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Home => Newsletters => May 15, 2007 • Family Meals Focus #16 • The weight dilemma for pregnancy

May 15, 2007 • Family Meals Focus #16 • The weight dilemma for pregnancy

May 15, 2007
FAMILY MEALS FOCUS #16
Interpreting the news and research about feeding and eating

Family Meals Focus #15 gave historical examples of the harm caused by over-concern about weight gain during pregnancy. That over-concern is coming back, based on current health and nutrition policy and assumptions relative to overweight:

High body weight is dangerous--it carries a big health risk.
Excess weight gain in pregnancy endangers the birth process.
Excess birth weight increases the risk for child overweight and negative health outcomes.
Weight-gain restriction during pregnancy is a viable preventative approach.

FMF #11, Interpreting the Obesity Data, pointed out that mortality rates are lower at BMI 25 to 30 than in the ''normal'' weight category of 18.5 to 25. Not only that, but mortality rates don't increase significantly until BMI climbs higher than 35¹ or, in studies that further break down the over-35 category, until BMI is above 40.² Illogical as it may be, heightened concern about overweight based on such arbitrary weight cutoffs isn't going away any time soon. Increasingly, that concern is focused on weight gain during pregnancy. In contrast to earlier guidelines that recommended letting women eat as much as they were hungry for and trusting them to gain the amount of weight that is right for them, current Institute of Medicine (IOM) guidelines incorporate arbitrary weight cutoffs in making recommendations for gaining the ''right'' amount of weight during pregnancy.³

Underweight (BMI < 19.8): Gain 28 to 40
Normal-weight (BMI 19.8-26.0): Gain 25-35 lb
Overweight (BMI of 26.1-29.0) gain 15-25 lbs
Obese (BMI >28) gain <13 lb

Such weight-gain guidelines create a serious weight dilemma for pregnant women who are told, on the one hand, ''Don't gain too much weight,'' and on the other hand, ''don't diet.'' This dilemma is particularly acute for women whose are defined as being overweight or obese by BMI cutoffs. Such women are warned that their high body weight combines with high weight gain to produce ''too-big'' babies (generally, babies whose weight is above 4500 g., or 9.9 lb) and to increase their own body weight after pregnancy.⁴

What's the matter with delivering a large baby? FMF #19 will address--and question--the idea that a large baby has an increased risk of overweight and ill health in later life. The obstetrical concern is that a large baby is difficult to deliver. Keep in mind that while incidence of high birth weight (> 4500 g) and cesarean delivery increased with increasing maternal weight gains, the increases were not statistically significant until the weight gain exceeded 18 kg (40 lb).⁵Also keep in mind the IOM statement from FMF #15 about the lack of predictive value for the individual woman of weight gain during pregnancy.

Interventions attempt to control weight gain

Not everyone accepts the IOM standards. Some clinicians say the weight-gain standards are too liberal and subscribe to the pre-1970 standards.⁴ Others try to impose current standards by instituting weight management programs that range from vague to specific. Results in clinical trials have been mixed.

Some interventions appear to have a counter-regulatory effect for overweight women, who gain more weight than controls. Normal-weight intervention women gain less weight than controls. Interestingly, many women refuse intervention.⁸
Other interventions have a counter-regulatory effect for high-income, normal weight women, who gain more weight than controls. Low-income intervention women in both the normal and overweight group gain and retain less weight than controls. High-income overweight intervention women gain the same amount as controls and retain more weight after pregnancy.⁷

Interventions help underweight women to gain weight during pregnancy

Seemly almost forgotten in the concern about excess weight gain and delivering a large baby is the more-critical concern about poor weight gain and infant prematurity and underweight:

Underweight and gaining too little weight risks premature delivery and low birth weight.⁶
Adolescents who gain too little weight are more likely to deliver low-birth-weight and preterm babies.¹⁰

While weight-reduction interventions have shown highly mixed results, interventions to help underweight women gain weight have been successful. Compared with women who attended only a nutrition class, women who received a nutrition class and multiple counseling sessions gained more weight and delivered heavier infants.^9,10

Family Meals Focus #17 addresses consequences of targeting weight gain during pregnancy.

Interventions attempt to control weight gain

Some interventions appear to have a counter-regulatory effect for overweight women, who gain more weight than controls. Normal-weight intervention women gain less weight than controls. Interestingly, many women refuse intervention.⁸
Other interventions have a counter-regulatory effect for high-income, normal weight women, who gain more weight than controls. Low-income intervention women in both the normal and overweight group gain and retain less weight than controls. High-income overweight intervention women gain the same amount as controls and retain more weight after pregnancy.⁷

Interventions help underweight women to gain weight during pregnancy

Seemly almost forgotten in the concern about excess weight gain and delivering a large baby is the more-critical concern about poor weight gain and infant prematurity and underweight:

Underweight and gaining too little weight risks premature delivery and low birth weight.⁶
Adolescents who gain too little weight are more likely to deliver low-birth-weight and preterm babies.¹⁰

Family Meals Focus #17 addresses consequences of targeting weight gain during pregnancy.

Reference List

1. Flegal KM, Graubard BI, Williamson DF, Gail MH. Excess Deaths Associated With Underweight, Overweight, and Obesity. JAMA. 2005;293:1861-1867_.

2. Bender R, Trautner C, Spraul M, Berger M. Assessment of excess mortality in obesity. Am J Epidemiol. 1998;147:42-48.

3. Food and Nutrition Board IoM. Nutrition During Pregnancy. Washington, D.C.: National Academy Press; 1990.

4. Abrams B, Altman SL, Pickett KE. Pregnancy weight gain: still controversial. Am J Clin Nutr. 2000;71:1233S-41S.

5. Cogswell ME, Serdula MK, Hungerford DW, Yip R. Gestational weight gain among average-weight and overweight women--what is excessive? Am J Obstet Gynecol. 1995;172:705-12.

6. Siega-Riz AM, Adair LS, Hobel CJ. Maternal underweight status and inadequate rate of weight gain during the third trimester of pregnancy increases the risk of preterm delivery. J Nutr. 1996;126:146-153.

7. Olson CM, Strawderman MS, Reed RG. Efficacy of an intervention to prevent excessive gestational weight gain. Am J Obstet Gynecol. 2004;191:530-6.

8. Polley BA, Wing RR, Sims CJ. Randomized controlled trial to prevent excessive weight gain in pregnant women. Int J Obes Relat Metab Disord. 2002;26:1494-502.

9. Orstead C, Arrington D, Kamath SK, Olson R, Kohrs MB. Efficacy of prenatal nutrition counseling: weight gain, infant birth weight, and cost-effectiveness. J Am Diet Assoc. 1985;85:40-5.

10. Rees JM, Engelbert-Fenton KA, Gong EJ, Bach CM. Weight gain in adolescents during pregnancy: Rate related to birth-weight outcome. Am J Clin Nutr. 1992;56:868-873.

Family Meals Focus by Ellyn Satter, MS, RD, LCSW, BCD. discusses trends, research and clinical issues in eating and feeding and interprets other research from a feeding-dynamics, eating-competence perspective. For past issues of Family Meals Focus, click here.

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DISCLAIMER: The information contained in Family Meals Focus is intended to inform our readers about issues relating to feeding dynamics in general and family meals in particular. It is not intended to replace specific advice from a health care professional. Copyright © 2006 Ellyn Satter