London, More than half of mums-to-be who are at risk of the dangerously high blood pressure condition -- pre-eclampsia -- are missing out on preventive aspirin treatment, say researchers.

Pre-eclampsia is the leading cause of premature birth, restricted fetal growth, and stillbirth and it increases the risk of hospital admission for the expectant mother before birth.

According to the study, published in the journal Drug and Therapeutics Bulletin, making aspirin available from local pharmacies could help ward off the condition,

"The UK national guidelines recommend that women at risk of pre-eclampsia should begin to take preventive low dose aspirin at 12 weeks of pregnancy," said study researcher Joanna Girling of West Middlesex University Hospital, London.

"So why is it that despite compelling evidence for its benefit and safety, more than 50 per cent of eligible pregnant women never start aspirin?" the author asked.

Concerns about taking any drugs during pregnancy and logistical issues, such as midwives in most maternity units not having legal powers to prescribe or supply aspirin, may account for the figures, she suggested.

When midwives can't prescribe, they advise mums-to-be to see their local doctors to get a prescription, but this obviously takes time, risking delays in the start of preventive treatment, or not starting it at all, the researchers said.

The easiest option would be to enable at-risk women to obtain supplies of low dose aspirin from their local pharmacy.

"It could be a lot cheaper than the unnecessary branded pregnancy-related nutrients and supplements that many women choose to buy," Girling suggested.

But, according to the researchers, the problem is that many pharmacists can't legally sell aspirin to ward off pre-eclampsia because it is not officially marketed for the treatment of the condition.

While some may be concerned that this suggests the use of aspirin for pre-eclampsia is unsafe, the absence of an official license for this indication is most likely for commercial reasons, because it's unlikely to be financially worthwhile, explained Girling.