How Pregnancy Increases Your Biological Age?

Biological age differs from chronological age in that it reflects the state of your body’s cells and tissues rather than the number of years you’ve lived. It’s a measure of how well your body is functioning in comparison to your actual age. Factors like diet, exercise, sleep, stress, and, as suggested by new research, pregnancy, can influence your biological age.

For example, someone with an active lifestyle and low stress levels might have a biological age that is younger than their chronological age. On the other hand, someone who doesn’t get enough sleep might find that their biological age is higher than their chronological age, reflecting additional strain on their body’s systems. In this way, biological age provides a more nuanced picture of your body’s overall health than simply counting the years.

A recent study published in Proceedings of the National Academy of Sciences found that pregnancy might accelerate biological ageing. It observed that women who had been pregnant at some point in their lives were more likely to exhibit signs of accelerated biological ageing as opposed to those who had never been pregnant.

During the study, researchers analysed blood samples from 1,700 women. In the blood samples, they investigated factors that might contribute to accelerated biological ageing, with a focus on ‘epigenetic clocks’ that reflect a cell’s age. These epigenetic clocks track molecular changes within cells, such as alterations in gene expression and DNA. They serve as a tool to measure the impact of certain variables on cellular age, including stress and both physiological and psychological experiences.

By using six different epigenetic clocks to assess 19 mutation indicators related to biological age, the researchers found that women who had experienced at least one pregnancy appeared biologically older compared to those who had not been pregnant before. In contrast, when the same six epigenetic clocks were applied to male participants, the study revealed that men who had fathered children did not show similar signs of biological ageing associated with having children.

This evidence could seem unsettling if taken at face value, but as we’ve learned, it’s important to remember that biological ageing is a complex process influenced by lots of factors. While pregnancy may contribute to transformation at a cellular level, it doesn’t necessarily mean that it will automatically lead to ill health or shorten a woman’s lifespan. Many women go through multiple pregnancies and remain healthy, active, and vibrant throughout their lives.

While pregnant, we experience a whole host of physical, metabolic, hormonal, and immunity adaptations. One theory is that these changes place a significant, yet natural, demand on the body, which could result in accelerated biological ageing markers.

Let’s take a look at some of them:

• Physical changes. During pregnancy, the body undergoes significant physical changes such as increased weight gain and changes in body composition. This additional burden on the skeleton can lead to joint stress and changes in posture, which accelerates biological ageing by affecting mobility and overall physical health.
• Metabolic changes. The body’s increased caloric and nutritional demands during pregnancy can lead to metabolic strain. Over time, this may affect the body’s ability to maintain optimal energy levels and metabolic function, which is linked to biological ageing.
• Hormonal changes. Pregnancy involves significant hormonal fluctuations, including higher levels of oestrogen and progesterone. Elevated amounts of oestrogen can sometimes lead to reduced bone density by affecting calcium metabolism, and this is associated with accelerated biological ageing.
• Immunity changes. Normally, your immune system fights off anything perceived as foreign. But during pregnancy, it needs to balance protecting you from infections while not attacking your baby, who has different genetic material from you. To do this, your body shifts to a more gentle mode of immunity that still guards against germs but also becomes more tolerant of your baby. The need to maintain a delicate balance between immune tolerance and protection can place added strain on the immune system. This might affect its efficiency, potentially leading to increased biological ageing.

These changes are a natural and necessary part of pregnancy, helping to create a safe environment for your baby to develop. However, the extra work that your body does during this time may also play a role in how your body ages at the cellular level, as it has to adapt and then readjust after giving birth.

While this might sound rather concerning, it’s important to consider all the data. In a paper published in the scientific journal Cell Metabolism, a research team from Yale School of Medicine reported that rapid acceleration in biological ageing caused by pregnancy was found to be gradually reversed a few months postpartum. In fact, the evidence suggested that this reversal, in terms of the effect size, was much greater than the increase in biological age found during pregnancy. In other words, this raises the idea that pregnancy could actually be associated with potential rejuvenation. 

And of course, it’s well known that pregnancy comes with many health benefits. For example, it’s been associated with a reduced risk of certain types of cancer, such as breast and ovarian cancer, especially when women have children at a younger age or breastfeed. And of course, emotional and psychological benefits of motherhood, including increased life satisfaction and a sense of purpose, have an overwhelmingly positive influence on a woman’s wellbeing.

Above all, the research provides us with an opportunity to look more closely at how pregnancy affects a woman’s body. It underscores the endurance involved in the process of bringing a baby into the world, and can be used to inform support strategies for expectant mothers.

If you find yourself worried about the idea of pregnancy affecting your biological age, remember that ageing is a natural process, and that it’s influenced by a multitude of factors. Pregnancy is just one of many experiences that can shape how our bodies age.

There are also many proactive steps you can take to prioritise your health and wellbeing during and after pregnancy. Maintaining a nutrient-rich diet, regular physical activity, and a healthy sleep schedule can help mitigate the impact of pregnancy on biological ageing. Activities such as antenatal yoga and deep-breathing exercises can also help to manage any anxiety you might be experiencing.

Ultimately, the relationship between pregnancy and biological age is complex and unique to each woman. Know that your body is capable of remarkable resilience as it prepares to bring your baby into the world.