Whether you are planning to have a pregnancy or not, you simply want to understand why during each month you experience some changes in your body, your mood and your preferences. It could be your hormones giving these signals as a result of your menstrual cycle.
The menstrual cycle has 4 phases:
1. The menstrual phase begins with your day 1 of menstruation. This is when the hormones estrogen and progesterone temporarily stops production which signals the brain that there was no pregnancy.
Absence of pregnancy triggers the brain to begin production of the follicle stimulating hormone (FSH).
2. The proliferative phase also called Estrogen phase starts with the increase in FSH that help in the maturation of the ovum or egg cell and thickening of the endometrial layer of the uterus.
Once the ovum is mature it begins to secrete estrogen, then another signal is sent to the brain halting FSH production which therefore initiates the luteinizing hormone (LH).
3. The secretory phase also called progesterone phase begins with the increase in LH that aids in the release of the mature ovum, ready for fertilization. Once the ovum is released from the ovary it leaves a structure called corpus luteum that secretes progesterone which is as important as estrogen in the anticipated pregnancy.
The ovum will live for 24 to 36 hours to wait for possible sperm fertilization. If ovum and sperm union is successful the cycle will continue in this stage followed by the fetal development for a period of 9 months.
This phase marks the start of your pre-menstrual syndrome (PMS) where you will feel nauseated, irritated, breast swelling and craving for foods.
4. If pregnancy however is not successful the ovum will die and the corpus luteum degenarates and marks the pre-menstrual phase. All the hormones will drop and temporarily stop production which is associated with the PMS manifestations of mood swing and minor depression.
The endometrial layer of your uterus will start to shed; this gives you the cramps and feelings of being bloated and abdominal pain. Once this phase is complete it will begin another cycle marked by another menstrual bleeding.
So if you want to know the safe period not to have a pregnancy, that is the pre-menstrual phase and if you and your partner are seriously considering having a baby the target phase is the secretory phase. This ruling however is assuming that you have a regular cycle meaning your menstrual flow begins after the same number of days.