What is luteal phase support in assisted reproductive technology (ART) and its purpose?

• A. Estrogen supplementation after embryo transfer
• B. Progesterone supplementation after embryo transfer to support endometrial receptivity and early pregnancy
• C. GnRH antagonist during follicular phase
• D. FSH stimulation for luteal phase

Answer: (B)

Luteal phase support involves giving progesterone after embryo transfer to keep the endometrium receptive and to protect an early pregnancy. In ART, the ovarian stimulation and use of GnRH analogs can impair the natural luteal function, so providing progesterone helps maintain a secretory endometrium and supports implantation and early placental support. Progesterone drives the endometrium to a receptive, decidual state and keeps the pregnancy progressing until the placenta can take over progesterone production. Estrogen after transfer isn’t the primary luteal support, and GnRH antagonists or FSH are used in other parts of the cycle (follicular phase) rather than to sustain the luteal phase.