From the first day of your first period onwards, you can have a baby; up until your last period comes, you can have a baby. This is how the fertility window for women is roughly reduced and commonly seen.
Not counting the Peruvian girl who holds the record as the world's youngest mother (at the end of the 1930s, she had a child at the age of five and a half, due to a combination of a rare medical condition that induced early puberty in her, and an unknown man who had intercourse with her), there are in fact countless eleven, twelve year old mother children, especially in developing countries.
For a long time, at the other end of the spectrum, the record for the woman who gave birth naturally (without fertility treatment) was held by a British woman who had a baby boy, in 1997, at the age of 59; in China, just recently in 2019, there was the case of a 67-year-old woman who gave birth to a baby girl, claiming to have conceived naturally.
In short, extreme cases aside, can it be safely said that between 13 – the average age of onset of periods – and 51 – the average age of menopause – the window is open? No, that is not quite the case. First of all, although it is potentially true that with the arrival of her period, the ovulation mechanism essential for pregnancy is triggered in adolescents (or sometimes pre-adolescents), it is also true that getting pregnant in the earliest years of a fertility carries with it a number of significant dangers, starting with the fact that the body – especially the reproductive system – has not yet fully grown and formed, and is therefore not yet fully prepared for the transformations resulting from pregnancy. The risk of death in childbirth is greater in very young girls; this is one of the grounds emphasised by all the activists around the world who fight against child forced marriage. But nor is the axiom true for the other end of the line. One does not remain fertile until her last period. In the document Age and Fertility - A Guide for Patients published in 2012 by the American Society for Reproductive Medicine it is quite clearly stated that women are not fertile right up to the menopause. The average age for the onset of menopause is 51, but «most women become unable to have a successful pregnancy sometime in their mid-40s». The paper points out that fertility declines naturally as women age; and while of course «the time decline begins and the rate at which it progresses [varies] widely in women, but always [begins] well before menopause». For every woman. Generally, fertility begins to decline, warns the American Society for Reproductive Medicine, towards the end of the decade between the ages of 20 and 30 and the beginning of the next one, and declines more rapidly after the age of 35. «Women who decide to delay pregnancy until after age 35 should obtain information on appropriate testing and treatment while remaining realistic about the chances for success with infertility therapy». Not least because the chances of success are rather low. «By learning about all of the options and being aware of their own needs and goals» the document further specifies «a woman and her partner will be prepared to make the best decisions». Particularly from the age of 40 (and even more so from the age of 45), the chances of getting pregnant during a menstrual cycle – either naturally, as a result of unprotected sexual intercourse; or artificially, by using fertility treatments including in vitro fertilisation (IVF) – remain below 5 per cent. The report cautions against the media, which, by telling stories of celebrities getting pregnant even at an advanced age through fertility treatments, creates a public perception that age can easily be counteracted. The decline in fertility that occurs in women is related to age and this «happens because both the quality and the quantity of eggs gradually decline».
This decrease in the quantity and, above all, quality of eggs is why, with advancing age, it becomes more difficult for women to become pregnant and more likely, when they succeed, to experience miscarriages. This is why, concludes the American Society for Reproductive Medicine, «a woman’s age is the most accurate test of egg quality».
After the age of 40, women wishing to have a child often hear fertility experts propose using heterologous in vitro fertilisation, in other words, using a gamete from outside the couple: in this case, not the sperm but the ovum. This is also what drives the market for cryopreservation of one's ova: having them extracted when younger and freezing them, with the intention of being able to use them for a later pregnancy.
These two options (using the ovum of a young external donor, or using one's own ovum frozen five or ten or fifteen years earlier) are proving to be quite effective, even if they do not completely counteract the fact that, in any case, the embryo is then implanted in the uterus of a woman who is the age she is, and that it must then take root and continue its growth there. It is by no means impossible in such cases to end up with a baby – just statistically more difficult.
Comments