Question

Which sequence of gonadotropin preparations is used to induce ovulation? (A) choriogonadotropin alfa then lutropin alfa (B) follitropin alfa then lutropin alfa (C) choriogonadotropin alfa then follitropin beta (D) chorionic gonadotropin (hCG) then lutropin alfa (E) follitropin alfa then follitropin beta

Short answer

(B) follitropin alfa then lutropin alfa.

Step-by-step solution

Understanding Gonadotropin Preparations

Gonadotropin preparations are hormones used to stimulate the development of follicles in the ovaries and induce ovulation in women. Key hormones involved are follitropin (FSH), lutropin (LH), and choriogonadotropin (hCG).

Identifying Preparation Function

FSH (follitropin alfa/beta) stimulates the growth of ovarian follicles. LH (lutropin alfa) promotes the maturation of the follicles and is usually followed by hCG, which acts like LH to trigger ovulation. Thus, ovulation induction typically begins with FSH, and once the follicles are adequately developed, an LH surge or hCG injection is given to induce the final maturation and ovulation.

Evaluating the Options

Review each choice with the roles and typical order of hormone administration: - (A) choriogonadotropin alfa then lutropin alfa isn't the usual sequence, as lutropin fosters maturation, not initiation. - (B) follitropin alfa then lutropin alfa where FSH stimulates follicle growth and LH supports maturation is appropriate for ovulation induction. - (C) choriogonadotropin alfa then follitropin beta is incorrect because hCG is used to induce ovulation, not to start. - (D) chorionic gonadotropin (hCG) then lutropin alfa is incorrectly ordered. - (E) follitropin alfa then follitropin beta isn't a logical sequence as both are forms of FSH.

Selecting the Correct Sequence

The correct sequence for inducing ovulation starts with FSH (such as follitropin alfa) for stimulating the initial growth and development of follicles, followed by LH (such as lutropin alfa) to encourage final maturation, positioning (B) as the correct answer.

Key concepts

Gonadotropin Preparations

Gonadotropin preparations are key hormones used in medical treatments to aid women in ovulating. These hormones are synthetic versions of the natural hormones involved in reproductive processes. The main types of gonadotropins include follitropin, lutropin, and choriogonadotropin. Each of these has its own role in stimulating and regulating the ovaries.

• Follitropin (FSH): This encourages the production and growth of mature ovarian follicles, essential for ovulation.
• Lutropin (LH): Primarily aids in the maturation of these follicles and works in sync with FSH.
• Choriogonadotropin (hCG): Mimics LH to trigger ovulation by stimulating the final development of the mature follicle and releasing the egg.

Each preparation is administered at a precise point in the treatment cycle to maximize the chances of successful ovulation and subsequent fertilization.

Follicle Stimulation

In the process of ovulation induction, follicle stimulation is a crucial step. This is primarily done using FSH, which stands for Follitropin Stimulating Hormone. FSH is responsible for stimulating the ovaries to produce and develop multiple follicles, increasing the likelihood of producing a mature egg ready for fertilization.

Follicles are tiny sacs found in the ovaries, each containing an immature egg. When treated with FSH, these sacs mature through a process called folliculogenesis.

Here's an overview of the process:

• FSH therapy begins at the start of a woman's cycle to initiate follicle growth.
• The goal is to produce several viable follicles, each potentially releasing an egg.
• Monitoring occurs through ultrasound and hormone level checks to ensure optimal growth.

This stimulated maturation is vital for the later stages of ovulation induction, where other hormones come into play to complete the process.

Hormone Administration

Hormone administration in ovulation induction is a carefully timed and controlled process. It's not just about injections but about orchestrating the body's natural reproductive hormones to increase the likelihood of pregnancy.

Timing and Sequence

• Initial Stages: Begin with FSH to stimulate follicle development. This often spans several days where the hormone is administered through injections.
• Maturation Phase: Once follicles reach a suitable size, LH or an hCG injection is administered. This acts as a trigger for ovulation, imitating the natural LH surge that induces ovulation.
• Monitoring: Ultrasound exams and hormone checks ensure follicles are responding well to treatment.

Proper hormone administration balances the need for follicle growth with the timing of ovulation, making it a core component of assisted reproductive techniques.

FSH and LH Roles

FSH (Follicle Stimulating Hormone) and LH (Luteinizing Hormone) are fundamental to the process of ovulation induction. Each plays distinct yet collaborative roles to ensure the body successfully releases a mature egg.

FSH's Role

• FSH stimulates the ovarian follicles, leading to their growth and development within the ovary.
• It prepares the follicles to respond to LH for maturation.

LH's Role

• Following FSH-induced growth, LH helps mature these follicles.
• It triggers the release of the egg from the most mature follicle during ovulation, known as the "LH surge."

Their roles are sequential and synchronized, with FSH being administered first, followed by LH or hCG, ensuring the follicles are ready for ovulation and potential fertilization. In assisted reproductive treatments, understanding the timing and roles of these hormones is critical for successful outcomes.