Effects of Vaginal Seeding on Infants' Body Mass Index and Allergy Risk for Caesarean-delivered Children

Study Overview
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Brief Summary
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This is a single-blind randomized controlled trial, aiming to evaluate the effects of vaginal seeding on body mass index as well as allergy risk for cesarean-delivered infants. It will be conducted in Liuyang city of China, and the targeted sample size is 106. All the eligible pregnant women will be randomly assigned to either the intervention or control group, and their babies of the participants will be followed up to 24 months of age.

Detailed Description
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Many studies have suggested that caesarean-delivered children are at higher risks of developing metabolic and allergic diseases like obesity and asthma, possibly because newborns born by caesarean section were lack of exposure to maternal vaginal flora. It is needed to explore a simple, convenient, and safe intervention strategy to reduce caesarean-related risks. In a recent non-randomized study, the authors found that exposure of caesarean-delivered newborns to maternal vaginal fluid at birth (i.e., vaginal seeding) could partially restore the microbiota of them at 30 days after births, but the long-term health consequences of restoring the microbiota of caesarean-delivered infants remain unclear. In this randomized study, the investigators aim to examine whether the changes in newborns' microbiota will persist to 24 month of age, and whether vaginal seeding will have any effects on body mass index and allergy risk from birth to 24 months of age. the investigators will enroll a total of 106 pregnant women, and the participants' infants will be followed up at 0 (before hospital discharge), 6, 12, 18 and 24 months. At each follow-up visit, a questionnaire survey including information on feeding, medication, and allergic status will be conducted, infants' height and weight will be measured, and feces will be collected. At 18-month-old visit, infants' venous blood will be also collected for the assay of multiallergen. The primary outcomes were body mass index and allergy risk index. The secondary outcomes included the microbiota profile, allergic symptoms and diseases, overweight/obesity, and adverse effects.

Official Title
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Effects of Vaginal Seeding on Infants' Body Mass Index and Allergy Risk for Caesarean-delivered Children: A Randomized Controlled Study

Conditions
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Overweight and Obesity, Allergy

Intervention / Treatment
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* Procedure: Vaginal seeding


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: local resident in Liuyang city Singleton, term pregnancy (≥37 weeks of gestation) Cesarean section before labor starts without maternal complications, or cesarean section after the start of labor but the cervix is less than 3 cm Vaginal pH< 4.5 at enrollment Exclusion Criteria: Positive testing for HIV, HBV, syphilis or GBS infection at gestation Vaginal infections such as genital herpetic lesions or chlamydia Bacterial vaginosis Trichomonas or fungous in leucorrhea Pregnant women or her spouse with severe allergic diseases, such as asthma and severe drug allergy Vaginal pH ≥4.5 at 1-2 hours before the cesarean section Other conditions not suitable for intervention as judged by obstetricians
Sexes Eligible for Study
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Female

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Prevention
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Single


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Vaginal seeding group<br>Swabbing infants born by C-section with a gauze incubated in the maternal vagina about an hour before the C-section. The gauze will be extracted prior to the C-section, kept in a sterile container in an incubator (37 ℃), and taken out from the incubator immediately before the swabbing. The infant will be swabbed with the gauze, starting from the lips, followed by the face, thorax, arms, legs, genitals and anal region, and finally the back. The swabbing will take around 15-20 seconds. | Procedure: Vaginal seeding<br>* The same as that stated in arm descriptions.<br>|
| No Intervention: Control group<br>Managed based on the standard practice in the study site | |

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| infant's body mass index | Body mass index in original scale and z-score | At 6 months | 
| infant's body mass index | Body mass index in original scale and z-score | At 12 months | 
| infant's body mass index | Body mass index in original scale and z-score | At 18 months | 
| infant's body mass index | Body mass index in original scale and z-score | At 24 months | 
| infant's allergy risk score | Calculated based on the measurements of multiallergens with 0-6 classes,higher values represent a worse outcome which means more susceptible to allergic diseases | At 18 months after birth | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Infants' gut microbiota profile | Intestinal flora will be detected by 16sRNA sequencing using feces samples | At baseline (Meconium), 6, 12 ,18 and 24 months after birth | 
| Rate of overweight/obesity | Defined by body mass index | At 6, 12 ,18 and 24months | 
| Rate of allergic symptoms and common allergic diseases | Collected by using a structured questionnaire | At 61, 12 ,18 and 24 months | 
| Rate of adverse effects | Infection-related diseases and others | From birth to 24 months | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Body mass index, Allergic risk, Vaginal seeding, Randomized controlled study, Caesarean delivery, Overweight and obesity