For many families who are encountering assisted reproduction for the first time, the term "in vitro fertilization" implies a series of uncertain and unpredictable steps: how many times do they need to visit the hospital, how many days they need to stay at each stage, what indicators are crucial, and why others' progress may differ from their own.

In fact, a complete cycle of in vitro fertilization treatment isn't simply a "one-month process." It consists of six clearly defined stages. By breaking down each step's tasks, duration, and key indicators, you can better understand the process and reduce your anxiety.

Stage 1: Pre-treatment Examination (about 1–2 weeks)

Key task: Obtaining the "permission to enter the treatment phase"

This is a comprehensive medical examination before starting the actual treatment. The purpose is to identify any contraindications, assess fertility potential, and determine whether the patient's physical condition is suitable for the stimulation cycle.

- **Female examination:** Levels of sex hormones on Day 2–4 of menstruation, AMH, thyroid function, number of antral follicles, as well as tests for infectious diseases, blood tests, coagulation status, liver and kidney function, and hysteroscopy/ultrasound assessments of the uterine cavity. Some tests must be done outside of menstruation. - - **Male examination:** Routine semen analysis and morphological analysis, along with infectious disease screening. It's recommended to abstain from sexual activity for 3–7 days before testing to ensure accurate results. - - **Significance:** The results of this step determine whether the patient is eligible for the treatment and which treatment plan is appropriate. These results serve as the basis for all subsequent treatments and are not merely formalities.

Stage 2: Treatment Plan Development and Downregulation Phase (0–14 days)

Key task: Developing a treatment plan to facilitate synchronized follicle growth

After obtaining all the examination reports, the doctor will develop a treatment plan based on the patient's age, AMH level, number of antral follicles, weight, and any previous medical conditions. Common treatment plans include the long-term protocol, antagonist therapy, micro-stimulation protocol, and natural cycle protocol. - - Treatments like the long-term protocol or extended protocol require downregulation first: This involves using medications to suppress pituitary function, ensuring that all follicles start on equal footing. This prevents dominant follicles from being released prematurely, allowing them to develop synchronously during the stimulation cycle. The duration of downregulation typically ranges from 14 days.

- For methods like antagonists or micro-stimulation, there's no need for downregulation. Patients can directly proceed with ovulation induction after menstruation begins.

- Important note: There's no such thing as "good" or "bad" methods. The choice of approach depends on individual circumstances. Younger patients with sufficient reserve compared to older patients with low reserve levels require different treatment approaches.

Stage Three: Ovulation Induction and Monitoring (8–12 days)

Key task: Promote the growth of follicles and monitor their development in real time.

This is the stage where patients are most frequently required to visit the hospital for injections. It also involves the most significant variations among individuals during the entire cycle.

- Daily procedures: Take ovulation-inducing drugs on time every day to promote the synchronized development of multiple follicles. The drug can be administered via subcutaneous or intramuscular injection. Some medications can be self-injected at home under medical supervision.

- Monitoring frequency: In the early stages of ovulation induction, follow-up visits should occur every 2–3 days. As the follicles approach maturity, the frequency increases to once or twice a day. During each visit, vaginal ultrasound and blood tests for estradiol (E2) and luteinizing hormone (LH) are performed.

- What doctors check: Ultrasound determines the number, size, and uniformity of follicles. Blood tests assess hormone levels and follicle development. Doctors adjust the dosage based on the results, ensuring that follicles don't grow too slowly, while also preventing ovarian hyperstimulation.

- Note: During this stage, don't compare your follicle count with others. Everyone has different baseline reserves. It's more important to have well-developed follicles with good quality than having a large number of follicles.

Stage Four: Night Injection and Egg Retrieval (approximately 2 days)

Key task: Capture mature eggs at the right moment.

When monitoring shows that enough dominant follicles have reached a diameter of 18–20 mm and hormone levels are within acceptable ranges, doctors will administer a "night injection" – a human chorionic gonadotropin (HCG) or similar medication – to trigger the final maturation of the eggs.

- The timing of the night injection is precise to the minute. It is usually administered at night, hence the name "night injection". 34–36 hours after the injection, egg retrieval surgery is performed. Any significant deviation in timing can affect the success rate of egg retrieval.

- Egg retrieval surgery: Generally conducted under general anesthesia, and completely painless. The entire procedure takes only 10–20 minutes. After the surgery, patients rest for 1–2 hours in the hospital before being allowed to leave once they are fine.

- Common misconceptions: More eggs do not necessarily mean better results. The number of eggs retrieved is related to ovarian response. Excessive focus on quantity can increase the risk of ovarian hyperstimulation syndrome (OHSS).

Stage Five: Fertilization and Embryo Culture (3–6 days)

Key task: Combine eggs with sperm, and cultivate the embryos in vitro.

On the day of egg retrieval, men also undergo sperm extraction. The embryology laboratory will determine whether conventional IVF or ICSI (intracytoplasmic sperm injection) should be used for fertilization. After fertilization, the embryos are placed in incubators for further culture.

- Day 2 (D2)/Day 3 (D3): Observe the fertilization process and the development of embryonic cells. Record the number of embryonic cells and their grading.

- Days 5–6 (D5/D6): The embryos develop to the blastocyst stage. Blastocyst culture involves a "natural selection" process; embryos that develop into blastocysts usually have better developmental potential.

- If PGT (Preimplantation Genetic Testing) is chosen, trophoblast cell biopsies will be performed during the blastocyst stage. Afterward, the embryos will be frozen until the test results are available, at which point transplantation can be scheduled.

- Important note: Not all fertilized eggs will develop into blastocysts. Elimination of some embryos is normal. A decrease in the number of embryos does not mean failure.

Stage Six: Transplantation and Pregnancy Testing (About2–4 weeks)

Key task: Place the embryos back into the uterus and wait for implantation to announce the pregnancy result.

There are two types of transplantation: fresh embryo transfer and frozen embryo transfer. The specific method is determined by the doctor based on the patient's physical condition after egg retrieval, endometrial conditions, and any necessary screenings.

- Endometrial preparation: Before transplantation, the endometrium is thickened and shaped through natural or artificial cycles (hormonal replacement therapy). It's typically required that the endometrial thickness be at least 7–8 mm.

- Transplantation procedure: The procedure is similar to a gynecological examination. It's non-invasive and causes minimal pain. The entire process takes about 5–10 minutes. After the surgery, there's no need to stay in bed for a long time; normal activities can continue.

- Luteal support: After transplantation, progesterone medications are used to support the endometrium and create conditions for embryo implantation. It's important not to stop taking these medications without consulting a doctor.

- Pregnancy test timing: On days 9–14 after transplantation, blood tests are conducted to measure HCG levels. These results serve as the official standard for determining pregnancy. It's not recommended to use early pregnancy tests too early, as fluctuations in hormone levels could cause unnecessary emotional distress.

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Final words

The above describes the timeline and steps involved in a standard cycle. However, achieving success "as planned" is a matter of luck, not a standard requirement.

Assisted reproduction is highly individualized: Some people require multiple cycles of treatment due to thin endometrium, others need more injections because their follicles grow slowly. Some may need to freeze embryos after egg retrieval... Any adjustments made by doctors based on your physical response represent the best possible decision. This doesn't mean there's something wrong.

For families planning to conceive, understanding the process isn't about setting strict deadlines. Instead, it's about being prepared and feeling more relaxed at each step along the way.

If you're unsure about any stage of this process, feel free to contact us for guidance on what to expect next. Leilawa believes that those who can see the whole picture will find it easier to complete the journey.