We need pregnant women from throughout Auckland to take part in the ECOBABe trial exploring babies' microbiome at birth.

The ECOBABe Study (Early Colonisation with Bacteria After Birth) is investigating whether babies born by caesarean section can be protected from a greater risk of obesity, by being given bacteria from their mothers’ vaginas soon after birth.

We need women who are having an elective caesarean section, as well as women planning a vaginal birth to compare the differences in the gut bacteria of c-section and vaginally born babies.

Babies born by caesarean miss out on the normal process of exposure to these bacteria, which happens during a vaginal birth. The bacteria are an important part of developing babies’ digestive and immune systems. The study is trying to see if mimicking the normal process can help babies born by caesarean.

Why is this study important?

There is growing evidence linking caesareans to an increased risk of babies later developing obesity and immune disorders, like asthma and diabetes. A large international study last year found children born by c-section were around 25 percent more likely to become obese than those born vaginally (even after other differences are taken into account). It is possible that the disruption to the normal process of bacterial colonisation is affecting the development of the immune system during this short, but potentially very important, time of transition. Currently, we know there is an association between caesarean birth and obesity, but we are still trying to identify what links them. The ECOBABe study is an important step in the journey.  

What is this study trying to find out?

The study is trying to find out whether giving c-section babies their mothers’ vaginal bacteria will result in them having similar gut bacteria to those they'd have if they were born vaginally. We will find out whether the bacteria colonise the babies’ gut, if taken orally when mixed in a small volume of sterile water.

The study will measure the range and number of different types of gut bacteria of all the babies by analysing their stools (poo). This will show us whether there are differences in the gut bacteria of c-section and vaginally born babies. The study will also measure the babies’ weight, height and body fat composition. 

Who can take part?

We are looking for women who are having an elective caesarean section, as well as women planning a vaginal birth.

Recruitment has started and we hope to recruit women across the whole Auckland region.

What does the study involve?

If you take part, you'll need to complete a background health questionnaire, as well as a diet and exercise diary for three days before your baby is born.

Caesarean births

If you are having a planned c-section, you’ll need to visit the Liggins Institute one week beforehand to have blood and swabs taken. These will check for any infections that could be passed on to the baby (most of them are repeats of ones you will have already been tested for earlier in pregnancy). We are doing these extra tests because this research involves a slightly different way of doing things, requiring extra care to be taken. On the day of your caesarean, after you’ve been admitted to hospital, you’ll put a small gauze into your vagina, and remove it after about 30 minutes, before going to theatre.

The researchers will put the gauze into a small amount of sterile water. Soon after birth they will put some of this mixture into some babies mouths via a small syringe. Other babies will be given only sterile water (placebo).

Vaginal births

If you are planning a vaginal birth, you will only need to do the postnatal follow-up outlined below.

Postnatal follow-up for all babies

Once your baby is born, you'll need to collect a small sample of their poo, and another sample at one and three months after the birth (a kit is provided).

At one and three months you'll bring your baby to the Liggins Institute to be weighed and measured. At the three month visit, the babies will also have a scan to measure their muscle, bones and fat. We will pay your transport costs for each visit.

Are there any risks in taking part?

This study has several potential benefits. Participating in this project could lead to a new method to transfer healthy gut bacteria to babies born by C-section.

All women in the caesarean section group will be screened one week in advance of their caesarean to minimise the risk of transmission of infections.

The body composition machine scans have extremely low radiation dose exposure that is comparable to one day outside in the sun, and do not constitute a safety concern to babies.

How can I find out more?

Please get in touch if you'd like to find out more about the study or to discuss your potential involvement. Email the research team on or call/text 027 606 5140.