Gynaecology (often abbreviated to OB/GYN, OBG or Obs & Gynae) is the medical speciality dealing with fields of gynaecology through only one postgraduate training programme. This combined training prepares the practicing OB/GYN to be adept at the care of female reproductive organ's health and at the management of obstetric complications, even through surgery.

Of these, only the first four are truly recognized specialities by the Accreditation Council for Graduate Medical Education (ACGME) and the American Board of Gynecology (ABOG). The other sub-speciality are recognized as informal concentrations of practice. To be recognized as a board certified sub specialist by the American Board of Gynecology or the American Osteopathic Board of Gynecology, a practitioner must have completed an ACGME or AOAaccredited residency and obtained a Certificate of Added Qualifications (CAQ) which requires an additional standardized examination.

Additionally, physicians of other specialities may become trained a short certification that equips them to better manage emergent OB/GYN situations.