egg4Have a menstrual cycle and ovulation date that are as predictable as a Swiss watch? Or you can tell from body cues when your body will be releasing an egg? As a result, you know exactly which days you can slide on whatever method of family planning you use or aim for specific days when trying to get pregnant?

Not so fast. A 2010 study in the journal Reproductive Biology and Endocrinology will have you thinking completely differently. Here’s why:

Turns out, experiencing a bout of intense stress–for example, from getting mugged, undergoing surgery, taking a high-stakes test or possibly even from doing high-intensity exercise–has the potential to trigger ovulation on virtually any day in your cycle, for example, during your period or after your usual ovulation date. And it can cause you to ovulate even when you’re not getting a period, for instance, because you’re pregnant or breastfeeding.

That’s because intense stress can set into motion a process that leads to ovulation: It can trigger the release of progesterone from the adrenal glands and shortly thereafter a surge of luteinizing hormone (LH) from the pituitary gland, which together can stimulate a follicle in your ovary to produce an egg under the right conditions, such as having a large-enough follicle and high enough level of estrogen.

The interaction between stress and fertility isn’t a new one. Research shows that chronic stress–say, due to long work hours or intense physical training–can actually prevent ovulation by thwarting the rise of LH, which is needed to produce an egg.

The takeaway here: It’s key to keep in mind how stress can play a role in when you ovulate. So, whether you’re looking to prevent pregnancy or you’re trying to conceive, consider using your preferred family planning method or ovulation tools all cycle long–not just the days leading up to the middle of your cycle.