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


ca. 4 Minuten


Do you think you ovulate regularly because you have your period reliably? Then you are unfortunately wrong. One thing is certain, ovulation and menstruation are not directly related to each other!

Background knowledge

The “school knowledge” suggests that menstrual bleeding is caused by the discharge of the unfertilized egg and consequently ovulation must have taken place in the respective cycle. But why should the shedding of an ovum, which is so tiny that it is invisible to the naked eye, cause a bleeding period of 3 to 5 days?

The female cycle is controlled by the interaction of several hormones and can be divided into 2 phases: The first phase of the cycle is also called the follicular phase. It is variable in duration, beginning with the onset of menstruation and ending with ovulation. At the beginning of the cycle, the increase in FSH concentration (pituitary hormones) causes the follicle to mature. The follicular cells in turn produce an increased level of estrogen. Just before the fertile phase, the sharp increase in LH leads to ovulation.

After ovulation, the corpus luteum that has developed from the follicle produces the hormones progesterone and estrogen. They are responsible for the cyclical changes of the endometrium. The second half of the cycle, the so-called corpus luteum phase, begins with ovulation and lasts about 12-16 days until the start of the next menstruation. Thus, menstruation is an important sign of a healthy cycle.

Ovarian and endometrial cycle

The menstrual cycle includes the ovarian and endometrial cycles. The ovarian cycle involves the maturation of the egg from the ovary, the ovary. During the fertile phase, the egg is formed and rejected here once a month. Then, fertilized or unfertilized, it travels through the fallopian tubes to the uterus. Once there, it finds a well-formed endometrium in a healthy cycle. A fertilized egg will then nest in it and there may be no menstrual bleeding. However, if the egg remains unfertilized, the built-up uterine lining is “no longer needed” in this cycle and is rejected (together with the egg) 12 to 16 days after ovulation: Menstrual bleeding occurs.

The endometrial cycle describes the monthly build-up and breakdown 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 in the fertile phase.* It is crucial for the success of pregnancy because without an intact endometrium the fertilized egg cannot implant. Your gynecologist can determine the respective thickness by ultrasound. If fertilization fails to occur, hormone production will then drop towards the end of the 4th week of the cycle. We perceive the shedding of the uterine lining as menstruation. In the following cycle, the endometrium builds up again to be “ready” for a fertilized egg.


Menstruation is therefore directly related to the endometrial cycle and only indirectly to the ovarian cycle. So you can get your period even without having ovulated before. The interplay between ovulation and menstrual bleeding is based on cyclical hormonal changes in the body. However, it is possible that the hormonal changes do not trigger ovulation, but are sufficient for changes in the endometrium. Thus, menstrual bleeding may occur without prior ovulation. To be sure that you ovulate regularly, you can use OvulaRing. This will reliably indicate ovulation and the fertile phase regardless of menstrual bleeding.

* Rabe T et al. 2013. Seminar in gynäkologischer Endokrinologie. Bd 2.


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