The researchers will study how babies respond to bottle nipples with different flow rates over a few days, and how this may affect how much milk they drink, their feeding patterns, and their sleep.

The study will enroll 220 mother-infant dyads.

Inclusion Criteria:

1. Mother-infant dyad: The biological mother is the legal guardian of the infant and has custody for ≥5 days per week (in cases of joint custody).
2. Maternal age: Mother is ≥18 years old.
3. Language: Mother understands spoken and written English sufficiently to provide informed consent, answer questionnaires and follow study instructions.
4. Gestational age: Infant was born at 37.0-42.0 weeks gestation.
5. Birthweight: Infant's birthweight was appropriate for gestational age.
6. Bottle feeding: Infant currently receives at least one bottle feeding of ≥2 ounces at least once per week.
7. Residence: Family lives within approximately one hours driving distance of Ann Arbor, Michigan to participate in an at- home appointment or is willing to drive to the U-M North Campus research site.
8. Infant age: Infant is 4.0-6.0 months old at enrollment.

Exclusion Criteria:

1. Current maternal depression or anxiety, as assessed by screening questionnaires, or any cognitive impairment that would limit ability to follow study instructions.
2. Infant developmental delay, genetic condition, or medical problems or diagnosis affecting current or future eating, growth, or development.
3. History of significant sucking or feeding difficulties or breastfeeding difficulties requiring significant medical intervention or support.
4. Current weight-for-age below the 10th percentile or significant history of poor weight gain.
5. Infant already typically uses a slower-flow nipple (flow rate < 5 mL/min).

The researchers will upload the study data to Deep Blue Data. Video-recordings and raw sucking data will not be included in the archived data on Deep Blue Data and will only be shared under appropriate data use agreements.

"Deep Blue Data provides access to digital research data that were developed or used in the support of research activities at U-M. All data in the repository are available for anyone to download without restriction." https://www.lib.umich.edu/collections/deep-blue-repositories

Data will be available by August 2029 and the researchers will leave it up a minimum of 3 years.

"All data in the repository are available for anyone to download without restriction." The data not in the repository, ideo-recordings and raw sucking data, University investigators pending approval of data sharing agreement.