It’s common to have questions on your trying-to-conceive (TTC) journey. Curiosity about your incredible body is a good thing — and something we can 100% get behind.
Here we dig into some of your top questions about fertile cervical mucus (CM), ovulation, lack of ovulation, and why ovulation predictor kits (OPKs) can let you down sometimes by failing to detect ovulation.
If you’ve been trying to conceive and tracking your fertility signs, then you probably already know fertile-quality CM precedes ovulation. But fertile-quality CM doesn’t confirm ovulation (tracking your basal body temperature (BBT) can confirm ovulation (14)), and it’s possible to produce fertile CM and not ovulate.
Before explaining why this may happen, let’s begin a few steps back in the process. Your body churns out estrogen after your menstrual flow ends, which results in the production of CM. As estrogen rises, your CM generally becomes wetter and more slippery, often producing CM that's similar to raw egg whites when you're most fertile (1). When your estrogen levels reach a certain threshold, ovulation is triggered and your body produces a surge of luteinizing hormone (LH) (1).
Except sometimes those steps occur — and you don’t ovulate. Not ovulating is called anovulation and it happens to most women sometime in their reproductive years (2). According to the American College of Obstetricians and Gynecologists (ACOG), up to 1/3 of women with “normal menstrual cycles” are anovulatory at some point (2).
The most obvious sign of anovulation is no menstrual flow, but you can still have a flow without ovulating (3). Even with a regular menstrual cycle and a rise in estrogen (to help produce the fertile CM we talked about), you still may not ovulate (4). Clinical researchers theorize that emotional or physical stress or your diet may be to blame for some cases of anovulation (4).
We talked earlier about “normal menstrual cycles” and anovulation, and now we’ll shift gears to discuss anovulation and irregular menstrual cycles. According to ACOG, an irregular cycle is one that’s (2):
An irregular menstrual cycle and an absence of ovulation can both be caused by hormonal problems (5). For example, 10% of women of reproductive age have polycystic ovary syndrome (PCOS), which can cause irregular cycles and anovulation. So it’s probably no shock that PCOS is one of the leading causes of female infertility (6).
Being overweight or underweight also can lead to anovulation, along with a condition called hyperprolactinemia, where your body makes an excess of the hormone prolactin (7).
Switching to a healthy fertility-boosting diet (Pro tip: find clinically proven fertility foods here) and losing weight can sometimes fix ovulation problems (5), but the success of these strategies hinges on the underlying reason you’re not ovulating. The American Society for Reproductive Medicine advises you to talk to your doctor if you don’t ovulate for 2 or more cycles in a row (8).
No, it's not possible to ovulate without a LH surge. That’s because LH is a hormone released by the pituitary gland and plays a fundamental role in the egg’s growth and maturation; a large burst of LH induces the release of a mature egg (9).
As we mentioned earlier, rising levels of estrogen can cause your CM to change from dry and infertile to wet and fertile — so it may look like estrogen is controlling the show, but it’s really not (1). And while there is a hormonal dance between estrogen and LH prior to ovulation, the bottom line is that LH controls the egg’s release (9). No LH surge, no ovulation.
OPKs test your urine for the surge of LH associated with ovulation, but OPKs may miss your LH surge even if you ovulated (10). The frustrating reality is the sensitivity of store-bought OPKs varies widely (11). By sensitivity, we mean the capacity to detect LH in your urine.
An assessment of commercially available OPKs found testing thresholds ranging from 20 to 50 mIU/ml (11). That’s a pretty significant variation. So if you experienced a low LH surge one month, and your test wasn’t very sensitive, your results may show you didn’t ovulate — when you actually did.
Research also shows the length of the LH surge varies widely (12), so you may be missing your surge. A 2013 paper in Fertility and Sterility analyzed the characteristics of 283 cycles of fertile women and found the median length of the LH surge was 5 days, but in some cycles the surge lasted only one day (12). According to the American Pregnancy Association, a LH surge may be as short as 12 hours (13).
Twelve hours is an extremely brief window to test. If you’re testing once daily, you may simply miss your LH surge.
We generally recommend relying on CM and BBT observations more than OPK results when you’re trying to conceive. For more on how these two fertility signs help you to pinpoint your fertile window, check out this post on BBT and brush up here on CM.
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