By Sara Fueyo Pestaña (Gynaecologist – Reg. No. 202008718).
If you are trying to conceive, it is essential to understand when ovulation occurs and which days represent a woman’s peak fertility. Having access to this information can help shorten the time it takes to achieve pregnancy and make the process easier and more manageable for the couple.
Ovulation is the process in which a woman’s ovary releases a mature egg, ready to be fertilized. This event does not always occur at exactly the same time, as it can vary depending on the woman and from month to month. Factors such as stress, hormonal fluctuations, or overall health may influence it.
The menstrual cycle is divided into three distinct phases:
This marks the beginning of each cycle and is characterized by bleeding, which results from the shedding of the endometrium. It usually lasts between 3 and 7 days.
During this phase, the ovarian follicles begin to mature under the influence of the follicle-stimulating hormone (FSH). Typically, only one follicle will fully mature and be released, while the rest are reabsorbed by the body.
After ovulation, the follicle that released the egg transforms into the corpus luteum, which produces progesterone—the hormone responsible for preparing the endometrium to support embryo implantation. If fertilization does not occur, the corpus luteum degenerates, leading to the onset of a new menstrual cycle.

There are several physical signs that may indicate when ovulation is taking place. The most common are:
In this sense, each body is different and reacts differently, but paying attention to these symptoms can be very useful in identifying your fertile days.
A woman’s most fertile window includes the day of ovulation and the five days preceding it. This is because sperm can survive in the female reproductive tract for several days, whereas the egg remains viable for fertilization for about 24 hours after being released. As a result, the fertile window extends beyond the exact moment when ovulation occurs.
Estimating ovulation and fertile days is not always easy, but there are different methods that can help. A traditional approach, in a regular 28‑day cycle, is to count fourteen days from the start of menstruation to estimate the time of ovulation.
However, since not all cycles are the same, more accurate tools may be used, such as menstrual calendars, mobile applications, or even ovulation tests that detect hormonal changes in urine.
It is important to remember that these methods provide guidance and do not replace professional medical evaluation. Nonetheless, understanding ovulation and the fertile window is a valuable way to connect with one’s body and improve reproductive health.
Practice Committee of the American Society for Reproductive Medicine; Practice Committee of the Society for Reproductive Endocrinology and Infertility.
Optimizing natural fertility: a committee opinion.
.
2022;
53-63
Recomendaciones sobre fertilidad natural que incluyen la duración de la ventana fértil, el momento de la ovulación, la frecuencia de las relaciones sexuales y los métodos para identificar los días fértiles:
https://doi.org/10.1016/j.fertnstert.2021.10.007?utm_source=chatgpt.com
Wilcox AJ, Weinberg CR, Baird DD.
Timing of sexual intercourse in relation to ovulation: effects on the probability of conception, survival of the pregnancy, and sex of the baby.
.
1995;
1517-1521
Estudio prospectivo sobre la relación entre el momento de las relaciones sexuales respecto a la ovulación y la probabilidad de concepción:
https://doi.org/10.1056/NEJM199512073332301
Dunson DB, Baird DD, Wilcox AJ, Weinberg CR.
Day-specific probabilities of clinical pregnancy based on two studies with imperfect measures of ovulation.
.
2019;
1835-1839
Estudio que analiza las probabilidades de embarazo según el día del ciclo y la relación temporal con la ovulación, estimando la duración de la ventana fértil:
https://doi.org/10.1093/humrep/14.7.1835
Wilcox AJ, Dunson D, Baird DD.
The timing of the “fertile window” in the menstrual cycle: day specific estimates from a prospective study.
.
2000;
1259-1262
Estudio prospectivo que analiza cuándo se produce la ventana fértil dentro del ciclo menstrual y demuestra que su momento puede variar considerablemente incluso entre mujeres con ciclos habitualmente regulares:
https://doi.org/10.1136/bmj.321.7271.1259