We’re well into December, a month full of rich food, festive parties and holiday cheer. Skip the homemade eggnog, enjoy the treats (with moderation) and don’t forget to stay active.

If you’re like most women, you probably aren’t increasing the amount you exercise during pregnancy. According to a WiserPregnancy survey, about two-thirds of pregnant women regularly exercise. Only 11% of women get more exercise during pregnancy than before, and the primary motivation is to control weight gain.

However, if you’re consuming calorie-laden holiday treats—and if your doctor gives you the okay to exercise—December is not the month to slack off exercising or eating a healthy diet. Of women who increase the amount they exercise during pregnancy, 61% do so to control weight gain.

Why is weight control during pregnancy important? For one, fit women who gain the recommended amount of weight (25 pounds on average) suffer fewer pregnancy discomforts. Delivery and postpartum recovery tend to be easier for new moms who did not gain excessive weight during pregnancy. Also, gaining too much pregnancy weight can lead to long-term health problems for you and your baby—you’ll be at higher risk for obesity, diabetes, high blood pressure and cardiovascular disease.

Exercise also has other benefits. Half of women (49%) stick to the exercise routine to keep their baby healthy. About 1/3 of women (31%) increase exercise to try to fight fatigue and other common pregnancy ailments.

What are you doing to stay healthy during the holiday season?

You wouldn’t think that pregnancy would turn a couch potato into Ms. Fitness. But often, that’s exactly what happens.

A recent WiserPregnancy survey found that almost 2/3 of pregnant women regularly exercise. Non-pregnant women? Only 32.9% of those 18 years and older regularly work out in their free time.

So why would a woman who’s not usually a gym rat start exercising when she’s expecting? One factor could those regular medical checkups, which include weigh-ins and potentially disapproving looks from the doctor.

But more likely, it’s hard to find excuses when your baby’s health is at risk.  Maternal weight gain affects baby size and well-being, and a large baby poses risks to both mother and child.

Then there are the feel-good benefits: More than half (57%) of pregnant women report that exercise is useful for managing pregnancy symptoms such as back pain, heartburn, constipation, shortness of breath, fatigue, headaches and nausea.  Also, you’re likely to look and feel better, lose baby weight faster and be less likely to suffer postpartum blues.

Are – or were – you exercising during pregnancy? Why or why not?  What helped keep you motivated?