Women's cells age up to two years faster during pregnancy, study shows

Wrinkles appearing and your hair going grey?

Parenting can feel like you're growing older by the minute - between the tantrums, the sleepless nights and the vast amounts of coffee we have to consume to even begin to survive the first two years.

And now it looks like our suspicions were bang on. And guys, it starts before the kids are even born.

Yes, really.

Recently, researchers at Northwestern University proved that having children does, indeed, speed up the process at which we age. A study published in Scientific Reports, found that each pregnancy can age a mother's cells by up to two years.

The researchers studied 821 women in the Philippines between the ages of 20 and 22, with various reproductive histories. They examined two separate markers of cellular ageing—telomere length and epigenetic age—to measure the toll pregnancy takes on the body.

"Telomere length and epigenetic age are cellular markers that independently predict mortality, and both appeared 'older' in women who had more pregnancies in their reproductive histories," Calen Ryan, lead author of the study and a doctoral student in biological anthropology at Northwestern, said in a statement.

"Even after accounting for other factors that affect cellular ageing, the number of pregnancies still came out on top."

The researchers were surprised to find that cellular ageing increased between about six months and two years for each additional pregnancy—a figure much higher than what they originally anticipated. Meanwhile, women who were currently pregnant had cells that looked significantly younger than predicted for their biological age.

Telomeres, which are stretches of DNA at the end of chromosomes, protect our DNA and make it possible for our cells to divide. Longer telomeres are associated with longer lives and better health. As people age and as cells divide and replicate, those telomeres shorten.

Given that there is hyper cell production during pregnancy, it makes sense that those telomeres would shorten and, therefore, appear to age dramatically.

"During pregnancy, more cells need to be produced for carrying and nurturing the foetus, such as in red blood cells, placental cells, and more," said Dr. Kim Langdon, an Ohio-based retired OB-GYN who writes at Parenting Pod.

"In addition, the cells in all organs such as the heart and uterus enlarge. This is known as hypertrophy—and when cells hypotrophy, their telomeres shorten."

Meanwhile, the epigenetic age begins to climb. This is an estimate of a person's biological age based on changes in the DNA that are caused by environmental factors, such as toxins and stress.

In other words, pregnancy puts a lot of pressure on the body. "I'm not really surprised," Langdon told Healthline about the findings. "Every OB-GYN knows the extreme stress to the system that pregnancy causes."

Throughout pregnancy, the blood volume increases by 50 percent as does the cardiac output, which puts strain on the heart. The kidney function increases and the lungs have reduced capacity, which causes breathlessness.

Why, then, did the pregnant women seem so much better off?

It may all come down to the immunological, hormonal, and physiological changes that take place during pregnancy to support development of the baby.

For example, pregnant women experience elevated oestrogen levels, which can lower oxidative stress and prevent damage to telomere length and epigenetic age. Once the baby is born, though, those shifts are no longer necessary.

The study supports previous evidence that women who have had more pregnancies are more susceptible to certain illnesses and have slightly shorter life spans.