Weighty Matters
It’s a common complaint voiced at gyms, in doctors’ offices, at weight-loss centers--wherever women contemplate their weight.
“I was thin until I had my baby.”
“I never lost my pregnancy weight.”
“I gained more weight with each baby.”
Americans’ battle with obesity has long been recognized as a major health problem. Now, in an effort to better understand the problem, researchers are looking at weight gain over a woman’s life cycle, with particular attention paid to pregnancy.
“We’re all getting fatter, but at every point along the curve, women are fatter than men,” says Jennifer Lovejoy, chief of the Women’s Health Research Program at the Pennington Biomedical Research Center, Louisiana State University. From age 25 to 34, she notes, men have a 3.9% chance of gaining 22 pounds. For women the risk is double--about 8.4%.
Why the difference? There are no clear-cut answers. But researchers like Lovejoy, a physiological psychologist, are pointing a finger at pregnancy as one possible factor.
“I was doing metabolic studies on women, and I was hearing from about half of these women--who were middle-aged and obese--that they became obese after their first pregnancy,” she says.
Until recently, few studies had been done on pregnancy weight gain and its effects on both maternal and infant health. But Lovejoy’s research along with other newer studies could precipitate a shift in thinking on how a pregnant woman puts on weight.
Putting on Pounds for the Baby’s Good
Long-term obesity in women has major health consequences, including an increased risk of heart disease, hypertension, diabetes and certain cancers. But the issue of pregnancy weight gain is touchy because the health of the mother must be balanced with the health of the baby. Given the nutritional needs of the growing fetus, pregnancy is no time to start a diet.
But the concept of eating for two has taken on mythic proportions.
“I think there are a lot of people, even physicians, who think, ‘The more weight you gain, the better. Don’t worry about it; you can lose it later.’ But that is just not the case,” Lovejoy says.
While researchers are still trying to figure out if the optimal weight gain for the mother is the optimal weight gain for the infant, there is some consensus that many pregnant women gain too much weight. Maternal obesity is defined in most studies as weight above 175 pounds or weight that is more than 50% beyond the ideal prepregnancy body weight.
Studies show that the average woman retains two to five pounds after having a baby. While adults tend to gain weight as they age, gaining two to five pounds over nine months is far beyond the normal pace related to aging.
And that’s the average woman. Many other women end up 20 pounds or more heavier long after childbirth. About 10% to 15% of women are at risk for retaining more than 22 pounds. Minority women are especially susceptible. Black women are twice as likely to retain 20 pounds as white women.
Studies have also shown that the more babies a woman has, the more weight she is likely to retain, regardless of her age.
Tammy (who asked that her full name not be used) typifies women who find themselves blessed with a baby but left dissatisfied with their bodies.
The Los Angeles homemaker became pregnant at 37. Tammy had waged a long battle with her weight and felt she was still about 10 to 15 pounds over her optimal weight when she conceived.
“Prior to getting pregnant, I had lost a good deal of weight. I had been on an eating plan, according to a doctor; portioning my food to get down to a good weight to get pregnant at,” she says.
Pregnancy put a quick end to dieting.
“Suddenly, to my psyche, being pregnant was a license to eat,” Tammy says. “I didn’t eat junk food but would feed myself whenever I was hungry. Then, when I was three months’ pregnant my obstetrician turned to me and said, ‘Now, dear, gaining 30 pounds during pregnancy is not a bad thing. But you’ve managed to do it in the first three months. This is the start of a bad trend.’ ”
Tammy quickly got her eating habits under control and gained only 15 pounds more during the last two trimesters. Her baby was born healthy and of average weight. But--five years later--Tammy is still struggling to lose 30 pounds she has retained from that pregnancy.
Many factors--including ethnicity, occupation and the interval between pregnancies--can contribute to weight retention after pregnancy. But Tammy’s case illustrates a few key factors that are thought to cause too much weight gain, Lovejoy says. These include the timing of weight gain, energy expenditure, hormonal changes and eating behavior changes during pregnancy.
A 1996 study, for example, tracked women as they gained weight throughout a pregnancy and how much they retained. It found that a whopping 86% of the weight gained in the first trimester is retained by the mother, whereas pounds added in the third trimester didn’t seem to stick to moms’ hips after childbirth because they contributed more to infant weight.
Another recent study also showed that energy expenditure in pregnant women varies widely among individuals. A woman in the first half of pregnancy--while needing to eat healthy--may not require lots of extra calories. But, Lovejoy notes, the Recommended Dietary Allowances for calories for pregnancy is an extra 300 calories per day in the second and third trimesters, no matter what the woman’s size or caloric needs.
“The RDAs for pregnant women are flat. But this research showed that in healthy women there is a huge difference [in calories needed],” she says. “Some women don’t need any extra calories at all until the third trimester. But if they start eating extra calories in the eighth week, you can see how there would be a problem with putting on too much weight.”
Many newly pregnant women, however, think they need to start eating for two--and often want to, says Elyse Resch, a Beverly Hills nutritionist who is counseling Tammy and is co-author of the book “Intuitive Eating” (St. Martin’s Press, 1995). “Intuitive eating” is defined as eating healthy while honoring one’s hunger and tastes and steering clear of dieting and food restrictions.
“To me, the key trigger is that prior to pregnancy, women are continually dieting and restricting themselves. A lot of women think they need to lose a lot of weight before pregnancy. Then, the moment they get pregnant, they give themselves license to eat. They eat anything they want. It’s almost a binge behavior,” Resch says. “What we need to teach women is to let go of restriction and dieting. So the moment you get pregnant, there is no problem because you are eating the same way as before pregnancy.”
Women may plan to lose the 60 pregnancy pounds after childbirth--but that’s easier said than done, Resch notes. “They have the stress of being a parent, and their needs are often not met. Especially if they are frustrated about having not lost the weight.”
Lovejoy agrees that psychological factors are a big part of the transformation from prepregnancy weight to post-pregnancy weight.
“I don’t think we really know why eating behavior changes. But hormones may also play a role. Hormones may be a disinhibitor of eating behavior,” she says.
Her research on weight gain during the female life cycle has shown that eating behavior varies during the menstrual cycle, with women eating foods higher in fat during particular times of the month and with yearnings for sweet foods highest when estrogen levels are highest.
“There is no reason to think that those same sorts of things aren’t going on in pregnancy. And it probably explains some of the cravings women have,” Lovejoy says.
Women also may be mistaken if they believe that breast-feeding will contribute greatly to their post-pregnancy weight loss, she says.
“In every single study that has looked at it, breast-feeding has not helped. If it’s greater [duration] than six months and if there are frequent feedings, it might help. But overall, breast-feeding is not going to resolve the obesity problems resulting from pregnancy.”
Like the RDAs for pregnant women, Lovejoy is critical that the RDA for breast-feeding women is a single number (an extra 500 calories a day is recommended) instead of a range.
“It’s the same issue; there is a one-size-fits-all RDA for calories for breast-feeding women. But there is no data [to support that]. I have no doubt that women vary tremendously in how much they really need,” she says.
Challenging the Notion That Big Means Better
Pregnant women, of course, have other things on their minds than pickles and ice cream. It is natural to worry over their baby’s health, and that may also contribute to a desire to eat.
But recent research has cast doubt on the idea that a generously sized mother and a big baby is optimal.
In a January article in the New England Journal of Medicine, obesity in pregnancy was called into serious question. A study of a large group of pregnant women in Sweden found that very thin women who still gained adequate weight during pregnant were far more likely to have healthier babies than obese women or even women of normal weight.
Maternal obesity during pregnancy increases the risk of hypertension, preeclampsia, gestational diabetes, thrombophlebitis, prolonged labor, delivery after 42 weeks of gestation and Caesarean section. Obese women who undergo C-sections tend to have more blood loss, prolonged operative time and increased rates of post-operative infection.
Finally, infants of obese women have a greater risk of some congenital abnormalities, such as spina bifida and heart defects.
“It seems like it’s not a good thing to have a too-big or a too-small baby,” says Lovejoy. “You are aiming for that in-between--six, seven or eight pounds. No more than 8 1/2. After that, you get into the risk of diabetes and other problems.”
Obstetrical guidelines today instruct women to gain weight according to their individual needs, about 20 to 30 pounds for most women. But it’s doubtful many doctors are tracking pregnancy weight gain so meticulously as to limit first- and second-trimester pounds.
And, says Resch, a woman with weight or eating problems might do well to seek the guidance of a nutritionist during pregnancy.
“[Obstetricians] don’t teach women to eat intuitively. They don’t tell them how to eat, just ‘don’t gain.’ ”
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The Significance of When Weight is Gained
Percentage of weight gained during these periods that is retained after delivery:
Weeks 1-20: 86%
Weeks 21-30: 68%
After 30 weeks:49%
Factors associated with obesity due to pregnancy:
* Absolute weight gain during pregnancy
* Pre-pregnancy weight
* Smoking
* Ethnicity
* Employment
* Exercise during pregnancy
* Dietary patterns
* Snacking frequency
* Educational level
* Number of pregnancies
* Interval between pregnancies
* Timing of weight gain during pregnancy
Source: Jennifer Lovejoy, PhD, chief of Women’s Nutrition Research Program, Pennington Biomedical Research Center, Louisiana State University
