course of your physical health.
Generally, you're referred to a gynecologist if you have a problem your family doctor cannot treat you for. Most family doctors in this area have some sort of training in the OB/GYN realm, and conduct all the necessary yearly pelvic exams, as well as providing pre and post natal care.
He, or she, will probably refer you to a gynecologist at least once during a normal pregnancy, but unless that gynecologist thinks that you need their care more, the bulk of your pregnancy health care will be done by the family doctor.
Here, you can't even book your own appointment with a specialist, it's all done on a referral basis by your primary care physician. Once you've seen that specialist, if you require their ongoing care, you can book your own appointments with them.
You can't even go to an eye specialist here without a referral by your family physician - that is, unless you're willing to forego the government provided health care funding, and pay for the entire appointment out of your own pocket.