As the common saying goes, age is just a number, but when it comes to getting pregnant and having a healthy pregnancy, it can matter. Having kids after 35 years of age can be a joyous event, but the chances of problems — such as down syndrome — rise.

My mother became pregnant at the age of 41 in the process of menopause and her pregnancy was considered risky due to her age. Fortunately, she gave birth and I turned out healthy, but she dealt with complications, such as gestational diabetes.

The world is shocked that Janet Jackson, who is just two weeks shy of her 50th birthday, was able to get pregnant and recently announced it publicly last week. Jackson’s pregnancy brings up the question for all women, can having children at an older age be risky for the baby and the mother? Many women today find themselves trying to conceive after the age of 35.

In April, Jackson announced she was taking a pause for the second leg of her “Unbreakable” world tour for the second time, as she and her husband are working on starting a family.

Studies show that birth rates have increased in women aged 35 and older within the last few decades.

The Center for Disease Control reports that this trend began in the 1970s and more than doubled from 1990 to 2012 in women ages 40-44. According to the CDC, the proportion of first births to women aged 35 and over increased by 23 percent from 2000 to 2014. First births to women ages 30-34 increased by 28 percent.

The milestones of the adolescent years, which include leaving the parental home, often extend well into a person’s 20s. Women and men in their 20s may complete education, leave home, establish a career, find a life partner and then have kids. Delays in these key life transitions can influence the timing at which women decide to become parents.

“It’s a general trend that as more women get an education and enter the workforce, they marry and start having kids later in life,” Stephanie Coontz, co-chair and Director of Research and Public Education for the Council on Contemporary Families, told Business Insider. Social and cultural factors also drive the trend. When “a country … does not enable women to combine work and family well and has strong motherhood penalties, [the trend] is going to be exacerbated by that,” said Coontz, who is also a professor at The Evergreen State College.

It’s understandable that a woman would want to pursue a well-paid career and establish herself before having kids. It is important for a woman who is planning on having children to be financially stable, in order to pay for the expenses necessary and be able to take a break to focus on having a family. Once a mother gives birth with her child, I think it is essential for moms to be present during the early stages of a child’s life. However, waiting too long to have children can be highly risky for expecting mothers and their child. Women over 35 years old should keep in mind the health risks of having kids.

There are some concerns in pregnancy that increase the risk for this population for those who are over 35 years old. According to the Ob-gyn from Baby Center, Richard Paulson, he states that, “Women who try to conceive after the age of 40 years old increase the risk of complications that can affect the child; such as uterine disorders, high blood pressure, preeclampsia, placenta prematurity, gestational diabetes and miscarriage.”

According to the National Institute of Child Health, “About 6 percent to 8 percent of pregnant women in the U.S. have high blood pressure; about 70 percent of them are pregnant for the first time. The effects of preeclampsia are an estimated 3 percent to 5 percent of pregnancies in the U.S. and 5 percent to 10 percent of all pregnancies globally.”

Lastly, according to the Centers for Disease Control and Prevention (CDC), “gestational diabetes affects 2 percent to 10 percent of pregnancies.”