Why monitor follicle development?
In many instances, having regular menstrual periods is a reliable sign that regular ovulation occurs. Sometimes, through, ovulation may be premature, incomplete, or altogether absent, despite apparent temperature elevations, positive ovulation predictor kits, changes in vaginal secretions, or mid-cycle cramping.
This test is performed around ovulation, usually Cycle Day 11-14.
In these instances, a poorly formed follicle may not release an egg; or may do so but at the wrong time, so when the egg which is released, it is incapable of being fertilized. In other cases, ovulation occurs but subsequent progesterone hormone production by the post ovulatory follicle (called the corpus luteum) may not be strong enough to allow implantation of an early embryo.
The purpose of ovulation and follicle monitoring is to uncover these types of disorders, since these disorders are highly treatable, usually with simple medications. If the timing of your menstrual cycle is irregular, or if your previous monitoring with temperature charts or ovulation predictor kits has been variable, then this type of monitoring is very likely to be very helpful.
Which tests are used to determine ovulation is normal?
At the time in your cycle when your ovulation is judged to be imminent, vaginal ultrasound can measure the actual size and shape of the follicle, while simultaneous measurement of the estrogen level in the blood indicates the overall health of the follicle. We look for a follicle that has an optimal size and shape on ultrasound, associated with appropriate blood levels of estradiol, progesterone, and LH.
If a small underdeveloped follicle is found, or the hormone levels are abnormally low or high, then treatment can improve the process of follicle maturation and egg development.
In almost all instances, if a follicle can grow adequately and produce the appropriate hormonal surges, the follicle wall responds by breaking open and releasing the egg it contains. However, if a mature follicle is found but it is incapable of releasing its own egg, then we can trigger ovulation using a medicine called HCG. In this situation, HCG can trigger egg release to occur approximately 36 hours after the medication is given. This is particularly helpful for timing intercourse and/or artificial insemination.