Chapter One: Heavy Issues
Many people believe that pregnancy contributes to obesity. However, research shows that women who gain as recommended while they are pregnant have no greater reason to fear a permanent battle with obesity than nonpregnant women of the same age. Instead, pregnant women should take comfort in knowing that by gaining that recommended 25 to 35 pounds they have made an important contribution to the health of their baby.
HOW MUCH WEIGHT
The current weight gain recommendations for women of normal weight during pregnancy are at a higher level than they have been in the past 20 to 30 years. In the 1960s, the typical expectant mother was told to limit her weight gain to 15 to 20 pounds. She was even encouraged to use appetite suppressants and low-calorie diets to limit her weight gain, thereby preventing weight-related health problems and making her delivery easier. In the 1970s, researchers saw a connection between low weight gain and the birth of preterm, low-birth-weight babies. As a result, the 1970s mom was told to gain 20 to 25 pounds. In the 1980s researchers saw a 20 percent reduction in low-birthweight babies among white mothers and a 7 percent reduction among black mothers who gained eight to ten pounds more than their 1970s counter-parts. As a result, weight-gain recommendations were increased even further. Today, the Institute of Medicine (IOM) offers a general weight-gain recommendation during pregnancy of 25 to 35 pounds, plus three different weight-gain guidelines based on a woman's weight for height before conception.
Weight-gain ranges are based on prepregnancy body mass index (BMI). BMI is defined as body weight divided by height squared, and it is considered a better indicator of nutritional status than weight alone. Use your prepregnancy weight to calculate your BMI with the help of the chart on page 3. Once you determine your prepregnancy BMI, select the interpretation that describes you: underweight, normal, overweight, or obese. A 5'8" woman weighing 140 pounds at conception has a "normal" BMI of 21.5. A 5'8" woman weighing 120 pounds, with a BMI of less than 19 is described as "underweight." Once your BMI is determined, select the recommended weight gain that matches your description.
HOW FAST SHOULD I GAIN?
Your doctor will weigh you at every visit. Some women hate these weight checks and feel they are the doctor's way of checking up on them to see whether they have been "good" or "bad." The truth is that your doctor is checking up on you, but only to look for signs of good or bad health. Weight can be a very effective tool when evaluating the progress of a pregnancy.
A gradual, steady weight gain is ideal. In the first 13 weeks most obstetricians like to see a weight gain of two to five pounds, followed by a steady increase of approximately one pound per week until delivery. A gradual gain in weight suggests that both lean and fat tissue are being added, whereas an erratic and sudden increase can indicate a dangerous problem, such as the retention of fluid that is one of the symptoms of preeclampsia.
Though the ideal might be a nice, steady, even weight gain, in reality most women will not gain weight in such a uniform manner. The British Journal of Obstetrics and Gynecology published a 1991 study that took a retrospective look at how mothers with a normal pregnancy outcome gain weight, and found that there was a wide variation in weight gain over the course of pregnancy. The slowest weight gain occurred before 16 weeks, after 35 weeks, and right before the eighth month between week 28 and week 32. The differences in average weekly weight gain among the mothers studied were related to number of pregnancies, BMI, smoking habits, and history of high blood pressure.
Many things can make it difficult to interpret weight gain. If the date of conception is uncertain, it is difficult to assess weight-gain patterns. In some cases, an unexpected weight gain can be related to how much food or liquid was consumed before a weight check. Whether a mother has a full or empty bladder or has had a bowel movement will affect the recorded weight. Even clothing and time of day affect weight measurements. The point is, a jump in weight does not always mean you ate too much or that something is wrong. In some cases it is a fluke in the weighing technique. As always, talk to your health-care provider and focus on the trend in weight gain, not just one reading.
To help practitioners and women make sense of what is considered a healthy weight-gain trend, the IOM has suggested recommended weight-gain patterns. With the help of your doctor, use these to establish a weight-gain goal that is right for you.
Adolescent women need to aim for the high end of the recommended weight ranges, and women under 5'2" should attempt to keep to the lower end. Women who are carrying twins may be advised to gain 35 to 45 pounds. The IOM suggests that women of normal weight who gain less that two pounds per month should investigate the reasons for slow weight gain with their doctor. And women who do not gain at least ten pounds by midpregnancy need to receive nutrition counselling. Gains of over six and a half pounds per month may need to be monitored, but food intake should not automatically be reduced. Weight gain continues to be important until the end of pregnancy. For instance, a low weight gain in normal-weight women in the last three months of pregnancy may be a cause of early delivery.
Is gaining above the recommended weight-gain levels even better for baby? The answer is, probably not. In a study of over 53,000 infants it was found that low birth weight decreased with increasing weight gain in average-weight women, but there was no further reduction in low birth weight when weight gains were higher than 30 to 40 pounds. Women with high weight gains are at increased risk for high-birth-weight babies, which can make delivery difficult. If you have a BMI higher than 29 you may be advised by your doctor to limit your weight gain to 15 to 25 pounds. (Some physicians may recommend an even lower weight gain based on a woman's medical history.) A lower weight gain may reduce an overweight woman's risk for a high-birth-weight infant.
No one can predict exactly how any individual woman will gain or lose weight but a review of the research can give mothers some reassuring news. In 1993, Sally Ann Lederman, Ph.D., then of Columbia University's School of Public Health, reviewed the pregnancy-related research to determine whether one's weight increases permanently as a result of pregnancy. The studies showed that the average woman generally retains less than three pounds of added weight (from before pregnancy to one year after delivery). A small number of women may retain a lot of their pregnancy weight, but this is more likely due to having been overweight at conception and to lifestyle changes rather than to pregnancy itself. The woman who begins her pregnancy overweight may be at greater risk for being heavier after delivery.
A study of 1,423 Swedish mothers who averaged the recommended 30-pound gain during pregnancy found that the average weight gain was only three pounds one year after delivery. In another study the weight-gain patterns of 795 American women who gained approximately 28 pounds during pregnancy were examined. It was found that they averaged only three pounds above their initial weight at their six-month postpartum visit. This research suggests that for an average-weight woman, weight retention related to pregnancy is about three pounds, six months to one year after delivery. It is important to note that there are big differences among the women in these studies. In the Swedish study, for example, 2 percent of the mothers gained 20 pounds from before pregnancy to one year after delivery. The women gaining the most weight tended to be overweight to begin with.
Being Overweight Before Pregnancy
Women who are overweight before pregnancy can benefit by setting weight-gain goals for their pregnancy with their doctor. In a study that looked back on the weight gains of 128 severely obese women, more than 70 percent of these mothers had retained over 20 pounds one year after delivery. This suggests that for the very overweight woman, pregnancy can contribute significantly to weight. In another study at the University of Utah the weight histories of 96 very obese mothers were compared to 115 non-obese women. It was observed that the obese mothers had gained 100 pounds by age 46 and the control group 31 pounds. The obese women retained more weight after their first pregnancy than the control group, and the obese women lost less weight after delivery and had greater gains between pregnancies than did the control group. (It may be that women who end up obese increase weight gradually over 20 years and some of that time pregnancy is happening.)
Women who gain excessive weight during pregnancy may increase their chance of induced labor and risk for an emergency cesarean section. Research suggests that obese women are more likely to have large babies no matter what their weight gain.
If you are overweight before pregnancy you may be at greater risk for retaining weight postpartum. With the help of your medical team, develop a weight-gain goal while pregnant and a weight-loss plan following delivery. The woman who begins her pregnancy overweight is at the greatest risk for being even heavier after delivery and will benefit most by considering her food selections very carefully.
For most women it is not pregnancy that is the cause of weight gain, but rather the fact they are getting older. In a study of over 41,184 postmenopausal women, even the women who had no children gained a significant amount of weight between ages 18 and 50. In this study, the difference in weight between women who had no children and those who had one to four children was small. In a large Finnish study that compared the weight of women with and without children, women who were over 35 and had no children weighed more than younger women who had had several children. It is not childbirth but aging that appears to explain the creeping weight many women experience.
Age has a bigger effect on weight than having children does, but women who have more than three children do tend to be heavier than women of the same age who have fewer children. This weight difference may not be due to pregnancy alone but may be the result of women having some of their children when they are older, when weight retention seems more common. Studies show that women over age 35 are more likely to retain greater weight after pregnancy than younger mothers.
The study on postmenopausal women suggests that as we age we can expect to gain about three-quarters of a pound per year. That's almost four pounds every five years, or 16 pounds in 20 years. This weight gain occurs independently of whether a woman has children or not.
In a 1994 report, Dr. D. F. Williamson looked at the weight history of 2,547 women age 25 to 45 who participated in the first National Health and Nutrition Examination Survey. These women were weighed in the early 1970s, then again ten years later. In that ten-year period, the women who had not had children had gained 3.52 pounds, the women who had had up to two children had gained 3.74 pounds, and the mother with three children had gained 4.84 pounds.
There is a difference in weight gain, but it is very modest and means women do not need to fear a life of obesity just because they decide to become mothers.
Higher Weight-gain Guidelines
The weight-gain recommendations are now set higher for most women than they were before and some women may wonder if this increases the chance of permanent weight gain. The Institute of Medicine's weight-gain guidelines of 25 to 35 pounds are a good five to ten pounds above the 1970 guidelines of 20 to 25 pounds. The additional weight gain increases the birth weight of babies at delivery, which decreases infant mortality but may also create a degree of apprehension among women who fear permanent weight gain by meeting these higher recommendations. In 1993, Kenneth Keppel, Ph.D., of the National Center for Health Statistics, examined the actual weight retention among women who reached these higher guidelines. Women were interviewed 10 to 18 months after delivery. At that time, the median weight for white women who gained as recommended was 1.6 pounds higher than their weight before pregnancy, for black women it was 7.2 pounds. Thus, white women who gain the recommended amount of weight do not need to fear retaining a substantial amount of weight; however black women are at greater risk for being heavier after delivery, perhaps because they are not getting accurate information about weight gain recommendations during pregnancy and they may need advice on how to lose weight following delivery.
Anyone who has a baby will experience lifestyle changes she never imagined. The mother who goes from full-time office worker to full-time, stay-at-home mom may find weight an issue for the first time. This is less the result of pregnancy, and more due to the access she now has to food and the reduced opportunity to exercise.
A 1992 study by Dr. C. W. Schauberger that examined the factors that influence postpartum weight loss found that women who delayed returning to work were likely to gain more weight than women who returned to work sooner. Women who returned to work two weeks after delivery were only one pound above their weight before pregnancy when they were examined six months after delivery. Women who did not return to paid work were almost five pounds heavier at six months postpartum.
This is important because it is estimated that more than half of new mothers do not work outside the home in the first year of their baby's life. Women who stay at home have more frequent contact with food and are often responsible for preparing meals for the family. It is important to identify the lifestyle changes pregnancy creates and the effect they can have on weight.
Lifestyle can be modified to meet healthful eating goals. For example, keep the cupboards stocked with healthful snacks, not high-calorie snack foods like chips and cookies. Start an exercise routine that works for you; find something you like and do it every day. Keep food out of sight and eat only when hungry or in designated areas such as the kitchen table -- not in front of the TV.
Another factor that affects postpartum weight is smoking. Fortunately, about 15 percent of pregnant women quit smoking on their own and another 40 percent will do so if encouraged by their family and physician. Quitting the habit improves the growth of the baby inside the mother, but women who quit smoking while pregnant may have a higher, but not necessarily excessive, weight gain. If you have quit smoking, congratulate yourself! Not only will it be good for your health, it will be good for the baby, both before birth and later, growing up in a smoke-free environment. If you have quit, you may have to be extra attentive to your eating and exercise habits after the baby is born to adapt to your new lifestyle.
Breast-feeding has been touted as an effective method for controlling weight postpartum. Breastfeeding is the ideal way for most women to feed their baby, but its effect on weight loss is not as great as was once thought. Dr. Lederman's review concluded that at six months postpartum, weight loss was greater for breast-feeding mothers, but at 12 months postpartum, there was no significant difference in weight between breast-feeding mothers and mothers who bottlefed their baby. However, the studies have shown that mothers who breast-feed can lose weight even if they are not dieting, while those who choose to bottlefeed have to reduce what they eat if they want to take off extra pounds.
Breast-feeding women require more calories while nursing, about 500 extra calories per day. This means they can eat more food because they also need more in order to meet the demands of making breast milk. Breast-feeding deserves to be promoted for the indisputable health benefits it can provide to your child, but it does not guarantee that you will lose weight. You may still need to match what you eat to fit your new life pattern.
EATING DISORDERS AND PREGNANCY
Though eating disorders and pregnancy have not been well researched, there is enough information to offer comfort and guidance on this issue. It is estimated that 1 percent of general practice patients are bulimic (a binge-purge pattern) and up to 2 percent of young women could be affected by anorexia nervosa (a disorder characterized by starvation, distorted body image, and extreme fear of obesity). Women who suffer from anorexia nervosa are less likely to become pregnant than women with bulimia, in part because anorexia nervosa results in a lower fertility rate, caused by very low body weight, and in part because women with this condition are usually less sexually active.
Eating disorders during pregnancy hold the potential for disaster. Women with eating disorders are often underweight at conception, increasing the risk of delivering a low-birth-weight infant. Obstetricians have reported increased rates of difficult labor among these women requiring medical intervention. A child born to a mother with an uncontrolled eating disorder may be at greater risk for early or breech delivery, cleft palate, and delayed development.
The news about eating disorders is not all gloomy, however. In a review of the clinical significance of eating disorders during pregnancy, Thomas A. Fahy has found that bulimic women show a temporary improvement in their binging and purging behavior during the late stages of pregnancy. In a study of 20 untreated women, 75 percent had stopped this behavior by the third trimester. However, symptoms did return after delivery and, in half the cases, eating habits were more disturbed. It is important to emphasize that these women were not in treatment for their disorders. In one case a bulimic woman had recurrent miscarriages between the third and fifth month. When the disorder was in remission, she was able to deliver two fullterm infants. In another eating-disorder observation, eight women, who had been afflicted with anorexia nervosa but gained an adequate amount of weight while pregnant, delivered healthy babies of normal weight. Seven of these women were in psychiatric treatment before or during pregnancy.
For any woman who is afflicted with an eating disorder, treatment and remission are important to a healthy pregnancy. The woman with an eating disorder who gains adequate weight will go a long way toward reducing her risk of pregnancy complications and improving the health of her child.
EATING DISORDERS AND PARENTING
An active disorder has the potential to be damaging while a woman is pregnant but the impact on the child does not stop there. Mothers who fear food and are intensely preoccupied with their body will experience conflicts with their own maternal responsibilities to feed and nurture appropriately. In a Danish study 17 percent of the babies born to women with anorexia nervosa showed failure to thrive in the first year. For bulimic mothers, the energy devoted to the rituals of planning and executing binges may take away from the time they spend parenting. In a study of the children of five bulimic women, the mothers had undue concern about weight, and the children were not well nourished.
In a review of this issue, Debra Franko, Ph.D., director of the Eating Disorder Program at the Harvard-affiliated Beth Israel Hospital states that shame, secrecy, and denial prevent women from sharing their problem with their doctors. In an ideal world, women would be asked about eating disorders during their prenatal exams and referred to a psychiatrist or an eating disorder clinic when a problem is identified. Research shows that women with eating disorders in remission or in treatment significantly reduce their complications.
Women who are aware of their eating disorders should also become aware of the weight gain recommended for their BMI. If you are underweight before conception, make a special effort to meet the recommended goals. Reread the beginning of this chapter to understand that weight gained during pregnancy is not permanent in the majority of women. Join a pregnancy support group or a pregnancy exercise class. These can be lots of fun and will give you an opportunity to discuss your fears and validate the feelings that come with pregnancy. Seek out a therapist who is trained in eating disorders. Having someone to share your feelings with can be helpful.
If you have an eating disorder it is just as important to take care of yourself after the baby is born. Join a parenting class. Get a few good books on feeding your baby and on the normal development of children. (There are some recommended titles in the back of this book.) In a culture that is obsessed with thinness some parents control food so much that they actually deprive their children of the food they need.
PUTTING THE WEIGHT ISSUE TOGETHER
Research shows that women who gain an average amount of weight while pregnant can expect to retain about two pounds above and beyond their expected weight increase with age. Women who gain significantly above their recommended levels are likely to retain more postpartum. Women who are the thinnest before conception should gain the most; underweight women should gain 28 to 40 pounds during their pregnancy. Proper weight gain is of most concern to thin women who are restricting their food intake. Women who do not eat enough cannot achieve nutrient balance. Early weight is important for the growth of the baby later and normalized maternal weight will optimize that growth, which is important to prevent restricted brain and organ development, and to optimize health.
Pregnancy itself does not lead to obesity except in a small percentage of women. Reaching the desired weight gain appropriate for your size is important. While pregnant, staying in the weight range developed between you and your doctor may be helpful in preventing a postpartum weight problem. You cannot predict or control how your body gains weight while you are pregnant, and every pregnancy (even each of yours) will be different -- just ask your doctor. Your responsibility is to eat well and eat the foods you need for good health. When you eat well, exercise appropriately, and rest as needed, your body will do all the work of building your baby.
The most common nutritional concern of women during pregnancy is excessive weight gain. However with realistic weight goals and a healthful eating plan, these fears about excessive weight gain do not need to become reality.
Copyright © 1999 by Eileen Behan