Known as the H2Oil study, global researchers led by the University of Adelaide's Robinson Research Institute compared the benefits of flushing the Fallopian tubes with either an oil or water-based solution in 1,119 women.
Almost 40 percent of previously infertile women in the oil group and 29 percent in the water group achieved successful pregnancies within six months.
The oil-based product used in the study was Lipiodol Ultra-Fluid, an iodized solution of fatty acids from poppy seeds, which is available in 47 countries worldwide.
Study author Professor Ben Mol, who was conceived after his mother underwent the same procedure, said: "Over the past century, pregnancy rates among infertile women reportedly increased after their tubes had been flushed with either water or oil during this procedure.
"Until now, it has been unclear whether the type of solution used in the procedure was influencing the change in fertility.
"Our results have been even more exciting than we could have predicted, helping to confirm that an age-old medical technique still has an important place in modern medicine.
"The rates of successful pregnancy were significantly higher in the oil-based group, and after only one treatment.
"This is an important outcome for women who would have had no other course of action other than to seek IVF treatment. It offers new hope to infertile couples."
The researchers are unsure as to how the oil-based poppy-extract solution improves fertility prospects, but they add it could be a cost-effective alternative to expensive IVF.
Professor Mol said: "It was long believed that testing a woman's Fallopian tubes could have fertility benefits through "flushing out" the kind of debris that hinders fertility.
"The reality is, we still don't really understand why there is a benefit, only that there is a benefit from this technique, in particular for women who don't present with any other treatable fertility symptoms.
"Further research would need to be conducted into the mechanisms behind what we're seeing.
"For now, and considering the technique has been used for 100 years without any known side effects, we believe it is a viable treatment for infertility prior to couples seeking IVF."
He said: "Not only is there a known benefit, but this flushing procedure is also a fraction of the cost of one cycle of IVF.
"Considering that 40 percent of women in the oil-based group achieved a successful pregnancy, that's 40 percent of couples who could avoid having to go through the huge costs and emotions associated with IVF treatment."
Until he embarked on the study, Professor Mol was unaware that he was conceived after his mother had the procedure.
He said: "My mother went from being infertile for many years to becoming pregnant.
"I also have a younger brother. So it's entirely possible - in fact, based on our team's research, it's highly likely - that my brother and I are both the result of this technique helping my mother to achieve fertility."
Professor Mol added, however, women should speak to their doctors before considering the alternative fertility treatment.
The study's results are published in the New England Journal of Medicine.
This comes after researchers from Monash Biomedicine Discovery Institute and University College London may have discovered one of the leading causes of genetic abnormalities in the eggs of older women, which often leads to miscarriages and disabilities.
A fault in how older women's eggs control levels of a protein known as securin may be to blame for female's reduced fertility as they grow older, they said.
