Children whose mothers took antibiotics during pregnancy face a greater risk of needing hospital treatment for infections, research suggests.
A study by the Melbourne-based Murdoch Children's Research Institute has found children born to mums who took antibiotics during pregnancy can have up to a 20 per cent higher chance of being hospitalised with an infection.
Those whose mothers who took antibiotics while pregnant and had vaginal births were at a greater risk of infection than those delivered by caesarean section.
The findings, published on Monday in the International Journal of Epidemiology, were based on a data from Denmark where about one-in-five mothers were prescribed antibiotics during their pregnancies.
The study's lead author Dr Jessica Miller said the findings highlighted the importance of using antibiotics sensibly to treat infections in pregnant women as the drugs can reduce the amount of "good" bacteria in the mother's gut's microbiome, which is passed on to babies during vaginal births.
"A healthy microbiome is important early in life for the developing immune system and possibly for preventing serious infection," she said.
About one-in-eight pregnant women in Australia are estimated to be prescribed antibiotics in pregnancy.
For their study, the researchers looked at data collected from more than 776,000 infants who were born in Denmark between 1997 and 2009.
Eighteen per cent of the children were born to mothers with at least one recorded antibiotic prescription during pregnancy.
More than 222,000 children ended up being hospitalised with an infection by the time they turned 14, with boys more likely than girls to need treatment.
The researchers found that children born vaginally to mothers prescribed antibiotics in pregnancy had the highest risk for needing hospital treatment for gastrointestinal infections.
They suggested this could be because when a baby is born vaginally their gut microbiome is formed from their mother's gut and birth canal, and could have been affected by the antibiotics taken before birth.
The gut microbiomes of babies born by caesarean section are based on their mother's skin and hospital environment.
However the researchers acknowledged their study could have some limitations, particularly because an infection suffered by a pregnant woman rather than antibiotic exposure could play a role in the risk faced by children needing hospitalisation for infections.
They said details of infections the mothers in the study were being treated for were not available to them.
The researchers were also not able to tell whether the mothers who were prescribed antibiotics before and during pregnancy took them as directed.
