Prucalopride is a medicine used to treat constipation. The main aim of the study is to measure prucalopride concentrations in breast milk. Other aims are to check the growth and development of babies breastfed by their mothers who took prucalopride and to check if the babies had any side effects.

During the study, participants will provide one set of milk samples over 24 hours using an electric breast pump. Breast milk samples will be collected at home and will be shipped to the laboratory.

Also, participants will be asked questions during telephone interviews every 2 months in the first year of their baby's life. They will also be asked to complete growth and development questionnaires about their baby.

Inclusion Criteria:

Participants cannot be enrolled before all inclusion criteria are confirmed.

• Female participants with an ability to voluntarily provide verbal followed by written, signed, and dated (personally or via a legally authorized representative) informed consent as applicable to participate in the study.
• Participants greater than or equal to (>=) 18 years of age at the time of consent. This inclusion criterion will only be assessed at the time of enrollment.
• Participants who are currently breastfeeding a singleton infant who is between 10 days and 11 months 0 days, inclusive. Note that participants pumping breast milk and bottle feeding their infant breast milk are allowed to participate.
• Participants who are currently exclusively breastfeeding or breastfeeding with supplemental formula and/or solid food. Infants who are exclusively breastfed and do not yet eat solid food are preferred.
• Participants who are currently treated as prescribed by their physician with MOTEGRITY or RESOTRAN (generic forms of prucalopride not allowed) for functional constipation, including chronic idiopathic constipation (CIC) and irritable bowel syndrome-constipation (IBS-C), for at least 5 consecutive days at the time of taking the first breastmilk sample.
• Participants who agree to the conditions and requirements of the study including the sample collection, interview schedule, completion of developmental questionnaires, and release of medical records.
• Participants with an understanding, ability, and willingness to fully comply with study procedures and restrictions.

Exclusion Criteria:

The participant will be excluded from the study if any of the following exclusion criteria are met:

• Participants who are breastfeeding an infant who: is hospitalized, has a major birth defect, or has a history of a disease that could affect absorption or drug disposition.
• Participants who have used MOTEGRITY or RESOTRAN while breastfeeding for a condition other than functional constipation.
• Participants who are pregnant at the time of enrollment.
• Participants who have started to wean their child from breast milk.
• Participants with a history of any hematological, hepatic, respiratory, cardiovascular, renal, gall bladder removal, or other current or recurrent disease that could affect the action, absorption, or disposition of prucalopride.

Female participants from United State (US) and Canada, who are currently being treated with prucalopride for functional constipation and breastfeeding a single infant between the ages of 10 days and 11 months 0 days. Infants will be followed for up to 12 months 30 days of age.

De-identified individual participant data from this particular study will not be shared as the data are subject to contractual (or consent) provisions that prohibit transfer to third parties.