The Importance of Monitoring during the Stimulation Phase

Your cycle preparation is followed by the stimulation phase. Your medical team needs to closely monitor your response to the medication administered during this phase and make adjustments if necessary, sometimes on a daily basis. Therefore, you should expect to have regular monitoring appointments during this phase. Monitoring refers to appointments during a fertility treatment cycle to check your hormone levels along with follicular and uterine lining development.

When does monitoring happen?

Monitoring appointments are frequent and normally begin on one of the first few days of your cycle and continue every 1 to 3 days until trigger shot. As you progress through your stimulation phase, your monitoring appointments become more frequent to keep a close eye on your body’s response to medication and to determine the optimal timing of the treatment.

What does monitoring involve?

During a monitoring appointment, you will undergo blood work and transvaginal ultrasounds. The bloodwork typically includes checking Estradiol, Progesterone, and LH levels. In some cases, your doctor may need to measure other hormones as well. During the ultrasound, the following factors are assessed:

Follicle count and size. Follicles are fluid-filled sacs that contain and protect the egg. The follicle count and size helps determine how well you are responding to the stimulation drugs. Keep in mind that ultrasounds are not always 100% accurate, and not every follicle has a mature egg. You will know the exact number of eggs only after the egg retrieval. As you continue taking fertility drugs, the follicles will grow larger. Doctors tend to retrieve eggs when most follicles are between 18 and 20 mm in size, though this can vary.

Uterine lining. The lining of a woman’s uterus, also called the endometrium, is where a developing embryo implants in the first few days of pregnancy. As the lining quality can affect the success of implantation, the thickness and shape of the uterine lining are also closely monitored during the ultrasound appointments.

After running your tests, your lab values and ultrasound results will be examined to determine if your follicles and uterine lining are developing properly. You will then receive information about the results and whether or not any adjustments to your medications are required.

The stimulation and monitoring phase can last anywhere from a few days to two weeks, and it ends when your lab results indicate prime timing for your trigger shot and subsequent egg retrieval.

Acknowledgement: a big thanks to Stefan Halisky for proofreading.