Τhe Cesarean section is one of the most common surgical procedures performed worldwide, and its already high rates are increasing rapidly in high- and middle- income countries. Almost 30% of childbirths in the US, more than 35% in Greece and over 50% in some regions of Latin America are Cesarean sections. At the same time, there is growing evidence that Cesarean delivery apart from its negative short-term effects on both the mother and the infant, also has long-term consequences in the child’s life. A new study conducted by Greek scientists from Athens and Sweden has demonstrated a link between elective (planned) Cesarean deliveries and high risk of developing the most common type of leukemia in children.
Since 1985, the World Health Organization (WHO) has been warning that the “ideal rate” of Cesarean sections should range between 10% and 15%. Recent studies confirm this, revealing that although the Cesarean delivery rate of 10% reduces maternal and newborn deaths, there is no further decrease in mortality rate when this rate exceeds 10%. Yet, in over half of the world’s countries, Cesarean deliveries exceed by far 15% of all childbirths. In 2008, WHO estimated that every year 6.2 million unnecessary Cesarean sections are performed, the cost of which amounts to 2.32 billion US dollars.
Besides the increased costs, more and more scientific studies suggest that the Cesarean delivery deprives the child of the “health boost” that the natural delivery has to offer. “Leukemia is just the tip of the iceberg,” says Eleni Petridou, head of the Greek-Swedish research team, a professor at the Laboratory of Hygiene, Epidemiology and Medical Statistics of the Athens University Medical School.
Recent studies have shown that children delivered by Caesarian section are 23% more likely to develop diabetes mellitus sometime later in their life, 22% more likely to develop asthma, 37% more likely to develop allergies and 80% more likely to suffer from gluten-sensitive enteropathy, also called celiac disease.
As the Cesarean childbirth rate grows worldwide, scientists have been investigating the association of C-section with carcinogenesis. However, in their recent research, published in March in the European Journal of Cancer Prevention, the Greek scientific team has made a useful distinction between “elective” and “emergency” Cesarean section. The study demonstrated that babies under three years old, who were delivered by elective Cesarean section are 60% more likely to develop acute lymphoblastic leukemia ― the most common type of leukemia at that age ― compared to those born by natural (spontaneous) delivery or by emergency Cesarean section.
“In emergency Cesarean delivery, the fetus has already prepared for the difficult process of natural birth,” says Ms Petridou, clarifying that the emergency C-section is performed after labor pains have started or once “the waters have broken.” During natural childbirth, as well as before an emergency C-section, a valuable and irreplaceable mechanism gets activated. “The levels of stress experienced by the newborn increase significantly, leading to an increase of stress-related hormones such as cortisol, adrenaline, and noradrenaline,” explains Thomas Thomopoulos, a Ph.D. candidate at the Athens University Medical School and co-author of the study. “Cortisol levels in the neonate’s blood during birth and for at least two weeks after birth, are much higher than the cortisol dose administered by oncologists at the beginning of leukemia treatment in children,” he says. These strong indications led gynecologist Alkistis Skalkidou, a professor at the Uppsala University in Sweden and research consultant for this study, to investigate to what extent induced labor, even in elective Cesarean sections, can prevent the above mentioned adverse effects.
“As these hormones are released, the ‘fight or flight’ reaction is triggered and gives the newborn the strength to survive in the new environment,” says Romelia Lelouda-Andreason, gynecologist, and head of the Obstetrics Department at the University Hospital of Halmstad in Sweden. “From an aquatic and sterile intrauterine ecosystem, the baby has to adapt quickly to a new air environment that is full of microbes.”
Labor stress is also beneficial in many other ways, as it “helps the neonate establish its respiration, enhances its alertness and also protects its heart and brain, by increasing blood flow to these vital organs,” says pediatrician Maria Karalexis, member of the above research group from the Athens University Medical School.
In the study, the researchers investigated the circumstances around the delivery of 1.099 children, who live in Greece and developed Acute Lymphoblastic Leukemia within the first three years of their life and compared their findings with those of healthy children. The researchers conducted a questionnaire survey of these children’s mothers and discovered that four out of five Cesarean sections were elective, with the majority of those conducted because the mother had a previous C-section.
Years ago, a woman’s Cesarean section would erase any hope of a potential future natural childbirth. Today, however, thanks to changes in surgical practices, in most cases it is possible for a mother to have a natural childbirth after a previous Cesarean delivery. More specifically, among the women who are attempting to give natural childbirth after a previous Cesarean delivery, three out of four succeed.
“Following a C-section, there is a small risk of almost 0.5% for uterine rupture, in other words, the rupture of the previous C-section caused by the contractions during natural delivery,” says gynecologist Lelouda-Andreason. However, with a good monitoring of childbirth that can be provided by any hospital, this small risk can be detected in time and then the doctors can perform an emergency Cesarean section. “In Sweden, most childbirths following a previous Cesarean delivery are natural. In our hospital, where 2,000 babies are born every year, we might come across only one case of uterine rupture every ten to twelve years!” she says.
The Greek phenomenon
“One of the most important reasons why so many Cesarean sections are performed in Greece is the ‘medicalisation’ of the entire process of reproduction, pregnancy, and childbirth,” says midwife Angelika Klimou. Ms Klimou did her postgraduate training in Finland and today is collaborating with a Greek gynecologist who specialises in natural deliveries after previous C-sections, usually referred to as a VBAC (vaginal birth after a previous c-section). In Greece every woman has 10 to 15 ultrasound scans during her pregnancy, while in Sweden the corresponding number is only two ultrasound scans, one of which is optional,” explains Ms Lelouda-Andreason. “In other words, a completely natural process becomes fully ‘medicalised,’ resulting in various fears that often lead to unnecessary C-sections,” she adds. “In some private maternity hospitals in Greece, the C-section rate reaches 75% of the overall birth delivery rate. Probably to serve various interests, too many Cesarean deliveries are performed without having the required clinical indications,” says professor of medicine and pediatrician George Hrousos, also a co-author of the survey.
According to WHO, the lack of an international standardised classification system for recording and comparing the Cesarean section rate in different clinics, hospitals, countries and geographical regions prevents a better understanding of this trend. WHO proposes the adoption of the Robson Classification System, which divides the women admitted to maternity hospitals for delivery into ten groups based on easily identifiable features, such as the number of previous gestations, fetal presentation, gestational age, prior uterine incisions, number of fetuses and onset of labor.
“We are not demonising Caesarian sections. One out of seven times, nature does not allow for a child to be born naturally, and in this case, the Cesarean section is imperative and life-saving,” says Ms Petridou.