Etymologically, hyperfertility would describe an excessively (hyper) fertile woman. If we are to believe the testimonies of women who would be confronted with it, we could define it as the propensity to get pregnant at or near every cycle without regular contraception, or even to become pregnant despite the use of a contraception. Hyperfertility would then be related to the average time of conception (around 4 months for a couple under 35) and thus describe a woman who tends to get pregnant more easily than average.

In reality, hyperfertility is not a medically recognized condition. It has not been the subject of any research work or any medical recommendation. And for good reason: it would be tantamount to admitting that getting pregnant naturally is a pathology.

How then to explain this increased tendency to get pregnant? For the medical profession, the explanation would be purely physiological. If not on contraception, a (young) woman of childbearing age has a 25% chance of getting pregnant in each cycle (after unprotected sex at the time of ovulation). If there are recognized disruptors of fertility (stress, excessive fatigue, abuse of substances such as tobacco, drugs, caffeine, etc.), not all women are exposed to them or react to them identically. What they consider hyperfertility is therefore often only a natural propensity to get pregnant, favored by a luck factor (1 in 4) and a healthy lifestyle (or at least a better tolerance to stressors).

As for pregnancies under contraceptives, they are more likely to be explained by the conjunction of prior factors and human error or the relative effectiveness of the methods in question. Thus, if the contraceptive devices display, for the most part, a theoretical effectiveness of nearly 100%, the High Authority of Health points out that their “practical” effectiveness does not guarantee not to become pregnant. A few examples: theoretically, the pill would protect 99,7% of fertilization. In practice, this rate drops to 91%, just like the patch. Similarly, if the male condom has a theoretical efficacy of 95%, it would only be effective, in practice, up to 85%.

As a reminder: 65% of unplanned pregnancies occur in women who use a method of contraception at the time of the onset of pregnancy (family planning figures).

If it is not recognized as pathological and does not seem to have a real medical basis, the notion of hyperfertility may prove more convincing in medical research to harmonize certain works on multiparity.

 The explanation? Traditionally, medical literature and practice distinguish three types of women

• nulliparous, who has no history of pregnancy,
• the primipara, who is a parturient having had only one child.
• the multipara, which gave birth to several children.

 Multiparity has been the subject of numerous medical studies because of the risks of complications associated with it. Thus, a woman who has had several deliveries would be more likely to suffer, during a subsequent pregnancy, from preeclampsia, hypertension, placenta preavia, postpartum hemorrhage, anemia, diabetes, etc. The very great multiparity would also increase the risks of giving birth to a stillborn child. Faced with these risks, the notion of multiparity has been refined in various research works in order to differentiate:

• moderate parity between 1 and 4 children,
• high parity between 5 and 9 children,
• very high parity between 10 and 14 children,
• extremely high parity beyond 15 children.

 However, this taxonomy has not been definitively validated, making the results of studies difficult to compare due to the cohorts defined differently. This is where hyperfertility comes in. Indeed, it is according to fertility criteria that Dr. Muktar Aliyu of Alabama-Birmingham University in the United States, proposed to reclassify multiparity. According to him, women with:

• between 2 and 4 children would fall into the “moderately fertile” category,
• between 5 and 9 children, in the “very fertile” category,
• between 10 and 14, in the “extremely fertile” category,
• over 15 children, in the “hyperfertile” category.

If its classification is not official today, it has the merit of starting a reflection around hyperfertility. And with a threshold of hyperfertility beyond 15 children, we can easily assume that it concerns few women in a country where contraception and family planning are easily accessible.

On another note, some research has attempted to explain recurrent miscarriages by a form of hyperfertility. Thus, a team from the neuroimmunology laboratory at the University of Utrecht hypothesized, in 2012, that recurrent miscarriages could be linked to the migration of endometrial cells. As a reminder, this migration originally participates in the good progress of the first days of pregnancy, favoring the implantation of the embryo (with the accelerated migration of these cells) or allowing to “reject” the embryos of poor quality (carrier of abnormalities). chromosomal) by inhibiting these cells.

Their observation: in normal times (apart from the presence of an embryo), the migration of endometrial cells was identical in women without a history of miscarriages and in women who had suffered repeated miscarriages. On the other hand, in the presence of a poor quality embryo, there was an inhibition of the migration of these cells in women with so-called normal fertility and a phenomenon of accelerated migration in women victims of miscarriages.

This study would thus tend to demonstrate that in these same women, the endometrial cells would be unable to distinguish the embryos according to their quality, which would therefore favor repeated pregnancies (which could be described as a form of hyperfertility) but also the risk of repeated miscarriages, the embryos of poor quality “not sorted” not being viable. These observations, carried out on a very small cohort of women (12), are however yet to be confirmed.