1. Why is luteal support necessary?

In a natural pregnancy, the corpus luteum formed in the ovary after ovulation secretes progesterone, which helps to prepare the endometrium for implantation. This also helps to keep the uterus calm and prevents excessive contractions. In assisted reproductive cycles, this process is disrupted: Ovulation-stimulating drugs inhibit pituitary function, and egg retrieval procedures extract follicular fluid containing granulosa cells. As a result, the function of the corpus luteum is significantly weakened, and the progesterone it produces often isn't sufficient to support embryo implantation and early development.

The role of luteal support is to fill this gap-by providing exogenous progesterone, it maintains the receptive state of the endometrium, stabilizes the uterine environment, and provides the necessary hormonal support for embryo implantation and early pregnancy. In simple terms, it acts as a "transition period shelter" for the newly implanted embryo. It is gradually removed once the placenta is developed and can secrete hormones on its own.

Currently, there are three common methods of administering luteal support in clinical practice. Each method has different absorption rates, resulting in varying experiences and tolerances:

Intramuscular injection is the most traditional method. The advantage is that it provides stable blood levels and accurate absorption. However, it requires daily injections at the clinic or at home. There may be hard lumps or pain at the injection site, and long-term use may be challenging for some people.

These are absorbed directly through the vaginal mucosa. The drug concentration in the uterus is higher, so side effects are relatively less. Patients can use them at home, which is more convenient. However, there may be issues like increased discharge and local discomfort. Some products require regular cleaning to remove residues.

They are convenient and non-invasive, but they undergo hepatic metabolism, so the amount that actually enters the bloodstream is limited. Therefore, they are usually used as an adjunct to other treatments rather than as the sole source of support throughout the cycle. Some people may experience drowsiness or dizziness after taking these medications.

The blood levels of different formulations vary. Doctors will choose the appropriate method based on your specific needs.

The choice of treatment plan, previous responses, availability and tolerance of the injection, etc., should be considered, or combined when necessary. There is no absolute "better" option between different dosage forms; only the "most suitable" one.

III. Complete Timeline: From Egg Retrieval to Discontinuation of Treatment

Starting Point: Medication usually begins on the day of egg retrieval, or a few days before transplantation. In cases involving frozen embryo transfer, the starting point of medication depends on the endometrial preparation method (natural cycle, artificial cycle), with artificial cycles often requiring earlier initiation.

First Phase – Until Positive Pregnancy Test: Medication continues uninterrupted. The goal during this phase is to maintain progesterone levels within the range required for optimal endometrial function. Any missed doses could lead to fluctuations in hormone levels.

Second Phase – After Positive Pregnancy Test: Continue with the original treatment plan. This is a point that is often misunderstood-many people think that once pregnancy is confirmed, the treatment can be stopped. In reality, the early stages of pregnancy are when progesterone support becomes even more critical.

Third Phase – Gradual Reduction of Dosage at 8–10 Weeks of Gestation: As the placenta develops and takes over hormone secretion, the need for external progesterone supplementation decreases. Doctors will adjust the dosage gradually until the treatment is completely discontinued. Most treatment plans have a window of 8–10 weeks for discontinuation, but the exact timing varies from person to person: the type of treatment plan, progesterone levels, whether there are multiple pregnancies, and any history of miscarriages can all affect this decision.

IV. Why It Is Absolutely Not Safe to Discontinue Treatment On Your Own

This is the most important point that needs to be emphasized in this article:The authority to adjust progesterone support lies with the doctor, not with the patient's feelings.

Risks: Suddenly stopping external progesterone supplementation can cause a significant drop in progesterone levels. During the 6–9 week period, the placenta has not yet fully developed the ability to secrete hormones independently, so the embryo still relies heavily on external hormones.

The correct way to reduce the dosage: Follow the doctor's instructions and reduce the dosage step by step – first decrease the dose, then extend the interval between injections, and finally stop using the medication altogether. Take breaks between each step to allow for observation, and have regular blood tests conducted as necessary. This process should be done gradually, rather than abruptly.

A common misconception: Some people want to stop using the medication early due to severe pain at the injection site, inconvenience during travel, or concerns about cost. Others reduce the dosage out of concern that too much hormone use might be harmful. Both of these approaches should be discussed with the doctor first. In cases where pain is an issue, it's possible to adjust the dosage or change the injection site. For those who worry about excessive hormone use, it's important to understand that exogenous progesterone is essential for maintaining pregnancy, not something that can be omitted.

V. Common side effects and corresponding treatments

Hardening and pain at the injection site
This is one of the most common problems with long-term injections. Treatment: Apply a warm towel to the affected area after injection (be careful not to use too hot a temperature, and avoid applying heat to the abdomen). Also, rotate the injection sites to prevent repeated injections in the same area. If there is significant redness, swelling, or pain, seek medical attention immediately to rule out infection.

Increased vaginal discharge
This is a normal phenomenon when the drug carrier dissolves. Most cases require no special treatment. It's recommended to use sanitary pads and keep the area clean and dry. Clean up any remaining residue as directed by your doctor. If there is itching, abnormal odor, or burning sensation, report this to your doctor to check for infection.

Sleepiness and dizziness from oral medications
You can adjust the time of taking the medication to bedtime, which can help reduce daytime fatigue and improve sleep quality. If these symptoms significantly affect daily activities, inform your doctor and discuss whether changing the dosage would be necessary.

Other signs that require attention
If you experience severe abdominal pain, increased vaginal bleeding (close to or exceeding menstrual flow), persistent fever, or widespread redness and swelling at the injection site, contact your doctor immediately. Do not try to diagnose or adjust the medication on your own.

6. Several Practical Tips

1. **Keep track of medication usage:** Record the time of day, type of medication, and dosage in a mobile phone note or medication card. This allows for easy reference during follow-up visits, preventing discrepancies due to memory errors.
2. **Establish regular times and procedures:** Set alarms and associate injections or medication with routine activities like washing up in the morning and evening. This helps reduce missed doses. When traveling, ensure sufficient medications and cold storage conditions are available (some medications require refrigeration).
3. **Avoid comparing with others:** The duration and dosage of progesterone support are determined based on individual hormone levels and treatment plans. Differences in timing between people-such as stopping medication at 9 weeks vs. 10 weeks-are normal and do not indicate one plan is "better" than another.
4. **Ask questions about stopping medication:** Discuss with your doctor ahead of time-ask about how long the medication will be used, how dosage reductions will be managed, and which indicators need to be checked during treatment. Knowing the process in advance is much safer than panicking when the deadline approaches.

Progesterone support is the longest and most patient-demanding phase of assisted reproduction cycles. It doesn't require special skills; it simply requires adherence to schedule, dosage, and medical advice. This "invisible perseverance" is crucial for ensuring a successful pregnancy.

For families taking this treatment, there are three key things to keep in mind:

Don't miss any doses, don't stop prematurely, and report any abnormalities promptly. The rest should be left to the doctor's judgment. Lelaiva always reminds patients that if anything changes during treatment and causes hesitation, they should consult a doctor first before making any decisions.