May 16, 2022

Highest Measures of Accuracy for Ovulation

The likelihood of conception increases if intercourse occurs within the fertile window, which is about five days leading up to ovulation. But when exactly does ovulation take place?

Although many women try to monitor their cycle either to increase their chances of conception or to prevent it, most do so inaccurately. According to a 2012 study, only about 12.7% of women estimated their ovulation correctly. Only thirteen out of 330 women in the study successfully determined their exact ovulation day. 

One reason for the low level of accuracy is that most women rely on one method of determining when they ovulate. While some divide their cycle length by 2, some add/subtract 14 days from the end of their cycle.

But there are so many ovulation indicators that it becomes inefficient to depend on one alone. For example, if you’ve always thought that ovulation occurs on the 14th day, you might have been getting it wrong all along. The study discovered that only 35.5% of the women ovulated on day 14, which, nevertheless, was the most common. 

To accurately estimate your ovulation day, it’s best to combine several indicators. 

The following four indicators combined have the highest degree of accuracy:

1. Cycle length (60% accuracy)

This is arguably the easiest way of estimating ovulation day, although it’s merely 60% accurate. To do this calculation, count the number of days from the first day of your last period to the first day of the following one. Then, from this figure, subtract 14 days from the end of your current cycle to estimate the day you’ll ovulate. 

The problem with this technique is that your cycle length isn’t the same every month. It varies due to many factors, such as hormonal imbalance. So it’s essential to know your average cycle length.

Most online ovulation calculators will request your average cycle length to increase the accuracy. 

2. Basal Body Temperature (75-90% accuracy)

Basal Body Temperature (BBT) measures a thermal shift, typically half a degree change in body temperature, as a sign that ovulation has occurred.

BBT is one of the simplest and least invasive methods of detecting ovulation. You measure your oral, vaginal, or rectal temperature first thing when you wake up every morning. Any modern digital or traditional glass thermometer that measures one-tenth of a degree will work well for BBT. 

3. Cervical Fluids (88-96% accuracy)

Notably, you’re most fertile when your cervical mucus is clear, stretchy, slippery, and abundant. Ovulation typically occurs during this time or a day after this secretion stops (your peak day). The increased estrogen level just before ovulation causes a change in cervical fluid. 

4. LH Surge (95-98% accuracy)

Luteinising Hormone (LH) with estrogen surges a few days before ovulation, indicating the opening of the fertile window.

To use the LH surge technique, you’ll urinate on LH test strips every morning, starting from a few days before you expect to ovulate. It rises sharply just before ovulation. 

Once you notice that surge, that day and the next few ones are a perfect time to have sex — or not (if you’re trying to prevent pregnancy).


Give it a go… 

Accurate estimation of ovulation day can help women trying to conceive increase their chances. If you’ve been trying and failing, try combining the above four techniques and you’ll most likely see results.


For more support with your fertility journey, speak to our Fertility Health Coach for a free consultation. Book Now.


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