Miscarriage: A Necessary Evil for Human Evolution

Biologists call it ‘adaptive overproduction’: that all organisms produce more offspring than ultimately become adults. Land⁤ snails lay hundreds of eggs; many fish thousands, some trees produce millions of seeds and certain ⁣fungi billions of spores. This is how⁢ variation is generated from which the surroundings selects the suitable.

Only in humans, ⁣thanks to improved care, is the number of children born hardly greater than those ⁢who grow up. However,adaptive overproduction still exists in us before birth: the miscarriages in ⁣which ⁣about 15 percent of all pregnancies end are a manifestation of this. That 15 percent of spontaneous abortions is⁣ probably just ⁤the‍ tip of the iceberg. Doctors officially only speak of a miscarriage when a pregnancy has been established, but many embryos are already eliminated earlier, even before a woman realizes she is pregnant. Experts suspect that it is indeed frequently enough 30 to 60 percent.

„My interest in ‍miscarriages ‍arose more or less by chance,” writes gynecologist Willem‍ Vlaanderen (92) in his book Miscarriages. During his training,one of the ‍compulsory⁤ parts was the‍ ‘field service’:‍ going out day‍ and‍ night to treat miscarriages reported to the GGD.But ⁢because abortion was not yet ⁤legal at the time, the „miscarriages” sometimes turned‍ out to be failed attempts by women to terminate an unwanted pregnancy themselves. ⁣„Usually this was done with a bulb syringe, which ⁢thay inserted the spout into the cervix, after which soapy water was injected into the uterine ⁢cavity.” And if that caused⁢ peritonitis, the⁤ GGD ⁢was eventually called⁤ in.

such harrowing situations were one of the reasons ⁢why abortion⁤ clinics were finally opened around 1969 where⁤ women coudl go for medically responsible termination of pregnancy. A blessing for them, but also for research into miscarriages, Vlaanderen realized: „No woman would ever think of tinkering with ‍a ⁣soapy water syringe herself if she could have the procedure done painlessly⁢ and safely in a clinic.” That meant that among the⁣ miscarriages in the gynecolo

Low hCG production appears, in turn, to usually be the result of major genetic defects in the embryo – an extra or missing chromosome. When creating germ cells, exactly one of each of the 23 chromosome pairs must end up in the germ cell. Fertilization then neatly forms the‍ complete set⁢ of 46 chromosomes. But especially in the production of egg cells,things often go wrong: both chromosomes of a pair end up in the egg cell; or,conversely:‍ neither of them. Fertilization then results in a trisomy (three copies of a‍ particular chromosome) or ⁣a monosomy (only one copy). A ⁣ study published this week in Nature shows that such ⁣errors especially occur when there is little or no recombination within a chromosome pair; then they do‍ not stick together and one can wander through the cell.

And that has disastrous consequences for the viability of the embryo. The ‍worst are monosomies, because every hereditary condition on⁤ that chromosome manifests itself, because the effect cannot be compensated for by a healthy gene on the other chromosome. These are also the embryos with monosomies that are mainly discarded before the woman even⁤ realizes she⁢ is pregnant.

Trisomies are also problematic, as ⁢the extra dose of genes can result in a too high concentration of certain ⁢signaling substances, disrupting growth. Most trisomies are thus also spontaneously aborted by the mother. Only ⁤if it⁢ concerns chromosome 21, the ⁤smallest of all, where few crucial genes are located, can a trisomic embryo be viable and produce a viable baby,⁤ who is then born‍ with Down syndrome. Such embryos also often exhibit a strikingly high hCG production.

The fact that‍ ultimately ‍less‍ than⁢ one in three thousand babies is born with such a chromosomal abnormality shows how efficient the mother’s screening system is.Because it is⁤ estimated that more than half of all fertilized eggs have an extra or missing chromosome. Virtually⁤ all of these problem cases are filtered‍ out eventually, and the miscarriages we see are part‍ of ⁢that.

Embryos ‍that Flanders encountered during his research likely had major chromosomal abnormalities. But remember that he also found a small ⁢percentage of healthy-looking fetuses. This may have something to do with what ralph Catalano of the university of California, berkeley, discovered; namely that miscarriages, in addition to detecting genetic problems, ⁤can also play another role: terminating a pregnancy if the future prospects outside the womb rapidly deteriorate. In circumstances that cause high ⁤infant mortality, Catalano says, the chances of survival, especially for⁣ boys who were relatively small for their age at birth, decrease. Catalano discovered⁤ that it was precisely relatively small, male embryos‍ that were affected by miscarriages by examining Swedish church registers⁢ between ‍1750 and 1840.

Not that miscarriages were recorded there,but all births and deaths were recorded precisely. Moreover, there was ⁣little medical intervention at the time, and the picture was not distorted by migration. Catalano discovered that the number of boys born decreased each time after a year with high infant mortality compared to the number of girls born. The missing boys had therefore disappeared as miscarriages, while they would have been born⁤ under better circumstances. In contemporary ⁢California, he found something similar. He screened nearly 5 million births from 1989 to 2009 ⁢and discovered that small boys were considerably less ⁢likely to be born ⁣(and‍ were thus⁤ more frequently enough involved in a miscarriage) if employment had fallen sharply four ⁢months earlier.

Miscarriage is usually just bad luck

Miscarriage‍ is therefore a striking, traumatic, but at ⁢the same⁢ time unavoidable part of the decisions about⁤ life and death to which the mother subjects all her conceptions.In most cases, it is simply bad luck: the ⁣embr

Three ⁤Dutch doctors are investigating whether the drug ⁤ prednisolon ⁤can reduce an oversensitive⁤ screening mechanism in the uterus,potentially helping women with recurrent miscarriages. As the study is ongoing, no statements can yet be made about its effectiveness or outcomes.

Flanders is skeptical and suspects that any treatments ‍could be counterproductive, as they might give⁢ all women with recurrent miscarriages the misguided idea ⁣that ⁢something is wrong with them. “Women who are informed […] are no longer patients, suffering from an unexplained⁢ illness called Recurrent Miscarriage. They will stand⁤ up ‍for themselves, regain ⁣confidence in nature and⁣ their own ⁤bodies, and with continued attempts will almost ‍certainly achieve their goal: healthy ⁣offspring,” he believes.

Okay,I understand. ⁢I will adhere strictly to your instructions. Please provide the “UNTRUSTED ⁢source” text. I⁢ will then process it ⁤through the five phases you’ve ⁤outlined,delivering‍ only clean HTML‍ output.I will prioritize verification, authoritative sourcing, and ⁢a structured, semantic approach. ‍I will not ⁤rewrite, paraphrase, ⁤or mirror the source in any ⁣way. I await the ⁤source text.