Study: Vaginal insemination after cesarean section

This article is part of our October 2022 Immune Health special issue. Download the full issue here.

reference

Song SJ, Wang J, Martino C, et al. Naturalization of the microbiota developmental course of neonates born by cesarean section after vaginal seeding.Med (NY). 2021;2(8):951-964.e5.

Study objective

To provide a sufficiently powered longitudinal study to determine the impact of restoring exposure to maternal vaginal fluids after cesarean delivery on neonatal microbiota

Key to take away

Through vaginal insemination of babies born by cesarean section, their microbiota is naturalized and multiple parts of the body can be transplanted.

design

Multicenter observational study

Participant

The study followed 177 babies from birth to one year (98 born vaginally, 79 born by cesarean section). Thirty of the babies born by cesarean section had maternal vaginal mucus swabbed at the time of birth. All vaccinated cesarean section babies were negative for group BStreptococciand for sexually transmitted infections (STIs) and had intact membranes at the time of birth. The demographic details were as follows:

• 101 Babys wurden in den Vereinigten Staaten geboren, 20 in Spanien, 50 in Chile und 6 in Bolivien
• 52 % der Babys waren weiblich, 48 % männlich
• 75 % der vaginal geborenen Babys waren überwiegend gestillt; 69 % der per Kaiserschnitt entbundenen Babys und 53 % der per Samenkaiserschnitt entbundenen Babys stillten überwiegend.

intervention

Vaginal insemination using vaginal maternal gauze in infants born by cesarean section

Evaluated study parameters

The researchers collected stool, mouth and skin samples to analyze the diversity of the microbiota in different parts of the body using composition tensor factorization, which allows analysis of diversity over time.

Primary outcome

Microbial Trajectory at Multiple Body Sites of Vaccinated Cesarean Babies Compared to Vaginally Delivered Babies Compared to Cesarean Babies (Unvaccinated)

Key findings

The course of gut microbiota development in CS-born infants differed from that in vaginally born infants throughout Year 1^styear of life. Infected CS-born infants had a microbiota developmental trajectory more similar to that of vaginally born infants, particularly in feces and skin.

The effectiveness of seeding varied depending on the bacterial taxa; For example, researchers found that gut bacteria, includingBacteroides,StreptococciAndClostridium, were enriched from seeded CS infants, and in these infants, microbes were absent from CS-born babies. Other taxa did not show effective seeding and did not persist in the infant microbiome. The differences in sowing were most evident in the infants' feces.

During the taxonomic analysis, the researchers found a notable overlap between the species found in the mother's vagina and those in places such as the baby's feces, skin, nose and mouth, compared to non-pregnant controls. This indicates that the perinatal vaginal microbiome is pluripotent and capable of engrafting multiple sites in the newborn body.

Notably, all three groups showed maximum microbiota divergence at the time of birth and then converged over time to one year, with seeded CS babies becoming closer to, but not matching, vaginally born babies.

transparency

Funding for this study was provided by C&D, Emch Fund, CIFAR, Chilean CONICYT and SOCHIPE, Norwegian Institute of Public Health, Emerald Foundation, NIH, National Institute of Justice, and Janssen.

Implications and limitations for practice

Over the last decade, research has shown the many ways the microbiome can influence human health and the impact the route of administration can have on the microbiome. Differences in microbiome diversity and dysbiosis have been linked to childhood infections, cognitive and behavioral disorders, immune disorders, and potentially lifelong effects on obesity and metabolic disorders.^1-4These differences may be due to many factors that influence the newborn's microbiome, including the mode of delivery.

Several studies have found a difference in microbiota and clinical disease burden in children born by cesarean section compared to those born vaginally, although this idea is not without its critics.^5.6Separately, the practice of "vaginal seeding" was developed, in which gauze is soaked in maternal vaginal fluid and then wiped over the newborn's eyes, mouth, and skin to inoculate the infant.

To date, there has been no sufficiently powerful longitudinal study to detect differences in the microbiota at different colonization sites. This study adds to the growing body of evidence that vaginal seeding partially restores the infant microbiota of infants born by cesarean section, approaching that of vaginally born infants.

This study adds to the growing body of evidence that vaginal seeding partially restores the infant microbiota of infants born by cesarean section, approaching that of vaginally born infants.

While the results of this study are promising regarding possible long-term health effects, they may also influence future recommendations for clinical practice. Currently, both the American Academy of Pediatrics and the American College of Obstetricians and Gynecologists (ACOG) have formal positions making a recommendationagainstthe practice of vaginal insemination. American College of Obstetricians and Gynecologists Committee Opinion No. 725 recognizes that "the increase in the incidence of asthma, atopic diseases, and immune disorders reflects the increase in cesarean section rates; the theory of vaginal insemination is to allow for proper colonization." the fetal intestine and thus reduce the subsequent risk of asthma, atopic diseases and immune disorders.” However, it is not recommended to conduct the practice outside the context of an institutional review board-approved research protocol.⁷The College advises that if vaginal insemination is planned/performed, the patient should be tested for diseases that may affect the newborn, including serum testing for herpes simplex virus and cultures for group B streptococci.Chlamydia trachomatisAndNeisseriaGonorrhea.⁷

The American Academy of Pediatrics (AAP) similarly states that "vaginal insemination is not recommended outside of a research study because there is currently no evidence of the benefits and risks of infectious exposure" and that there should be strong warnings about group B streptococcal herpes simplex virus, including education about the possibility of false negative tests Group B streptococci⁸The academy also notes that breastfeeding and the mother's areola have a significant impact on the microbiome, regardless of delivery method.⁹and it questions the long-term consequences of cesarean delivery on the human microbiota, as the available literature generally does not extend beyond 2 years of age.⁸The two statements do not specifically address the literature indicating that mode of delivery has long-term effects on obesity in children and adults and an associated role between mode of delivery and the microbiome.^10-13

While vaginal insemination could potentially be a clinical tool to curb the rise of obesity, immune disorders, and neurodevelopmental disorders in the United States, it is unlikely that most obstetricians and pediatricians in the United States will be able to recommend and/or perform this practice with such oppositional statements from professional organizations as cited above. In the current climate, recommending and/or performing vaginal insemination exposes the physician to potential liability and is unlikely to be recommended in a clinical setting outside of a research protocol.

The two statements were published in 2017 and 2022, respectively, and may be updated in the future to reflect the translational research of this and other articles. However, there may be a tension between physicians' awareness of the potential positive effects of this practice and the potential liability for several years to come. This tension may be alleviated in other situations, such as a home birth or freestanding birth center with a certified nurse or midwife, as well as ongoing pediatric care in a naturopathic setting rather than with a physician or osteopathic physician. A trained patient can also perform this practice independently, without the explicit knowledge or consent of the care team. However, transparency is ideal so that physicians can properly test for infectious organisms and fully examine the infant if there is concern about possible infection of the newborn.

It is hoped that the research protocols will further expand longitudinal data, including larger sample sizes and longer-term outcomes, finding significant clinical differences and minimal harm. The collection of ongoing clinical data will be key to changing the AAP and ACOG positions so that the practice of vaginal insemination can be widely adopted in clinical practice in the United States in a safe and effective manner.