Serena Williams is one of the world’s best tennis players. Although she may have announced her pregnancy online by accident (oops!), the 35-year-old athlete is 20 weeks along and will miss the remainder of the 2017 professional tennis season. Kelly Bush Novak, William’s spokeswoman, confirmed the tennis star will return for the 2018 circuit.

Athletes, in particular, need to pay careful attention to elements of training during pregnancy. Guidance from their OB-GYN is critical. Dr. Jacqueline Walters, M.D., is a nationally known, board-certified obstetrician and gynecologist who has been in private practice for 18 years; the Atlanta, Georgia-based physician has also made a recent burst onto the small screen as a cast member of Bravo’s hit reality series, “Married to Medicine.” Dr. Walters told LifeZette, “Pregnant competitive athletes must be closely followed by an obstetrical provider due to [their] high level of exercise intensity. Their bodies are accustomed to that level, though the fetus/placenta could be affected by that level of exercise.”

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She added, “There is no rhyme or rhythm when it comes to the appropriate amount, type, cutoff point, and regimen of exercise during pregnancy due to the fact that each woman and pregnancy is different.”

Of any hard limitations on the expectant mom, such as heart-rate elevation, blood-pressure checks, or the like, Dr. Walters said, “Pregnant women don’t have to adhere to the <140 heart-rate limit any further” — but she noted that each woman should “listen to” her own body. “In [the] case of a pre-existing heart condition, a woman will need special care during pregnancy. During a pregnancy, blood volume increases by 30 percent to 50 percent to nourish the growing baby, which clearly stresses the heart and circulatory system.”

Many athletes and women in general wonder if there is a cutoff point for exercise during a pregnancy. “There is no cutoff point for exercise during pregnancy,” said Walters, adding that women should “pay close attention to signs that may indicate a problem with health or the pregnancy. Stop exercising immediately and contact a health care provider.”

A woman’s entire center of gravity changes as the fetus develops. This adjustment affects both posture and gait. Carrying the extra weight of the growing baby can increase the likelihood of back pain as well.

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Dr. Lama Toylaymat, a double board-certified physician in OB-GYN and maternal-fetal medicine, has practiced medicine for over 18 years. Based in Central Florida, Toylaymat is rated as one of the world’s top 10 gynecologists by www.RateMDs.com. Her website addresses the risks of falling for expectant moms.

“Pregnant women should not try a new, strenuous activity.”

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“Activities in which there is a high risk of falling … should be avoided,” she says, adding, “Some racquet sports also increase the risk of falling because of [one’s] changing balance” — hence the safety precaution taken by Williams in not completing the 2017 pro tennis tour.

Most people believe pregnancy is not the time to begin any new diet or exercise regimen. However, Dr. Walters noted, “If a woman has never exercised regularly before pregnancy, she can safely begin an exercise program during pregnancy after consulting with her health care provider.”

Walters said there are numerous benefits of exercise for expectant moms. Among other things, exercise can potentially help prevent gestational diabetes — which develops during pregnancy. Also, “exercise can be a major tool to relieve stress during pregnancy and can definitely build more stamina needed for labor and delivery.” She added, “Pregnant women should not try a new, strenuous activity,” and “walking and swimming are considered safe to initiate when pregnant.”

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Taylaymot agreed with those thoughts. “Exercise will increase [a pregnant woman’s] energy and mood, and may improve sleep.”  She added that “regular activity also helps keep one fit during pregnancy and may improve the ability to cope with labor. This will make it easier for a mom to get back in shape after the baby is born” — something every new mother wants to hear.

The protocol overall for athletes and “everyday women” alike has significantly improved over the years. Training and activity in a safe and sensible manner benefit both mother and baby. Remember that what a mom-to-be eats also helps the baby’s growth as well as the mom’s overall health.

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Take heed of a health care professional’s advice — and never place the growing baby in danger. Above all, moms-to-be should enjoy the miracle and the gift of pregnancy and birth.

Based in Boynton Beach, Florida, Christine King is founder and CEO of Your Best Fit, a health and wellness company that provides fitness, nutrition, and design and management services for individuals, private clubs, luxury communities, and corporations.