Could a substance used as a supplement by athletes be the key to a healthy birth weight for babies? It's a novel theory that has found some footing in new Australian research.
A study by Melbourne's Hudson Institute of Medical Research and Monash University has found women with lower levels of a naturally produced amino acid called creatine gave birth to smaller babies.
The more creatine that was found in the urine samples of 278 expectant mothers studied, the less likely they were to have an underweight baby, lead researcher Dr Hayley Dickinson said.
"We showed that for every unit increase in the amount of creatine that the mother had in her urine there was just over a one unit increase in the birth weight centile," she said.
The researchers also found that for each extra unit of creatine detected in the mother's urine, the baby would be 11 millimetres longer.
"While for the most part small babies are fine, they go on to live normal healthy lives, some are at increased risk for stillbirth, or poor development outcomes as they get older," Dr Dickinson said.
The team does not recommend pregnant women start taking supplements. Rather, Dr Dickinson said half of the body's creatine is produced by meat and fish in the diet and the findings are a reminder for pregnant women to eat well.
The other half is produced naturally by amino acids in the body.
The research has already paved the way for a large study of 900 pregnant women who are being recruited from Monash hospitals in Clayton and Dandenong. The team needs donations to help them keep the study going.
"Ultimately, if we were able to show that women with good healthy levels of creatine have good pregnancy outcomes, then we might suggest that there was a recommended creatine intake," Dr Dickinson said.
New mother Katrina Wadeson is participating in the research because she hopes it will lead to better outcomes for mothers and babies.
"You just hope that they're of a good size and that they're not underweight," she said. "If there's a link then that's great; they might be able to give out supplements."
Creatine made headlines in March when a former teammate of All Blacks legend Jonah Lomu speculated it could be responsible for the rare kidney condition that is believed to have contributed to his death.
Joeli Vidiri, who played with Lomu in the 1990s and was also diagnosed with nephrotic syndrome, which affects three in 100,000 people, said both men were on creatine as part of their training.
Athletes have been taking creatine for decades because it is believed to help load energy into their cells.
Dr Dickinson said there was no evidence high doses were dangerous, but that supplement safety during pregnancy would be studied