Does miscarriage, early menopause or starting periods young cause heart problems?
Having children at a young age or having lots of children could also mean a woman is more likely to have a heart attack or stroke, research has suggested. But how good was the research? We look behind the headlines.
16 January 2018
New research has suggested that the age when a woman starts her periods, has her first child or goes through the menopause is linked to her risk of heart attack and stroke.
Starting to menstruate before the age of 12, having children at a younger age or going through menopause before age 47 were all linked to an increase in risk of heart attack and stroke in later life. Experiencing a miscarriage or stillbirth, or having a hysterectomy were also linked to a higher risk.
The researchers suggest that women who fall into one of these categories should get more frequent screening for heart and circulatory disease, and that health professionals should be aware of these possible risk factors.
How good was this research?
A weakness of all studies like this is that a percentage increase in risk has limited meaning for any individual unless they know what their overall risk is in the first place. If your overall risk is low, an increase of 5 or 10 per cent in that risk will probably still be a low risk. You can reduce your risk of heart and circulatory disease by not smoking, doing regular physical activity and eating a healthy diet.
A strength of this research, led by the University of Oxford and published in the journal Heart, is the large number of people it included, of both genders. They looked at more than 267,000 women and 215,000 men aged between 40 and 69 who were healthy and had no history of cardiovascular disease. The researchers then looked at what happened to those participants in the following seven years up to 2017, or until they had their first heart attack.
Participants filled in questionnaires about their lifestyle, environment, and medical history, including their reproductive history. Altogether, 9,054 participants developed one or more cardiovascular diseases, 34 per cent of whom were women. A possible weakness of the study is that some information was self-reported by the participants, meaning the answers they gave could be inaccurate, especially when it related to events many years previously.
A weakness was that it didn’t include data on several pregnancy-related factors that have been shown to be associated with the risk of heart and circulatory disease in later life, including breastfeeding, gestational diabetes, gestational obesity, pre-eclampsia and polycystic ovary syndrome.
The BHF view
Christopher Allen, Senior Cardiac Nurse at the British Heart Foundation, said: “Coronary heart disease kills more than twice as many women as breast cancer in the UK. Further studies are needed to better understand if and how a women who starts her period before the age of 12 has a higher risk of heart disease in later life, along with the impact of other factors such as early menopause, pregnancy complications and hysterectomies.
“It’s important that women of all ages look after their hearts, and those over 40 take advantage of the free NHS health checks which cover your risk of cardiovascular disease. But if you are worried about your reproductive history and heart disease then speak to your GP.”
The media coverage
The story was widely covered in the Daily Mail, Guardian, Telegraph, and Huffington Post, among others.
In the Daily Mail article it says 'The team analysed Biobank data, which included records of 267,440 women up to the age of 69.' But it would be more useful if it made clear that it was women aged 40-69, as readers may be in their 20s and 30s and think the research applies to them, which is currently doesn't.
If you are worried about your reproductive history and heart disease then speak to your GP
They also say that the research found 'a strong link' between all of the conditions, but for some conditions there was a weaker link. For example one miscarriage was only linked to a 6 per cent higher risk of heart disease, and each year older you are before you first child led to only a 3 per cent decrease in your risk.
The Telegraph's coverage is good, except it says that 'women with reproductive problems are at greater risk of heart disease'. This may be a bit misleading as some people may think this means problems such as infertility, which the study did not look at.
More detail about the findings
The study found that starting periods early (before the age of 12) was linked to a 10 per cent higher risk of having a stroke or heart attack as an adult. Childhood obesity is known to be linked with earlier periods, but the women in the study who had early periods had an increased risk even if they were not overweight – although the study did not look at whether they had been overweight as children. The study didn’t state how many participants in the study had started their period before the age of 12 (the average age in the study was 13).
The researchers found a link between miscarriage and stillbirth and an increased risk of heart attack and stroke. Each miscarriage increases the risk of heart attack by six per cent, they said. Stillbirth was associated with a 44 per cent increased risk of stroke, but not of heart attack. The researchers said: "This study is the first to suggest that miscarriage is more strongly associated with heart attack whereas stillbirth is more strongly associated with stroke."
The report did not study the reasons, but suggests that there could be some of the same factors behind miscarriage, stillbirth, and heart attack or stroke. This could be that the same underlying problems in the blood vessels could cause problems with the placenta in pregnancy (which could lead to miscarriage and stillbirth) as well as heart and circulatory disease. These problems may be linked with inflammation and problems with the lining of the blood vessels, which are both known to be factors in the development of heart attack and stroke.
Women who went through natural menopause before the age of 47 were at a 33 per cent higher risk of cardiovascular disease, and at a 42 per cent increased risk of stroke, the research suggests. The average age of menopause in the UK is 51.
The higher risk for women with an early menopause is usually thought to be linked to the fact that oestrogen levels drop at the time of menopause, and oestrogen is known to have a protective effect on your heart. But the researchers say that it could be that heart and circulatory problems could lead to early menopause - for example if the blood vessels supplying the ovaries become damaged.
Having had a hysterectomy (removal of the womb) was associated with an increased risk of heart attack (12 per cent) but not of stroke. Having a hysterectomy at a younger age increased the risk.
Do children raise your heart risk?
Both men and women with children were at a significantly higher risk of heart attack (21 per cent increased risk for women, and 13 per cent for men), but not of stroke. A larger number of children was linked to an even higher risk. These findings had been adjusted to take into account other factors that might affect the results, such as social status or smoking. But because the increase in risk was seen in men as well as women, the researchers think the link must be caused by social or lifestyle factors rather than biological reasons.
The risk of heart attack and stroke in women was higher for women who had their first child young - the later they had their first child, the lower the risk (the average age in the study of first child was 26). Again, the results were the researchers thought this could be to do with social or lifestyle factors.