PARIS - An exceptionally long-running investigation has backed use of the Pill to ease menstruation pain, according to a study published Wednesday.
The findings come from health research spanning 30 years, gathering more than 1,400 Swedish women born in 1962, 1972 and 1982.
They filled out a lengthy questionnaire when they were enrolled in the probe at the age of 19, and did the same again five years later at the age of 24.
Those who took oral contraceptives reported significant drops in two acknowledged measurements of pain.
Age was also a factor. As a woman aged, the severity of period pain decreased somewhat, but this effect was independent from the Pill, and smaller.
The investigation, led by gynaecologist Ingela Lindh at Gothenburg University's Institute of Clinical Sciences, is published online by the European journal Human Reproduction.
The Pill is sometimes prescribed by doctors to reduce period pain, and many women attest to its effectiveness, but the scientific verdict has so far been mixed.
Two big reviews of the evidence, carried out in 2007 and 2009, said there had been a lack of randomised controlled trials to provide a clear answer.
Randomised control trials are the gold standard of clinical research.
They entail enrolling volunteers who are randomly assigned either to a group that uses the genuine treatment or to a comparison group which uses dummy pills as a comparison.
The new paper could help provide a definitive answer, its authors hope.
The probe is unusually long and uses each volunteer as a personal benchmark to measure the impact of the Pill and ageing on period symptoms.
Menstrual pain, known as dysmenorrhoea, has been estimated to account for 600 million lost working hours and two billion dollars in lost productivity annually in the United States alone.