Children born after medical birth interventions such as induction and c-section are more likely to develop health problems, compared with those born through spontaneous vaginal birth, a new study shows.

The research is a collaboration between Western Sydney University and a team of international researchers, and is said to be a world-first.

The study, published in the journal Birth, looked at almost 500,000 women and their babies between 2000-2008. The researchers followed the health of the children until 2013.

What Did The Study Look At?

The researchers used birth records from New South Wales (Australia) to select a sample of healthy, low risk mothers who had no pre-existing or pregnancy-related health conditions.

Women were included in the study only if they:

Were between 20 and 35 years of age
Didn’t smoke or take drugs
Gave birth between 37 and 41 weeks’ gestation to a single baby within a normal weight range.

When these exclusion criteria were applied, the study cohort consisted of nearly 500,000 healthy, low risk women, 55% of whom were having their first baby. Almost 70% of the women were Australian born, with an average age of 29 years.

Dr Lillian Peters, an epidemiologist at two Dutch universities, led the data analysis while she was a visiting postdoctoral fellow at Western Sydney University. Dr Peters says the study is unique in that it looks at the use of hormones to start and stimulate labour as well as the mode of birth.

What Did The Records Show About Birth Interventions?

The records were analysed and showed a wide range of births among the women:

88% had pain medication during labour
43% were induced or had augmentation during labour
38% had a spontaneous vaginal birth with no medical intervention
11% had a planned (elective) c-section
7% had an unplanned (emergency) c-section, after induction/augmentation.

What Did The Study Find?

The researchers followed the health of the children for the first 28 days after birth, and up to five years of age.

The results showed:

Babies born by forceps and vacuum, following induction/augmentation had the highest rates of jaundice and feeding problems.
Babies born by c-section had the highest rate of low temperature needing medical intervention.
At five years of age, babies born by c-section, particularly emergency c-section, had the highest rates of metabolic health issues such as obesity and diabetes.
Eczema, and respiratory infections such as bronchitis and pneumonia were highest among babies born after any form of intervention during labour and birth.

How Does Birth Mode Affect Future Health?

Lead researcher Professor Hannah Dahlen, from Western Sydney University, stresses the study did not aim to make women feel guilty about having interventions, but to increase efforts to bring more evidence-based practice to labour care.

Over the last decade, there has been an increase in the study of the human microbiome – the bacteria that live on and in us, from birth.

Our gut microbiome is made up of trillions of bacteria and their genetic material, which live in the gastrointestinal tract.

Babies born vaginally are ‘seeded’ by their mother’s bacteria as they are born, whereas babies born via c-section miss out on this seeding. Studies have shown a marked difference in the type of bacteria found in vaginally born babies, compared with babies born via c-section.

In 2012, Professor Dahlen and an international team of researchers developed the Epigenetic Influence and Impact on Childbirth (EPIIC) hypothesis.

The EPIIC hypothesis suggests normal labour and birth exert a healthy and positive form of stress on babies. This healthy stress affects certain genes, especially those which program the immune response, among others.

This new study could be the first to link physiological stress, caused by interventions during birth, with altered genes, connected with immune responses in babies. This is known as epigenetic modulation, and it has huge implications for the way in which women give birth.

What Does All This Mean?

This study highlights the very real downstream effects of medical intervention during labour and birth. There is an urgent need to change the way maternity care is provided, so as to reverse the decreasing chances of women having normal births.

Changes might include increasing the accessibility of midwifery-led models of care, and taking a more evidence-based approach to maternity care overall.

In the current birth culture, women are more likely to give birth in a hospital setting. Most women are only informed about the immediate and short-term risks of interventions, not about the long-term impact.

There is now a significant amount of research to show spontaneous vaginal birth has the best outcomes for both mothers and babies, in the short and long term.