Studies using hormonal and ultrasound tests have established that a woman is fertile from five days before ovulation to 24 hours after ovulation (that is, six days total per menstrual cycle). Ovulation occurs around the 14th day after the start of menstruation. Identifying the six-day fertile window is the critical component of any method, “natural family planning.”
According to this, the percentage probability of pregnancy due to unprotected sex during this fertile period is:
• Five days before ovulation: 4%.
• Two days before ovulation: 25 to 28%.
• During the 24 hours after ovulation: 8 to 10%.
• For the rest of the cycle: 0%.
Based on this, the probability of pregnancy during menstruation does not exist and, but these probabilities are related to the regularity and length of the cycle. In cases of irregular periods, or menstrual disorders, there may be errors in the interpretation of the menstrual cycle and these percentages may vary.
Knowing the menstrual cycle, as well as having adequate information about the fertile days of the woman is the best tool to be able to know oneself and control when a woman can become pregnant.
The fertile interval in each cycle is approximately six days and includes the five days before ovulation plus the day of ovulation. The length of the fertile period is not affected by age, but can vary between women. The greatest chance of conception occurs when intercourse takes place a day or two before ovulation and on the day of ovulation. In the non-fertile period, the probability drops significantly, even reaching zero in menstruation. Despite this, these probabilities are related to the regularity and length of the cycle. In cases of irregular periods, or menstrual disorders, these percentages may vary. It would be in these cases, in which there could be some probability, especially if irregular blood loss of the cycle is confused with the real menstruation.
Knowing the menstrual cycle is the best tool to control when a woman can become pregnant. (Freepik)
Women can predict the time of ovulation by noting changes in cervical mucus (the highest chance of conception occurs on the day of maximum clear and slippery mucus production), or by using kits that can be purchased at the pharmacy to measure luteinizing hormone (a spike of this hormone occurs at ovulation). Another way to control ovulation is by taking your body temperature in the morning before getting up, which rises precisely in the period of ovulation.
Sperm and ovum at stake
On the other hand, all these probabilities of becoming pregnant or not are also related to the lifespan of sperm within the female reproductive tract (no more than five days) and with the even more limited lifespan of the egg after ovulation (less than 24 hours). As a result, the fertile window does not exceed six days per cycle.
Predicting the onset and determining the end of the six-day fertile window are critical components of one method, “natural family planning.”
Fertility awareness-based methods involve the identification of the fertile days of the menstrual cycle using a combination of cycle length and physical manifestations of ovulation (change in cervical secretions, basal body temperature), and based on this information, avoiding sexual intercourse or using barrier methods on those days.
During sexual practice the only method that can prevent pregnancy is use contraception during the woman’s fertile days or throughout the month, depending on the type of family planning used.
In women with regular cycles and in which ovulation is correctly identified, the pregnancy percentage during menstruation is practically nil. Despite this, in the event of possible doubts regarding the cycle, contraception can be used. If a method is not used regularly or regularly, spermicidal creams disable the functionality of the sperm and lower the risk of pregnancy.
Disease contagion
Despite this, we must mention that barrier methods they are the only effective ones in preventing sexually transmitted diseases. During menstruation increases risk transmission of some diseases and therefore it is necessary, in case of risk, to use protection by means of a male condom.
It is necessary to use male condoms. (Pixabay)
The position of intercourse, the presence or absence of a female orgasm, and the female position (for example, lying supine, that is, stretched out looking up) after male ejaculation do not appear to affect the likelihood of conception.
Some lubricants can simulate that they lower the risk of pregnancy in the laboratory, however, one study found no difference in fertility between those who used and did not use lubricants.
Premenopause and menopause
The average menstrual cycle of a woman lasts 28 to 35 days. There is relatively little cycle variability among women between the ages of 20 and 40. In comparison, significantly greater cycle variability occurs during the first five to seven years after the first period and during the last 10 years before the cessation of menstruation, that is, before the onset of menopause.
In both adolescence and pre-menopause, cycles are more irregular and often without correct ovulations. The risk of pregnancy decreases as there are fewer ovulations and not being correct cycles, but the risk of pregnancy does not disappear completely. Even due to the irregularity and lack of foresight in the face of cycles that are not always the same, the risk can increase if contraception is not planned correctly. Cycle irregularities that can interfere with good control of the menstrual cycle are more frequent at these times, adolescence and pre-menopause. In both cases, despite lower fertility, lack of control and confusing the phases of the cycle can increase the risk of pregnancy if natural planning is not good.
The process of conception
The phases the duration of the menstrual cycle is summarized as follows:
The first day of menstruation represents the first day of the cycle. Then the cycle is divided into two phases: the follicular phase and the luteal phase. The average adult menstrual cycle lasts 28 to 35 days, with approximately 14 to 21 days in the follicular phase and 14 days in the …