Typically women obsess about their size, regardless of health ramifications and when they fall pregnant, these attitudes persist. Society at large fears fat, even during pregnancy. But a healthy weight gain plays a huge role in a healthy pregnancy.

On no account cut back on eating as it deprives you of good nutrition and results in a small, sickly baby suffering from persistent health problems.

With almost two-thirds of women at childbearing age in the U.S. being overweight or obese, be sure to reduce your weight before you conceive.

How much weight should you gain during pregnancy? Start with your Body Mass Index (BMI), a ratio between your height and weight at the time of conception and for most people a reliable indicator of their body fat.

Google 'BMI calculator', select one of the sites, specify English or metric, enter your height and weight, and out pops your BMI. Less than 18.5 is considered underweight, 18.5 to 24.9 normal, 25 to 29.9 overweight, and 30 plus obese.

To give you an idea, a 5-foot-6-inch woman weighing between 115 and 154 pounds is considered normal.

Recommended weight gain guidelines during pregnancy

Following these guidelines issued by the Institute of Medicine (IOM) in May 2009, lowers health risks for both mothers and their babies.

If your pre-pregnancy weight was in the healthy range for your height (a BMI of 18.5 to 24.9), you should gain between 25 and 35 pounds. In the first trimester your gain will be 3 or 4 pounds, partly water weight and partly materials to help your very tiny baby grow. Thereafter gain 1 pound a week for the rest of your pregnancy to ensure optimal baby growth, a more comfortable pregnancy and a safe delivery.

Underweight women (a BMI of below 18.5) may be less fertile because of their low body fat, but if you conceived, gain a total of 28 to 40 pounds; 5 to 6 pounds in the first trimester and slightly more than 1 pound a week for the second and third.

If you were overweight for your height (a BMI of 25 to 29.9), gain a total of 15 to 25 pounds; 2 to 3 pounds in the first trimester and slightly more than 1/2 pound per week for the second and third trimesters.

If you were obese (a BMI of 30 or higher), gain between 11 and 20 pounds; 1 pound in the first trimester and slightly less than 1/2 pound per week for the second and third trimesters.

If you are expecting twins, gain 37 to 54 pounds if you started at a healthy weight; 31 to 50 pounds if you were overweight; and 25 to 42 pounds if you were obese, gaining roughly 1 1/2 pounds a week in the second and third trimesters.

Some obstetricians and gynecologists would like to see these figures shift downwards, with women in the healthy range gaining 20 to 25 pounds instead of 25 to 35. The lower figures were recommended in the 1970s and are considered sufficient for a healthy baby yet also make it easier for women to get back to their pre-pregnancy weight.

Chart your weight gains

If you suffer from morning sickness and nausea in your first trimester, food may not appeal to you and any weight gain will be negligible. Not to worry. Later on in your pregnancy is when the growing baby especially needs calories and nutrients for proper development and by then your morning sickness will be long gone.

Toward the end of your pregnancy you may gain a little more, stop, or even notice a slight weight loss at the very end. Plus-sized women have reserves in their stored fat and may actually lose a little weight during their pregnancy.

Restricting your food intake and trying to lose weight while expecting is not recommended because the fat stores you burn may contain substances dangerous to the baby. Gaining muscle is permitted, though first discuss exercising with your doctor beforehand.

Should you have one or two 'growth spurts' gaining several pounds over a short period and then level off, do not be concerned.

But if you suddenly gain more than five pounds a week during the second half of your pregnancy, beware; this could be a sign of pre-eclampsia, a serious condition threatening both you and your baby.

Contact your doctor too if you fail to gain weight for more than two weeks between the fourth and eighth month of your pregnancy.

How to stay within the recommended range

Eating healthily while pregnant is best for you and the developing baby. Your doctor will determine what constitutes a healthy weight gain for you. He will also educate you as to what to eat and how to exercise.

The old maxim 'eating for two' does not give you free reign to eat double what you normally do.

If your weight at conception falls in the normal range of BMI, during the first 12 weeks of your pregnancy you need 100 to 200 extra calories a day; for the remainder 200 to 300, with underweight women needing 300 to 500 extra calories a day.

300 calories is not a lot. For example, an extra snack of four fig bars and a glass of skim milk covers it.

Dangers of gaining too much weight or being overweight at conception

Although most overweight women enjoy healthy pregnancies and deliver without complications, there are potential risks. You could miscarry, it may be difficult to hear the baby's heartbeat and measure the size of the uterus, after the birth you will find it difficult to lose weight and most probably will weigh more in later pregnancies. You risk complications such as high blood pressure, gestational diabetes and pre-eclampsia. Your baby may be too large at birth, making vaginal delivery long and painful, increasing the likelihood of you needing a cesarean delivery, and the child will probably become overweight or obese himself. Moreover you will probably have trouble breastfeeding, partly because of poor milk production and partly because you find it difficult to position the baby for nursing.

In order to lower your risks, medical tests such as ultrasounds to measure the size of your baby and a glucose tolerance test to screen for gestational diabetes, may be advised during your pregnancy.

Dangers of gaining too little weight

Those who start pregnancy underweight or who do not gain enough during pregnancy, risk stunted fetal growth, delivering a low-birth-weight baby weighing less than 5.5 pounds, and preterm delivery which can cause severe health problems for the infant, even death, if birth is too premature.

Obeying these guidelines

Women are strongly advised to comply with these recommended weight gains. Admittedly your metabolism, activity level and genetics play a role, but with regular visits to your doctor, you can both ensure your pregnancy progresses smoothly.

Gaining weight gradually means your baby has a steady supply of nutrients, some of which are stored for breastfeeding, lowering your chances of hemorrhoids, varicose veins, stretch marks, backache, fatigue, indigestion, and shortness of breath during pregnancy.

Guidelines to gain healthy weight

Eat five to six small meals a day comprising nutrient dense food which nourishes you and your baby. Seek foods like fresh fruit, vegetables, nuts, dried fruit, peanut butter, yogurt, cheese, whole grains, lean protein, fatty fish, and dairy products. Limit junk food, candy, cookies, donuts, cake, pie, potato chips soda and coffee, loaded with calories but no nutrition. Avoid smoking and alcohol.

If you need to gain weight faster, add butter, cream cheese and sour cream to meals, and nonfat powdered milk to mashed potatoes, scrambled eggs and hot cereal.

What to do if you need to slow down your weight gain during pregnancy

Instead of restricting your eating, make healthier choices. Substitute high calorie fried foods and whole milk products with foods mentioned above and you will feel satiated. Limit sweetened drinks and drink water, club soda or diluted fresh fruit juice instead.

Regular moderate exercise, such as walking, swimming or yoga, is effective both during your pregnancy and once your baby is born.

You need to tread a fine line between eating extra calories, staying active without burning them all, and gradually gaining weight.

If you feel anxious about your increasing weight

If in the past you carefully watched your weight, you will feel uncomfortable seeing it creep upwards. Remind yourself that some weight gain is important for a healthy pregnancy and will disappear after the birth.

Losing those extra pounds after you give birth

A 25 pound weight gain during your pregnancy is distributed in the following way: the baby 7.5 pounds, amniotic fluid 2.0 pounds, placenta 1.0 pound, breast tissue 1.5 pounds, uterus increase 2.0 pounds, extra blood supply 3.0 pounds, retained water 2.0 pounds, and protein and fat stores for delivery and breastfeeding 6.0 pounds.

You will lose roughly half your pregnancy weight in the first six weeks after delivery. The rest took nine months to put on so allow that length of time to lose it. Do so by eating healthily and exercising sensibly and it may well come off sooner.

Do not drastically reduce your calorie intake in an attempt to speed up your weight loss since you need energy to cope with being the mother of a newborn baby. When you breastfeed weight comes off faster because you burn 1000 to 1500 calories a day producing milk.

Exercise also plays a valuable role after the birth of your infant. It helps you lose weight, build muscle, become more flexible, relieves depression and increases your self esteem.

Remember a pregnancy is all about carrying a growing baby inside you, a real miracle of nature. Eating the right amount of quality food rewards you with not only a healthy baby, but also rapid weight loss after the birth.

How Much Weight Should You Gain During Pregnancy