What is Ovulation?

Ovulation is the release of an egg from the ovary. The hormonal changes that accompany the development of the egg result in the menstrual cycle. Regular uterine bleeding is the end result of a coordinated dance between your pituitary gland, your ovaries and your uterine lining.  It surprises us to learn that our ovaries present a large cohort (>25) of available eggs every month..  Each egg develops inside a tiny cyst that we call a follicle. 

In a normal cycle, a pituitary hormone called FSH stimulates the development of a single “dominant” follicle containing the winning egg!  At ovulation, the dominant follicle releases the “winning” egg and the rest of the cohort dies off. .

The follicular cells around the egg make estrogen (specifically estradiol) for first 12 to 18 days of the cycle..  Rising estradiol levels provoke a burst of a second pituitary hormone called LH.  The LH surge stimulates the release of the egg and causes the cells of the follicle to convert from estrogen production to progesterone production.  In one of nature’s true mysteries the cells that make progesterone (now called the corpus luteum rather than the follicle) are programmed to die off after 11 days, the progesterone level declines, and menstrual bleeding begins. 

How can you know if you ovulated? Basal body temperature increases about a half degree after ovulation in response to progesterone production.  So, a basal body temperature chart can help you see whether you ovulated, but only in retrospect. For a prospective approach, most home ovulation monitoring focuses on detecting the LH surge.  A blood test for progesterone levels drawn about cycle day 21 is an easy way to confirm that you ovulated.

When you get pregnant in a cycle, the hormones of the pregnancy sustain the corpus luteum and progesterone production continues allowing the embryo to implant and grow.

What is Anovulation?

Patients with polycystic ovarian syndrome don’t ovulate regularly.  For a variety of reasons, their pituitary gland does not cycle as expected, so the ovarian follicles don’t respond.  Patients tend to have modest levels of estrogen production all the time and no 2-week time of progesterone production.  As a result, their cycles are few and sometimes very heavy when they do occur. Also, pregnancy is hard to achieve.  One of the real frustrations is that you can have either no LH surge (never a positive OPK) or a chronic high LH level (OPK always positive).

A reproductive endocrinologist can help you decipher all this, look for causes of anovulation, and make recommendations for medication and lifestyle modifications that will help!  Feel free to reach out to us.