This study is about preparing women with excessive weight to have better breastfeeding outcomes. By doing this study, the investigators hope to learn more about how hand expression of breast milk or colostrum during pregnancy can help prepare a mother to breastfeed after she has her baby and about how her diet affects the composition of her breast milk and her baby's growth and development.

The American Academy of Pediatrics recommends exclusive breastfeeding for at least 6 months followed by continued breastfeeding with the introduction of complementary foods as long as desired. When started during the first hour after birth, breastfeeding is more successful. In Arkansas, 74% of infants are breastfed at some point and 24% are exclusively breastfed through 6 months. As such, human milk serves as the primary source of nutrition for many infants. Current research demonstrates lower breastfeeding initiation and shortened duration of breastfeeding in women with obesity. Barriers are present to supporting women with obesity and overweight to successfully breastfeed and meet the breastfeeding recommendations. One barrier is that women with pre-pregnancy obesity have an increased risk of delayed lactogenesis II.

It is unclear what the most effective strategies may be to support women with obesity and overweight to meet their breastfeeding goals. Specifically, there is lack of evidenced-based literature for women with overweight and obesity who want to breastfeed. Findings suggest that targeted interventions in early pregnancy can help ameliorate the effects of obesity and poor breastfeeding initiation as an innovative opportunity to improve breastfeeding rates in this group. Recent research shows that women with overweight and obesity who receive additional support and education to breastfeed from a physician increase their likelihood to initiate breastfeeding. Educational interventions and support, specifically from health professionals tailored towards women with overweight and obesity may improve breastfeeding initiation, exclusivity, and duration.

Antenatal breastmilk expression (ABME) is an innovative technique of colostrum expression in the later weeks of pregnancy (36 weeks to birth) that can be used as a targeted intervention to support women at risk of not breastfeeding or early breastfeeding cessation. ABME starting at 37 weeks gestation has been shown to have the potential to hasten the onset of lactogenesis II, can improve postpartum engorgement, decrease need for supplementation in infants, and improve exclusive breastfeeding duration up to six months postpartum. The limited research on ABME has been mostly in regards to mothers with gestational diabetes and/or for reduction of newborn hypoglycemia. In a recently published systematic review, the findings demonstrated that there is limited evidence and few research studies that have tested the feasibility of antenatal breastmilk expression. Based upon these reviews and the limited evidence from small qualitative studies, more research is needed regarding the efficacy, feasibility, and acceptability of ABME to help women with excessive weight to meet their breastfeeding goals.

Breastfeeding can play a significant role in improving maternal and child outcomes, especially in preventing childhood obesity. Epidemiological and experimental studies support the influence mother's diet in milk composition via several pathways that modulate direct and indirectly certain milk components. Dietary habits, and excessive weight among other factors has been associated with compositional changes in human milk including increased human milk concentrations of leptin, insulin, C-reactive protein, fat, protein and some oligosaccharides. All of these have also been associated with elevated infant fat mass index, even after considering daily human milk volume intakes or adjusting for maternal body mass index and birth weight. In the United States, more than half of women of childbearing age are with excessive weight, which may affect their milk composition and be an early programming of health in later life.

Despite such evidence, no specific dietary recommendations currently exist for lactating women with excessive weight to promote optimal breastfeeding outcomes, human milk composition, infant growth, and infant body composition. In fact, the current report of the Dietary Guidelines for Americans Advisory Committee (2025) pointed to numerous gaps in knowledge that limited their ability to provide strong dietary recommendations for pregnant and lactating women with excessive weight. Therefore, understanding the associations between human milk composition and developmental outcomes can lead to strategies for modifying maternal dietary habits when needed. Considering that most factors happening in the first 1000 days of life represent risk for the development of later childhood obesity are modifiable, a study that will investigate quantitative and qualitative the role of maternal diet on breast milk composition, associate maternal and infant metabolic state and anthropometric characteristics can contribute with evidences to next recommendations for these public.

Hypothesis and/or Specific Aims or Objectives The primary aim of the study is to test whether prenatal and postnatal intervention strategies can impact breastfeeding outcomes for women with excessive weight. The objectives of the study is to test a dietary intervention designed to meet the Dietary Guidelines for Americans and to evaluate whether health care professional education about ABME during pregnancy can improve breastfeeding outcomes and human milk composition in women with overweight or obesity.

The study proposes the hypotheses that in lactating women with excessive weight a dietary intervention during the first 5.5 months postpartum will optimize human milk composition and breastfeeding outcomes. Completion of this research plan will provide evidence-based data for future dietary guidance for lactating women with excessive weight.

The further hypothesize that antenatal breastmilk expression starting ~ 37 weeks gestation will improve breastfeeding outcomes, such as breastfeeding initiation, duration, exclusivity, and decreased delay in lactogenesis II, in women with overweight and obesity.

Outcomes

• Primary: Dietary intervention and ABME interventions will improve breastfeeding outcomes, such as optimizing human milk composition, and breastfeeding initiation and duration, compared to the lactation support group.
• Secondary: Breastfeeding exclusivity up to 6 months, decreased delay in lactogenesis II, and increased breastfeeding self-efficacy, and human milk composition.

Inclusion Criteria

• Age 18 or older
• Less than 37 weeks of pregnant with singleton fetus
• Pre-pregnancy excessive weight (Body Mass Index ≥ 25 kg/m2)
• Interested in breastfeeding
• Willing to express colostrum from around 37 weeks of pregnancy if randomized to the prenatal intervention group
• Willing to express human milk for sample collection during a 24-hour period
• Willing to adhere to a meal plan for 5.5 months post-partum if randomized to the postnatal intervention group
• Able to engage in study procedures for the first 24 months postpartum
• Reside in Central Arkansas region Exclusion Criteria
• Pre-existing conditions (e.g. diabetes, hypertension, heart disease, thyroid disorders);
• Use of recreational drugs, tobacco, or 2 or more servings of alcohol per month
• Food allergies, intolerances, or preferences interfering with the meal plan
• Medical history including any contraindication to breastfeeding (medications or supplements incompatible with breastfeeding, substance use)Multiparous pregnancy
• History of breast surgery or radiation
• Congenital defects
• Preeclampsia

We do not plan to share individual participant data (IPD) from this study. The data will be used in aggregated form only, solely for the purposes of scientific publication and dissemination of the study results. Individual-level data will not be made available to other researchers due to privacy concerns, ethical restrictions, and the terms of the informed consent provided to participants.