Wanting children may shape where a couple decides to live, which car they drive, and countless other choices.

While they're getting their lives ready for a family, fertility experts suggest they also make sure their bodies are ready. About 1 in 8 couples struggle with infertility.

Dr. Margareta Pisarska, director of the Cedars-Sinai Fertility and Reproductive Medicine Center, is a leading fertility specialist and researcher.

"You hope and expect you can have a family any time you want, and when you find it is more difficult than you had imagined, it puts a lot of stress on everybody involved," she says. "We try to minimize that stress, but it is very hard. We hope some of our discoveries will transform the field of infertility and help more people in the future."

Taking care of your body—eating healthy foods, exercising, maintaining a healthy weight—is a good start. Here's what else you should know if you'd like to have children today or down the road.

Read: Q&A: What to Expect at Your OB-GYN Appointment

Women are born with all the eggs they will ever have—about 300,000 by the time they reach puberty. Studies show that healthier eggs tend to be released earlier in the reproductive life span, Dr. Pisarska says. Men, on the other hand, produce sperm about every 3 months throughout their lives.

Both need to be healthy for conception to occur. While women tend to become the focus of infertility issues, about 30% of infertility cases are solely due to problems with sperm production, and many times infertility is related to both partners.

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"I tell my patients to take charge of their reproductive health," Dr. Pisarska says. Women who want to have children don't have to wait for the "right time"—or even a partner—to know their bodies.

She suggests that women have candid talks with their doctor about their fertility, including their egg and uterine health. "It's important for women to assess their fertility to see where they stand in terms of their own bodies," she says. "This may impact their decision to hold off on family planning and plan for a family sooner."

Tests can assess ovarian health and determine how many eggs a woman has, and ultrasounds can check for factors like fibroids that may affect uterine health.

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For women under age 35 with no complicating factors, try for a year before seeking a fertility specialist. For women older than 35, go in for an evaluation after six months.

Dr. Pisarska recommends women age 40 or older immediately talk to fertility specialists for an evaluation, as they more often have difficulty getting pregnant. If they're going to need medical interventions for their fertility, it's better to know that from the beginning. "We're dealing with a time factor, and we do not want to miss our window of opportunity to help couples," she says.

If you're having problems, err on the side of seeking help. "Some people say if you don't stress, you'll get pregnant, but if you've been trying for a period of time, you should be evaluated further to see what is contributing to you not getting pregnant instead of simply trying stress reduction."

"There is definitely great joy at the end of some of our journeys with our patients, but there is also a lot of sadness and ups and downs," Dr. Pisarska says. It can be stressful, and sometimes couples take breaks to regroup.

Doctors check three main areas when evaluating couples for infertility:

• Are women having regular periods? Is their ovarian reserve good?
• Are their fallopian tubes and uterus normal?
• Is the sperm healthy?

Women having difficulty with ovulation can potentially be treated with medication. Couples in which women have poor ovarian reserve or scarred fallopian tubes, or in which men have abnormal sperm parameters, may need in-vitro fertilization, in which an egg is fertilized outside the body, then implanted. Multiple options are available for couples having difficulty with conception, Dr. Pisarska says.

At the same time, she and others in the field are working to better understand why infertility occurs so it can be more effectively treated and perhaps even prevented.