How is IVF treatment used to suspend normal hormone secretion and induce superovulation for pregnancy?

SouravNovember 9, 2024

Answer

In vitro fertilization (IVF) treatment involves a series of hormonal manipulations to suspend normal hormone secretion and induce superovulation, which is crucial for increasing the chances of successful pregnancy. Here’s how this process works:

Suspension of Normal Hormone Secretion

1. Use of GnRH Agonists:
   • Gonadotropin-releasing hormone (GnRH) agonists are commonly used in IVF protocols to suppress the natural menstrual cycle. By administering these agents, the secretion of luteinizing hormone (LH) and follicle-stimulating hormone (FSH) from the pituitary gland is inhibited. This suppression prevents premature ovulation and allows for better control over ovarian stimulation later in the cycle.
2. Downregulation of the Hypothalamus-Pituitary-Ovarian Axis:
   • The administration of GnRH agonists leads to a state known as “downregulation,” where the ovaries are quiet, and endogenous hormone production is minimized. This allows for a more predictable response to subsequent fertility medications. The downregulation typically takes about two weeks and is followed by a controlled ovarian stimulation phase.

Induction of Superovulation

1. Controlled Ovarian Stimulation:
   • After achieving adequate suppression, fertility hormones, primarily FSH (and sometimes LH), are administered to stimulate the ovaries to produce multiple follicles. This process is known as controlled ovarian stimulation or superovulation . The goal is to increase the number of mature eggs available for retrieval, enhancing the chances of fertilization.
2. Monitoring Follicular Development:
   • Throughout this stimulation phase, patients undergo regular monitoring via transvaginal ultrasound and blood tests to assess follicular growth and estradiol levels. Adjustments to medication dosages may be made based on these assessments to optimize follicle maturation.
3. Triggering Ovulation:
   • Once several follicles reach an appropriate size (usually around 18 mm), a trigger injection of human chorionic gonadotropin (hCG) is administered. This injection mimics the natural LH surge that induces final oocyte maturation and prepares them for retrieval