London, Apr 23 (IANS) : Tens of thousands of women should reconsider use of the so-called third generation contraceptive pill to reduce the risk of a potential blood clot.

Women taking so-called third generation contraceptive pills, developed in the 1980s, are up to three times more likely to suffer a blood clot than those who use older varieties, according to new research based on British and US records.

With no other real advantages of the newer drug, scientists said it would be ‘prudent’ to make the older pills the ‘first line of choice’.

Scientists say doctors should prescribe pills that contain the hormone levonorgestrel, rather than drospirenone, the British Medical Journal reports.

Susan Jicks of Boston University School of Medicine and colleagues carried out two studies into the two types of birth control drugs and found the difference in threat was dramatic, according to the Telegraph.

They said their findings ‘provide further evidence that levonorgestrel oral contraceptives appear to be a safer choice’.