The fertile period is the period of a menstrual cycle where fertilization of the ovary unit may occur. The fertile period lasts about five days before and three days after ovulation (with the presence of spermatozoids).
The menstrual cycle is counted from the first day of the period until the last day before the following period. The first day of the period is also the first day of the menstrual cycle.
A girl can learn more about her fertility using several methods if she follows the changes during the menstrual cycle:
- Calendar method, by the duration of the menstrual cycle;
- By measuring her basic body temperature;
- By following the thickness of the cervical mucous;
- Symptom-thermal method;
Determining the ovulation by determining the hormones in the urine and mucus with a device for personal use.
Example 1: the menstrual cycle lasts 30 days
If the cycle lasts 30 days, from that number we will subtract 14 days and get the day of the ovulation = the 16th day of the cycle. If the ovulation is on the 16th day of the cycle, fertile days will be from the 11th to the 19th day of the cycle.
30-14=16th day (ovulation)
16-5=11th day (beginning of fertile days) 16+3=19th day (end of fertile days)
Using the calendar method of counting the period of ovulation, we will firstly subtract from the number of days of the menstrual cycle 14 days so that we calculate the day of the ovulation. From the ovulation day, we subtract 5 days and add 3 days to the ovulation. This is how we calculate the fertile days or the fertile interval.
If the last period began on 10th October, the next one will occur in about 30 days, and that is 9th November. The fertile period will be in the interval from the 20th to the 28th of October (from the 11th to 19th day of the cycle). The rest of the days in the cycle are infertile.
If the last period occurred on 5th August, the next period should occur in 26 days, and that is on 31st August. The fertile period will be from the 11th to the 19th of August (from the 7th to the 15th day of the cycle). The rest of the days are infertile.
Example 2: the menstrual cycle lasts 26 days
If the cycle lasts 26 days, from that number we will subtract 14 days and get the day of the ovulation = the 12th day of the cycle. If the ovulation is on the 12th day of the cycle, fertile days will occur from the 7th to the 15th of the cycle.
26-14=12th day (ovulation)
12-5=7th day (beginning of fertile days)
12+3=15th day (ending of fertile days)
The longer the menstrual cycle is, the number of infertile days increases, and vice versa – the shorter the menstrual cycle is the number of infertile days decreases. In case of very short menstrual cycles, ovulation may take place during the period, i.e. during the days of menstrual bleeding. During this time, the girl can get pregnant.
Each and every girl should keep a menstrual diary in order to get familiar with her menstrual cycle and her fertility.
Since most the girls do not have a regular menstrual cycle (always identical time span between the two periods) this method can be proven unreliable.
Estimation of a fertile period can serve as a natural method of preventing unexpected pregnancy – combined with restraining sexual relations during this time.
In the case of desired pregnancy assessment of fertile days can serve for determining the best time for conception.
Contractions of the uterus in regular time spans prepare the woman for giving birth. This is the first delivery period (A). It usually lasts 12-14 hours. The amnion (containing water by which the child was surrounded) bursts and the cervix is widened so as to let the child’s head out. The child is gradually moving toward the delivery channel (vagina).
The second delivery period (B, C, and D) usually lasts about one hour. Hormones help widen the vagina and the pelvis making the way for the child. The uterus contracts more strongly and the child usually makes its way forward by the head, and sometimes by the legs. After the delivery, the umbilical cord is tied and cut off.
The third delivery period (E), when the uterus releases the placenta and fetal wrappings last about 15 minutes. Today there are numerous ways of making the delivery shorter and easier for women (the so-called active birth management) as well as enabling painless delivery by anesthetics. The delivery can be done by operation by the so-called Caesar’s cut if there are reasons for that due to the condition of either mother or the child.