A couple with severe male-factor infertility due to oligozoospermia is preparing for their first treatment cycle using assisted reproductive technology. During the informed consent process, the reproductive endocrinologist details the timeline of the procedure to ensure the patients understand the clinical commitment required. Arrange the following clinical and laboratory steps of an in vitro fertilization (IVF) cycle in their correct chronological sequence, from the initiation of the treatment cycle to its completion.
- 1Controlled ovarian hyperstimulation using exogenous gonadotropins
- 2Administration of an hCG trigger shot for final maturation
- 3Transvaginal ultrasound-guided oocyte retrieval
- 4In vitro fertilization of oocytes via intracytoplasmic sperm injection (ICSI)
- 5Embryo transfer into the uterine cavity
Answer
The correct chronological sequence for an IVF cycle is: controlled ovarian hyperstimulation, followed by an hCG trigger shot, transvaginal oocyte retrieval, laboratory fertilization (ICSI), and finally embryo transfer.
An IVF cycle must closely follow the physiological requirements of oocyte development while optimizing for a higher yield. Multiple follicles are first stimulated with gonadotropins over several days. Final maturation is then induced by a trigger shot. The eggs must be retrieved surgically 34-36 hours later, before natural ovulation occurs. Once outside the body, they are immediately fertilized in vitro. Finally, after a short period of laboratory culture, the resulting embryo is placed back into the uterus.
Step-by-Step Solution
Key Concept
Chronological Sequence of In Vitro Fertilization (IVF) Procedures