Matern Child Health J (2016) 20:270–280 DOI 10.1007/s10995-015-1826-7
The Associations of Maternal Weight Change with Breastfeeding, Diet and Physical Activity During the Postpartum Period Nancy Lo´pez-Olmedo1 • Sonia Herna´ndez-Cordero1 • Lynnette M. Neufeld2 • Armando Garcı´a-Guerra1 • Fabiola Mejı´a-Rodrı´guez1 • Ignacio Me´ndez Go´mez-Humara´n3
Published online: 2 November 2015 Ó Springer Science+Business Media New York 2015
Abstract Objective To determine the association between breastfeeding practices, diet and physical activity and maternal postpartum weight. Methods This was a secondary data analysis of a randomized community trial on beneficiaries of the Programa de Desarrollo Humano Oportunidades, recently renamed Prospera (n = 314 pregnant women), without any diseases that could affect body weight. Generalized estimating equations were used to determine the association between postpartum weight change and changes in diet, physical activity and type of breastfeeding. Results The mean postpartum weight change from the first to the third month was 0.6 ± 2.2 kg. Women who breastfed exclusively for 3 months had a 4.1 (SE = 1.9) kg weight reduction in comparison with women who did not provide exclusive breastfeeding or who discontinued breastfeeding before 3 months (p = 0.04). There was no association between postpartum weight change and physical activity (p = 0.24) or energy
Electronic supplementary material The online version of this article (doi:10.1007/s10995-015-1826-7) contains supplementary material, which is available to authorized users.
intake (p = 0.06). Conclusions Exclusive breastfeeding was associated with maternal postpartum weight reduction. These results reinforce the World Health Organization recommendation of exclusive breastfeeding during the first 6 months of life in order to reduce the risk of weight retention or weight gain in postpartum women. It has been well established that exclusive breastfeeding is beneficial for both infants and mothers, but promoting breastfeeding as a strategy to promote postpartum weight loss is of paramount importance, especially in countries like Mexico where excessive weight in women of reproductive age is a public health problem. Keywords Body weight Postpartum period Breastfeeding Mexico
Significance What is already known on this subject? Postpartum weight retention can increase the risk of obesity in later life in women. The retention has been associated with pre- and 1
Nancy Lo´pez-Olmedo [email protected]
Nutrition and Health Research Center, National Institute of Public Health, Av. Universidad 655 Col. Santa Marı´a Ahuacatitla´n, C.P. 62100 Cuernavaca, Morelos, Mexico
Lynnette M. Neufeld [email protected]
Global Alliance for Improved Nutrition (GAIN), Rue de Vermont 37-39, 1202 Geneva, Switzerland
Centro de Investigacio´n en Matema´ticas A.C., Unidad Aguascalientes, Fray Bartolome´ de las Casas 314, Barrio de la Estacio´n, C.P. 20259 Aguascalientes, Aguascalientes, Mexico
& Sonia Herna´ndez-Cordero [email protected]
Armando Garcı´a-Guerra [email protected]
Fabiola Mejı´a-Rodrı´guez [email protected]
Ignacio Me´ndez Go´mez-Humara´n [email protected]
Matern Child Health J (2016) 20:270–280
postnatal health determinants, such as pre-pregnancy body mass index, weight gain during pregnancy, and breastfeeding in studies carried out in high income countries. What this study adds? This study examines the association of maternal weight change with breastfeeding, diet and physical activity during the postpartum period in poor urban women, adjusting for important covariates using longitudinal analyses. This study indicates that breastfeeding is an important contributor to maternal weight loss during the postpartum period.
Introduction Obesity is considered a public health problem worldwide due to its high prevalence and its association with cardiovascular diseases, hypertension and diabetes mellitus . In Mexico, data from the 2012 National Health and Nutrition Survey (ENSANUT-2012) indicate that the prevalence of overweight and obesity in women was 73 % . Pregnancy is the reproductive stage where there is natural and rapid weight gain. Weight gain during this stage, within the recommended ranges [i.e. 11.3–15.9 kg (25–35 lb) for women with adequate pre-pregnancy BMI], is important for optimal growth and development of the fetus as well as for allowing for the energy reserve needed by women during breastfeeding [3, 4]. However, when pregnancy-associated weight gain and/or postpartum weight retention (PWR) is excessive, women have a higher risk of becoming overweight or obese in later life . PWR or postpartum weight change (PWC) has been associated with pre- and postnatal health determinants, e.g., prepregnancy body mass index, weight gain during pregnancy, and breastfeeding [6–8]. Factors related to PWR or PWC during the postpartum period have generally been studied separately [9–11]. Most studies carried out in high income countries on PWR or PWC and breastfeeding have had small samples sizes (\300 women) and used different definitions for breastfeeding practices (i.e. for ‘‘exclusive breastfeeding’’) [12, 13]. Studies examining the association between breastfeeding, diet and PWR have not considered other related factors such as gestational weight gain or parity, or they have focused on analyzing the effect of breastfeeding by energy and macronutrient consumption on weight retention [14, 15]. The main objective of studies carried out in middle and low income countries has primarily been to determine the effect of reproductive events as risk factors for undernutrition in rural-dwelling women. Research concerning changes in maternal weight, diet, physical activity and breastfeeding practices in vulnerable urban women is relevant given the alarming prevalence of overweight and
obesity among this group of women. Also, urbanization in Mexico has been associated with a higher prevalence of overweight and obesity due to increased access to high energy density foods and reductions in recreational spaces . The Programa de Desarrollo Humano Oportunidades, recently renamed Prospera, is a conditional cash transfer program aimed at improving human development and wellbeing among Mexicans through the development of health, education and nutrition. The overarching aim of this program is to promote equality and overcome poverty. It has been documented that the combined prevalence of overweight and obesity among women of reproductive age (20–49 years of age) who were beneficiaries of Prospera in 2004 was 63.9 % (39.6 % overweight and 24.3 % obese) . In 2011, upon external evaluation of the program in urban areas, it was reported that the prevalence of overweight and obesity in women was 65.5, 77.0, and 75.0 % for women age 20–29, 30–39 and 40–49 years, respectively . The aim of this study was to determine the associations between maternal weight change at 3 months postpartum with breastfeeding, physical activity and diet in women beneficiaries of Prospera in southern Mexico.
Materials and Methods Design and Study Population This was a secondary data analysis of a randomized community trial of micronutrient supplementation in pregnant women. The objective of the primary study was to compare the effect of three types of micronutrient supplementation on the nutritional status, as well as on postpartum weight gain and/or retention in women Prospera beneficiaries in urban areas of the southern region of Mexico. This region is characterized by micronutrient deficiencies in women and children, such as anemia in pregnant women (19.0 %) and low iron stores in women (21.6 %). In addition, preschool children in this area have a high prevalence of stunting (23.7 %) [19–22]. In this context, coverage of the Prospera Program is 33.4 % in this region . Prospera, according to its operating rules, provides nutritional supplements to children under 5 years of age and pregnant and lactating women who are beneficiaries. For the original study, adult women ([18 years) who were \24 weeks pregnant at the time of recruitment were selected. During the study, pregnant and lactating women beneficiaries received supplements either in the form of tablets, powder or a fortified food supplement (Nutrivida). The three supplements included exactly the same amount of micronutrients (iron, zinc, vitamins A, E, C, B12 and folic acid);
however, Nutrivida also had macronutrients (carbohydrates, protein, fat and sodium) and therefore, energy (194 kcal per portion). The study took place in 54 urban locations representing four states in southern Mexico (Veracruz, Puebla, Oaxaca and Tabasco). Women reporting a previous diagnosis or hospitalization or those who were under treatment for chronic hypertension, diabetes mellitus or other diseases that affect body weight and/or ability to consume supplements were excluded.
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Physical Activity and Reproductive History Physical activity was collected using the International Physical Activity Questionnaire (IPAQ, long form) . This version requests information in detail about activities performed according to four domains: leisure time physical activity, domestic (yard) activities and gardening, work-related physical activity and transport-related physical activity. Reproductive history was obtained by questionnaire.
Data Collection Data were collected at baseline of the original trial (*20th week of gestation), the 37th week of pregnancy and during the first and third month of the postpartum period. Data collected during each stage included measured body weight and height, questions about breastfeeding and complementary feeding practices, as well as maternal dietary intake and physical activity. Sociodemographic information was collected only at baseline through questionnaire. Anthropometry Body weight measurements were carried out with women fully clothed (clothing weight was estimated) and without shoes using electronic Tanita scales (Tanita Corp., Arlington Heights, IL). Height was determined at 1 month postpartum with stadiometers (Schorr Industries, Glen Burnie, MD). All measurements were done in the participant’s home and performed in duplicate using standardized techniques by previously trained field staff . Breastfeeding Practices The participants’ breastfeeding status (yes or no), duration and intensity of breastfeeding (times mother breastfed infant during the day and night at the time of the study) were asked. In addition, information about complementary feeding was obtained (whether the infant received other foods or liquids in addition to breast milk). If so, participants were asked for a list of liquids and/or foods provided (i.e. cow or goat’s milk, atole [hot corn-based beverage] with or without milk, porridge and fruits). There was an option for specifying other solid and liquid foods. Dietary Intake Maternal dietary intake was collected using a Food Frequency Questionnaire (FFQ) from the previous 7 days. It was adapted from a previously validated FFQ in the Nutrition and Health Nutrition Survey from the National Institute of Public Health (INSP by its Spanish acronym), Cuernavaca, Mexico .
Definition of Variables Anthropometry Weight change was defined as the difference in weight between the first and third postpartum month. BMI was categorized according to World Health Organization (WHO) criteria: underweight (\18.50 kg/m2), normal weight (18.50–24.99 kg/m2), overweight (25.00–29.99 kg/ m2) and obesity (C30.00 kg/m2) . Breastfeeding Practices Breastfeeding practices were classified according to WHO criteria, defining exclusive breastfeeding as infants receiving no liquids or solid foods other than human milk with the exception of oral rehydration solution (ORS), drops and syrup supplements. Predominantly breastfed infants received breast milk as the predominant source of feeding, but also ORS, drop and syrups, other liquids such as water, water-based drinks and fruit juices. Complementary breastfeeding was defined as infants who received other semi-solid, liquid or solid foods including non-human milk or formula (in addition to breast milk). Women were classified as non-breastfeeding if they reported not breastfeeding their children at the time of the interview . Change in breastfeeding practices was classified as follows: women who continued offering breast milk to their children exclusively for up to 3 months postpartum were classified as exclusive breastfeeding. The classification of predominantly breastfed was assigned to women who changed from exclusive breastfeeding to predominant breastfeeding or maintained the practice of predominant breastfeeding during the postpartum period studied. Complementary breastfeeding was defined as women who changed from exclusive or predominant to complementary breastfeeding or maintained complementary breastfeeding up to the third month postpartum. Finally, women who stopped breastfeeding before 3 months or who never breastfed their child were categorized as non-breastfeeding (Supplemental Table 1).
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Dietary Intake Energy intake was estimated using a Food Composition Table compiled by INSP. Intake and adequacy observations greater than 5 standard deviations from the general distribution of energy were excluded from the analysis, according to Rodriguez-Ramirez, et al. . Physical Activity From the physical activity questionnaire, multiples of the resting metabolic rate (MET) per minute per day were calculated. In addition, physical activity levels were classified as low, moderate and high . Women were classified as having a high level of physical activity if they met one of the following two criteria: vigorous-intensity activity for at least 3 days achieving a minimum total physical activity of at least 1,500 MET-minutes/week or 7 or more days of any combination of walking, moderateintensity or vigorous-intensity activities achieving a minimum total physical activity of at least 3000 MET-minutes/ week. The pattern was classified as moderate if either of the following criteria were met: 3 or more days of vigorous-intensity activity of at least 20 min/day or 5 or more days of moderate-intensity activity and/or walking of at least 30 min/day or 5 or more days of any combination of walking, moderate-intensity or vigorous-intensity activities achieving a minimum total physical activity of at least 600 MET-minutes/week. Those women who did not meet the above criteria were considered to have a low level of physical activity. Other Variables and Potential Confounders The rate of late gestational weight gain was estimated as the difference between weight at baseline and weight at about the 37th week of gestation divided by the time between measurements . This rate indicates the weight gain between the second and third trimester of pregnancy because women were recruited at approximately the 20th week of gestation. We constructed an indicator of socioeconomic status (SES) with principal components analysis . This methodology has been validated to describe SES differentiation in other population and has been used previously in Mexican populations [2, 32]. It includes variables related to housing conditions (such as flooring and roofing materials), ownership of home appliances (refrigerator, stove, washing machine, television, radio, video player, telephone and computer) and number of rooms (other than bathroom, kitchen and corridors). We further divided the standardized factor obtained into tertiles to represent three SES
categories: low, middle and high. Smoking during pregnancy was identified through medical history reported by women. Statistical Analysis All statistical analyses were performed using Stata v.12.0 (Stata Corp. 2011, Stata Statistical Software: Release 12. College Station, TX: StataCorp LP). We compared characteristics of those women included at baseline and at the first postpartum month with the characteristics of those who were excluded from the analysis using the t test, Wilcoxon sum or v2. Likewise, these tests were used to analyze the differences in maternal characteristics from the first to the third month. The Kruskal–Wallis equality-ofpopulations rank test was used for comparing the mean weight change by type of supplement. Multiple linear regression analyses using generalized estimating equations were carried out where weight change from the first to the third postpartum month was the dependent variable and the change in energy consumption (kcal), physical activity (MET/day) and breastfeeding practices (non-breastfeeding, complementary breastfeeding, predominant breastfeeding and exclusive breastfeeding, the last one as a reference) were the independent variables . Bivariate analyses were first conducted to explore the association between PWC and the independent variables in their categorical and continuous form. Energy consumption (kcal), and physical activity (MET/day) were included as continuous variables and breastfeeding practices were included in the saturated model since they better predicted postpartum weight change (r-squared = 0.95). All potential confounders were considered for the saturated model. Also, the type of supplement assigned and the location where the women resided were taken into account in the saturated model in order to control for the primary study design. Parity and age were collinear (r = 0.6, p \ 0.01); therefore, it was decided to include only the age in the final model. We excluded covariates that were not associated with postpartum weight (p value [0.05) and for which exclusion did not produce changes [10 % of the coefficients from the final model. Conversion factors of changes in energy consumption, physical activity and rate of gestational weight gain were estimated for each 1000 kcal/day, 1000 MET/day, and 100 g/week, respectively, for a better understanding of the results. p values \0.05 were considered statistically significant. Ethical Considerations The study was approved by the Research, Biosecurity and Ethics Committees at INSP.
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Results There were 314 women included in the final sample. We excluded 117 women with values outside of the acceptable range for weeks of gestation, gestational weight gain, energy consumption and/or numbers of nursing infants from the analyses, as well as 254 women with incomplete data for the main variables (Fig. 1). Women included in the analysis were mostly multiparous (p = 0.03) and had a full-term delivery (p \ 0.01) and a greater proportion breastfed their offspring by 1 month postpartum (57.6 vs. 42.3 %, p \ 0.01) compared with excluded women (Table 1). More than 50 % of women included in the analysis had an elementary level of education. Most of the women were married or living with a partner and were housewives (Table 1). Almost 50 % of the women were either overweight (36.6 %) or obese (18.1 %) during the first month postpartum (Table 2). These values increased to 40.1 and 19.4 % at the third month postpartum, respectively. On average, weight change between the first and third month postpartum was 0.6 ± 2.2 kg with 48.1 % of women maintaining their postpartum weight or increasing it by 3 kg; and 11.8 % of them with an increase of [3 kg. Weight change by type of supplement was no different (p = 0.71). The percentage of women who continued with exclusive breastfeeding at the third month postpartum was 43 %. This value was 15 percentage points lower than what was reported in the first month. The median energy consumption was 2244 and 2305 kcal/day at the first and third month postpartum, respectively, with no difference between the two study periods (p = 0.78). Women who continued with exclusive breastfeeding until the third month postpartum had a weight reduction of 4.1 (SE = 1.9) kg in comparison with women classified as non-breastfeeding (saturated model 1, Table 3) (p = 0.04). Increase in energy consumption from the first to the third month postpartum was not associated with weight gain during the same period. Increase in
Fig. 1 Flow chart of women included in the analysis
physical activity was not associated with weight gain at 3 months postpartum (p = 0.06). Although not of primary interest to the study, a positive association was found between weight gain during pregnancy (p = 0.01) and socioeconomic status (p B 0.05) with postpartum weight change. The remaining covariates (prematurity, smoking during pregnancy, type of supplement and residence location) showed no significant association with postpartum weight change and their exclusion did not produce changes of [10 % in the coefficients. In the final model, excluding covariates not associated with PWC, the above associations remained statistically significant (Model 2, Table 3).
Discussion The results of this study indicate that exclusive breastfeeding until 3 months postpartum was associated with weight loss from the first to the third month postpartum when compared with other breastfeeding modalities or discontinuation of breastfeeding in the same period in women who are beneficiaries of the Prospera program in urban areas of the southern region of Mexico.
Breastfeeding Practices These results were similar to those from the National Birth Cohort in Denmark . The authors reported that women who breastfed exclusively and for a longer time retained a lower body weight than women who breastfed their children exclusively or nearly exclusively for a shorter time (p \ 0.01). A possible explanation of greater weight loss during the postpartum period among women who breastfed exclusively is the following: during pregnancy *30 % of weight gain is fat mass stored
Basal informaon: 715 Diabetes Mellitus: 4 Maternal age