Do I ovulate because I have my period and does that make me fertile?

Do you think you ovulate regularly because your periods are reliable? Unfortunately, you’re wrong. The fact is, ovulation and menstruation aren’t directly linked!

Background information

Conventional wisdom suggests that menstruation is caused by the expulsion of the unfertilized egg. If we follow this explanation, ovulation must therefore have occurred during that cycle. But why would the release of an egg cell—which is so tiny that it cannot be seen with the naked eye—cause bleeding that lasts 3 to 5 days?

How the female menstrual cycle works

The female cycle is regulated by the interaction of several hormones and can be divided into two phases: The first phase of the cycle is also called the follicular phase. Its duration tends to vary; it begins with the start of your period and ends with ovulation. At the beginning of the cycle, a rise in the hormone FSH (pituitary hormone) triggers the maturation of the follicle. The follicle cells, in turn, produce increasing levels of the hormone estrogen. Shortly before your fertile phase, the sharp rise in LH triggers ovulation.

You can calculate your ovulation and fertile days online here:

After ovulation, the corpus luteum—which develops from the follicle—produces the hormones progesterone and estrogen. These hormones are responsible for the cycle-related changes in the uterine lining. The second phase of the cycle, known as the luteal phase, begins with ovulation and lasts about 12–16 days until the start of the next period. Menstrual bleeding is therefore an important sign of a healthy cycle, but it does not indicate whether ovulation actually took place and how fruitful you are.

Ovarian and endometrial cycles

The menstrual cycle consists of the ovarian cycle and the endometrial cycle.

The ovarian cycle

The ovarian cycle involves the maturation of an egg cell in the ovary. During your fertile window, an egg cell is produced once per cycle and is “released” during ovulation. Afterward, whether fertilized or not, it travels through one of the two fallopian tubes toward the uterus. Once it arrives there, in a healthy cycle, it finds a well-developed uterine lining.

A fertilized egg then implants itself there, and menstruation may not occur. However, if the egg remains unfertilized, the uterine lining that has built up during this cycle is “no longer needed” and is shed (along with the egg) 12 to 16 days after ovulation: this results in menstrual bleeding.

The endometrial cycle

The endometrial cycle describes the monthly thickening and shedding of the uterine lining (endometrium) in a healthy cycle. The thickness of the endometrium varies from about 2 mm at the beginning of the cycle to 9 mm during the fertile phase.* It is crucial for a successful pregnancy, because without an intact uterine lining, the fertilized egg cannot implant. Your gynecologist can determine the current thickness via ultrasound. If fertilization does not occur, hormone production drops toward the end of the 4th week of the cycle. We perceive the shedding of the uterine lining as menstrual bleeding. In the following cycle, the uterine lining builds up again to be “ready” for a fertilized egg.

Conclusion

Menstruation is therefore directly linked to the endometrial cycle and only indirectly to the ovarian cycle. This means you can get your period even without having ovulated beforehand. Cyclical hormonal changes in the body are fundamental to the interplay between ovulation and menstrual bleeding. However, it is possible that while these hormonal changes do not trigger ovulation, they are sufficient to alter the uterine lining. This can result in menstrual bleeding without prior ovulation. To ensure that you are ovulating regularly, you can use the OvulaRing. It reliably indicates ovulation and your fertile window, independent of menstrual bleeding.

* Rabe T et al. 2013. Seminar on Gynecological Endocrinology. Vol. 2.

Related links:

OvulaRing.com – Understanding My Cycle

doccheck.com – the menstrual cycle