Understanding Your Menstrual Cycle: A Simple Guide
For many women, the menstrual cycle is something we briefly learned about in middle school and then left behind in the classroom. At least, that’s the case where I live in Germany. If you’re feeling unsure about what’s really happening in your body each month, don’t worry—you’re not alone. Let’s break it down and take a closer look at the fascinating process of your monthly hormonal cycle.
The menstrual cycle is typically divided into three key phases: the follicular phase, the ovulatory phase, and the luteal phase. While the average cycle lasts 28 days, this can vary depending on the length of your follicular phase, which often accounts for most of the variation.
Your cycle starts with the follicular phase on the first day of your period. In this phase a few follicles in your ovaries begin to mature. Usually, only one will fully develop into an ovum (egg), which will be released during ovulation. At the same time, your uterine lining—the endometrium—thickens to prepare for a potential pregnancy.
Ovulation, the second phase, is the shortest but the most crucial for a possible pregnancy. It lasts just 24 to 48 hours, during which the mature ovum is released. Interestingly, some women can physically feel ovulation as a sharp pain in the lower abdomen, a sensation called Mittelschmerz (literally "middle pain" in German). The five days leading up to your ovulation and the ovulatory phase are the time in your cycle in which sexual intercourse can lead to a pregnancy.
Following ovulation comes the luteal phase, when your body prepares for the possibility of pregnancy. If the egg is fertilized and implants in the uterine lining, the cycle takes a new direction. However, if implantation doesn’t happen, your body sheds the endometrium, and your period begins. This phase typically lasts 13 to 15 days and is when many women experience premenstrual symptoms like mood swings, fatigue, or bloating.
It’s important to note that the length of your cycle is mostly determined by the follicular phase. A longer or shorter cycle generally means this phase varies, while the luteal phase remains relatively consistent.
Now, let’s talk about the hormonal symphony that drives this cycle.
Hormonal flux of the menstrual cycle
At the start of your cycle, hormone levels are at their lowest. This low hormone phase includes both estrogen and progesterone at minimal levels. During this time, your brain signals the release of follicle-stimulating hormone (FSH), which prompts follicles to begin maturing. These growing follicles produce estrogen, causing its levels to rise and ushering in the first high hormone phase of the cycle.
Once estrogen reaches a certain peak, it triggers the release of luteinizing hormone (LH), which leads to ovulation. Following ovulation, levels of LH, FSH, and estrogen drop, bringing the cycle back to a low hormone phase for a brief period.
But the story doesn’t end there. After ovulation, the ruptured follicle—now called the corpus luteum—produces progesterone along with a small amount of estrogen. Progesterone is essential for maintaining the endometrium and ensuring it’s ready for implantation. During this time, estrogen also helps prevent the maturation of additional follicles. This is the second high hormone phase of the cycle.
If the egg isn’t fertilized, the corpus luteum disintegrates, and levels of estrogen and progesterone drop. Without these hormones to sustain it, the endometrium breaks down and is shed during your period. And just like that, the cycle begins anew.
Understanding how your body works can feel empowering, especially when it comes to something as essential as your menstrual cycle. It’s not just a monthly inconvenience—it’s a beautifully orchestrated process that highlights the incredible complexity of the human body.