Follicle Growth Series

The Follicle Growth Series evaluation is designed to follow the growth and maturation of an ovum (egg) in the ovary. When you’re born, there are thousands of eggs in both ovaries. Once you reach puberty, the reproductive system matures and starts to ripen and release an egg each cycle. A woman who ovulates normally will release approximately 400 eggs during her active reproductive years. Each egg lies within a small fluid filled sac called a follicle. This follicle is surrounded by cells that are capable of producing the female hormones estrogen and progesterone. When the ovary receives a signal from the pituitary gland in the brain, it will start the process of maturing an egg and finally releasing it on the surface of the ovary. This process can be observed by the use of ultrasound (sonography). Sound wave signals are sent out from the ultrasound probe and as they bounce off the pelvic organs, they return to the probe and an image of the pelvic organs is seen on a screen. Ultrasound has been safely used for many years in obstetrics and gynecology and is not known to be harmful.

The follicle or sac which houses the egg will enlarge and grow while the egg undergoes its maturing process. This “follicle growth” can be followed with ultrasound. When the egg is released (ovulation), the follicle will collapse, giving us evidence by ultrasound that ovulation has taken place. Problems that may result from a malfunction in the ovulation process can usually be identified so that proper therapy can be instituted as early as the next cycle.

It’s necessary to follow the growth of an egg for several days in order to complete the evaluation, which is why it’s called a “follicle growth series.” Proper scheduling is critical to obtain meaningful information that can help treat your specific problem. You will need to call the Fertility Center of Dallas within the first few days of the start of your period so that your series can be scheduled. Depending on your particular situation, it may be necessary to perform four or five sonograms. The procedure is usually painless, but some mild discomfort may occur. A small ultrasound probe will be inserted into the vagina, providing an accurate image and, unlike an abdominal sonogram, does not require a full bladder. The growth of the follicle will be documented by photographs and plotted on a chart. After the series has been completed, the results will be discussed with you and you will be informed of what therapy may be recommended.

Follicle-stimulating hormone (FSH):

The hormone used to stimulate multiple eggs. FSH is given by daily injection and sold as Gonal-f®, Follistim®, Repronex®, and Bravelle®. The dose and the number of days vary depending on follicle development.


Ultrasound uses sound waves to make sonar pictures of the abdomen. We use a series of ultrasound scans to obtain a three-dimensional picture of the ovaries and to follow follicle growth in the ovary. Through ultrasound, we can observe follicle growth, number, size, and maturity. This allows us to time hCG administration. Ultrasound may be performed abdominally or vaginally and is painless. There have been no reported harmful effects on developing eggs or on early pregnancy.

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