When Am I Most Fertile?

This might be one of the most commonly asked questions related to sex and women’s health. One of the more important ones too. Whether you want to conceive or prevent a pregnancy, it’s vital to know your body and how it works.

There are several things considering fertility that many women are not aware of. For instance, a frequent misconception (that explains many unplanned pregnancies) is that you’re fertile only around the day of your ovulation when the egg gets released from the ovary. This is only partly true…

While you are indeed most fertile within a day or two either side of ovulation, you can get pregnant if you have sex at any point during the week before your ovulation. This is because the sperm can live inside a woman’s body for up to 5 days.

All this suggests that your fertile window—AKA the days when you can most likely get pregnant—can last for 6 days or more, depending on your body, sexual activity, and characteristics of the partner’s sperm (e.g., how long can his sperm survive).

How to Calculate the Fertile Window?

Although experts usually talk of a 6-day fertile window (five days before your ovulation plus ovulation day), there is no one-fits-all formula.

An interesting study that included almost 6,000 pregnant women showed that the most fertile day was Day 12 of the menstrual cycle (day 1 being the first day of the last menses). All in all, the conception rose sharply 7 days after the last menstrual period and went back to zero on Day 25 (3 days before the start of the next period). However, 2% of the women included in the study had their fertile window already on Day 4, and 5% could conceive on Day 21 of the cycle.

Considering these findings, the safe days would probably be Day 1 – Day 3 (while you are still bleeding), and Day 25 – Day 28 (just before your period), calculating for a 28-day cycle. In other words, theoretically, you can get pregnant on most days of your cycle.

Tired of science and just want a simple answer?

Here’s a simplified guideline that can help you understand your fertile window better. However, don’t forget that every person’s cycle is unique.

5-6 days before ovulation…. possibly fertile   

4 days before ovulation…. fertile

2-3 days before ovulation…. most fertile

Ovulation day…. fertile

1-2 days post ovulation…. possibly fertile

As already mentioned, it’s not unheard of that women also conceive earlier or later in the cycle, so you need to consider that.

How Do I Know When I’m Ovulating?

Since fertile days are connected with your day of ovulation – when the egg travels to the Fallopian tube where it stays for about 12 to 24 hours—you first need to be able to recognize the signs of ovulation. Statistically, the ovulation should occur on Day 14 of the cycle. However, not many women adhere to the laws of science. Therefore, it might be useful to know how your body changes.

The most obvious signs of ovulation include:

  • Changes in your vaginal discharge; you can notice mucus that is stretchy and clear, like egg white. To test it, insert a clean finger in your vagina and remove some mucus. If you stretch it between your fingers, it should be wet and slippery.
  • Mild pain in your pelvis or lower abdomen (usually only on one side, known as Mittelschmerz).
  • Tenderness or soreness in your breasts.
  • Light spotting.
  • Change in libido; sometimes, the sex drive increases.

Did you know?

Purportedly, some women’s sense of smell gets sharper during the ovulation, both for musky (male) smells and smells in general.  It seems that when we are fertile, we become more aware of the world around us. One must love nature!

[1] Stirnemann, J. J., Bernard, J.-P., Samson, A., & Thalabard, J.-C. (2013). Day-specific probabilities of conception in fertile cycles resulting in spontaneous pregnancies. Human Reproduction, 28(4), 1110–1116

[2] McNeil, J., Cameron, J. D., Finlayson, G., Blundell, J. E., & Doucet, É. (2013). Greater overall olfactory performance, explicit wanting for high fat foods and lipid intake during the mid-luteal phase of the menstrual cycle. Physiology & Behavior, 112113, 84–89.