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Well.., given the high rate of C-sections in the US (32%) and many other countries, this is disturbing news. A study found that if a woman delivers her first baby by C-section (Cesarean birth), than her rates of conceiving again and also carrying the second baby successfully to term (a live birth) are lower than women who deliver a first baby vaginally.

The Penn State College of Medicine researchers looked at "unprotected intercourse and resulting conceptions", so it really was a measure of conception rates, and not a matter of choice. The study followed more than 2000 women for 3 years after the first birth, but it is unknown if these findings continue in year 4 and more. By the way, other studies over the years have had similar findings.

What could be causing these results? The researchers point out that it has been reported that many women (61%) develop a defect at the site of the cesarean incision (a cesarean scar defect) that may increase the risk of infertility.

From Science Daily: Women who deliver by C-section are less likely to conceive subsequent children

Women who deliver their first child by cesarean section (C-section) are less likely to conceive a second child than those who deliver vaginally, despite being just as likely to plan a subsequent pregnancy, according to Penn State College of Medicine researchers. The team followed more than 2,000 women for three years after they delivered their first child.  ...continue reading "Conception Rates Are Different After C-Sections and Vaginal Births"

After my January 9, 2015 post I was asked more about the microbial differences in babies who had been born by cesarean vs vaginal deliveries. What could be done about this? Should this be of concern when C-section rates in some places are approaching 50% of all births?

Well, some researchers are concerned, including Dr. Dominguez-Bello, who is doing ground-breaking research in this area. She is doing a long-term study in which babies born by cesarean section are immediately swabbed with a gauze cloth laced with the mother's vaginal fluids and resident microbes. Several (but not all) articles that I looked at said that the gauze is a "saline-soaked gauze".

Summary of the method:1) Incubate gauze in mother's vagina for 1 hour 2) Extract gauze before C-section  3) Expose newborn to the vaginal gauze (Mouth first, then face, then rest of body). If for some medical reason they don’t (and there is a C-section), then this is a restoring intervention.

Note that Dr. Dominguez-Bello always first checks to make sure the mother is HIV-negative and strep-B negative, and showing no signs of a STD. The basic premise is that babies should have crossed the mother's birth canal to be "seeded" with the mother's microbes, but if for some medical reason they don’t (and there is a C-section), then this is a (somewhat) restoring intervention.

From Feb. 2014 New York Academy of Sciences: Hats Off to Bacteria!

Why are bacteria in the body? What do we, and the bacteria, gain from this arrangement? And who's in charge? "There is a dialogue," Dominguez-Bello said, "sometimes a fight, sometimes a good dialogue. We have evolved with them. The first form of life on Earth was bacteria. Whatever came after had to deal with bacteria, cope with bacteria, associate with bacteria ...  ...continue reading "Can Missing Birth Canal Bacteria Be Restored to Cesarean Birth Babies?"

Another research result from the American Gut Project, an amazing crowdsourced project. While differences were found in the fecal microbiome (microbial community) of adults born by cesarean section vs vaginal delivery, it is unknown whether this has any possible effects on diseases or risks of diseases during adulthood. This study is online as of 8 November 2014, but still In Press. From EBioMedicine:

Diversity and Composition of the Adult Fecal Microbiome Associated with History of Cesarean Birth or Appendectomy: Analysis of the American Gut Project

Adults born by cesarean section appear to have a distinctly different composition of their fecal microbial population. Whether this distinction was acquired during birth, and whether it affects risk of disease during adulthood, are unknown.

Prenatal and early postnatal exposures and events can affect the entire life course. As one example, cesarean birth has been associated with an increased likelihood of asthma and cardiovascular disease in children (Renz-Polster et al., 2005, Thavagnanam et al., 2008 and Friedemann et al., 2012), hypertension in young adults (Horta et al., 2013), and obesity in both children and adults (Pei et al., 2014, Darmasseelane et al., 2014,Blustein et al., 2013 and Mueller et al., 2014). ... As well summarized by Arrieta and colleagues, several studies have noted differences in the neonatal fecal microbiota by route of delivery (Arrieta et al., 2014). ... More recently, with comprehensive analysis based on next generation sequencing of 16S rRNA genes, Dominguez-Bello and colleagues reported that route of delivery was associated with differences in the composition of the microbial populations that initially colonized the offspring. Notably, neonates who were born vaginally were colonized by vagina-associated bacteria, whereas those born by cesarean section were initially colonized by skin-associated bacteria ( Dominguez-Bello et al., 2010).

Early life alteration of the gut microbiota may have a lasting effect. Trasande et al. observed that exposure to antibiotics up to age 6 months was associated with elevated body mass index (BMI) up to age 7 years (Trasande et al., 2013).

The 16S rRNA V4 region was sequenced by the American Gut Project....Of the 1097 participants, cesarean birth was reported as “yes” by 92, “no” by 948, and missing or uncertain by 57. Likewise, appendectomy was reported as “yes” by 155, “no” by 961, and missing or uncertain by 21.

This analysis was primarily motivated by the observation that the composition of the microbiome of neonates differed significantly between those born vaginally and those born by cesarean section (Arrieta et al., 2014 and Dominguez-Bello et al., 2010). With vaginal delivery, the neonatal microbiome resembled the vaginal microbiome, with high relative abundance of Prevotella and especially Lactobacillus taxa. In contrast, cesarean-delivered neonates had a diverse array of taxa resembling the skin microbial community, including Staphylococcus, Streptococcus, Propionibacterineae, Haemophilus, and Acinetobacter ( Dominguez-Bello et al., 2010). Cesarean-delivered neonates and infants typically have a paucity of Bifidobacterium and Bacteroides species ( Arrieta et al., 2014).

In the current analysis, we observed that the fecal microbiome composition differed in adults who reported that they had been delivered by cesarean section. This suggests that a difference by route of delivery may persist into adulthood. Of the taxa noted to be increased in cesarean-delivered neonates and infants ( Arrieta et al., 2014, Penders et al., 2006 and Dominguez-Bello et al., 2010), only Haemophilus and certain Clostridia genera had elevated abundance in the fecal microbiome of cesarean-delivered adults ( Table 3).