Ultrasound Monitoring of Follicle Growth

Ultrasound monitoring of follicular growth is an important method for diagnosing and monitoring ovulation in women. This method, also known as folliculometry, allows you to determine the moment of ovulation and identify possible disorders in the development of follicles.

During the early follicular phase, usually several follicles begin to develop. Further, only one of them is ahead of the others in development - this is called the dominant follicle. At this moment, its dimensions exceed 15 mm, and all others undergo atresia (reverse development). The dominant follicle continues to grow by an average of 2-3 mm per day and by the time of ovulation its diameter reaches 18-24 mm.

With an ideal 28-day cycle, the first ultrasound examination can be performed on days 8-10 of the cycle or immediately after the end of menstruation. In the future, ultrasounds are performed every 1-2 days (depending on the results of the next study, the doctor may prescribe the next examination earlier or later) until the day that ovulation has occurred is established, or until menstruation begins (if ovulation is due to any reason). - for some reason it never happened).

The main criterion for successful ovulation is the presence of a dominant follicle of ovulatory size before ovulation (18-24mm), the presence of a corpus luteum in the ovary and free fluid in the pelvis after ovulation. However, visualization of a follicle up to 15 mm and the corpus luteum in its place a week later does not always guarantee full ovulation. As well as a single ultrasound that did not show a dominant follicle or corpus luteum on any given day. In such cases, more careful and frequent monitoring is necessary.

With successful ovulation, the dominant follicle is identified, develops to ovulatory size (18-24mm), then ovulation occurs (ultrasound signs of ovulation - the disappearance of the dominant follicle, the appearance of free fluid in the retrouterine space, signs of the formation of the corpus luteum at the site of the follicle). Also, an important sign of successful ovulation is a high level of progesterone a week after ovulation (according to a blood test).

Atresia (regression) of the follicle is a decrease in the size of the unovulated follicle. In this case, the dominant follicle is identified, develops, but then stops developing (perhaps without even reaching the size of a mature follicle) and regresses (shrinks) - there is no ovulation. Characteristic signs of follicular atresia are: a decrease in the size of the unovulated follicle, the absence of free fluid in the retrouterine space, the absence of the corpus luteum and low levels of progesterone (corresponding to the first phase).

Monitoring follicle growth using ultrasound is a very effective method for monitoring ovulation and pregnancy planning. Thanks to folliculometry, it is possible to promptly identify disturbances in the development of follicles and carry out the necessary treatment. Ovulation is a key moment in the female cycle and its control plays an important role in a woman’s reproductive health.