Researchers discovered that most women have two waves of follicle development, but what does that mean for ovulation?
By OBGYN and fertility expert Dr. Kenosha Gleaton
Stepping back, what is ovulation?
Ovulation is the period of your menstrual cycle when an egg is released from an ovary. This usually occurs around two weeks before your period, and it’s a common belief that your ovaries alternate releasing an egg. Each ovary contains 1-2 million primordial follicles, each of which contains an egg. Once a follicle matures and is released, the egg waits to be fertilized (or if it doesn’t, menstruation occurs). If you’re trying to get pregnant, it’s important that you have sex when you’re ovulating to increase the chances of conception.
It’s been taught for years that ovulation only occurs once a month, but is this true? Some research has stated otherwise.
Why research made some people question everything
In one study using daily ultrasounds, researchers discovered that 68 percent of women exhibited two waves of follicle development, even though they reported having regular menstrual cycles. This means that the follicles that contain unreleased eggs mature and develop in some women twice in one month.
These results may look promising for anyone struggling to get pregnant, but the truth is they are misleading. Follicular development may have happened twice, but as one of the authors pointed out, ovulation doesn’t occur until the final wave of follicular development- a process that only occurs once a month.
Hyperovulation: two eggs, one month
The mechanism causing multiple eggs to be released in one month is something called hyperovulation, or multiple ovulation. This occurs when both ovaries release an egg during your cycle. When this happens, if both eggs are fertilized, it leads to fraternal twins. In the case of hyperovulation, you aren’t ovulating twice. Your ovaries release two eggs (one egg per ovary) instead of the usual one.
What this means for people trying to conceive
If you’re trying to conceive, you can use ovulation tests to track your cycle and optimize your chances of getting pregnant. If an egg is being released, it will be preceded by high LH levels (AKA a positive ovulation test result). It’s impossible to know exactly how often hyperovulation occurs, but one study found that 21% of women had at least one cycle where hyperovulation occurred. It’s no guarantee that it’ll happen to you, but there are some factors that increase the probability of releasing multiple eggs.
Factors that increase the probability of ovulating more than once
- Age: Perhaps the #1 factor to increased ovulation is age. The older women get, the more difficult it can be to inhibit follicle stimulating hormone (FSH), a key hormone for initiating ovulation.
- Genes: It’s likely that genes play a large role in hyperovulation and twinning. Ever notice how twins seem to run in the family?
- Stopping birth control: It’s not a guarantee that every time a woman stops taking hormonal birth control, hyperovulation will occur. However it is a fairly common, reasonable factor. The cessation of hormones that inhibit FSH release could mean your brain ends up overshooting it’s FSH production.
What this means for ART
What we do know is this: women with regular menstrual cycles typically ovulate once a month. While hyperovulation can occur from time to time, the technology we have now doesn’t allow us to actually detect released eggs, so there’s not much we can alter with ART at the moment.
Understanding reproductive health
Constant developments in research and technology are teaching us more about reproductive health every day. Although we can’t get the answers to all of our questions right now, we’re learning more about fertility and the human body every day. While it would be ideal for those TTC if ovulation occurred multiple times a month, it’s not likely. Hyperovulation can occur from time to time, but it’s more likely that your body releases one egg, one time per menstrual cycle. If you’re interested in tracking ovulation, try out Natalist’s at-home ovulation test.