Just like the seasons (spring, summer, autumn, winter), the cardinal directions (north, east, south, west) and the lunar phases (new moon, waxing moon, full moon, waning moon), also the menstrual cycle can be divided into four phases. On average, every phase lasts about a week. The average menstrual cycle is therefore 4 x 7 days = 28 days. This can be found in every biology textbook.
New research: 29.3 instead of 28 days
In real life, however, a woman’s biological clock isn’t as regular as clockwork. Only very few women menstruate exact in this rhythm of 28 days. Also, a woman’s menstrual cycle changes over time. In the beginning and at the end of her fertile life there can be some start-up and winding down problems due to hormonal imbalance. Hormonal changes can for example lead to anovulation, which results in periods that seem to last forever. Therefore, everyting between 21 and 36 days is considered ‘normal’.
A study that was recently published in Nature Digital Medicine compared the cycle of 124.648 Swedish, American and British users of a fertility awareness app. The result? Only 13% of the more than 600,000 cycli has a length of 28 days. It looks like the average length of a menstrual cycle is 29.3 days. Nice to know: the moon cycle is 29.5 days.
1. Menstrual phase
Day one of your menstruation is also day one of your menstrual cycle. The uterus sheds the unfertilised egg together with its lining, called endometrium. The pituitary gland in the brain releases FSH, follicle-stimulating hormone, which stimulates the ovaries to produce estrogen, so new eggs can grow and develop. Eggs are the biggest cells in the human body and can be seen without a microscope. From a holistic point of view, phase 1 also represents new moon and winter.
2. Pre-ovulatory phase
In the ovaries, several follicles with eggs inside start maturing. Usually, only one develops completely. Estrogen and progesterone levels rise, making you feel stronger and more energetic. A lot of women also feel like having sex during this phase. No coincidence, as chances of getting pregnant are rising as well. Phase 2 stands for waxing moon and spring.
3. Ovulation phase
Usually around day 14, it’s time for ovulation. The egg leaves the ovary and travels through the fallopian tube to the uterus. During ovulation, the body temperature rises a bit and some women experience cramps. If the egg gets into contact with sperm cells in the uterus, you can get pregnant. When the egg travels through the fallopian tube, the estrogen and progesterone levels start to decrease. The ovulation phase symbolises full moon and summer.
4. Premenstrual phase
In the third week of the cycle, estrogen and progesterone levels are at their lowest point. This can lead to retaining fluids, sensitive breasts and irritability. In other words: PMS, which stands for premenstrual syndrome. Seeing as most complaints happen in the premenstrual phase, women aren’t usually grumpy during their periods, but in the week before the bleeding starts. Emotions rise and some women feel the need to retreat into their inner selves. Not surprisingly, this phase stands for waning moon and autumn.