When you want to have a baby, it is natural to hope that the pregnancy will happen as soon as possible. To optimize your chances of getting pregnant quickly, it is important to calculate your ovulation date so that you know the best time to conceive.

To have a baby, there must be fertilization. And for there to be fertilization, you need an oocyte on one side and a sperm on the other. However, this only happens a few days per cycle. To maximize your chances of pregnancy, it is therefore important to detect this “fertility window”, the right time for conception.

For this, it is essential to calculate the date of ovulation. On regular cycles, it takes place on the 14th day of the cycle, but some women have shorter cycles, others longer, or even irregular cycles. It is therefore difficult to know when ovulation occurs. You can then use different methods to know your ovulation date: the temperature curve, the observation of cervical mucus and ovulation tests – these being the most reliable method.

Once the date of ovulation is known, it is possible to determine its fertility window which takes into account on the one hand the lifespan of the spermatozoa, on the other hand that of the fertilized oocyte. To know :

• once released at the time of ovulation, the oocyte is only fertilizable for 12 to 24 hours;
• sperm can remain fertilizing in the female genital tract for 3 to 5 days.

Experts recommend having intercourse at least every other day around ovulation, including before. However, knowing that this good timing does not guarantee 100% the occurrence of a pregnancy.

It is impossible to answer this question as fertility depends on many parameters: the quality of ovulation, the uterine lining, cervical mucus, the condition of the tubes, the quality of sperm. However, many factors can influence these different parameters: age, diet, stress, smoking, alcohol consumption, overweight or thinness, operative sequelae, etc.

We can however give, purely indicative, averages. Thus according to the latest figures from INED (1), out of 100 couples of average fertility wishing a child, only 25% will achieve pregnancy from the first month. After 12 months, 97% will be successful. On average, couples take 7 months to become pregnant.

An important factor to take into account is the frequency of sexual intercourse: the more numerous, the more the chances of conceiving increase. So over a period of one year, it was calculated that:

• by making love once a week, the chances of getting pregnant are 17%;
• twice a week, they are 32%;
• three times a week: 46%;
• more than four times a week: 83%. (2)

However, these figures should be adjusted according to a key factor in fertility: the age of the woman, because female fertility decreases sharply after 35 years. Thus, the probability of having a child is:

• 25% per cycle at 25 years;
• 12% per cycle at 35 years;
• 6% per cycle at 40 years;
• almost zero beyond the age of 45 (3).

When a couple embarks on “baby trials”, the onset of menstruation can sound like a little failure every month. However, it should be kept in mind that even by scheduling sexual intercourse at ovulation, the chances of pregnancy are not 100% in each cycle, without this being a sign of a fertility problem.

Also specialists advise not to “think too much about it”, even if this is difficult when the desire for children is growing stronger and stronger.

Doctors speak of infertility when, in the absence of contraception and with regular intercourse (at least 2 to 3 per week), a couple fails to conceive a child after 12 to 18 months (if the woman is aged under 35-36). After 37-38 years, it is advisable to establish a first assessment after a waiting period of 6 to 9 months, because fertility decreases rapidly at this age, and with it the effectiveness of AMP techniques.