Sponsors asked the IOM's Food and Nutrition Board and the Division of Behavioral and Social Sciences and Education Board on Children, Youth, and Families to review and update the IOM (1990) recommendations for weight gain during pregnancy and recommend ways to encourage their adoption through consumer education, strategies to assist practitioners, and public health strategies.The committee was asked to address the following tasks: 1. Review evidence on the relationship between weight gain patterns before, during, and after pregnancy and maternal and child health outcomes, with particular attention to the prevalence of maternal obesity racial/ethnic and age differences, components of GWG, and implications of weight during pregnancy on postpartum weight retention, maternal and child obesity, and later child health. 2. Within a life-stage framework consider factors in relation to GWG that are associated with maternal health outcomes such as lactation performance, postpartum weight retention, cardiovascular disease, metabolic processes including glucose and insulin-related issues, and risk of other chronic diseases; for infants and children, in addition to low birth weight, consider early developmental impacts and obesity-related consequences (e.g., mental health, diabetes). 3. Recommend revisions to the existing guidelines, where necessary, including the need for specific pregnancy weight guidelines for underweight, normal weight, and overweight and obese women and adolescents and women carrying twins or higher-order multiples. 4. Consider a range of approaches to promote appropriate weight gain, including: individual (behavior), psychosocial, community, health care, and health systems; timing and components of interventions; and ways to enhance awareness and adoption of the guidelines, including interdisciplinary approaches, consumer education to men and women, strategies to assist practitioners to use the guidelines, and public health strategies. 5. Identify gaps in knowledge and recommend research priorities.

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Weight Gain During Pregnancy: Reexamining the Guidelines

Aims As part of a larger study to estimate the global burden of disease and injury attributable to alcohol: to evaluate the evidence for a causal impact of average volume of alcohol consumption and pattern of drinking on diseases and injuries; to quantify relationships identified as causal based on published meta-analyses; to separate the impact on mortality versus morbidity where possible; and to assess the impact of the quality of alcohol on burden of disease. Methods Systematic literature reviews were used to identify alcohol-related diseases, birth complications and injuries using standard epidemiological criteria to determine causality. The extent of the risk relations was taken from meta-analyses. Results Evidence of a causal impact of average volume of alcohol consumption was found for the following major diseases: tuberculosis, mouth, nasopharynx, other pharynx and oropharynx cancer, oesophageal cancer, colon and rectum cancer, liver cancer, female breast cancer, diabetes mellitus, alcohol use disorders, unipolar depressive disorders, epilepsy, hypertensive heart disease, ischaemic heart disease (IHD), ischaemic and haemorrhagic stroke, conduction disorders and other dysrhythmias, lower respiratory infections (pneumonia), cirrhosis of the liver, preterm birth complications and fetal alcohol syndrome. Dose-response relationships could be quantified for all disease categories except for depressive disorders, with the relative risk increasing with increased level of alcohol consumption for most diseases. Both average volume and drinking pattern were linked causally to IHD, fetal alcohol syndrome and unintentional and intentional injuries. For IHD, ischaemic stroke and diabetes mellitus beneficial effects were observed for patterns of light to moderate drinking without heavy drinking occasions (as defined by 60+ g pure alcohol per day). For several disease and injury categories, the effects were stronger on mortality compared to morbidity. There was insufficient evidence to establish whether quality of alcohol had a major impact on disease burden. Conclusions Overall, these findings indicate that alcohol impacts many disease outcomes causally, both chronic and acute, and injuries. In addition, a pattern of heavy episodic drinking increases risk for some disease and all injury outcomes. Future studies need to address a number of methodological issues, especially the differential role of average volume versus drinking pattern, in order to obtain more accurate risk estimates and to understand more clearly the nature of alcohol-disease relationships.

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The relation between different dimensions of alcohol consumption and burden of disease - an overview

Dose–response relationship between alcohol consumption before and during pregnancy and the risks of low birthweight, preterm birth and small for gestational age (SGA)—a systematic review and meta‐analyses

Lifestyle behaviors such as cigarette smoking, weight gain during pregnancy, and use of other drugs play an important role in determining fetal growth. The relationship between lifestyle risk factors and low birth weight is complex and is affected by psychosocial, economic, and biological factors. Cigarette smoking is the largest known risk factor for low birth weight. Approximately 20% of all low birth weight could be avoided if women did not smoke during pregnancy. Reducing heavy use of alcohol and other drugs during pregnancy could also reduce the rate of low birth weight births. Pregnancy and the prospect of pregnancy provide an important window of opportunity to improve women's health and the health of children. The adoption before or during pregnancy of more healthful lifestyle behaviors, such as ceasing to smoke, eating an adequate diet and gaining enough weight during pregnancy, and ceasing heavy drug use, can positively affect the long-term health of women and the health of their infants. Detrimental lifestyles can be modified, but successful modification will require large-scale societal changes. In the United States, these societal changes should include a focus on preventive health, family-centered workplace policies, and changes in social norms. any of the known risk factors associated with low birth weight, such as socioeconomic status, ethnicity, genetic makeup, and obstetric history, are not within a woman's immediate control. However, there are things that a woman can do to improve her chances of having a normal, healthy child. Lifestyle behaviors, such as cigarette smoking, use of other drugs, and nutrition, play an important role in determining fetal growth. Detrimental habits can be modified, but successful modification requires more than just a dose of individual "self control." Stopping lifelong addictive behaviors is very difficult, and a woman who suffers from them requires support and assistance not only from family members and individuals close to her, but also from the health care system and society.

The Role of Lifestyle in Preventing Low Birth Weight

In a prospective study of 712 pregnancies, we examined associations between maternal smoking, alcohol, and caffeine consumption and fetal growth. We interviewed patients at entry into care [12.9 +/- 4.3 (standard deviation) weeks], and at 28 and 36 weeks of gestation. We found the expected reductions in adjusted birthweight among women who smoked throughout pregnancy: 168 gm [95% confidence limits (CL) = -326, -10] for low/moderate amounts ( 15 cigarettes per day). We also found a decrease in birthweight (-179 gm; 95% CL = -364, 7) among smokers who reported quiting early in pregnancy. First trimester alcohol consumption (average: four drinks per week) was associated with a 155-gm reduction in fetal growth (95% CL = -324, 15), even after adjustment for number of cigarettes smoked. The association, observed with all types of alcohol consumption, was stronger among smokers (-270 gm) but was also present in nonsmokers (-115 gm). Caffeine consumption showed no relation to fetal growth, even among heavy consumers, although they were relatively few. This study implicates heavy maternal smoking at any point in pregnancy, including solely in the early months, and possibly moderate alcohol drinking as causes of low birthweight.

Maternal Smoking, Alcohol Drinking, Caffeine Consumption, and Fetal Growth: Results from a Prospective Study

Heavy maternal drinking during pregnancy has consistently been linked to decreased intrauterine growth, but the effect of smaller amounts of alcohol is less clear. In this study, the relationship between fetal growth and "moderate" drinking by low-risk, nonsmoking prenatal patients is explored. The sample consists of 144 women seen for the first time at the prenatal clinic of University College Obstetrics Hospital, London, England, between July 1979 and May 1980 and meeting the following criteria: white, aged 19-35 years, 8-16 weeks gestation at first prenatal visit, nonsmoker, nonalcoholic, lower middle class or higher, and in general good health. Average daily consumption of 10 g of ethanol (about one drink) in the week prior to recognition of pregnancy is related to a decrease in infant birth weight of 225 g, after adjustment for gestational age, sex of child, and maternal age, weight, height, pregnancy weight gain, social class, gravidity, and parity. In addition, consumption of this amount in the week before first prenatal visit is related to a comparable decrease in birth weight for male but not for female infants. These findings suggest that risk of decreased intrauterine growth begins very early in pregnancy, and that fetal response to later alcohol use may vary with sex of the child.

Paul D. Sampson

Papers

Fetal growth and moderate drinking in early pregnancy