What are the functions of the corpus luteum (corpus luteum)?

From the Guidelines

The corpus luteum is a temporary endocrine structure that forms in the ovary after ovulation and serves several critical reproductive functions, primarily producing progesterone to prepare and maintain the uterine lining for potential pregnancy, as supported by the most recent study 1. The corpus luteum plays a vital role in the menstrual cycle and early pregnancy maintenance. Its primary function is to produce progesterone, which helps prepare the uterine lining for a potential pregnancy. Additionally, it secretes estrogen, relaxin, and inhibin, which work together to support early pregnancy if fertilization occurs. Some key points about the corpus luteum include:

• It forms in the ovary after ovulation and is essential for preparing the uterine lining for a potential pregnancy.
• It produces progesterone, which helps maintain the uterine lining during early pregnancy.
• If pregnancy occurs, the corpus luteum continues to function until the placenta develops enough to take over hormone production, around 8-12 weeks.
• If pregnancy does not occur, the corpus luteum degenerates after about 14 days, becoming the corpus albicans, which allows progesterone levels to drop and triggers menstruation.
• The corpus luteum can be distinguished from other ovarian structures, such as a tubal ring, by its hypoechoic appearance and the presence of a claw sign, which indicates an ovarian origin 1.
• The corpus luteum is typically characterized by a central cystic component with a smooth thickened wall, avascular internal echoes, and peripheral vascularity, as seen in ultrasound images 1.

From the Research

Functions of the Corpus Luteum

The corpus luteum has several key functions, including:

• Secreting the hormone progesterone, which is essential for maintaining pregnancy 2, 3, 4, 5
• Preparing the womb for pregnancy by producing progesterone 2
• Supporting pregnancy for the first 6-8 weeks until the placenta takes over 2, 4
• Regressing if pregnancy does not occur, allowing for another menstrual cycle to begin 3, 4

Role in Pregnancy

The corpus luteum plays a crucial role in pregnancy, including:

• Providing an appropriate uterine environment for maintenance of pregnancy 3, 4
• Secreting progesterone and other substances like estradiol and relaxin to support pregnancy 4
• Being stimulated by human chorionic gonadotropin (hCG) secreted by the blastocyst and trophoblast cells until 8-9 weeks of gestation 4

Regulation and Maintenance

The corpus luteum is regulated and maintained by:

• Luteinizing hormone (LH) from the anterior pituitary 3
• Growth hormone, prolactin, and estradiol in some species 3
• Progesterone-induced signaling pathways that mediate luteal granulosa cell activity 6
• Vascular-Endothelial-Growth Factor (VEGF) which plays a major role in neo-angiogenesis and supply of LDL-Cholesterol for steroidogenesis 4

Consequences of Dysfunction

Dysfunction of the corpus luteum can lead to:

• Problems getting pregnant or staying pregnant 2
• Failure of implantation and embryonic wastage 5
• Recurrent or threatened miscarriage, although the evidence for corpus luteum dysfunction in these cases is limited 2