Mothers who breastfeed their babies for at least 12 months are less likely to develop ovarian cancer, a new study from Perth suggests.
Curtin University's research supports the long-suggested theory that there are benefits to mothers who breastfeed because ovulation occurs less often, which some experts believe decreases the risk of ovarian cancer.
During research in Guangzhou, China, information was collected on the length of lactation and the number of children breastfed from a sample of 493 ovarian cancer patients and 472 hospital-based controls.
Professor Colin Binns said China was chosen because of its high population, which provided a higher sample.
"The lower incidence of ovarian cancer in China suggests there are factors operating there to reduce the incidence which we wanted to explore," he said.
"We also knew that Chinese women breastfed for longer than women in the western world."
Professor Binns said the results added further knowledge to the limited amount of research from countries with a low incidence of the disease.
He said it also provided more detail on the breastfeeding variables associated with a reduced risk of ovarian cancer.
"Increased ovulation heightens the risk of cell mutation, which can cause ovarian cancer," Professor Binns said.
"As breastfeeding often delays ovulation, we were able to effectively demonstrate that breastfeeding for 20 months would decrease the risk of ovarian cancer by 50 per cent, and that the 20 months of breastfeeding could be spread over a number of children and still have the same effect."
The results recommended mothers breastfed for at least 12 months to gain substantial benefit.
Ovarian cancer is the seventh most common cause of cancer mortality among women and accounts for four per cent of all cancers in women.
As it was difficult to diagnose and treat and often had a poor prognosis, research on prevention strategies was essential, Professor Binns said.
The research will be published in the American Journal of Clinical Nutrition next month.