By Dr. Sara Fueyo Pestaña (Gynaecologist – Reg. No. 202008718).
A very common question is whether it’s possible to get pregnant outside what are known as “fertile days,” that is, the days when a woman’s body is ready to receive sperm and therefore conceive.
But to what extent can we rely on the idea that pregnancy won’t occur outside those days? Can we depend only on fertile days to achieve pregnancy, or is it also possible during the rest of the month?
The menstrual cycle can last between 21 and 35 days, although it most commonly lasts around 28 days. Ovulation, meaning the moment when the ovary releases an egg, usually occurs around the middle of the cycle. To calculate fertile days:
From there, it’s important to know that the most fertile days are the 2–3 days before ovulation and the day of ovulation itself. This is because sperm can survive up to 5 days in the female body, while the egg lives between 12 and 24 hours.
Example: In a 28-day cycle, ovulation usually occurs around day 14, so the fertile window would be approximately from day 11 to day 15.
If your period is not regular, you can track your cycle length over several months to establish an average and make these calculations more accurately.
If you are trying to conceive, in addition to calendar tracking, there are other natural methods that can help you better identify your fertile window:
When combined, these methods can provide a more accurate picture than the calendar alone.
Yes, it is possible to get pregnant on any day of the month, although not with the same probability. During fertile days, the chance of pregnancy per cycle may range between approximately 20% and 30% in couples without fertility issues. Outside this window, the probability decreases significantly, but it is not zero.
This is because ovulation is not always exact. Stress, hormonal changes, or certain conditions can cause it to occur earlier or later than expected. In addition, cycles are not always regular, and since sperm can survive for several days, intercourse on a “non-fertile” day could coincide with an early ovulation.
For this reason, there are no 100% safe days if contraception is not used.
The process of achieving pregnancy begins with ovulation. The ovary releases an egg that can be fertilized by a sperm in the fallopian tube. The fertilized egg then travels to the uterus, where it implants in the endometrium, the inner lining of the uterus, leading to the development of a baby.
It is important to understand that if any of these steps does not occur properly, pregnancy will not happen. This process depends on very precise coordination between hormones, reproductive organs, and timing within the cycle. Even having intercourse during “fertile” days does not guarantee pregnancy, it only increases the chances.
In any case, the most important thing is:
Wilcox AJ, Weinberg CR, Baird DD.
Timing of Sexual Intercourse in Relation to Ovulation.
The New England Journal of Medicine (NEJM).
1995;
The New England Journal of Medicine. 333(23):1517-1521
Artículo científico (texto completo):
https://www.nejm.org/doi/full/10.1056/NEJM199512073332301
Wilcox AJ, Dunson D, Baird DD.
The timing of the "fertile window" in the menstrual cycle: day specific estimates from a prospective study.
BMJ Publishing Group.
2000;
BMJ. 321(7271):1259-1262
Artículo científico (texto completo):
https://pmc.ncbi.nlm.nih.gov/articles/PMC27529/
Practice Committee of the American Society for Reproductive Medicine.
Optimizing natural fertility: a committee opinion.
American Society for Reproductive Medicine (ASRM).
2022;
Fertility and Sterility. 117(1):53-63
Opinión del comité / Guía clínica:
https://www.fertstert.org/article/S0015-0282(21)02130-0/fulltext
Dunson DB, Colombo B, Baird DD.
Changes with age in the level and duration of fertility in the menstrual cycle.
European Society of Human Reproduction and Embryology (ESHRE).
2026;
Human Reproduction. 17(5):1399-1403
Artículo científico (texto completo):
https://academic.oup.com/humrep/article/17/5/1399/845579
Stirnemann JJ, Samson A, Bernard JP, Thalabard JC.
Day-specific probabilities of conception in fertile cycles resulting in spontaneous pregnancies.
European Society of Human Reproduction and Embryology (ESHRE).
2013;
Human Reproduction. 28(4):1110-1116
Artículo científico (texto completo):
https://academic.oup.com/humrep/article/28/4/1110/650256
Privacy Policy
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