The ties that bind: pregnancy and heart disease

Heart disease is one of the most common causes of death in the world. Most people have heard of heart disease, and most people can tell you what to do, or not do, to stay heart-healthy. Smoking, being overweight or obese, and a lack of exercise are all bad for your heart. But what if I suggest that having children is another?

This might sound like a strange proposition. After all, heart attacks and strokes happen to much older people (typically 60 years or older) than having a child (normally for women in their 20s to 30s). There’s a whole body of research based around identifying pregnancy-related risk factors for heart disease. It’s called cardio-obstetrics.

Pregnancy and the heart

When a woman becomes pregnant, it’s no understatement to say that her body undergoes huge changes. It’s not just the size of her waist that increases, a woman’s heart grows by almost 12%, which has to support the 50% increase in the volume of blood that is circulating her body, by the end of a pregnancy. This gives some idea of the huge demands placed on a woman’s body, and her heart in particular.

Typically, things return to normal after birth. However, for some women there may be long-lasting effects. These effects may arise after a woman has had a large number of children (five or more) or because she has experienced pregnancy complications such as preterm birth (birth of the infant before 37 weeks gestation), high blood pressure during pregnancy (such as pre-eclampsia), or the infant is small for the gestational age it was born at (less than the 10th centile).

Some people will notice that smoking or diet, for example, can contribute to the development of pregnancy complications and heart disease. However, the links between pregnancy complications, or large numbers of children, and subsequent heart disease are still found even when smoking, diet, alcohol, exercise and ethnicity are taken into account.

More than just pregnancy

There are a number of different theories as to what might be linking pregnancy and heart disease. It’s possible that there is some physiological damage that arises after multiple pregnancies or, in particular, pregnancy complications. Alternatively or in conjunction, some women may have low lying, undiagnosed conditions before pregnancy that predispose her to both pregnancy complications and heart disease.  But the plot thickens when fathers are studied.

A study of more than 200,000 British men found that those with four or more children were more likely to have heart disease than men with fewer children. Although the risks were lower for men with four or more children than for women, this suggests the link might not physiological alone. This will come as no surprise to anyone who has children or has seen parenting up close. Stressful, with little downtime and limited options for healthy relaxation (going out for a run with a 2-year-old isn’t feasible, but eating chocolate with them is). It’s no wonder that parents with four or more children, who have the most constraints on their time, are more likely to develop heart disease.

Identifying women at risk

So far, this all sounds rather depressing. A woman who has one traumatic experience (a complicated pregnancy) is more likely to have another (heart disease) years later. But this doesn’t need to be to have a sad ending. There is some hope.

Firstly, there is a long period of time between having children and the average age women have a heart attack. Therefore, if women know that they are at greater risk, then they have a window of opportunity to do something about it. We’ve all had it drummed into us what to do to be heart healthy (don’t smoke, eat healthy, exercise regularly). The challenge, and I readily acknowledge it is a challenge, is enacting those changes.

Ideally, this shouldn’t be the sole responsibility of those who are at greater risk: it is much easier to make positive changes in your life if it’s done with your family or community. Realism plays a big part as well. If it is not realistic to start running for 30mins three times a week, perhaps eating an extra portion of fruit and vegetables a day is achievable.

This isn’t necessarily an easy message nor is there an easy solution, however being armed with knowledge is vital. It’s also important to point out that children aren’t completely bad for a woman’s health. They might not be great for your heart, but having children appears to be protective against some cancers, including ovarian and some kinds of breast cancers.

So overall this shouldn’t put women off having children. Large numbers of women will develop heart disease in their lifetime. Knowing ways to identify those women early on and help them to make positive choices to protect their heart is a valuable step forward.