Pregnancy: The weight dilemma

by Ellyn Satter, Registered Dietitian and Family Therapist

Current 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.” Women can address the weight dilemma by working toward becoming eating competent. To gain weight appropriately during pregnancy, women can:

• Feed themselves faithfully
• Give themselves permission to eat in accordance with their internal cues of hunger, appetite and satiety.  

Women with high body weight targeted

The weight-gain dilemma is particularly acute for women whose are defined as being overweight or obese by BMI cutoffs. Institute of Medicine (IOM) guidelines incorporate arbitrary weight cutoffs in making recommendations for gaining the ”right” amount of weight during pregnancy.¹

• 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

 Women in the overweight” and “obese” categories 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.²  However, while incidence of high birth weight (> 4500 g or 10 lb) and cesarean delivery increases with increasing maternal weight gains, the increases are not statistically significant for pregnant women as a group until the weight gain is 40 lb and above.³  It is impossible to predict for individual women.

Weight-restriction interventions show mixed results

Weight reduction dieting spoils a fine pregnancy, and it doesn’t work better than at any other time.

As we said in the last issue, weight reduction dieting will spoil a fine pregnancy. Moreover, it doesn’t seem to work any better during pregnancy than at any other time. Some weight restriction interventions appear to result in more weight gain and increased weight retention after pregnancy, others less, depending on income level and degree of overweight^4,5 Overall, studies of intervention have been limited and few in number.⁶ Interestingly, many women refuse intervention.⁵ 

Weight-gain interventions are helpful

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.⁷
• Adolescents who gain too little weight are more likely to deliver low-birth-weight and preterm babies.⁸

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.^7,8

A word of encouragement

Pregnancy is a fine time to discover the joy of eating and develop rewarding and sustainable eating patterns that provide the nutritional foundation for family life. Like all the rest of us, pregnant women are entitled to become eating competent: to enjoy eating, eat well, and trust their bodies to gain weight in the way that is right for them and for their baby.