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Difficulty: MediumReproductive Endocrinology and Infertility

A 32-year-old woman with a history of severe pelvic inflammatory disease and bilateral tubal occlusion is preparing to undergo in vitro fertilization (IVF). She and her partner are reviewing the upcoming treatment protocol with their reproductive endocrinologist. Arrange the following steps of a standard IVF cycle in the correct chronological order from first to last.

  1. 1Controlled ovarian hyperstimulation with exogenous gonadotropins
  2. 2Administration of a human chorionic gonadotropin (hCG) or GnRH agonist trigger
  3. 3Transvaginal ultrasound-guided oocyte retrieval
  4. 4In vitro fertilization of oocytes with prepared sperm
  5. 5Transcervical embryo transfer into the uterine cavity

Answer

The correct chronological sequence for an in vitro fertilization cycle is: 1) Controlled ovarian hyperstimulation, 2) Administration of hCG or GnRH agonist trigger, 3) Transvaginal oocyte retrieval, 4) In vitro fertilization of oocytes, and 5) Embryo transfer.
In vitro fertilization (IVF) requires a precise, physiologically timed sequence of interventions. First, exogenous gonadotropins (FSH/LH) stimulate the simultaneous growth of multiple follicles (controlled ovarian hyperstimulation). Once ultrasound monitoring confirms adequate follicular size, a trigger shot (hCG or GnRH agonist) is administered to mimic the mid-cycle LH surge, causing final oocyte maturation. Approximately 34 to 36 hours later—just prior to spontaneous ovulation—the mature oocytes are harvested via transvaginal ultrasound-guided aspiration. The retrieved oocytes are then immediately fertilized in the laboratory with processed sperm. Finally, after 3 to 5 days of laboratory culture (at the cleavage or blastocyst stage), the resulting embryo is transferred into the uterine cavity.

Step-by-Step Solution

1
Administer exogenous gonadotropins
Multiple ovarian follicles develop
To override natural single-follicle dominance and maximize the oocyte yield for the cycle.
2
Administer hCG or GnRH agonist
Final oocyte maturation
To mimic the physiological LH surge, which completes the first meiotic division of the oocytes and loosens them from the follicle wall.
3
Perform transvaginal oocyte retrieval
Oocytes are extracted from the ovaries
To systematically collect the eggs precisely before they are spontaneously ovulated and lost in the pelvic cavity.
4
Combine oocytes and sperm in vitro
Zygote formation
To facilitate fertilization outside the body, bypassing the patient's occluded fallopian tubes.
5
Perform embryo transfer
Embryo is placed in the uterus
To allow for proper embryo implantation and the establishment of a clinical pregnancy.

Key Concept

The standard sequence of in vitro fertilization (IVF) involves ovarian hyperstimulation, a final maturation trigger, oocyte retrieval, in vitro fertilization, and embryo transfer.

Alternative Method

While standard IVF involves conventional insemination of the oocyte in a petri dish, patients with severe male factor infertility would have Intracytoplasmic Sperm Injection (ICSI) performed during the fertilization step. The chronologic sequence of the cycle remains identical.
Estimated Time:1m 0s
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Topics

Reproductive Endocrinology and Infertility

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