While OB/GYN is considered one specialty, it comprises two distinct fields. Obstetrics (the OB) involves care during pre-conception, pregnancy, childbirth, and immediately after delivery. Gynecology (the GYN) involves care of all women’s health issues.
Obstetrics and gynaecology or obstetrics and gynecology is the medical specialty that encompasses the two subspecialties of obstetrics and gynecology. It is commonly abbreviated as OB-GYN or OB/GYN in US English and Canadian English, and as obs and gynae or O&G in British English.