RecruitingNot ApplicableNCT07467694

Postnatal Exercise to Activate Baby's Brown Fat

Impact of Acute Exercise and Habitual Physical Activity on Human Milk Composition and Childhood Obesity Risk

Sponsor

Joslin Diabetes Center

Enrollment

200 participants

Start Date

Dec 1, 2025

Study Type

INTERVENTIONAL

Conditions

Exercise Pregnancy Physical Activity Childhood Obesity Breastfeeding Lactation Childhood Obesity Prevention

Summary

The purpose of this study is to learn how exercise and physical activity during pregnancy and after pregnancy may affect the composition of breastmilk. Certain changes in breast milk after exercise may have an impact on how infants use energy. Understanding this process may improve public health recommendations for exercise during and after pregnancy. This study can help investigators learn more about how maternal exercise patterns may affect body growth and obesity risk in infants who are breastfed. This research may help identify how different factors can influence healthy weight and early development in infants.

Eligibility

Sex: FEMALEMin Age: 18 YearsMax Age: 45 Years

Inclusion Criteria6

y of age at the time of enrollment
Pre-gravid or first trimester BMI 18.5 -40 kg/m2
Uncomplicated singleton pregnancy
Intention to exclusively breastfeed for \>3 months and, if parity \>1, that they successfully breastfed a previous pregnancy
Term pregnancy (gestational age 37 to \<42 weeks)
Infant with birth weight \>10th percentile of weight for gestational age

Exclusion Criteria8

Any obstetric contra-indication to exercise at 1 month
Diagnosis of uncontrolled (HbA1c \>7%) type 1 or type 2 diabetes, or gestational diabetes managed with insulin
Intrauterine growth restriction
Pre-eclampsia or other pregnancy complications
Alcohol, cannabis or tobacco use
Known congenital metabolic, endocrine disease, or congenital illness affecting infant feeding/growth
Major fetal anomalies
Musculoskeletal issues that would make exercise difficult

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Interventions

BEHAVIORALActive group

For participants randomized to the Active group, there will be weekly phone calls with study staff during which step counts and exercise bouts from the previous week will be reviewed, and exercise goals for the following week will be gradually increased.