Eating probiotics, like those found in some yoghurts, could help women avoid postnatal depression.
New research suggests taking them during pregnancy prevents anxiety in the early days of parenthood.
Postnatal depression affects 10 to 15 percent of women, but Kiwi researchers may have found a simple solution.
Probiotics are live microorganisms known to improve the health of the gut and researchers say there's growing evidence that a healthy gut is linked to a healthy mind.
"When we improve the health of the gut and brain chemistry is altered, then the theory is that things like emotional responses and behaviour are affected as well," University of Auckland's Dr Rebecca Slykerman told Newshub.
Researchers found those taking the probiotic during pregnancy had significantly fewer symptoms of depression and anxiety once their babies were born.
Miriam Wood was one of more than 400 pregnant women who took part in the study. She says the results are encouraging for future mums.
"Maybe in the future it will become the normal part of pregnancy care," she told Newshub.
"Like we take folic acid and that's just prescribed by the GP and part of what you do every day, maybe it will be that pregnant women take a probiotic as well."
Probiotics are typically found in fermented foods as well as some yoghurts, so doing something as simple as upping your intake could help prevent postnatal depression - though more research needs to be done.
"We don't know if this effect is present for all probiotics, because not all probiotics are equal, or whether it's just this particular probiotic," Dr Slykerman said.
This study only looked at one strand of probiotic, Lactobacillus rhamnosus HN001. It's currently found in the Go Healthy 'Go Derma Protect' product sold in some pharmacies.
There are still questions over the dose, the type and how long women would need to take it for, but it's hoped it could be a natural, safe and potentially effective treatment so fewer women suffer.