WHEN MY client Tina Johnson got pregnant, she became concerned about her workouts and weight-training exercises. Which would be the best and safest during her pregnancy?

"I want to make sure I'm giving my baby and myself the very best start possible. I've done my research and the evidence is clear that exercise provides numerous benefits for me and my baby," she said.

Indeed, many experts and all the latest research agree that exercise is one of the best things you can do if you are contemplating getting pregnant or already expecting.

Since 1994, the American College of Obstetrics and Gynecology guidelines have stated that "during pregnancy, woman can continue to exercise and derive health benefits even from mild-to-moderate exercise routines."

Obviously, pregnancy is not the time to take up a contact sport or train for your first marathon. However, it isn't a nine-month pass to veg out. The bottom line? Use common sense when choosing an exercise program - and check first with your doctor before doing anything.

Some researchers suggest that exercise during pregnancy may reduce excessive weight gain, help shed post-pregnancy weight and improve a mom-to-be or new mom's overall mood.

Here are 10 simple guidelines to ensure a fit pregnancy for you and your baby.

1. Maintain a healthy diet.

Throughout your pregnancy, eat plenty of fruits and vegetables. You are not eating for two, so don't go bingeing on chips, cakes, cookies and ice cream. At the most, you may need an additional 300 calories a day. Have a couple of pieces of fruit or some vegetables and you'll make that quota in no time.

Remember, the average baby weighs about seven pounds. If you pack on the pounds during your pregnancy, you could increase your chances of gestational diabetes and pre-eclampsia. Not to mention that many women never shed those excess pregnancy pounds.

2. Keep exercising.

If you were maintaining an exercise routine before pregnancy, you should be able to continue with it - for the most part. If you are new to exercise, take it easy and start with some basics, like walking. Be reasonable and use common sense.

3. Keep lifting, too.

If you have been doing a regular strength-training program, you should be able to do so throughout your pregnancy with some modifications. Naturally, you'll want to keep your intensity low to moderate and avoid putting excessive stress on your joints.

Your strength-training program should emphasize maintaining good muscle tone. This is not the time to begin your power-lifting career.

4. Do yoga.

Yoga is always good but can be especially beneficial to pregnant women. Look for yoga classes specifically designed for pregnant women.

5. Watch that weight gain.

While you should expect to gain weight during your pregnancy, there is no need to go overboard. According to the latest guidelines, underweight women should gain 25 to 35 pounds and overweight women should gain no more than 15 to 25 pounds.

According to the World Health Organization, the median weight gain for pregnant women in the United States is 30 pounds. (Median means half gain more and half gain less.)

6. Reassess after the first trimester.

After the first trimester (three months), avoid doing any exercises that call for you to lie on your back. Lying on your back reduces blood flow to your baby and can elevate your blood pressure.

7. Do your Kegels.

As many as 25 percent of women suffer from urinary incontinence (leaking urine) after giving birth. To avoid this, be sure to do pelvic floor muscle exercises daily throughout your pregnancy.

The easiest way to locate these muscles is to stop the flow of urine while urinating. The muscles that are engaged when you do this are your pelvic floor muscles. Do this a minimum of 30 repetitions a day (except while urinating), but you can do up to 100 if you like.

8. Drink plenty of fluids.

Be sure to stay properly hydrated throughout your pregnancy by drinking plenty of water. Carry your water bottle with you throughout your workout and sip frequently during your workout.

9. Keep cool.

Avoid exercising in extreme heat and humidity. If you are going to exercise outdoors, be sure not to do it during the hottest period of the day in the mid-afternoon. And stay out of the sauna, steam room and hot tub, too.

10. Relax.

Be sure to include relaxation time in your daily regimen as well. Mediation and relaxation exercises may help boost your energy and increase your feelings of well-being throughout your pregnancy. *

Kimberly Garrison is a certified personal trainer and owner of One on One Ultimate Fitness in Philadelphia (www.1on1ultimatefitness.com).

E-mail her at

kimberly@1on1ultimatefitness.com. Her column appears each Thursday in Yo! Chat with her on her Daily News weblog, the Girlfriends' Locker Room, at www.girlfriendslockerroom.com. Her new podcast, "Philly Fitness and Health," is available for download every Thursday at www.philly.com.