Obstetrics (OB) and gynecology (GYN) are two distinct medical specialties that are almost always practiced together. The “OB” covers everything related to pregnancy: pre-conception planning, prenatal care, labor and delivery, and recovery after birth. The “GYN” covers all other aspects of reproductive health, from cancer screenings and menstrual problems to urinary tract issues and fertility testing. Most doctors train in both and practice as OB/GYNs, but some choose to focus on only one side.
What Obstetricians Do
An obstetrician manages the entire arc of pregnancy. That starts before conception for people planning a pregnancy and continues through prenatal visits, labor, delivery, and the postpartum period. Routine prenatal care includes monitoring fetal growth, screening for complications like preterm labor or gestational diabetes, and helping patients prepare for delivery.
When complications arise, obstetricians handle them directly. They perform cesarean deliveries, induce labor when a pregnancy goes past its due date, manage high-risk pregnancies, and treat conditions like preeclampsia or ectopic pregnancy. A physician who focuses exclusively on obstetrics does not treat health issues outside of pregnancy.
What Gynecologists Do
A gynecologist manages reproductive health across a person’s entire life, independent of pregnancy. The scope is broad: cervical cancer screenings (Pap tests and HPV tests), breast cancer screening referrals, testing for sexually transmitted infections, and evaluation of conditions like endometriosis, ovarian cysts, uterine fibroids, and polycystic ovary syndrome.
On the diagnostic side, gynecologists perform biopsies of the cervix or uterine lining, use transvaginal ultrasound to detect cysts or tumors in the reproductive organs, run hormonal blood tests to evaluate fertility or irregular bleeding, and use a magnifying instrument called a colposcope to inspect the cervix for signs of cancer. They also handle surgical procedures: removing ovarian cysts, performing hysterectomies, repairing pelvic organ prolapse, and performing tubal sterilization for permanent contraception.
A physician who focuses exclusively on gynecology does not deliver babies or treat pregnant patients. They do, however, cover a surprisingly wide range of general health concerns. Many gynecologists screen for HIV and hepatitis C, check for anemia in patients with heavy bleeding, evaluate urinary tract infections, and test for blood clotting disorders. For many women, a gynecologist functions as a de facto primary care provider during certain stages of life.
How OB/GYNs Combine Both Roles
The vast majority of physicians in this field practice as OB/GYNs, meaning they handle both pregnancy care and general reproductive health. This is why the same doctor who does your annual Pap test can also manage your prenatal care and deliver your baby. The combined training makes this possible: after completing medical school, OB/GYN residents spend 48 months (four years) in a residency program accredited by a national council, gaining hands-on experience in both obstetrics and gynecology before becoming board-eligible.
In practice, some OB/GYNs lean more heavily toward one side depending on their patient population, hospital setting, or personal preference. A doctor in a large urban practice might spend most of their week delivering babies, while one in a smaller clinic might focus primarily on gynecologic visits and refer high-risk pregnancies out.
Subspecialties Within OB/GYN
After completing their general residency, some OB/GYNs pursue additional fellowship training in one of four recognized subspecialties:
- Maternal-fetal medicine: focuses on high-risk pregnancies, using advanced fetal ultrasound and specialized procedures to manage complications that go beyond routine obstetric care.
- Gynecologic oncology: treats cancers of the reproductive system through surgery, chemotherapy, and palliative care.
- Reproductive endocrinology and infertility: addresses hormonal disorders and infertility using techniques like in vitro fertilization and specialized surgery.
- Female pelvic medicine and reconstructive surgery: treats disorders of the pelvic floor and urinary system, including prolapse repair and bladder function testing.
If your OB/GYN identifies a condition that falls into one of these areas, they’ll typically refer you to the appropriate subspecialist for more targeted care.
Which Type of Appointment Do You Need?
If you’re pregnant or planning to become pregnant, you need obstetric care. If you’re coming in for a cervical cancer screening, birth control, irregular periods, pelvic pain, or any reproductive health concern unrelated to pregnancy, that falls under gynecology. Since most providers practice both, you usually don’t have to choose. Booking with an OB/GYN covers you either way.
The distinction matters more in specific situations. If you’ve already gone through menopause and have no plans for pregnancy, a gynecology-only practice may suit you well. If you have a high-risk pregnancy, you may be referred to a maternal-fetal medicine specialist rather than staying with a general OB/GYN. And if you’re being seen for something like an ovarian mass or abnormal bleeding that could indicate cancer, your gynecologist may refer you to a gynecologic oncologist.
Current Screening Guidelines
One of the most common reasons people see a gynecologist is cervical cancer screening. Current guidelines recommend starting screening at age 21. For people aged 21 to 29, a Pap test every three years is the standard approach. Starting at age 30 through 65, there are three options: an HPV test alone every five years, a Pap test alone every three years, or both tests together every five years. Screening generally stops after age 65 for people with consistently normal results.
These screenings are a core part of gynecologic care and one reason regular visits matter even when you feel perfectly healthy. Your gynecologist or OB/GYN will also use these visits to screen for STIs if you’re at increased risk, discuss contraception, evaluate menstrual changes, and address any new symptoms.