Use of an intensity ratio to describe breastfeeding exclusivity in a national sample

Previous High-Intensity Breastfeeding Lowers the Risk of an Abnormal Fasting Glucose in a Subsequent Pregnancy Oral Glucose Tolerance Test

Breastfeeding is associated with reduced lifetime cardiometabolic risk, but little is known regarding the metabolic benefit in a subsequent pregnancy. The primary aim of this study was to investigate the association between breastfeeding duration and intensity and next pregnancy oral glucose tolerance test (OGTT) results. A retrospective cohort study was conducted from March 2020 to October 2022. All multiparous women who met inclusion criteria and gave birth during the study period were eligible for inclusion. Analysis was stratified by risk for gestational diabetes (GDM). High GDM risk criteria included previous GDM and BMI > 35 kg/m2. The association between breastfeeding duration and high-intensity breastfeeding (HIBF) and subsequent pregnancy OGTT were assessed with multivariate logistic models adjusted for statistically and clinically relevant covariables. There were 5374 multiparous participants who met the inclusion criteria for analysis. Of these, 61.7% had previously breastfed for >6 months, and 43.4% were at high risk for GDM. HIBF was associated with 47% reduced odds of an abnormal fasting glucose in a subsequent pregnancy OGTT (aOR 0.53; 95%CI 0.38-0.75; p < 0.01). There was no association between HIBF and other glucose results on the OGTT. Women who smoked were least likely to breastfeed at high intensity (aOR 0.31; 95%CI 0.21-0.47; p < 0.01). South Asian women had 65% higher odds of HIBF than women who identified as White/European (aOR 1.65; 1.36-2.00; p < 0.01). This study highlights the importance of exclusive breastfeeding to potentially reduce the prevalence of GDM and may also translate into long-term reduction of cardiometabolic risk.

Understanding the Impact of Perceived Social Support for Breastfeeding Among African American Women: Results From the Mama Bear Feasibility Trial

Purpose

Perceived Social Support (PSS) can impact breastfeeding behaviors, and a lack of PSS potentially contributes to disparities in breastfeeding rates for African American women (AA). Objectives were to describe PSS at two timepoints and test associations between PSS and breastfeeding intensity for AA.

Methods

Data are from a feasibility trial of breastfeeding support among AA. The Hughes Breastfeeding Support Scale was used to measure PSS (Emotional, Informational, Tangible; total range = 30–120) in pregnancy (T1, n = 32) and early postpartum (T2, n = 31). Scale means were compared with t-tests. Associations between PSS at T1 and breastfeeding intensity (ie, quantitative measure of breastfeeding) were assessed with linear regression.

Results

Total PSS (mean ± SE) was high at both time points (T1 = 90.5 ± 4.8; T2 = 92.8 ± 3.1). At T2, older participants or those living with a partner had higher total PSS scores compared to those younger or living alone. Emotional PSS was significantly higher at T2 than T1 with no differences in tangible or informational PSS over time. Mixed-feeding, exclusive breastfeeding, and exclusive formula feeding was distributed at 39%, 32%, and 29%, respectively. Total PSS was not associated with breastfeeding intensity.

Conclusion

Women reported high levels of social support, and emotional PSS increased over time in this small sample of AA. PSS and sources of PSS are understudied, especially among AA, and future studies should explore quantitative methods to assess PSS. The results of such assessments can then be used to design breastfeeding support interventions.

Prolactin and Maternal Metabolism in Women With a Recent GDM Pregnancy and Links to Future T2D: The SWIFT Study

CONTEXT

Prolactin is a multifaceted hormone known to regulate lactation. In women with gestational diabetes mellitus (GDM) history, intensive lactation has been associated with lower relative risk of future type 2 diabetes (T2D). However, the role of prolactin in T2D development and maternal metabolism in women with a recent GDM pregnancy has not been ascertained.

OBJECTIVE

We examined the relationships among prolactin, future T2D risk, and key clinical and metabolic parameters.

METHODS

We utilized a prospective GDM research cohort (the SWIFT study) and followed T2D onset by performing 2-hour 75-g research oral glucose tolerance test (OGTT) at study baseline (6-9 weeks postpartum) and again annually for 2 years, and also by retrieving clinical diagnoses of T2D from 2 years through 10 years of follow up from electronic medical records. Targeted metabolomics and lipidomics were applied on fasting plasma samples collected at study baseline from 2-hour 75-g research OGTTs in a nested case-control study (100 future incident T2D cases vs 100 no T2D controls).

RESULTS

Decreasing prolactin quartiles were associated with increased future T2D risk (adjusted odds ratio 2.48; 95% CI, 0.81-7.58; P = 0.05). In women who maintained normoglycemia during the 10-year follow-up period, higher prolactin at baseline was associated with higher insulin sensitivity (P = 0.038) and HDL-cholesterol (P = 0.01), but lower BMI (P = 0.001) and leptin (P = 0.002). Remarkably, among women who developed future T2D, prolactin was not correlated with a favorable metabolic status (all P > 0.05). Metabolomics and lipidomics showed that lower circulating prolactin strongly correlated with a T2D-high risk lipid profile, with elevated circulating neutral lipids and lower concentrations of specific phospholipids/sphingolipids.

CONCLUSION

In women with recent GDM pregnancy, low circulating prolactin is associated with specific clinical and metabolic parameters and lipid metabolites linked to a high risk of developing T2D.

Breastfeeding Self-Efficacy as a Predictor of Breastfeeding Intensity Among African American Women in the Mama Bear Feasibility Trial

Background: Improving breastfeeding rates among African American (AA) families is an important public health goal. Breastfeeding self-efficacy, a known predictor of breastfeeding behavior, has seldom been assessed among AAs, in relation to breastfeeding intensity (% breastfeeding relative to total feeding) or as a protective factor in combating the historical breastfeeding challenges faced by people of color. We aimed to test the association between breastfeeding self-efficacy assessed during pregnancy and breastfeeding intensity assessed in the early postpartum period. Methods: This was a secondary data analysis of a randomized controlled feasibility trial of breastfeeding support and postpartum weight management. AA women were recruited during pregnancy from a prenatal clinic in Detroit, MI. Data presented, in this study, were collected at enrollment (n = 50) and ∼6 weeks postpartum (n = 31). Linear regression models were used, adjusting for potential confounders. Results: There were no differences in breastfeeding intensity by study arm; data are from all women with complete data on targeted variables. Age ranged from 18 to 43 years, 52% were Women, Infant's, and Children program enrollees, and 62% had ≥ some college. Breastfeeding self-efficacy during pregnancy was a significant predictor of breastfeeding intensity in the early postpartum period (β = 0.125, p < 0.05) with only slight attenuation in the fully adjusted model (β = 0.123, p < 0.05). Implications for Practice: Our results confirm that self-efficacy is an important predictor of breastfeeding practice. Furthermore, the simple act of assessing breastfeeding self-efficacy permits an opportunity for women to reflect on breastfeeding possibilities, and can inform individualized confidence-building interventions to improve the disproportionately low breastfeeding rates among AAs. Clinical Trial Registration number NCT03480048.

Intensive lactation among women with recent gestational diabetes significantly alters the early postpartum circulating lipid profile: the SWIFT study

BACKGROUND

Women with a history of gestational diabetes mellitus (GDM) have a 7-fold higher risk of developing type 2 diabetes (T2D). It is estimated that 20-50% of women with GDM history will progress to T2D within 10 years after delivery. Intensive lactation could be negatively associated with this risk, but the mechanisms behind a protective effect remain unknown.

METHODS

In this study, we utilized a prospective GDM cohort of 1010 women without T2D at 6-9 weeks postpartum (study baseline) and tested for T2D onset up to 8 years post-baseline (n=980). Targeted metabolic profiling was performed on fasting plasma samples collected at both baseline and follow-up (1-2 years post-baseline) during research exams in a subset of 350 women (216 intensive breastfeeding, IBF vs. 134 intensive formula feeding or mixed feeding, IFF/Mixed). The relationship between lactation intensity and circulating metabolites at both baseline and follow-up were evaluated to discover underlying metabolic responses of lactation and to explore the link between these metabolites and T2D risk.

RESULTS

We observed that lactation intensity was strongly associated with decreased glycerolipids (TAGs/DAGs) and increased phospholipids/sphingolipids at baseline. This lipid profile suggested decreased lipogenesis caused by a shift away from the glycerolipid metabolism pathway towards the phospholipid/sphingolipid metabolism pathway as a component of the mechanism underlying the benefits of lactation. Longitudinal analysis demonstrated that this favorable lipid profile was transient and diminished at 1-2 years postpartum, coinciding with the cessation of lactation. Importantly, when stratifying these 350 women by future T2D status during the follow-up (171 future T2D vs. 179 no T2D), we discovered that lactation induced robust lipid changes only in women who did not develop incident T2D. Subsequently, we identified a cluster of metabolites that strongly associated with future T2D risk from which we developed a predictive metabolic signature with a discriminating power (AUC) of 0.78, superior to common clinical variables (i.e., fasting glucose, AUC 0.56 or 2-h glucose, AUC 0.62).

CONCLUSIONS

In this study, we show that intensive lactation significantly alters the circulating lipid profile at early postpartum and that women who do not respond metabolically to lactation are more likely to develop T2D. We also discovered a 10-analyte metabolic signature capable of predicting future onset of T2D in IBF women. Our findings provide novel insight into how lactation affects maternal metabolism and its link to future diabetes onset.

TRIAL REGISTRATION

ClinicalTrials.gov NCT01967030 .

Association of infant diet with subsequent obesity at 2-5 years among children exposed to gestational diabetes: the SWIFT study

AIMS/HYPOTHESES

This longitudinal analysis evaluated the independent and joint associations of any breastfeeding (BF) or exclusive BF (EBF) and intake of sugar-sweetened beverages (SSBs) and 100% fruit juice from birth to 1 year with subsequent overweight and obesity among young children exposed to gestational diabetes (GDM).

METHODS

The analysis utilised prospectively collected data from participants enrolled in the Study of Women, Infant Feeding and Type 2 Diabetes after GDM (SWIFT); 1035 pregnant women (20-45 years) diagnosed with GDM, of whom 75% were of Black, Hispanic or Asian race and ethnicity. Mother-infant dyad characteristics and infant dietary intake were assessed via research protocols at in-person examinations, telephone interviews and monthly mailed surveys from birth to 1 year. Child weight, length and height were obtained from electronic health records at birth (2008-2011) and ages 2-5 years (2010-2016) to classify BMI percentile groups (n = 835).

RESULTS

Adequate BF (≥6 months), adequate EBF duration (≥6 months), and SSB and 100% fruit juice intake in the first year were independently associated with child obesity at ages 2-5 years (all p < 0.05). Compared with children with adequate EBF and no intake of SSB or 100% fruit juice, those with adequate EBF and intake of 100% fruit juice and/or SSBs had a four- to fivefold higher odds of obesity (aOR 4.2, 95% CI:1.6, 11.2 for 100% fruit juice; aOR 4.5, 95% CI:1.4, 8.5 for fruit juice or SSBs; and aOR 4.7, 95% CI:1.4, 15 for SSBs; all p < 0.01), while those with inadequate EBF (<6 months) and intake of 100% fruit juice and/or SSBs had a six- to 12-fold higher odds of obesity (aOR 6.4, 95% CI:2.4, 17.2 for fruit juice; aOR 6.6, 95% CI:2.7, 14.8 for fruit juice or SSBs; and aOR 12.2, 95% CI:4.3, 25 for SSBs; all p < 0.001). Compared with children with adequate BF and no intake of SSB or 100% fruit juice, those with adequate BF and intake of 100% fruit juice and/or SSBs had a threefold higher odds of obesity (aOR 3.1, 95% CI:1.1, 7.3 for fruit juice; aOR 3.3, 95% CI:1.3, 8.3 for fruit juice or SSBs; and aOR 3.4, 95% CI:1.3, 8.5 for SSBs; all p < 0.05), while those with inadequate BF (<6 months) and intake of 100% fruit juice and/or SSB were associated with five- to tenfold higher odds of obesity (aOR 4.8, 95% CI:2.3, 12.2 for fruit juice; aOR 6.0, 95% CI:2.5, 12.8 for fruit juice or SSBs; aOR 9.5, 95% CI:3.7, 15.1 for SSBs; all p < 0.05).

CONCLUSIONS/INTERPRETATION

This is the first study to prospectively evaluate the relation of BF or EBF duration and intake of SSB and 100% fruit juice during the first year of life with subsequent obesity in children exposed to GDM. Adequate BF or EBF combined with avoidance of SSB and 100% fruit juice during early infancy may ameliorate future child obesity in this high-risk population.

Association of Infant Temperament With Subsequent Obesity in Young Children of Mothers With Gestational Diabetes Mellitus

IMPORTANCE

Infant temperament is associated with excess weight gain or childhood obesity risk in samples of healthy individuals, although the evidence has been inconsistent. To our knowledge, no prior research has examined this topic among children exposed to gestational diabetes mellitus (GDM) in utero.

OBJECTIVE

To prospectively evaluate infant temperament in association with overweight and obesity status at ages 2 to 5 years among children born to mothers who experienced GDM.

DESIGN, SETTING, AND PARTICIPANTS

This prospective cohort study took place at Kaiser Permanente Northern California medical centers. We studied singleton infants delivered at 35 weeks' gestational age or later to mothers who had been diagnosed with GDM. Data were collected from 2009 to 2016, and data analysis occurred from June 2017 to October 2018.

EXPOSURES

The primary exposures in the child's first year were soothability, distress to limitations, and activity aspects of temperament, as assessed by a validated questionnaire. Modifiable covariates in the child's first year included breastfeeding intensity and duration monthly ratio scores, along with the timing of the introduction of sugary beverages and complementary foods.

MAIN OUTCOMES AND MEASURES

The primary outcome was child overweight and obesity status, assessed at ages 2 to 5 years. Multinomial logistic regression models estimated adjusted odds ratios and 95% CIs for infants whose temperaments were measured at 6 to 9 weeks of age and categorized as elevated (≥75th percentile) or not elevated in the 3 domains. We controlled for nonmodifiable and modifiable covariates across models.

RESULTS

A total of 382 mother-infant pairs participted, including 130 infants (34.0%) who were non-Hispanic white, 126 infants (33.0%) who were Hispanic, 96 infants (25.1%) who were Asian, 26 infants (6.8%) who were non-Hispanic black, and 4 infants (1.1%) who were of other races/ethnicities. In descriptive analyses, elevated infant soothability and activity temperaments were associated with the early introduction of 100% fruit juice and/or sugar-sweetened beverages (at ages <6 months) and shorter breastfeeding duration (from 0 to <3 months), while elevated distress to limitations was associated with early introduction of complementary foods (at ages <4 months). Elevated soothability consistently was associated with a higher odds of later childhood obesity, with adjusted odds ratios across models ranging from 2.22 (95% CI, 1.04-4.73) to 2.54 (95% CI, 1.28-5.03). Greater breastfeeding intensity and duration (12-month combined) score was associated with lower odds of obesity, independent of infant temperament and other covariates.

CONCLUSIONS AND RELEVANCE

Among this high-risk population of infants, elevated soothability was associated with early childhood obesity risk, perhaps in part because caregivers use sugary drinks to assuage infants. Soothability temperament may be a novel screening target for early obesity prevention interventions involving responsive feeding and emotion regulation.

Breastfeeding and growth during infancy among offspring of mothers with gestational diabetes mellitus: a prospective cohort study

BACKGROUND

Breastfeeding (BF) may protect against obesity and type 2 diabetes mellitus in children exposed to maternal diabetes in utero, but its effects on infant growth among this high-risk group have rarely been evaluated.

OBJECTIVES

The objective of this study was to evaluate BF intensity and duration in relation to infant growth from birth through 12 months among offspring of mothers with gestational diabetes mellitus (GDM).

METHODS

Prospective cohort of 464 GDM mother-infant dyads (28% White, 36% Hispanic, 26% Asian, 8% Black, 2% other). Weight and length measured at birth, 6-9 weeks, 6 months and 12 months. Categorized as intensive BF or formula feeding (FF) groups at 6-9 weeks (study baseline), and intensity from birth through 12 months as Group 1: consistent exclusive/mostly FF, Group 2: transition from BF to FF within 3-9 months and Group 3: consistent exclusive/mostly BF. Multivariable mixed linear regression models estimated adjusted mean (95% confidence interval) change in z-scores; weight-for-length (WLZ), weight-for-age and length-for-age.

RESULTS

Compared with intensive BF at 6-9 weeks, FF showed greater increases in WLZ-scores from 6 to 9 weeks to 6 months [+0.38 (0.13 to 0.62) vs. +0.02 (-0.15 to 0.19); p = 0.02] and birth to 12 months [+1.11 (0.87 to 1.34) vs. +0.53 (0.37 to 0.69); p < 0.001]. For 12-month intensity and duration, Groups 2 and 3 had smaller WLZ-score increases than Group 1 from 6 to 9 weeks to 6 months [-0.05 (-0.27 to 0.18) and +0.07 (-0.19 to 0.23) vs. +0.40 (0.15 to 0.64); p = 0.01 and 0.07], and birth to 12 months [+0.60 (0.39 to 0.82) and +0.59 (0.33 to 0.85) vs. +0.97 (0.75 to 1.19); p < 0.05].

CONCLUSIONS

Among offspring of mothers with GDM, high intensity BF from birth through 1 year is associated with slower infant ponderal growth and lower weight gain.

Associations of infant feeding with trajectories of body composition and growth

Background: The extent to which breastfeeding is protective against later-life obesity is controversial. Little is known about differences in infant body composition between breastfed and formula-fed infants, which may reflect future obesity risk.Objective: We aimed to assess associations of infant feeding with trajectories of growth and body composition from birth to 7 mo in healthy infants.Design: We studied 276 participants from a previous study of maternal vitamin D supplementation during lactation. Mothers used monthly feeding diaries to report the extent of breastfeeding. We measured infants' anthropometrics and used dual-energy X-ray absorptiometry to assess body composition at 1, 4, and 7 mo. We compared changes in infant size (z scores for weight, length, and body mass index [BMI (in kg/m²)]) and body composition (fat and lean mass, body fat percentage) between predominantly breastfed and formula-fed infants, adjusting in linear regression for sex, gestational age, race/ethnicity, maternal BMI, study site, and socioeconomic status.Results: In this study, 214 infants (78%) were predominantly breastfed (median duration: 7 mo) and 62 were exclusively formula fed. Formula-fed infants had lower birth-weight z scores than breastfed infants (-0.22 ± 0.86 and 0.16 ± 0.88, respectively; P < 0.01) but gained more in weight and BMI through 7 mo of age (weight z score difference: 0.37; 95% CI: 0.04, 0.71; BMI z score difference: 0.35; 95% CI: 0, 0.69), with no difference in linear growth (z score difference: 0.05; 95% CI: -0.24, 0.34). Formula-fed infants gained more lean mass (difference: 303 g; 95% CI: 137, 469 g) than breastfed infants, but not fat mass (difference: -42 g; 95% CI: -299, 215 g).Conclusions: Formula-fed infants gained weight more rapidly and out of proportion to linear growth than did predominantly breastfed infants. These differences were attributable to greater accretion of lean mass, rather than fat mass. Any later obesity risk associated with infant feeding does not appear to be explained by differential adiposity gains in infancy.

The study of women, infant feeding and type 2 diabetes after GDM pregnancy and growth of their offspring (SWIFT Offspring study): prospective design, methodology and baseline characteristics

BACKGROUND

Breastfeeding is associated with reduced risk of becoming overweight or obese later in life. Breastfed babies grow more slowly during infancy than formula-fed babies. Among offspring exposed in utero to maternal glucose intolerance, prospective data on growth during infancy have been unavailable. Thus, scientific evidence is insufficient to conclude that breastfeeding reduces the risk of obesity among the offspring of diabetic mothers (ODM). To address this gap, we devised the Study of Women, Infant Feeding and Type 2 Diabetes after GDM Pregnancy and Growth of their Offspring, also known as the SWIFT Offspring Study. This prospective, longitudinal study recruited mother-infant pairs from the SWIFT Study, a prospective study of women with recent gestational diabetes mellitus (GDM). The goal of the SWIFT Offspring Study is to determine whether breastfeeding intensity and duration, compared with formula feeding, are related to slower growth of GDM offspring during the first year life. This article details the study design, participant eligibility, data collection, and methodologies. We also describe the baseline characteristics of the GDM mother-infant pairs.

METHODS

The study enrolled 466 mother-infant pairs among GDM deliveries in northern California from 2009-2011. Participants attended three in-person study exams at 6-9 weeks, 6 months and 12 months after delivery for infant anthropometry (head circumference, body weight, length, abdominal circumference and skinfold thicknesses), as well as maternal anthropometry (body weight, waist circumference and percent body fat). Mothers also completed questionnaires on health and lifestyle behaviors, including infant diet, sleep and temperament. Breastfeeding intensity and duration were assessed via several sources (diaries, telephone interviews, monthly mailings and in-person exams) from birth through the first year of life. Pregnancy course, clinical perinatal and newborn outcomes were obtained from health plan electronic medical records. Infant saliva samples were collected and stored for genetics studies.

DISCUSSION

This large, racially and ethnically diverse cohort of GDM offspring will enable evaluation of the relationship of infant feeding to growth during infancy independent of perinatal characteristics, sociodemographics and other risk factors. The longitudinal design provides the first quantitative measures of breastfeeding intensity and duration among GDM offspring during early life.

Breastfeeding, long-chain polyunsaturated fatty acids in colostrum, and infant mental development

BACKGROUND

Breastfeeding has been associated with improved neurodevelopment in children. However, it remains unknown to what extent nutritional advantages of breast milk may explain this relationship.

OBJECTIVE

We assessed the role of parental psychosocial factors and colostrum long-chain polyunsaturated fatty acid (LC-PUFA) levels in the relationship between breastfeeding and children's neurodevelopment.

METHODS

A population-based birth cohort was established in the city of Sabadell (Catalonia, Spain) as part of the INMA-INfancia y Medio Ambiente Project. A total of 657 women were recruited during the first trimester of pregnancy. Information about parental characteristics and breastfeeding was obtained by using a questionnaire, and trained psychologists assessed mental and psychomotor development by using the Bayley Scales of Infant Development in 504 children at 14 months of age.

RESULTS

A high percentage of breastfeeds among all milk feeds accumulated during the first 14 months was positively related with child mental development (0.37 points per month of full breastfeeding [95% confidence interval: 0.06-0.67]). Maternal education, social class, and intelligence quotient only partly explained this association. Children with a longer duration of breastfeeding also exposed to higher ratios between n-3 and n-6 PUFAs in colostrum had significantly higher mental scores than children with low breastfeeding duration exposed to low levels.

CONCLUSIONS

Greater levels of accumulated breastfeeding during the first year of life were related to higher mental development at 14 months, largely independently from a wide range of parental psychosocial factors. LC-PUFA levels seem to play a beneficial role in children's mental development when breastfeeding levels are high.

Predictors of breastfeeding exclusivity in a WIC sample

OBJECTIVE

To examine predictors of breastfeeding exclusivity in low-income women who received services from a Chicago area clinic of the Special Supplemental Nutrition Program for Women, Infants and Children Program (WIC).

DESIGN

A secondary data analysis of existing clinical and administrative data.

SETTING

An urban community health center serving low-income families.

PARTICIPANTS

Two hundred and thirty-five (235) low-income women who initiated breastfeeding and received WIC services.

METHODS

Logistic regression models were fit to existing prenatal and postpartum data to determine predictors of breastfeeding exclusivity during the immediate postpartum period.

RESULTS

Only 23% of the sample breastfed exclusively. Women who received first-trimester prenatal care were more likely to exclusively breastfeed than women who entered prenatal care in later trimesters (OR = 2.02, p ≤ 0.05). Women who declared intentions prenatally to exclusively breastfeed were more likely to exclusively breastfeed than women who did not intend to breastfeed (OR = 3.85, p ≤ 0.001). Overweight/obese women were less likely to exclusively breastfeed than normal/underweight women (OR = 0.50, p ≤ 0.05).

CONCLUSION

Findings from this study can be used to develop tailored interventions to promote breastfeeding exclusivity among low-income WIC recipients.

Randomized, controlled trial of a prenatal and postnatal lactation consultant intervention on duration and intensity of breastfeeding up to 12 months

OBJECTIVE

To determine whether an individualized, prenatal and postnatal, lactation consultant intervention resulted in increased cumulative intensity of breastfeeding up to 52 weeks.

DESIGN

The randomized, nonblinded, controlled trial recruited women from prenatal care. Baseline prenatal interviews covered demographic data and breastfeeding experience, intention, and knowledge. Interviews at 1, 2, 3, 4, 6, 8, 10, and 12 months after birth collected data on weekly feeding patterns, infant illness, and infant health care use.

SETTING

Two community health centers serving low-income, primarily Hispanic and/or black women.

PARTICIPANTS

The analytic sample included 304 women (intervention: n = 145; control: n = 159) with > or = 1 postnatal interview.

INTERVENTION

Study lactation consultants attempted 2 prenatal meetings, a postpartum hospital visit, and/or home visits and telephone calls. Control subjects received the standard of care.

OUTCOME MEASURES

Cumulative breastfeeding intensity at 13 and 52 weeks, based on self-reports of weekly feeding, on a 7-level scale.

RESULTS

The intervention group was more likely to breastfeed through week 20 (53.0% vs 39.3%). Exclusive breastfeeding rates were low and did not differ according to group. In multivariate analyses, control subjects had lower breastfeeding intensity at 13 weeks (odds ratio [OR]: 1.90; 95% confidence interval [CI]: 1.13-3.20) and 52 weeks (OR: 2.50; 95% CI: 1.48-4.21). US-born control subjects had lowest breastfeeding intensity at 13 weeks (OR: 5.22; 95% CI: 2.43-11.22) and 52 weeks (OR: 5.25; 95% CI: 2.44-11.29). There were no significant differences in breastfeeding intensity among the US-born intervention, foreign-born intervention, and foreign-born control groups.

CONCLUSIONS

This "best-practices" intervention was effective in increasing breastfeeding duration and intensity. Breastfeeding promotion should focus on US-born women and exclusive breastfeeding.

Feeding effects on growth during infancy

OBJECTIVE

To examine the effects of formula, other milks, other liquids, cereals, and other solid foods on growth during infancy.

STUDY DESIGN

Observational cohort study nested within a large (n=17,046), cluster-randomized trial. We compared growth [weight-for-age, length-for-age, and weight-for-length z scores (WAZ, LAZ, WLZ) and head circumference (HC)] during the intervals 1 to 3, 3 to 6, 6 to 9, and 9 to 12 months, using hierarchical multivariate regression to control for size at the beginning of each interval, maternal education, geographic region, and urban versus rural location.

RESULTS

Mixed BF and formula/other milk were associated with significantly higher (versus breast milk only) LAZ at 1 to 3 months (+0.038 and +0.047, respectively). In the 3- to 6-month interval, mixed BF and formula/other milk led to significantly higher WAZ (+0.125 and +0.139) and LAZ (+0.081 and +0.075), whereas cereal intake was associated with large and highly significant reductions in both measures (-0.293 and -0.240) and in HC (-0.291 cm). Mixed BF and formula/other milk continued to have positive albeit smaller associations with WAZ and LAZ in the 6- to 9-month and 9- to 12-month intervals.

CONCLUSIONS

Our results confirm the growth-accelerating effects of formula and other milks (versus breast milk) on weight and length gain throughout infancy, with a dose-response gradient and largest associations observed at 3 to 6 months.