Methods of determining infertile days or Safe days to avoid or delay pregnancy is in use for thousands years as a natural birth control method. Studies shows that implimenation of modern scientific knowledge along with these calendar based charts will improve the accuracy of safe period calculation methods. The idea behind safe period calculator is to prevent or delay unwanted pregnancy naturally without any side effects. Currently there are several methods of natural family planning, like rhythm method and mucus method are used by peoples around the world and they are less reliable as a birth control method.
Menstrual cycles have several days at the beginning that are infertile (pre-ovulatory infertility), a period of fertility, and then several days just before the next menstruation that are infertile (post-ovulatory infertility). The first day of bleeding is considered day one of the menstrual cycle. In this safe period calculator, days 1 to 7 and day 21 to rest of the cycle is calculated as "Safe Period" or "safe days" for individuals with regular 26-32 days cycles. Plese read the method overview for more information. Proper use of Safe Period Calculation method along with coitus interruptus (withdrawal method or pull-out method) is a suggested as a sin free or green family planning method for couples with self control over sexuality. Withdrawal method is not suggested for adolescents or those having casual sex. Others may use condoms during unsafe days to avoid serious and potentially life-threatening risks associated with the use of contraceptive pills.
The menstrual cycle, is commonly divided into three phases: the follicular phase (pre-ovulatory phase), ovulation, and the luteal phase (post-ovulatory phase). The length of each phase varies from woman to woman and cycle to cycle, though the average menstrual cycle is 28 days. Menstrual cycles are counted from the first day of menstrual bleeding.
The follicular phase (or proliferative phase) is the phase of the menstrual cycle; before ovulation, during which follicles in the ovary mature. It ends with ovulation. The main hormone controlling this stage is estradiol.
Ovulation is the process in a female’s menstrual cycle by which a mature ovarian follicle ruptures and discharges an ovum. The time immediately surrounding ovulation is referred to as the ovulatory phase. A woman gets pregnant around the days when ovulation occurs.
The luteal phase (or secretory phase) is the latter phase of the menstrual cycle. It begins with the formation of the corpus luteum and ends in either pregnancy or degradation of the corpus luteum. The corpus luteum is a temporary endocrine structure, involved in production of estrogen and progestogen, which is needed to maintain the endometrium, the inner membrane of the uterus.
The infertility period depends on the life span of sperm and on the life span of the egg. The average time of ovulation is the 14th day of an average length (28 day) menstrual cycle. Ovulation time vary for each individual, and can occur from 12th to 19th day of the cycle. Sperm can live up to 3 to 5 days in a womans reproductive tract, so it is possible to become pregnant if unprotected sex occurs 5 days before ovulation. The life span of the typical egg is relatively short, only around 24 hours. If fertilization does not occur within that time frame, the egg will die.
In Safe period Calculator© Method, day 1-7 of a regular menstrual period lasting from 26 to 32 days are calculated as infertile or safe; considering the 3-5 day life span of sperm cells in the female reproductive track. Post ovulatory infertility period is calculated based on the fact that; if ovulation occurs on 19th day, fertilization can result until 20th day of the cycle, considering the short life sapan of the egg. Since it is a calendar based method, results may vary from women to women.
World Health Organization (WHO) data shows that approximately 80% of menstrual cycles ranges from 26 to 32 days, and this safe period calculation system is adjusted to reflect these data.
Check with your doctor about the effectiveness of natural family planning methods before using safe period calculator as a natural birth control method. Expected perfect use failure rate for this method is 3 - 4% per year.
If your average menstrual cycle length in last 6 months falls between 26 and 32 and the variation between the shortest cycle and longest cycle during this time is 7 days or less, you may utilize the safe period calculator method for birth control.
If your average menstrual period length is less than 26 days or more than 32 days and the variation between the shortest cycle and longest cycle during past six periods is 8 days or more, you may not use this method.
Soon after child birth: you must wait for 6 regular periods, before using this method.
This method is not recommended for teens and those reaching menopause.