Is Vaginal Birth an Evolutionay Advantage or an Outmoded Natural Function? A Midwife’s Perspective


When the English midwife Jane Sharp wrote The Midwives Book in 1671, almost all births took place at home with a midwife in attendance, medical men being relatively few in number. Hobby reports that, at this period, around ‘80–85 % of all babies survived at least for a few years post-delivery’ and ‘a woman’s cumulative risk of dying in childbed, through her probable six or seven pregnancies, was less than 10 percent’.18 using a hook19


and mentions the name of ‘Francis Ruset’.20


Sharp discusses the removal of a dead child She also


refers to other early Caesarean advocates, while expressing the personal opinion that the operation was untenable ‘whilest the Mother is alive’,21


although, if the ‘child was thought to be alive and


the mother at the point of death’, Sharp would endeavour to ‘assist the child in breathing by keeping open the mother’s mouth and privities [private parts], to aerate the fetus’ until a post-mortem Caesarean operation could be performed.20


Further Work (1700–1900)


Surgeons in France carried out more operations during the ensuing decades. Statistics provided by Jean Baudelocque of France to John Hull of England around 1799 present some interesting but sobering cases of successful and unsuccessful caesarean sections. In his Observations on Mr Simmons’s Detection …, John Hull recorded a total of 112 known cases since 1500, in which 43 mothers had died and 69 had survived. He also included Baudelocque’s data of known cases in France since 1750, in which only 31 out of 73 women’s lives had been preserved by the Caesarean operation.22


During the late 19th century, the operation was pioneered in Britain, particularly in Scotland23


and North West England,24 which


happened to have the most cases of severe cephalopelvic disproportion, mainly attributed to rickets. The first successful operation in England was performed in 1793 by a Mr Barlow of Chorley, Lancashire, on a woman who had laboured for five days. By the 1880s, significant improvements in operative technique had been made: the uterus was sutured in layers, the abdomen was cleared of excess blood, aseptic technique had improved, and women were operated on slightly earlier when in better condition and less likely to suffer from infection.


From Dangerous to Banal (1900–2012)


In the early 20th century, the problem of bony dystocia gradually began to decrease, whereas the CS rate continued to increase slowly but steadily.4


In 1902, the Midwives Act aimed to ensure midwives were all registered and educated to a minimum standard upon qualification. Their role in working with women was seen as crucial, along with sanitary reforms, if significant improvements to the poor state of the health of the nation were to be achieved. Over the course of the 20th century, a number of medico-social and political changes took place, which facilitated open access to antenatal and intrapartum surveillance by midwives, general practitioners and obstetricians, increasing opportunities for more timely medical intervention. Subsequent health policies led to more centralised maternity services and promoted a dramatic decline in home births and an equally dramatic rise in hospital births, to the point when, in the Peel Report of 1970, hospital birth was recommended for all.25 There were also improvements in birth mortality and morbidity rates, which were initially attributed to increased levels of medical intervention, but subsequently also more widely to improvements in the general health of women and in the environment.26


Clinical EUROPEAN OBSTETRICS & GYNAECOLOGY SUPPLEMENT Adaptation


The fortunes of the peppered moth Biston betularia provide a classic example of a relatively rapid biological adaptation. The predominant phenotype of populations of the moth inhabiting unpolluted environments is predominantly light with some dark specks. However, it was observed that, in heavily polluted industrial areas, where the bark of trees was darkened by soot and grime, the predominant phenotype had become much darker. This can be explained by the existence of strong selection pressure, in such an environment, against the lighter phenotype, which was highly visible against the darkened tree bark, leading to selective predation by birds.28


Once


pollution levels decreased, the lighter phenotype re-established itself, as now the darker moths were more visible against the lighter bark.


Another example of a type of genetic mutation which became established through conferring selective advantage in a particular environment, this time in human populations, is the haemoglobin abnormality that gives rise to sickle cell disease. Although the homozygous form of this condition is deleterious, the heterozygous form confers considerable protection against malaria, leading to the selective transmission of the gene among populations in affected areas. A similar instance of advantageous micro-evolution was the acquisition, via the spread of a genetic mutation, of lactose tolerance in early pastoral communities.


There are instances where the effects of deleterious genes in human populations are commonly ameliorated via medical technologies; here, selection pressures against individuals affected by a genetic condition are considerably reduced, leading to possible increases in the frequency of the deleterious mutation within these populations. Isoimmunisation, the risk of which is reduced via anti-D injections, provides one example. Similarly, certain congenital defects are becoming rarer, although they have not been eradicated from the gene pool; prenatal diagnosis provides women with the option to abort an affected pregnancy.


Evolution of the Human Species


Four million years ago, the early hominids developed the ability to walk on their ‘hind legs’ (bipedalism), which appeared to give them a number of evolutionary advantages, giving rise to a variety of teleological explanations.29


First, the shift to bipedal locomotion freed up their ‘front feet’ to be used as hands, which led to the use of tools 9


The Female Pelvis and the Process of Evolution The concept of adaptation is fundamental to evolutionary theory. An adaptation is a change or modification that enables an organism to survive in order to reproduce and transmit its genes within a given environment.


developments in anaesthesia and pharmacology (chiefly antibiotics and oxytocics, but also the contraceptive pill in 1960) and the use of blood transfusions and radiography all contributed to the rise in CS rates. Medical litigation led to defensive obstetrics, and the use of more birth technology increased foetal surveillance and promoted foetal medicine. Parallel developments in the fields of paediatrics and neonatology facilitated life support for increasingly pre-term infants and new reproductive technology contributed to higher rates of multiple pregnancy.4,27


While birth was revolutionised in the West, the


original indication for the Caesarean operation, bony dystocia, faded somewhat into the background.


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