Does infant feeding method influence maternal postpartum weight loss?

Breast-feeding and postpartum weight retention: a systematic review and meta-analysis

OBJECTIVE

Weight gained during pregnancy and postpartum weight retention might contribute to obesity in women of childbearing age. Whether breast-feeding (BF) may decrease postpartum weight retention (PPWR) is still controversial. The purpose of our systematic review and meta-analysis was to investigate the relationship between BF and PPWR.

DESIGN

Three databases were systematically reviewed and the reference lists of relevant articles were checked. Meta-analysis was performed to quantify the pooled standardized mean differences (SMD) of BF on PPWR by using a random-effect model. Heterogeneity was tested using the χ 2 test and I 2 statistics. Publication bias was estimated from Egger's test (linear regression method) or Begg's test (rank correlation method).

RESULTS

Among 349 search hits, eleven studies met the inclusion criteria for the meta-analysis. Seven studies were conducted in the USA, one in Brazil, one in France, one in Georgia and one in Croatia. Compared with formula-feeding, BF for 3 to ≤6 months seemed to have a negative influence on PPWR and if BF continued for >6 months had little or no influence on PPWR. In a subgroup meta-analysis, the results did not change substantially after the analysis had been classified by available confounding factors. There was no indication of a publication bias from the result of either Egger's test or Begg's test.

CONCLUSIONS

Although the available evidence held belief that BF decreases PPWR, more robust studies are needed to reliably assess the impact of patterns and duration of BF on PPWR.

Body image among Turkish women during the first year postpartum

In this study, we investigated the body image of Turkish women in their first year postpartum. We recruited 440 postpartum women who had applied to the outpatient clinics of the Maternity and Children's Hospital in the city of Ordu, Turkey. The mean of the women's body image scores was over the "middle level." The women's body image scale (BIS) score showed a significant negative relation with age, number of births, weight before pregnancy, weight gain, during pregnancy, weight soon after childbirth, present weight, postpartum weight gain, and postpartum body mass index (BMI).

Maternal visceral adiposity by consistency of lactation

The purpose of this study was to examine the assocation between lactation and maternal visceral adiposity among US women who were on average 7 years postpartum. This cross-sectional analysis included 89 women who gave birth between 1997 and 2002, who did not have preeclampsia, prepregnancy hypertension or prepregnancy diabetes, and enrolled in The Women and Infant Study of Healthy Hearts (WISH). Computed tomography was used to assess abdominal adiposity. History of lactation was self-reported. Visceral adiposity was greater by 36.96 cm(2) (95% CI: 20.92,53.01) among mothers who never breastfed than mothers who breastfed for ≥3 months after every birth, even after adjustment for age, parity, years since last birth, site, socioeconomic, lifestyle, psychological, and family history variables, early adult BMI, and current BMI. Similarly, in fully adjusted models, mothers who breastfed any of their children for less than 3 months had 20.38 cm(2) (95% CI: 2.70, 38.06) greater visceral adiposity than mothers who consistently breastfed all their children for 3 or more months. This study found that 7 years postpartum visceral fat depots are significantly greater among mothers who lactated for less than 3 months after the birth of each of their children. These results provide a potential physiologic basis for prior findings that women who do not consistently breastfeed are at an increased risk of diabetes, cardiovascular disease, and the metabolic syndrome.

Pre-pregnancy and pregnancy predictors of obesity

Obesity has progressively become a global epidemic that constitutes one of the biggest current health problems worldwide. Pregnancy is a risk factor for excessive weight gain. Factors that may predict development of obesity in later life mainly include gestational weight gain, pre-pregnancy nutritional status, age, parity and race. Change in lifestyle factors, such as eating habits, enrollment in physical activity, smoking and duration of lactation, in addition to the above factors, may also contribute to the development of obesity but are still not fully understood. Women who retain more body weight after pregnancy have, in general, larger pregnancy body weight gain, higher pre-pregnancy body mass index, marked weight changes in previous pregnancies, lactate slightly less and stop smoking during pregnancy to a larger extent. In addition, irregular eating habits and decreased leisure time activity after delivery influence postpartum weight retention. Taking into consideration the epidemic of obesity, with all its adverse long-term consequences, there is an increasing need to promote counseling before, during and after pregnancy on the role of diet and physical activity in reproductive health.

Associations of excess weight gain during pregnancy with long-term maternal overweight and obesity: evidence from 21 y postpartum follow-up

BACKGROUND

The contribution of gestational weight gain (GWG) to the development of obesity may have important implications for mothers in their later lives. However, whether GWG is a strong predictor of body mass index (BMI) 2 decades after the index pregnancy is unknown.

OBJECTIVE

We examined the long-term effect of GWG by using a community-based birth cohort study.

DESIGN

We followed a subsample of 2055 women from an original cohort of 7223 women who gave birth in Brisbane, Australia, between 1981 and 1983. Multivariable regression and multinomial regression were used to examine the independent associations of GWG per gestational week and Institute of Medicine (IOM) categories of combined prepregnancy BMI and GWG with BMI and its categories 21 y after the index pregnancy.

RESULTS

In analyses using GWG per week as a continuous exposure variable, maternal BMI (in kg/m(2)) increased, on average, by 0.52 (95% CI: 0.31, 0.73) for a 0.1-kg/wk greater GWG. This association became stronger when adjusted for maternal prepregnancy BMI. Analyses with IOM categories showed a greater postnatal increase in BMI for women defined as having excessive GWG (3.72, on average; 95% CI: 3.12, 4.31) than for women with adequate GWG. The women who gained excess weight during pregnancy had increased odds of being overweight [odds ratio (OR): 2.15; 95% CI: 1.64, 2.82] or obese (OR: 4.49; 95% CI; 3.42, 5.89) 21 y after the index pregnancy. These associations were independent of other potential factors.

CONCLUSION

Weight gain during pregnancy independently predicts the long-term weight gain and obesity of women.

Parity and breastfeeding in relation to obesity among black and white women in the southern community cohort study

OBJECTIVE

This research sought to describe associations among parity, breastfeeding, and adult obesity in black and white women in the southeastern United States.

METHODS

Cross-sectional data from 7,986 white women and 23,198 black women (age 40-79 years) living in the southeastern United States and enrolled in the Southern Community Cohort Study during 2002-2006 were used to examine self-reported body mass index (BMI) and weight change since age 21 in association with parity and breastfeeding. Multiple linear regression and logistic regression with adjustment for demographic and lifestyle factors were used.

RESULTS

At all levels of parity and breastfeeding, black women had higher BMI and weight gain since age 21 than white women. Compared to nulliparity, five or more live births was associated with increased odds of obesity in white women (odds ratio [OR] = 1.37, 95% confidence interval [CI] = 1.08-1.74) and, to a lesser extent, in black women (OR = 1.22, 95% CI = 1.07-1.38). In white women, breastfeeding for more than 12 months compared to none was associated with decreased odds of obesity (OR = 0.68, 95% CI = 0.56-0.82), whereas in black women, no association between obesity and breastfeeding was seen.

CONCLUSIONS

The associations between childbearing factors and measures of adult obesity appear to be larger in white women compared to black women but relatively small overall. However, when considered as part of the constellation of factors that lead to obesity, even these small associations may be important in an overall obesity prevention strategy.

The positive association between number of children and obesity in Iranian women and men: results from the National Health Survey

BACKGROUND

To date, few studies have assessed the association between the number of children and obesity in couples. We aimed to investigate this association in men and women aged 20-75 years.

METHODS

Data from the National Health Survey were considered in this investigation. It included 2728 women and men (1364 couples) aged 20-75 years. Height and weight were actually measured rather than self-reported. A generalized estimating equation model was used to estimate the odds of obesity (body mass index (BMI > or = 30)) as a function of the number of children adjusted for age, sex, education, economic index, workforce, smoking and place of residence.

RESULTS

We infer that each additional child has at least 5% and at most 34% increase in the odds of obesity in men and at least 4% and at most 29% increase in the odds of obesity in women. Our test of interaction by sex showed that the association between the number of children and obesity was not different among men and women. Among women, factors that increased obesity included age, low education, having more children, being inactive workforce and being nonsmoker. Among men, these factors included high economic index, low education, having more children, and being nonsmoker.

CONCLUSION

Our results show an association between the number of children and obesity among men. We would recommend interventions to reduce the number of children to prevent obesity in men.

Long-term weight development in women: a 15-year follow-up of the effects of pregnancy

OBJECTIVE

The aim of this study was to evaluate how well prepregnancy BMI, gestational weight gain, and postpartum weight retention predict retention of weight 15 years later among parous women.

RESEARCH METHODS AND PROCEDURES

The Stockholm Pregnancy and Women's Nutrition (SPAWN) study is a long-term follow-up study of women who delivered children in 1984 to 1985 (n = 2342). The participants initially filled out questionnaires about their eating and exercise habits, social circumstances, etc. before, during, and at 1 year after pregnancy. Anthropometric data were also sampled. Fifteen years later, these women were invited to take part in the follow-up study. Anthropometric measurements were collected, and similar questions were asked. Five hundred sixty-three women participated in the SPAWN 15-year follow-up study. The sample was divided into groups to examine three presumably critical time periods: 1) overweight and normal weight before pregnancy; 2) low, intermediate, and high weight gainers during pregnancy; and 3) low, intermediate, and high weight retainers at 1 year after pregnancy.

RESULTS

The overweight women did not gain more weight during pregnancy or retain more weight at 1 year follow-up. High weight gainers during pregnancy retained more weight at the 1-year and the 15-year follow-ups. High weight retainers had gained more during pregnancy and retained it at the 15-year follow-up. Fifty-six percent of the high weight gainers during pregnancy ended up in the high weight retainers group.

DISCUSSION

Women who are overweight before pregnancy do not have a higher risk of postpartum weight retention than normal weight women. Thus, it is not necessarily the initially overweight woman who should be the target or focus of weight control programs during or after pregnancy. Both high weight gainers and high weight retainers had higher BMI at the 15-year follow-up, although only 56% of the high weight gainers during pregnancy were also classified as high weight retainers at the 1-year follow-up. Weight retention at the end of the postpartum year predicts future overweight 15 years later.

Breastfeeding and postpartum weight retention in a cohort of Brazilian women

BACKGROUND

The relation between postpartum weight retention and breastfeeding practices is controversial.

OBJECTIVE

Defining breastfeeding as the period when a child is exclusively or predominantly breastfed, we studied the association between breastfeeding duration and postpartum weight retention.

DESIGN

We followed 405 women aged 18-45 y who were assessed at 0.5, 2, 6, and 9 mo postpartum. The outcome variable, postpartum weight retention, was expressed as the difference between the observed weight at each follow-up and the reported prepregnancy weight. The main statistical procedure used was the longitudinal mixed-effects model.

RESULTS

Mean postpartum weight retention at the end of the study was 3.1 kg. Single women aged > or = 30 y retained more weight than did younger single women or married women. The combined effect of breastfeeding duration and percentage of body fat at baseline was significant only for women with < 30% body fat. According to the model's prediction, when women who had 22% body fat and breastfed for 180 d were compared with those who had 22% body fat and breastfed for only 30 d, each month of breastfeeding contributed -0.44 kg to postpartum weight retention. When only the percentage of body fat was varied, the total effect was 3.0, 1.7, 1.2, and 0.04 kg in women with 18%, 25%, 28%, and 35% body fat, respectively.

CONCLUSIONS

These results support the hypothesis of an association between breastfeeding and postpartum weight retention and suggest that encouraging prolonged breastfeeding might contribute to decreases in postpartum weight retention.

Impact of Breastfeeding on Maternal Nutritional Status

This review covers the impact of breastfeeding on maternal postpartum weight loss and micronutrient status. Results regarding the impact on weight loss have been conflicting. This may be due to differences in study quality. Of six observational studies in which postpartum weight change was estimated (rather than measured directly), only one showed an association with breastfeeding. By contrast, six of the seven studies in which postpartum weight change was measured showed greater weight or fat loss in women who breastfed longer, particularly at 3 to 6 months postpartum. The results of the higher quality studies are consistent with two experimental studies conducted in Honduras, which demonstrated that the degree of breastfeeding affects the rate of weight loss. Thus, it appears that breastfeeding does enhance the rate of weight loss postpartum, but the effect is relatively small and may not be detectable in studies that lack adequate statistical power, have imprecise data on postpartum weight change, or do not account for the exclusivity and/or duration of breastfeeding. There is very little information with regard to micronutrient status during lactation. Nutrient requirements for vitamins A, B6, and C, and for iodine and zinc are increased by more than 50%, but lactation may actually be protective against maternal iron deficiency. More research is needed on the effects of lactation on maternal nutritional status and on strategies for optimizing nutrient intake to meet the needs of both the mother and her infant.

Effect of lactation on maternal body weight: a systematic review

The impact of lactation on maternal weight after delivery remains unclear. To address this question, we performed a systematic review of the literature. We searched PubMed, POPLINE, EMBASE, and LILACS computerized databases for relevant articles and classified the evidence using the U.S. Preventive Services Task Force rating system. We found 42 studies, of which 28 contained relevant information: 15 prospective cohort studies, 1 retrospective cohort study, 1 cross-sectional study, and 11 case-series reports. The methods used in these studies varied widely, thus precluding aggregation of results. Level II-2 and III evidence supports a class "C" recommendation: insufficient evidence exists to support an effect of lactation on maternal weight after delivery. Better longitudinal studies with a clear definition of breast-feeding; clear, specific outcome measures; study periods extending 1 or 2 years after delivery; and better control of potentially confounding factors will be needed to resolve this question.

TARGET AUDIENCE

Obstetricians & Gynecologists, Family Physicians.

LEARNING OBJECTIVES

After completion of this article, the reader will be able to compile the literature on the effect of lactation on maternal weight, to compare the various studies, and to summarize the data on the effect of lactation on maternal weight gain.

Obesity and weight change related to parity and breast-feeding among parous women in Brazil

OBJECTIVE

Studies on the independent role of parity in long-term body weight change in economically developing countries are scarce and inconclusive, and only a few studies have taken into account patterns of breast-feeding. This association was examined in a national cross-sectional survey representative of Brazilian parous women.

DESIGN AND SETTING

The survey conducted in 1996 measured women's height and weight in the household and data on weight prior to the first pregnancy, parity and breast-feeding were recalled.

SUBJECTS

A sample of 2338 parous women, 15 to 49 years of age, 29 months after last delivery on average, had current body mass index (BMI, in kg m(-2)) modelled through hierarchical multiple linear regression analysis. Explanatory variables included parity, days of predominant breast-feeding, BMI pre-pregnancy, socio-economic, geographic, demographic and other reproductive variables.

RESULTS

Prevalences of overweight (BMI = 25.0-29.9 kg m(-2)) and obesity (BMI > or = 30.0 kg m(-2)) were 25.2% and 9.3%. The overall mean weight gain per year after the first pregnancy was 0.90 kg for an average time since first pregnancy of eight years. BMI pre-pregnancy modified the association between current BMI and parity. Therefore, weight change attributed to parity calculated for a woman of average height (1.56 m) was 0.60 kg greater for primiparous women with a BMI pre-pregnancy of 30 kg m(-2), compared with women with BMI pre-pregnancy of 25 kg m(-2). This greater weight retention among obese women was 1.21 kg for women with two children and 1.82 kg for women with three or more children. Parity reduced the effect of weight loss associated with lactation (1.75 kg for six months of lactation among primiparous women and 0.87 kg among women with three or more children). For the sub-sample of 793 primiparous women, a weight decrease of 300 g was associated with each month of predominant breast-feeding for all prior BMI levels.

CONCLUSIONS

In this study, weight change associated to reproduction was highly dependent on BMI previous to pregnancy and the effects of parity and lactation were small.

Breast-feeding has a limited long-term effect on anthropometry and body composition of Brazilian mothers

The effect of lactation on maternal nutrition is controversial. Some studies have shown that breast-feeding reduces maternal weight, whereas some have not. All studies have been restricted to the first 2 y after delivery. We investigated the effect of lactation on maternal nutrition 5 y after delivery. All mothers giving birth in the city of Pelotas, Brazil, in 1993 were interviewed and weighed soon after delivery; information was also obtained on prepregnancy weight. In 1994, information on breast-feeding duration and pattern was collected for a 20% subsample. They were seen again in 1998, and those eligible (nonsmokers, no subsequent pregnancy, last birth weight > or = 2500 g) underwent measurements for weight, height, waist, hip and arm circumferences, triceps and subscapular skinfolds. The following indices were calculated in 312 women: body mass index, waist/hip ratio, arm fat area, the percentage of body fat assessed through skinfolds, and weight and body mass index change since before conception. The percentage of body fat was also measured through bioimpedance for half of the sample. After adjustment for confounding, all outcomes generally showed a similar pattern, i.e., mothers who breast-fed for 6-11.9 mo had lower measurements than those with shorter or longer durations. However, only the association with bioimpedance was significant (P < 0.03), and that for arm fat area tended to be significant (P = 0.06). Exclusive or predominant breastfeeding at 4 mo was associated with lower waist circumference (P = 0.05) and the percentage of body fat measured through skinfolds (P = 0.04). This study suggests that the relationship between breast-feeding and long-term changes in maternal weight is complex and, in this population, not particularly strong.

Body composition changes during lactation are highly variable among women

Changes in body weight and composition in response to the metabolic load imposed by lactation are highly variable among and within diverse populations. In most reports, rates of weight loss did not differ between lactating and nonlactating women. Despite differences in the hormonal milieu between lactating and nonlactating women, only subtle short-term differences were observed in postpartum changes in body composition. Regional patterns of fat deposition and mobilization did not differ between lactating and nonlactating women in most studies. Changes in body composition during lactation are responses to a sequence of complex neuroendocrine and biochemical stimuli that may be significantly modified by environmental factors. Gestational weight gain was the strongest determinant of postpartum weight and fat mass change, which supports the premise that biological mechanisms are aimed at restoring prepregnancy body weight and composition.

Parity-associated body weight: modification by sociodemographic and behavioral factors

This research examines the association between parity and body weight and how this relationship is modified by sociodemographic and behavioral factors. Using multiple linear regression analysis, the study assessed the relationship between parity and relative body weight (as Body Mass Index, BMI) and how this relationship interacts with seven sociodemographic and seven behavioral factors in a national sample of 5,707 women from the Second National Health and Nutritional Examination (NHANES II) survey. After adjusting for sociodemographic factors, the amount of weight associated with parity averaged about 0.5 kg per child. However, parity-associated weight differed by sociodemographic and behavioral factors, and was much larger in some subgroups. Among 18-45 year olds, the amount of weight associated with parity was greater in blacks than in whites, less in employed than unemployed white women but greater in employed than unemployed black women, less in smokers than nonsmokers, less in those with a high level of recreational exercise, and differed with the level of nonrecreational physical activity depending on race. Among 46-74 year olds, the amount of weight associated with parity was greater in married than unmarried women, and less in those who were active outside of recreation versus those who were less active. These results suggest that sociodemographic and behavioral variables modify the relationship between parity and body weight, and provide insight for identifying women who are at risk for having greater BMI with higher parity. This information may be applicable to the targeting and design of interventions to prevent postpartum weight retention.

Breast-feeding reduces maternal lower-body fat

The effect of breast-feeding on maternal anthropometric measures during the first 6 postpartum months was studied in 24 women. Mothers, who were seen in the hospital shortly after delivery and at monthly intervals thereafter, kept a record of their infant-feeding practices and provided three 24-hour dietary recalls per month. The women were placed in one of three groups according to their infant-feeding practices: breast-feeding exclusively, combination of breast- and formula-feeding, and formula-feeding only. Changes in anthropometric variables at 6 months postpartum were similar in the three groups, but mothers who breast-fed exclusively or partially had significantly larger reductions in hip circumference measurements (3.6% and 3.1%, respectively) and were less above their prepregnancy weights at 1 month postpartum (7.8% and 8.5% above prepregnancy weight, respectively) than mothers who fed formula exclusively (0.68% reduction in hip circumference and 13.7% above prepregnancy weight). Our findings indicate that a woman's choice of infant-feeding practice influences postpartum anthropometric changes, but these effects may be temporary.