Overview of trimesters

Pregnancy is a time of tremendous change in a woman's life and it can be both and emotional and physical roller coaster ride.

Leslie Beck, author of Leslie Beck's Nutrition Guide to a Healthy Pregnancy joined Balance Television host Dr. Marla Shapiro to talk about some things you need to know to successfully manage all three trimesters of pregnancy.

Pregnancy Weight Gain

The most common questions women typically have about pregnancy are weight-related, agreed Beck and Shapiro.

"A lot of women are freaked out about having to gain weight all of a sudden and they look at the scale and they see numbers they've never seen before," Beck said. "But women need to gain weight and at no point in a woman's pregnancy should she attempt to lose weight."

How much weight a woman should gain during pregnancy, Beck said, is dependent on her pre-pregnancy weight or Body Mass Index (BMI).

• BMI less than 20: gain 28 to 40 lbs
• BMI between 20-27: gain 25 to 30 lbs
• BMI over 27: gain 15 to 25 lbs

Women who are underweight prior to becoming pregnant need to gain a little more and women who are overweight should gain less. These weight gains are the ones associated with the best outcomes for both mom and baby, Beck said.

"Especially in the first trimester, women only need to gain a little bit," Beck explained. "Some women don't gain at all and that's okay because the baby isn't really growing in the first trimester. I usually aim for about 3-5 pounds in the first trimester. The average weight gain for women in the first trimester is 3-8 pounds actually."

For the duration of the pregnancy, we look for about a pound per week on average, she said. If a woman is expecting twins, the average is approximately 1-1/2 pounds per week.