Huge Study: Cesarean Birth Major Risk Factors for Chronic Disorders in Children

The release of the largest study of its kind confirms yet again that the Cesarean epidemic in the U.S. deserves more attention, and women deserve better information and options. Evidence continues to emerge that birth by surgery, while sometimes necessary and wanted, is not benign.

Increasingly, researchers are finding relationships between Cesarean birth and babies’ future health. The latest findings come from a mammoth study including two-million full-term births over 35 years in Denmark—showing that children born by Cesarean had “significantly increased risk” of developing certain chronic disorders.

Children born by surgery were more frequently hospitalized for these disorders than those born vaginally. They showed a 20% greater chance of asthma, a 10% greater chance of juvenile rheumatoid arthritis, a 17% greater chance of leukemia, and an over 40% greater chance of developing immune deficiencies, as well as higher chances of systemic connective tissue disorders and inflammatory bowel disease (IBD).

“We have shown, for the first time, that Caesarian sections can constitute a joint risk factor [for] several immune disorders — both childhood disorders such as asthma and allergies, and those which develop later in life,” Professor Hans Bisgaard from the Danish Child Asthma Centre at Copenhagen University Hospital in Gentofte, quoted in ScienceNordic on December 9, 2014 (“Giant study links C-sections with chronic disorders”)

Improving Birth executive board member Heather Thompson, MS, PhD, has been working at the intersection of molecular and cellular basic research and clinical science for 20 years. She currently works as Research Director at Mountain Midwifery Center in Englewood, Colorado. Dr. Thompson reviewed the study, which appears in the January 2015 issue of the American Academy of Pediatrics medical journal Pediatrics, and was interviewed for this article.

“Since the 1980s, the U.S. has exceeded a 15% Cesarean rate—the rate that the World Health Organization suggested could not be exceeded without harm¹ –and now we’re at almost 33%. The fact of the matter is, we’ve never known the long-term effects of Cesarean surgeries, even as they are occurring at higher and higher rates,” said Dr. Thompson. “Women are often led to believe that birth by surgery is relatively risk-free for them and safe for their babies, but more and more evidence is stacking up to show that we cannot make those assumptions.”

Correlation is not Causation

The results are compelling, although it’s important to understand that they show correlation, not causation. That is, they show a strong association between the presence of these immune diseases and the occurrence of Cesarean birth, but more research is needed to determine whether Cesarean birth is the cause of these problems, or merely an associated event.

Denmark saw an increase in the rate of C-sections from 5% in the 1970s to 20% in 2010. The U.S. saw a similar but even more dramatic rise to over 32% in 2012, according to Centers for Disease Control figures here. This is the same timeframe during which we have seen an increase in immune-related disorders in westernized countries.² The Danish study suggested this correlation was important, and their data supports that assertion.

This is probably at least partly attributable to the “western lifestyle”; in general, the prevalence of immune-related diseases is higher in westernized countries.³ It is not seen in immigrants who spend their early life in another country, but this relationship is seen in children of immigrants who have been moved to a westernized country early in their lives. ⁴ And while these diseases certainly have a genetic component, this study shows that cesarean birth is one of the shared environmental factors that “triggers the progression towards disease.”⁵

There are likely other factors at play, as well. Some of those (maternal age, parity, birth weight, among others) were controlled as confounders in this study.

Findings Support Prior Research

The idea that the mode of birth affects disease is not a new one. A number of smaller studies have shown a relationship between cesarean birth and chronic immune disease. We aren’t sure exactly how this works, but some of the hypotheses are based on data showing that:

• Babies have different gut microbiomes after cesarean birth vs. vaginal birth. It is interesting to note that the gut microbiome of a baby who experienced some labor before a surgical birth is closer to that of a vaginally birthed baby than that of a baby who did not (as in a planned Cesarean birth). ⁶
• Blood immune markers (leukocytes, neutrophils, monocytes and natural killer cells – all participants in the first lines of immune defense) are different at birth in babies born by Cesarean than born vaginally. ^7,8 Leukocyte composition continues to be different at one year of age. ⁹
• Stress hormone induction (cortisol) is lower in cesarean birthed babes, which may affect immune system maturation. ¹⁰
• Prophylactic antibiotics are given to women giving birth by surgery ¹¹, which is “likely to affect the microbiome of the newborn child.” ⁵

Public Health Implications

Emerging research points to the microbiome of babies as being a determinant in long-term health and even epigenetic changes—British documentary filmmakers have recently released a full-length film on this subject (see MicroBirth).

Further, we know that the bowel microbiome of babies is very sensitive to what they are being given to eat. Formula feeding, specifically, causes profound changes to both the pH and the microbiome of the gut. ¹²  High rates of Cesarean births and low rates of breastfeeding together, like we have in the U.S., may very well be exacerbating the issues we see with our babies’ guts now, and in their disease states, later.

A Message to Women from Improving Birth

Information about birth and modes of birth should be treated as what it is–important health information for personal decisions–and is not intended to shame women or make them feel bad.  At the same time, withholding information from women because we don’t want to cause hurt or guilt is a misplaced effort.  It’s a perpetuation of what is truly hurting women and babies today: known but undisclosed risks of procedures like Cesarean section, biased information from care providers, pressure because of non-health factors, and a lack of options when, for example, over 40% of U.S. hospitals have mandatory surgery policies for women with prior Cesareans.

Cesareans can be necessary, wanted, and life-saving.  Many are done for good reason, and every woman has the right to choose them.  It is clear, however, that many women today do not have a meaningful right not to choose them, as illustrated most recently in the case of Rinat Dray, the New York mother whose doctor wrote in her records that he “decided to override her refusal to have a C-section” and her decision to opt for a vaginal birth (see the New York Times article here).  Widespread bans on vaginal birth (see “VBAC Bans: The Insanity of Mandatory Surgery “) and physician tendency toward surgical birth in some places make it difficult or even impossible for too many women and their babies to avoid unnecessary, unwanted surgeries.

Many other women, meanwhile, are agreeing to Cesareans without being given full, accurate information, as has been shown by research (see Childbirth Connection’s high quality Listening to Mothers national surveys) and reported by thousands of women across the country. Many women are unaware of risks like greater morbidity and even mortality rates for themselves; a 9 in 10 chance of having all future babies by surgery (Centers for Disease Control and Prevention, 2012, linked here); and the increased likelihood of placental abnormalities in future pregnancies and births, posing serious, even life-threatening, risks to mom and babies.¹³ The data from this study adds to the growing body of information women must be provided as part of the informed consent discussion around Cesarean surgery.

It’s important for the public to understand that C-section rates have risen in the U.S. for decades: 1) without lowering the mortality rate for babies ¹⁴, 2) without lowering the mortality rate for mothers—it has actually risen dramatically, or 3) in the absence of research on the long-term risks of Cesarean birth.

Improving Birth is all about support and respect for women.  We want them to be healthy, well, and confident.  We don’t tell people how to give birth, and, because we respect women, we don’t withhold information, either.  We think it is also worth noting that, at time of publication, this study had not yet been reported in U.S. media.

Dr. Thompson concluded: “Women must have accurate and unbiased information about how they are giving birth in order to weigh the full spectrum of these risks and benefits. Whatever they decide, they should be supported and treated with respect.”

Want more? See the ScienceNordic article here, and purchase the study here.  Contact Improving Birth for quotes, interviews, and more here.

References

1. World Health Organization. Appropriate technology for birth.; 1985:436–7.
2. Bach J-F. The effect of infections on susceptibility to autoimmune and allergic diseases. N. Engl. J. Med. 2002;347(12):911–20.
3. Worldwide variation in prevalence of symptoms of asthma, allergic rhinoconjunctivitis, and atopic eczema: ISAAC. The International Study of Asthma and Allergies in Childhood (ISAAC) Steering Committee. Lancet. 1998;351(9111):1225–32.
4. Strachan DP. Family size, infection and atopy: the first decade of the “hygiene hypothesis”. Thorax. 2000;55 Suppl 1:S2–10.
5. Sevelsted A, Stokholm J, Bønnelykke K, Bisgaard H. Cesarean Section and Chronic Immune Disorders. Pediatrics. 2015;135(1):e92–8.
6. Azad MB, Konya T, Maughan H, et al. Gut microbiota of healthy Canadian infants: profiles by mode of delivery and infant diet at 4 months. CMAJ. 2013;185(5):385–94.
7. Nikischin W, Peter M, Oldigs HD. The influence of mode of delivery on hematologic values in the umbilical vein. Gynecol. Obstet. Invest. 1997;43(2):104–7.
8. Thilaganathan B, Meher-Homji N, Nicolaides KH. Labor: an immunologically beneficial process for the neonate. Am. J. Obstet. Gynecol. 1994;171(5):1271–2.
9. Huurre A, Kalliomäki M, Rautava S, Rinne M, Salminen S, Isolauri E. Mode of delivery – effects on gut microbiota and humoral immunity. Neonatology. 2008;93(4):236–40.
10. Gitau R, Menson E, Pickles V, Fisk NM, Glover V, MacLachlan N. Umbilical cortisol levels as an indicator of the fetal stress response to assisted vaginal delivery. Eur. J. Obstet. Gynecol. Reprod. Biol. 2001;98(1):14–7.
11. Smaill FM, Grivell RM. Antibiotic prophylaxis versus no prophylaxis for preventing infection after cesarean section. Cochrane database Syst. Rev. 2014;10:CD007482.
12. Fan W, Huo G, Li X, Yang L, Duan C. Impact of diet in shaping gut microbiota revealed by a comparative study in infants during the six months of life. J. Microbiol. Biotechnol. 2014;24(2):133–43.
13. Guise J-M, Eden K, Emeis C, et al. Vaginal birth after cesarean: new insights. Evid. Rep. Technol. Assess. (Full. Rep). 2010;(191):1–397.
14. Caughey AB, Cahill AG, Guise J-M, Rouse DJ. Safe prevention of the primary cesarean delivery. Am. J. Obstet. Gynecol. 2014;210(3):179–93.