Luteal support refers to the administration of medication, typically hormonal, to enhance the function of the corpus luteum or to supplement the hormones it produces during the luteal phase of the menstrual cycle. This practice is primarily utilized in the field of reproductive medicine, particularly within assisted reproductive technology (ART) procedures such as in vitro fertilization (IVF) and intracytoplasmic sperm injection (ICSI).
The primary objective of luteal support is to ensure that the endometrium (the lining of the uterus) is sufficiently prepared for embryo implantation and to maintain the early stages of pregnancy. In a natural menstrual cycle, the corpus luteum produces progesterone, which stabilizes the uterine lining. However, in stimulated cycles common in ART, the natural production of progesterone is often impaired or suppressed due to the medications used for controlled ovarian hyperstimulation or the aspiration of follicular cells during egg retrieval. This condition is frequently referred to as a luteal phase defect.
The most common pharmacological agent used for luteal support is progesterone. It is administered through various routes, including vaginal (gels, inserts, or suppositories), intramuscular injection, or oral tablets. The choice of administration typically depends on clinical protocols and patient tolerance. Another agent occasionally used is human chorionic gonadotropin (hCG), which acts by stimulating the corpus luteum to produce endogenous progesterone and estrogen. However, the use of hCG for luteal support is associated with an increased risk of ovarian hyperstimulation syndrome (OHSS), leading many practitioners to prefer direct progesterone supplementation.
Clinical guidelines and systematic reviews generally support the use of luteal support in IVF cycles to improve clinical pregnancy rates and live birth rates. The duration of support varies by clinical practice; it typically begins on or shortly after the day of oocyte retrieval or embryo transfer and may continue until a pregnancy test is confirmed or through the first trimester of pregnancy, by which time the placenta typically assumes the role of hormone production.