The pros of giving healthy women regular low dose aspirin to stave off serious illness, such as cancer and heart disease, are outweighed by the cons, suggests a large study published online in the journal Heart.

But the balance begins to shift with increasing age, and limiting this form of primary prevention to women aged 65 and above, was better than not taking aspirin at all, or treating women from the age of 45 onwards, say the researchers.

They base their findings on almost 30,000 healthy women, who were at least 45 years old and taking part in the Women’s Health Study.

Participants were randomly assigned to take either 100 mg of aspirin or a dummy tablet (placebo) every other day, to see whether aspirin curbed their risk of heart disease, stroke, and cancer.

During the trial period, which lasted 10 years, 604 cases of cardiovascular disease, 168 cases of bowel cancer, 1832 cases of other cancers, and 302 major gastrointestinal bleeds requiring admission to hospital were diagnosed.

Over the subsequent seven years, a further 107 cases of bowel cancer and 1388 other cancers were diagnosed.

Compared with placebo, regular aspirin was linked to a lower risk of heart disease, stroke, bowel cancer, and in some women, other cancers, but only marginally so.

And this slight health gain was trumped by the prevalence of internal gastrointestinal bleeding, which affected two thirds of the women taking the non-steroidal anti-inflammatory drug.

The risk of gastrointestinal bleeding rose with age, but so too did the drug’s impact on lowering the risk of bowel cancer and cardiovascular disease, with the balance appearing to tip in favour of the drug for women aged 65 and above.

The researchers calculated that over 15 years, 29 over-65’s would need to be treated with aspirin to prevent one case of cancer or heart disease/stroke.

“Recent findings that both daily and alternate day aspirin can reduce cancer risk, particularly for colorectal cancer, have re-ignited the debate on aspirin in primary prevention,” write the researchers.

But they conclude that blanket treatment “is ineffective or harmful in the majority of women with regard to the combined risk of cardiovascular disease, cancer and major gastrointestinal bleeding.”

Women who take folic acid prior to conception may be less likely to have offspring born small for gestational age, researchers say.

Babies are deemed small for gestational age (SGA) if their birth weight is in the lowest 10% of babies born.

SGA is primarily caused by fetal growth problems during pregnancy, such as intrauterine growth restriction (IUGR). This can develop when the fetus fails to receive the required nutrients and oxygen it needs to grow.

At birth, SGA can cause an array of complications, such as reduced oxygen levels, polycythemia (excess red blood cells) and low blood sugar. It can also increase the risk of health problems later in life, such as diabetes, high blood pressure, obesity, cardiovascular disease and mental health issues.

Folic acid – a type of B vitamin – is already highly recommended for women of a childbearing age due to studies claiming the vitamin can reduce the risk of a child developing neural tube defects, such as spina bifida. The American Pregnancy Association say prior to and during pregnancy, women should take around 400 mg of folic acid a day.

The researchers from this latest study – including Khaled Ismail of the University of Birmingham in the UK – set out to determine how folic acid supplementation before conception and during pregnancy affected offspring’s risk of SGA.

Risk of SGA lowest among women who start taking folic acid before conception

By analysing data from a UK regional database, the team identified 108,525 pregnancies whereby data on mothers’ folic acid supplementation was accessible.

Almost 85% of women had taken folic acid during pregnancy. Information on when women began taking folic acid was available for 39,416 women. Of these, 10,036 (25.5%) began taking folic acid prior to conception.

Overall, 19.3% of babies were born SGA; 13.4% of these babies had a birth weight in the lowest 10%, while 7% of babies had a birth weight in the lowest 5%.

Results of the study revealed that the highest rates of SGA occurred among babies whose mothers had not taken folic acid before conception or during pregnancy, with 16.3% of these babies born with a weight in the lowest 10% and 8.9% born with a weight in the lowest 5%.

Of the mothers who began taking folic acid during pregnancy, 13.4% had babies with a birth weight in the lowest 10%, while 7.1% had babies with a birth weight in the lowest 5%.

Among women who began taking folic acid prior to conception, however, the percentage of babies with a birth weight in the lowest 10% stood at 9.9%, while the percentage with a birth weight in the lowest 5% was 4.8%. This indicates that taking folic acid before conception can significantly reduce the risk of SGA.