Question

The corpus luteum is maintained for the first 10 weeks of pregnancy by a. hCG. b. \(\mathrm{LH}\). c. estrogen. d. progesterone.

Short answer

The hormone responsible for maintaining the corpus luteum during the first 10 weeks of pregnancy is hCG. It helps prevent the degeneration of the corpus luteum, allowing it to continue producing progesterone to support the endometrial lining. Hence, the correct answer is a. hCG.

Step-by-step solution

We need to analyze the functions of the given hormones for determining their role in the maintenance of the corpus luteum during pregnancy. a. hCG (human chorionic gonadotropin): It is produced by the developing embryo and then by the placenta. It plays a critical role in maintaining the corpus luteum and preventing its degeneration during early pregnancy. b. LH (luteinizing hormone): It is released by the anterior pituitary gland and plays a significant role in stimulating ovulation in non-pregnant women. However, its role diminishes once the woman becomes pregnant, and hCG takes over its functions for maintaining the corpus luteum. c. Estrogen: It is a primary female sex hormone and is involved in the menstrual cycle, but it does not have a direct role in maintaining the corpus luteum during pregnancy. d. Progesterone: It is a hormone secreted by the corpus luteum, which helps maintain the endometrial lining necessary for early pregnancy. However, it is not responsible for the preservation of the corpus luteum itself. #Step 2: Select the correct option#

After analyzing the roles of the given hormones, the hormone responsible for maintaining the corpus luteum during the first 10 weeks of pregnancy is hCG. The hCG hormone helps to prevent the degeneration of the corpus luteum, which in turn continues to produce progesterone to support the endometrial lining. So, the correct answer is: a. hCG.

Key concepts

Human Chorionic Gonadotropin (hCG)

Human Chorionic Gonadotropin, commonly known as hCG, is a hormone pivotal to the sustaining of a pregnancy in its initial stages. Produced first by the cells around the developing embryo and later by the placenta, hCG sends signals to the corpus luteum to continue the production of progesterone.

This process is vital because progesterone maintains the uterine lining (endometrium), providing a supportive environment for the embryo. Without hCG, the corpus luteum would degenerate, leading to a drop in progesterone and possibly a miscarriage. Importantly, the role of hCG in mimicking luteinizing hormone allows the corpus luteum to stay active beyond its usual lifespan in the absence of pregnancy, which is typically just two weeks.

Luteinizing Hormone (LH)

Luteinizing hormone, better known as LH, is an essential player in the female menstrual cycle. It is secreted by the anterior pituitary gland and triggers ovulation — the release of an egg from the ovary. Besides prompting ovulation, LH is also responsible for the creation of the corpus luteum from the remnants of the follicle that released the egg.

In non-pregnant women, the secretion of LH is critical for the functioning of the corpus luteum. However, once a woman conceives, hCG largely assumes the role of LH, maintaining the corpus luteum's progesterone production necessary for the pregnancy's initial stages. This take-over allows the pregnancy to continue smoothly, as the woman's body transitions from relying on LH to relying on hCG.

Female Reproductive Endocrinology

Female reproductive endocrinology is a field focusing on the hormones and their functions within the female reproductive system. This includes the study of hormones such as estrogen, progesterone, follicle-stimulating hormone (FSH), and LH, which orchestrate the menstrual cycle, as well as hCG, which comes into play during pregnancy.

Understanding these hormones' interactions is fundamental to appreciating how women's bodies prepare for potential pregnancy monthly and adapt when pregnancy occurs. It is the delicate balance between these hormones that regulate ovulation, prepare the uterine lining, support implantation, and sustain a pregnancy.

Pregnancy Hormones

Pregnancy is a complex time of change within a woman's body, supervised by an intricate interplay of hormones. These hormones, including hCG, progesterone, estrogen, oxytocin, and prolactin, play various critical roles from conception to delivery.

Progesterone maintains the uterine lining and decreases uterine contractions to prevent early labor. Estrogen helps the uterus grow, maintains the uterine lining, and stimulates breast tissue growth. Oxytocin is known for its role during labor to induce contractions. Prolactin prepares the breasts for milk production. Together, these hormones ensure the health and development of the fetus–and prepare the mother's body to give birth and nurse her child.