Newer types of the Pill double the chance of blood clots

Women taking newer brands of the Pill are up to twice as likely to suffer blood clots as those using older types, a study found.

And that risk is four times greater than for those who do not take any contraceptive pills.

It is estimated that a million women are using the 'third-generation' contraceptive pills, which tend to not have side effects – such as weight gain and headaches – found in older brands.

But these newer drugs also further increase the likelihood of blood clots in the leg or arm, according to the study.

The research comes after Fallan Kurek, a 21-year-old teaching assistant, collapsed and died from a blood clot on her lung less than a month after she had started taking the Pill.

Her parents blame the fatal clot on the Pill, which her GP had prescribed to regulate her periods.

She had been taking a Pill with a progestogen hormone called levonorgestrel, which the study says is among the lowest risk as a second-generation Pill, but it is still two-and-a-half times more likely to cause clots than not taking any oral contraceptives.

About 28 per cent of women of child-bearing age take the Pill, and all types that contain oestrogen and progestogen increase the risk of clots. 

This in turn raises the risk of a clot on the lung – a pulmonary embolism – which can be fatal. Doctors writing in the British Medical Journal warned that women must be advised of this increased risk, which is raised even further if they also have a family history of blood clots, are overweight or smoke.

The researchers at Nottingham University found that the highest risk was in third-generation contraceptives with drospirenone – which is found in Yasmin – or those with desogestrel, gestodene or cyproterone.

Nancy Berry had been taking third-generation contraceptive pill Femodene for a month when she died of a blood clot at the age of 16. Nancy, from Bexley in south-east London, had gone on the pill with her mother Yvonne's permission, hoping that it would help with painful periods.

Within 24 hours of developing breathing difficulties – a symptom initially dismissed by hospital doctors as a panic attack – the teenager was dead.

After her death in 1995, pathologists found no illness that could explain the clot. But a coroner recorded an open verdict at inquest, ruling the drug was not to blame.

The latest study's lead researcher Yana Vinogradova said findings from Denmark in 2011 were similar, with the latest research 'an important clarifying study'.

She said: 'The results from our study and the Danish study provide guidance for relevant authorities concerned with prescribing guidelines or those involved with regulation of safety of medicines.'

The study used prescription data from two large UK general-practice databases to measure the link between use of combined oral contraceptives and risk of blood clots in women aged between 15 and 49.

The researchers found that current users of any combined oral contraceptive are at an increased risk compared with non-users of a similar age and health status. 

The risks for women using newer pills were around 1.5 to 1.8 times higher than for women using older pills.

The number of extra cases per year per 10,000 treated women was lowest for levonorgestrel – found in brands such as Microgynon – and norgestimate, with six extra cases. It was highest for desogestrel and cyproterone, which had 14 extra cases.

Dr Helen Stokes-Lampard, from the Royal College of GPs, added: 'The combined pill is an excellent contraceptive choice for the majority of women. 

'As with any prescribed drug, there is always the possibility of negative side effects but GPs understand the risks associated with the pill – and different generations of the pill – and will take these into account, along with medical and family history, before prescribing it to their patients.'

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