A worldwide study involving Kiwi parents and babies has unexpectedly found fortifying typical pregnancy supplements with probiotics and other nutrients could reduce preterm births.
Oddly, that's not what the scientists behind the Nutritional Intervention Preconception and during Pregnancy (NiPPeR) study were looking for at all.
Medical experts in Auckland, Singapore and Southampton in the UK were instead hoping their cocktail would improve mothers' blood glucose levels during pregnancy and prevent gestational diabetes, which can cause pregnancy complications and increase the child's risk of type 2 diabetes and obesity.
"The nutritional supplement didn't reduce the risk of higher blood glucose in mothers... but what it did do is, there were fewer preterm births in the treatment group. That is an interesting finding in itself," Wayne Cutfield of the Liggins Institute at the University of Auckland told Newshub.
"Whenever you have a hypothesis to test, you hope to see a positive outcome, so it is a bit disappointing... Having said that, there are still other things to untangle from this study, there's just so much information."
Dr Cutfield is one of three lead investigators in the NiPPeR study, which began in 2015 with the recruiting of nearly 1800 women in Auckland, Southampton and Singapore. Twice a day before and during their pregnancies they consumed a nutritional supplement - half got standard stuff like folic acid, iron, calcium, iodine and beta carotene, while the other half got those plus two kinds of probiotics, vitamins D10, B6 and B12, riboflavin and myo-inositol - a kind of sugar.
Samples were also collected from the mothers, fathers and after they were born, the babies too.
"We've collected wees, we collected lots of blood... hair from mothers and babies, we've collected poos from mothers and babies, we've collected lots of things that give us a huge amount of information. Breast milk as well," said Dr Cutfield.
This week the first paper from the study was published in journal Diabetes Care - the main finding that the supplement didn't achieve its intended goal of improving blood-sugar levels for women in pregnancy. But there were 58 percent more preterm births - before 37 weeks - in the control group.
"That wasn't the intention of the study - it was a secondary outcome, but a very interesting one," said Dr Cutfield.
"A lot more work needs to be done because preterm births, premature infants are very, very common - they're up to about 10 percent of all babies born. Preterm birth is a major issue for pregnant women.
"There are issues with breathing, growth, learning issues, and the more pre-term the baby, the greater the risks are. The cost of a very, very preterm baby is enormous in terms of intensive care for months, to get them big and strong enough to be able survive the outside world, and they have lots of medical problems."
It's not clear exactly how the fortified supplement might have prevented preterm births, but the paper says it could be down to the "anti-inflammatory effects of myo-inositol and a contribution from the potential synergistic effect of micronutrients, including zinc and vitamin D".
While examining that link might require an all-new study, there's plenty more to be found in the data collected in this one, which Dr Cutfield called "one of, if not the most complex pregnancy study ever conducted".
He said thanks to the "exceptional" commitment of the women involved - the retention rate far higher than usual - there will be "several years of analysis and also follow-ups" which could uncover more unexpected discoveries.
"There is an enormous amount of further information to come from this study about the health and the wellbeing of mothers and their infants, and also whether there are other benefits or effects from the nutritional supplement. We're studying these children out to three-and-a-half, and we hope to be able to study them longer."