Today’s society tends to roll back the age of first pregnancy from year to year. At the biological level, however, there is one fact that does not vary: fertility declines with age. Maximum between 25 and 29 years, it decreases slowly and gradually between 35 and 38 years, and more quickly after this deadline. Thus at 30, a woman wishing to have a child has a 75% chance of succeeding after one year, 66% at 35 and 44% at 40. Male fertility also declines with age.

Every pregnancy begins with the encounter between an oocyte and a sperm. However, this oocyte can only be fertilized within 24 hours of ovulation. To maximize the chances of pregnancy, it is therefore important to detect this “fertile period”.

On regular cycles, ovulation is on the 14th day of the cycle, but there are great variations from woman to woman and from cycle to cycle. For the purpose of conception, it is therefore advisable to detect the date of ovulation with one of its techniques: temperature curve, observation of cervical mucus, ovulation tests.

Experts recommend having intercourse at least every other day around this time, including before, because sperm can remain fertilizing in the female genital tract for 3 to 5 days. They will thus have time to go back to the tubes to eventually meet the oocyte released during ovulation. Be careful, however: this good timing does not guarantee the occurrence of a pregnancy. In each cycle, the probability of pregnancy after having had sexual intercourse at the key time is only 15 to 20% (2).

In our way of life and environment, many factors affect fertility. Accumulated in a “cocktail effect”, they can actually decrease the chances of pregnancy. As far as possible, it is therefore important to eliminate these various factors, especially since most of them are harmful to the fetus once the pregnancy has set in.

• tobacco could lower female fertility by more than 10 to 40% per cycle (3). In men, it would alter the number and mobility of spermatozoa.
• alcohol can cause irregular, non-ovulatory cycles and increase the risk of miscarriage, while in men it is believed to impair spermatogenesis.
• stress affects libido and triggers the secretion of different hormones that can have an impact on fertility. During significant stress, the pituitary gland secretes in particular prolactin, a hormone which, at too high levels, risks disrupting ovulation in women and men, causing libido disorders, impotence and oligospermia (4). Practices such as mindfulness help fight stress.
• excess caffeine could increase the risk of miscarriage, but studies remain conflicting on the subject. As a precaution, however, it seems reasonable to limit your coffee consumption to two cups per day.

Many other environmental factors and lifestyle habits are suspected of influencing fertility: pesticides, heavy metals, waves, intensive sport, etc.

Food also has a role to play in fertility. Likewise, it has been proven that being overweight or, on the contrary, very thin can impair fertility.

Dance The Great Book of Fertility, Dr. Laurence Lévy-Dutel, gynecologist and nutritionist, advises to pay attention to its various points to preserve fertility:

• favor foods with a low glycemic index (GI), as repeated hyperinsulinemia would interfere with ovulation
• reduce animal proteins in favor of vegetable proteins
• increase dietary fiber intake
• watch your iron intake
• reduce trans fatty acids, which can potentially damage fertility
• consuming whole dairy products once or twice a day

According to a recent American study (5), daily intake of a multivitamin supplement during conception could reduce the risk of miscarriage by 55%. However, be careful with self-prescription: in excess, some vitamins can be harmful. It is therefore advisable to seek professional advice.

No study has been able to demonstrate the benefit of this or that position. Empirically, however, we advise to favor positions where the center of gravity plays in favor of the path of the spermatozoa towards the oocyte, such as the Missionary position. Likewise, some specialists recommend not getting up immediately after intercourse, or even keeping your pelvis raised by a cushion.

It is also a controversial subject and difficult to verify scientifically, but it could be that the female orgasm has a biological function. According to the theory of “up suck” (suction), uterine contractions triggered by orgasm lead to a phenomenon of aspiration of sperm through the cervix.