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Hormonal Control of the Ovarian Cycle01:30

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The ovarian cycle is meticulously regulated by the hypothalamic-pituitary-gonadal axis. This cycle orchestrates the release of a mature oocyte, essential for reproduction.
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The ovarian cycle regulates endometrial changes throughout a single menstrual cycle via the coordinated action of gonadotrophin-releasing hormone (GnRH) and gonadotrophins.
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The menstrual cycle includes a critical component known as the ovarian cycle, which undergoes two main phases each month—the follicular phase and the luteal phase. The follicular phase is variable and averaging around 14 days. Ovulation, triggered by a surge in luteinizing hormone (LH), marks the transition between the two phases. The second phase, the luteal phase, is relatively consistent, lasting approximately 14 days, and is marked by the activity of the corpus luteum. While a cycle...
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Oogenesis02:07

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In human women, oogenesis produces one mature egg cell or ovum for every precursor cell that enters meiosis. This process differs in two unique ways from the equivalent procedure of spermatogenesis in males. First, meiotic divisions during oogenesis are asymmetric, meaning that a large oocyte (containing most of the cytoplasm) and minor polar body are produced as a result of meiosis I, and again following meiosis II. Since only oocytes will go on to form embryos if fertilized, this unequal...
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Folliculogenesis is the development of ovarian follicles, the specialized structures within the ovarian cortex where oogenesis, or egg development, occurs. This process is essential for female reproductive health and begins during fetal development when primordial follicles are formed. Each primordial follicle comprises a primary oocyte in the center, surrounded by a single layer of squamous pre-granulosa cells. These follicles remain dormant in late prophase I of meiosis until triggered by...
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The gonads, namely the testes in males and the ovaries in females, are pivotal in producing gonadal hormones that orchestrate the intricate processes of sexual development and reproduction.
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Fertility Preservation Through Oocyte Vitrification: Clinical and Laboratory Perspectives
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Ovarian stimulation with GnRH analogues.

Ivan S Montenegro1,2, Mariana Faller2, Isabel C A de Almeida2

  • 1Gynecology and Obstetrics Service of the Hospital de Clínicas de Porto Alegre, Assisted Reproductive Sector, Federal University of Rio Grande do Sul.

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|June 28, 2022
PubMed
Summary

This study found that both long agonist and flexible antagonist protocols are equally effective for assisted reproduction. The antagonist protocol offers faster stimulation initiation and easier medication use, while the agonist protocol has scheduling advantages but a longer lead time.

Keywords:
Assisted reproductive technologyaccessequitypublic health caresocial class

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Area of Science:

  • Reproductive Endocrinology
  • Assisted Reproductive Technologies

Background:

  • Ovarian stimulation protocols are crucial for assisted reproduction.
  • Gonadotropin-releasing hormone (GnRH) agonist and antagonist protocols are widely used.

Purpose of the Study:

  • To compare the efficacy and outcomes of long GnRH agonist versus flexible GnRH antagonist protocols in assisted reproduction techniques.
  • To analyze intermediate results including patient demographics and ovarian response parameters.

Main Methods:

  • A cross-sectional study involving 50 patients undergoing assisted reproduction.
  • Comparison of two ovarian stimulation protocols: long GnRH agonist and flexible GnRH antagonist.
  • Statistical analysis using Student's t-test and analysis of covariance.

Main Results:

  • No statistically significant differences were observed in body mass index, oocytes recovered, fertilized oocytes, cleaved oocytes, or FSH dose between the groups.
  • A statistically significant difference was found in the mean age of patients between the two groups (P = 0.031).
  • No cases of ovarian hyperstimulation syndrome were reported in either group.

Conclusions:

  • Both GnRH agonist and antagonist protocols demonstrate comparable results for assisted reproduction.
  • The antagonist protocol offers advantages in ease of use and faster stimulation start.
  • The agonist protocol, while offering scheduling benefits, has a longer lead time and potential risks like ovarian hyperstimulation syndrome.