Birth control pills impair memory

Women taking contraceptive pills face problems with their memory, new research says.

University of California, Irvine researchers have shown that hormonal contraception pills "alter memory".

The medications do not damage memory. "It's a change in the type of information they (women) remember, not a deficit," said researcher Shawn Nielsen.

"There are only a handful of studies examining the cognitive effects of the pill, and more than 100 million women use it worldwide," said Nielsen, according to a university statement.

The change makes sense, said Nielsen, who works with neurobiologist Larry Cahill, because contraceptives suppress sex hormones such as oestrogen and progesterone to prevent pregnancy, the journal Neurobiology of Learning and Memory reports.

Those hormones were previously linked to women's strong "left brain" memory by Cahill's research group. "This new finding may be surprising to some, but it's a natural outgrowth of the research we've been doing on sex differences for 10 years," Cahill said.