Marriage calendar, otherwise known as The calendar method, or the Ogino-Knaus method, is the natural method of family planning. It is based on a long-term and systematic recording of the length of a woman's menstrual cycles. In order for the marriage calendar to be a reliable method of determining fertile days in a cycle, earlier observation of the menstrual cycles is necessary, at least one year. The calendar method uses the observation that approximately 14 days pass from ovulation to the end of the cycle as a basis for calculating fertile days. The time before ovulation is a variable and uncertain time as to a woman's fertility or infertility.
See the video: "How to do an ovulation test?"
1. The Ogino-Knaus calendar method
The method of natural planning of the Ogino-Knaus family is based on the assumption that in a healthy woman the menstrual cycle is normal, i.e. it is regular with an accuracy of one day, and ovulation (ovulation, release of an egg from the ovary into the fallopian tube) takes place in the half of the cycle. Based on the calendar method, you can determine the peak of a woman's fertility, i.e. the day of ovulation. When determining the period of a woman's fertility in the cycle, it is also necessary to take into account the survival time of the egg and the possibility of sperm survival in the woman's reproductive tract. Due to the fact that in the fertile mucus sperm can survive up to 3-5 days, the fertile period is considered to be 5 days before ovulation. A woman's fertility period in the cycle also extends to 3-4 days after ovulation. The Ogino-Knaus method should not be considered as a method of contraception.
2. Calculation of fertile days
After taking into account the possibility of longer and shorter cycles in a woman than the observed ones, the following scheme for calculating the fertile days in the cycle is obtained.
If you want to determine the first fertile day in the cycle, subtract 20 from the number of days of the shortest cycle in the last twelve months, e.g. the shortest cycle: 26 days ---> 26-20 = 6
The first fertile day in your cycle is the sixth day of your menstrual cycle.
If you want to determine the last fertile day in the cycle, subtract 11 from the number of days of the longest in the last twelve months of the cycle, e.g. the longest cycle: 29 days ---> 29-11 = 18
The last fertile day in your cycle is the eighteenth day of your menstrual cycle.
With regular menstrual cycles, there are no changes. You simply subtract 20 from the number of days in your cycle - then you get the first day of your fertile period, and subtract from 11 from the number of days in your cycle, you work out the last day of your fertile period in your cycle. According to the marriage calendar, the fertile days in a regular cycle are probably:
- 26-day cycle - from the sixth to the fifteenth day of the cycle,
- 28-day cycle - from the eighth to the seventeenth day of the cycle,
- 29-day cycle - from the ninth to the eighteenth day of the cycle,
- 30-day cycle - from the tenth to the nineteenth day of the cycle,
- 31-day cycle - from the eleventh to the twentieth day of the cycle.
When the cycles during the annual follow-up are irregular - ranging from 26 to 31 days - the fertile days in each cycle should be counted from the sixth to the twentieth day of the menstrual cycle.
3. The effectiveness of a marriage calendar
Factors that may undermine the credibility and accuracy of the calculations are: colds and fever, sleep problems, insomnia, fatigue, non-compliance with the circadian rhythm (e.g. shift work), alcohol consumption, taking antibiotics, stress, transient hormonal disorders, and climate change. In order to increase the effectiveness of the calendar method, natural family planning is additionally based on the Billings method or on measuring body temperature. The Pearl Index for a marriage calendar is 14-40.
The calendar method is recommended for women experienced in cycle observation or for those for whom an unplanned pregnancy is not a problem. Doctors recommend combining a marriage calendar with the observation of other symptoms of the fertile period in a woman's cycle.
The fertile days in the cycle are indicated, among others, by symptoms such as: presence of cervical mucus in the vagina, swelling and soreness of the breasts, tenderness of the nipples, pain in the lower abdomen, jump in core body temperature by a few lines, ovulatory spotting.
4. Advantages and disadvantages of a marriage calendar
The undoubted advantage of the marriage calendar is that it does not interfere with the woman's body. This method of family planning is completely natural and has no health side effects. It can be used by all women, because it is not associated with contraindications or ideological prejudices. It is a cheap method that teaches you discipline and systematic observation of your own body. A marriage calendar can be used for natural pregnancy planning - then the emphasis is on intercourse during the fertile days.
The marriage calendar is not recommended for women who:
- do not have a permanent sexual partner,
- like frequent and spontaneous sex,
- menstruate irregularly,
- have trouble sleeping and don't get enough sleep,
- they get up at night to the baby,
- are breastfeeding
- are over 40 years of age,
- have entered the period of premenopause,
- are stressed,
- do not know the annual cycle observation status before starting the method.
Only systematic observation of cycles allows for the effective use of a marriage calendar.