What is the purpose of luteal phase support in IVF cycles?

• A. To support implantation and early pregnancy
• B. To stimulate more follicles
• C. To suppress the immune system
• D. To prevent fertilization

Answer: (A)

Luteal phase support provides progesterone to maintain the endometrium after embryo transfer, creating a receptive secretory lining that can accept and sustain an early pregnancy. In IVF cycles, ovarian stimulation and certain medications can impair natural luteal function, so adding progesterone helps keep the endometrium supportive during the critical early weeks until the placenta can produce enough progesterone on its own. This direct support of implantation and early pregnancy explains why the primary purpose is to aid early pregnancy establishment.

Stimulation of more follicles is part of the ovarian stimulation phase, not luteal support. Suppressing the immune system is not the main goal of luteal support, and preventing fertilization would misalign with its purpose since the aim is to support a pregnancy after fertilization has occurred.