Strassman's study showed that blood taken from women who use birth control pills contained much higher levels of hormones compared to women who don’t, but she cautions that many women report the pill as having a positive effect on their lives.

“Not enough has changed over the generations of these drugs and given how many people take hormonal birth control worldwide — millions — the pharmaceutical industry shouldn’t rest on its laurels,” Strassman said.

Read the full article at The Independent.