Researchers are planning to test growth hormone injections on pregnant women after successful trials on sheep.
The new treatment injected a hormone, similar to insulin, into the amniotic fluid surrounding the sheep's foetus, which boosted lamb growth later in pregnancy.
Foetal growth restriction, caused by a lack of sufficient nutrients and oxygen, affects about 10 percent of babies globally. There is no treatment at present except to induce birth early.
Study leader Frank Bloomfield, director of the Liggins Institute, said the successful trial with lambs could pave the way for a better solution.
"For the first time there might be a potential treatment for babies who are not growing well in the womb, which in developed countries like New Zealand is usually due to placental problems."
The trial was to find out if there were any risks with this treatment, since all previous experiments over the past 15 years or more had ended before the lamb was born.
Professor Bloomfield said researchers knew the hormone growth injection improved growth very reliably but not whether it resulted in problems with survival rates, health, or development following birth.
"The real purpose of this study was to test that, and make sure that as the lambs went through labour, were born, and grew up afterwards, there weren't any adverse affects.
"And indeed we showed that there weren't."
The next step is to test the insulin growth factor in humans in clinical pregnancies, and to explore the benefits from a specific placenta hormone.
"We identified that another hormone produced by the placenta, called C-type natriuretic peptide, actually correlates very well from concentrations in the mothers blood with the well being of the foetal lamb.
"If this was also true in humans this could be a new way of monitoring foetuses at risk just with a simple maternal blood test."
Profesor Bloomfield said lambs were a well recognised animal to use for human pregnancy trials.
"They're of a similar size to human babies, they have a similar development in the womb which means some of the findings we have in sheep can also be applicable to humans.
"Also they are very tolerant to interventions in pregnancy without initiating labour, which is really important."