-Healthy, postpartum women as determined by medical history aged 18 - 45 years of age inclusive. -Women 1-4 days postpartum from delivery of full-term infants. Full-term will be defined as estimated gestational age of greater than or equal to 37 completed weeks of pregnancy determined by menstrual dating and concordant with ultrasound findings as per ACOG bulletin #101). -Provide written informed consent prior to initiation of any study procedures. -Available for the entire study period. -Able to understand and complete all relevant study procedures during study participation (women who ultimately have limited ability to breast feed after enrollment will not be excluded from the study).