OB-GYN is an acronym for obstetrics and gynecology. OB-GYN nurses provide nursing care related to all aspects of the female reproductive system, from the onset of menstruation to post-menopause. OB-GYN nurses include staff nurses in hospitals, clinics and birthing centers, nurse practitioners and certified nurse midwives. Each has a different scope of practice, and their duties differ in some ways.

Staff Nurse

An OB-GYN staff nurse is a registered nurse who provides direct care to women, and sometimes to infants. OB-GYN nurses may work in hospital labor and delivery and post-partum units, as well as at birthing centers and maternity or outpatient clinics. Their duties include admitting patients, taking medical histories and assisting physicians during procedures. They may administer medications, apply fetal monitoring devices or perform ultrasounds. They may also lead childbirth preparation classes or educate women individually about sexually transmitted diseases, birth control or prenatal care.

Nurse Practitioners

Nurse practitioners, or NPs, who specialize in OB-GYN may be independent practitioners in private practice, work with a doctor whose specialty is obstetrics and gynecology, or provide direct care. NPs are master's-prepared registered nurses who have a wider scope of practice than the average RN. As advanced practice nurses, OB-GYN NPs perform many duties that are essentially the same as those of a physician. They may diagnose pregnancy or reproductive problems, prescribe medications, perform procedures and order diagnostic tests. NPs in the field of obstetrics may perform prenatal care up to the point of delivery, and post-natal care after the delivery.

Certified Nurse Midwives

Certified nurse midwives, or CNMs, specialize in obstetrics and gynecology for women of all ages. Like NPs, CNMs are advanced-practice nurses with authority to diagnose and prescribe. A CNM can provide all of the care an NP provides as well as manage labor and deliver babies. They do not perform cesarean sections, however. In addition, CNMs perform pelvic exams, prescribe contraceptives and fit women for birth control devices such as IUDs. Certified nurse midwives often practice outside of a hospital and deliver babies at home or in birthing centers.

Specialty Certification

Any of the registered or advanced practice nurses who work in the field of OB-GYN may be certified in that specialty. For some employers, certification is a requirement, and in some states, certification is required for advanced practice nurses. Generally, two years of practice in a specialty and a bachelor’s degree are required before the nurse can take a certification exam. The nurses must complete continuing education courses relevant to the specialty of OB-GYN, or they must retake the exam every five years to maintain certification.