Luteal phase support is typically continued through which stage?

• A. The first trimester
• B. Only until a pregnancy test
• C. Throughout pregnancy
• D. Not used after embryo transfer

Answer: (A)

Luteal phase support provides progesterone to keep the endometrium receptive and to support early pregnancy, especially after embryo transfer in assisted reproduction where corpus luteum function can be suboptimal. This support is typically continued through the first trimester because placental progesterone production takes over as pregnancy progresses, generally by the end of the first trimester. Once the placenta is reliably producing progesterone, exogenous luteal support is no longer required. Stopping at a pregnancy test is usually too early, and continuing throughout the entire pregnancy is not standard unless there are specific indications. Luteal support is indeed used after embryo transfer, so that option isn’t correct. Therefore, the usual practice is to continue through the first trimester.