Obstetrics
Cesarean section has transformed the anatomy of women into a few generations
A study reveals that the female basin has narrowed three centimeters since 1900. In parallel, babies born by Cesarean section have larger heads.
In almost half of the cases, the cesarean is scheduled.
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- The average width of the female basin has decreased by three centimeters since 1900.
- Babies born by Cesareanus have a greater crankish circumference.
- Natural deliveries are gradually becoming more complex without medical assistance.
- In Switzerland, cesarean levels vary between 29% and 40%.
To come to the world, a baby must go through the basin of his mother. The wider the pool, the easier the delivery. However, in previous centuries, when a baby could not be born, the mother and the child died in excruciating suffering. Only progress in medicine and cesarean have changed the situation. Even women with a narrow basin and babies with a big head can now survive.
In recent decades, the number of births per cesarean has increased considerably in many countries, including in Switzerland. A recent international study shows the speed of this development. Since the start of the XXe A century, the average width of the female basin has decreased by almost three centimeters.
Risk of reduced mortality thanks to the cesarean
As part of its study, an Australo-Polish team analyzed the evolution of the dimensions of the female basin in Australia, Poland and Mexico over a period of seventy to nineteen years. It turns out that the women’s basin decreased by 0.42 mm per year of birth in Australia, 0.47 mm in Poland and 0.42 mm in Mexico.
The researchers also measured the crankish circumference of 6,310 Polish babies born between 1994 and 2014. Children born by Cesareanus present an average of a tower significantly larger than babies born natural.
Researchers identify several factors to explain the narrowing of the female basin. Modern obstetrics is one of the most important medical advances, with its techniques such as cesarean women, forceps assisted deliveries and obstetric suction cups. “Over the past two hundred years, these methods have been used in up to 40% of births in studied countries,” write study authors. Caesareans have experienced a sharp increase since the 1970s. In addition, the width of the pool seems to be a hereditary characteristic.
At the same time, the birth rate would have decreased by six to seven children per woman to only 1.32-1.79, which would also have reduced the statistical risk of death during childbirth. “Thus, the evolutionary advantage of a large pool and a small head among newborns disappears,” read.
The evolution of Homo Sapiens has placed our species in the face of a dilemma. A narrow basin is preferable to stand up and maintain a good posture. At the same time, human beings need a large skull to house their brain. Natural delivery becomes more and more difficult. Studies demonstrate That these difficulties appeared in our ancestors millions of years ago, at the first chapters in the history of humanity.
The rate of cesarean women varies strongly from one canton to another
What is surprising is that a physical transformation is already manifested after only a century, a relatively brief period in human history.
Is the evolution so fast? Until recently, it was thought that in humans, because of the time of generation, twenty-five years on average, the effects of evolution only occurred after millennia or, at best, centuries, explains Martin Häusler, professor of evolutionary medicine at the University of Zurich.
Another study carried out two years ago Had already proved that evolution can sometimes occur at a much faster rate. “Mathematical models have shown that in the absence of selection pressure due to the high frequency of Cesareans, the female basin could shrink in just a few decades,” added the scientist. We could expect this phenomenon especially since the 1970s and 80s, particularly due to the low birth rate. In the past, less than 5% of deliveries were done by cesarean in Europe and Australia.
In Switzerland, according to data from the Federal Statistics Office, a third of babies were born by Cesarean in 2023, with large differences between the cantons. In Zurich, 40% of births are made by Cesarean, while in French -speaking Switzerland, this rate is less than 29%. 55% of Caesareans were scheduled in advance, while the others were emergency cesareans, decided during childbirth work.
However, programmed cesareans can be justified by medical reasons. “The most common causes are a position of the baby by the siege, cesareans during previous deliveries, previous operations at the uterus or a problematic positioning of the placenta,” says Gabriela Stocker, chief doctor of the Obstetric Service of the Triemli Hospital in Zurich.
On the other hand, contrary to popular belief, when a cesarean is planned for medical reasons, being able to choose the date of childbirth is only an accessory advantage. “Fear of pain, to hurt oneself during childbirth or to develop problems of the Pelvic floor later influences the requests of cesarean sections,” adds the doctor. Some women also fear losing control or facing complications during childbirth.
Impossible births without medical assistance such as cesarean
The evocation of the cesarean is very old. She was already present in Greek mythology and, according to legend, Julius Caesar would also have come to the world by Cesarean. In ancient Rome, if a child died during childbirth, it was removed from the belly of his mother.
Switzerland also has its legend. Around the year 1500, Jakob Nufer, who practiced the castration of pigs, would have achieved a cesarean on his wife after several days of childbirth painthus managing to save the mother and the child. This event was only reported in writing long after it occurred. It would be more fable than a proven historical fact.
The cesarean has become a reliable and safe procedure only thanks to modern medicine, anesthesia techniques and, above all, with sterile conditions.
The study authors come to an obvious conclusion concerning the current trend. Natural births could one day become impossible without medical interventions such as the cesarean. “This is the most likely scenario for me,” concludes Martin Häusler. “But I don’t think it will happen during the XXIe century.”
Translated from German by Emmanuelle Stevan
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