Although, in some situations, pregnancy, indeed, occurs after a single unprotected sex, in fact, your chances of getting pregnant from having unprotected sex one time are relatively low.
For example, in the case of regular unprotected sex contacts, within one month, the average probability of pregnancy is approximately between 15% and 20%.
Regularly unprotected sexual contacts within one year lead to the occurrence of pregnancy in approximately 80% to 90% of the cases.[adHere]
What are the factors that increase or diminish the probability of pregnancy?
Your chances of getting pregnant from having unprotected sex depend on some conditions:
- the quality of sex
- the moment of sexual intercourse
- methods of contraception used before, during, or after sexual intercourse
Are there days when unprotected sex can not lead to a pregnancy?
Referring to the risk of unwanted pregnancy on different days of the menstrual period, the following important moments should be highlighted:
- a certain pregnancy risk exists on any day of the menstrual period, that is, on any day of a woman’s fertile life
- there are no absolute safe days where the occurrence of pregnancy is impossible at a level of 100%
For this reason, in all cases in which pregnancy is undesirable upon sex intercourse, you should use contraceptive methods in order to completely eliminate the possibility of developing a pregnancy after intercourse.
Why is there a chance to get pregnant in any day of the menstrual cycle?
As you know, for pregnancy it is necessary that the male sexual cells (sperm) meet the female sexual cell (ovule).
Spermatozoon enters the female genital tract during vaginal intercourse, and the ovules are released approximately once a month during ovulation.
As recent studies have shown, even in perfectly healthy women with a regular menstrual period, the moment of ovulation is not always easy to predict.
In about 30% of the cases, ovulation occurs between the 10th and the 17th day after the start of the menstruation, approximately in the first two weeks after the end of the menstruation.
In the other 70% of the cases, ovulation occurs either immediately after menstruation, in days just before menstruation, or even during menstruation.
Due to the fact that the lifetime of an ovum, not fertilized after ovulation, does not exceed 24 hours, for the development of a pregnancy, it is necessary for the ovule to meet with the sperm on the first day after the egg is produced. This requires the sexual intercourse to take place a few days before ovulation, or not later than a few hours after its end.
Can you get pregnant few days before menstruation or even during menstruation?
A common view is that the likelihood of getting pregnant only occurs with 1 or 2 weeks after the end of the menstrual period and that a few days before and after menstruation, the chances of getting pregnant are equal to zero. This is totally wrong and scientifically unjustifiable.
Indeed, in the middle of the menstrual cycle, approximately from the 10th day to the 17th day after the start of menstruation, the probability of pregnancy is at the maximum peak.
However, even if at a lower level, chances of getting pregnant are present on any other day of the menstrual cycle, including the menstruation days.
The probability of pregnancy occurring within a few days before or after menstruation, or directly during menstruation, is approximately between 1% and 6%.
In this regard, the sexual intercourse that takes place a few days before menstruation or during menstruation can not be considered absolutely safe from the point of view of pregnancy.
How can reliable days be calculated, when conception is impossible?
As mentioned above, absolute safe days do not exist. However, in some situations, the need to calculate the days with the lowest probability of conception appears. For example, in the cases of couples who do not want to use contraception and for whom the occurrence of a pregnancy, although not desirable, it is acceptable.
More or less accurately calculating the ‘safe days’, when the pregnancy occurrence probability is minimal, is only possible under a regular monitoring of the menstrual period, baseline temperature, menstruation, and other parameters.
This method is called schedule planning using the calendar method.
If you intend or are already using the safe day’s calculation as the main contraceptive method, you should know that the effectiveness of this method does not exceed 80%. This means that if you only use this method of protection for 1 year, the probability of getting pregnant will be 25%.
Is it possible for a pregnancy to occur during the first sexual intercourse and loss of virginity?
Yes, it’s possible. During the first sexual intercourse, when you lose your virginity, the risk of pregnancy may be quite higher than expected. For that reasons, you should take contraceptive measures during your first sexual intercourse.
The effectiveness of different contraception methods
The listed below effectiveness of different contraception methods is calculated taking into consideration one year of regular sexual intercourse.
- Condoms 85% to 99%
- Interrupted sexual intercourse 70% to 90%
- Calendar method (Calculation of safe days) 75% – 90%
- Oral Contraceptives (if properly taken) 90% to 99%
- Intrauterine device (IUD) 99.2% – 99.9%
As shown in the info above, none of the modern methods of contraception has a 100% efficiency. However, some of them provide a relatively high level of protection.
These being said, your chances of getting pregnant from having unprotected sex one time are very small, though it is not impossible. If you don’t want to get pregnant you should opt for a contraception method.