Heart worry for Pill jab women

Women who are given long-lasting contraceptive injections may suffer physical changes which increase their risk of heart disease, claim researchers.

There is no evidence yet to directly link the jabs to heart problems.

However, the team of scientists from Imperial College School of Medicine say that there is enough evidence to concern women who already had heart risks before they started taking the drug.

They suggest that the drug may, if taken over a longer period, restrict the ability of the body's arteries to contract and expand.

This could render the arteries more vulnerable to suffer from the clogging and hardening which can lead to heart disease.

The injections are seen as a convenient alternative to taking the contraceptive pill every day or using barrier methods such as condoms.

They are often prescribed to women whom doctors think have a higher risk of heart problems because other types of contraceptive pill have already been shown to increase the risk of blood clots.

A single injection of the drug, called Depo-Provera, or DMPA, lasts for three months.

However, the latest research suggests that the jab may not prove to be an entirely risk-free alternative for some women.

Artery test

The Imperial team, led by Professor Dudley Pennell, looked at a small number of women taking DMPA.

They evaluated their arterial function by scanning the brachial artery in the arm, both at the end of a three-month DMPA cycle, and again just after the new jab.

A sample of women not taking DMPA were checked during their period, and when they were ovulating.

Widening of the arteries triggered by changes in blood flow was greatly restricted in the DMPA group - 1.1% compared with 8.0% in the non users.

This is probably happening because the injection works by blocking hormonal signals that activate ovulation.

This means that women using the drug have very low levels of oestradiol - ovarian oestrogen - in the blood.

This hormone is important in the constriction of blood vessels.

In effect, the injection is creating a temporary menopause.

Effective

Professor Pennell said that DMPA remained a highly-effective contraceptive, and was certainly safe in women who did not have any existing cardiovascular risk factors, such as smoking.

He said it was particularly effective for women who had limited access to health care, for example in developing countries - or those who had trouble complying with the routine of daily contraceptive pills.