Situation: A nurse at a lying-in clinic prepares mothers and their healthy term newborns for discharge and follows them up by telephone and home visits during the first weeks after birth. The mother of a 3-week-old girl who receives only breast milk says, "It is very hot these days, so I want to give her something to drink between feeds." The baby has 7 wet diapers a day with pale yellow urine and is active. Which response by the nurse is BEST?

Exclusive breastfeeding for the first 6 months means no water, formula, or other drinks, and breast milk meets fluid needs even in hot weather. Her 7 wet diapers with pale urine show that she is well hydrated, so the best response uses these findings to reassure the mother and supports feeding on demand. Expressed milk by cup is safe but unnecessary for a baby who breastfeeds well, and it adds work and a risk of contamination.

Core concept: exclusive breastfeeding and hydration assessment

The question tests whether you can apply the exclusive breastfeeding recommendation for the first 6 months and use objective hydration findings to guide parent education. For a healthy term infant receiving only breast milk, no supplemental water, oral rehydration solution, or other liquids are needed, even when the environmental temperature rises ^[1].

Breast milk alone provides sufficient free water to maintain hydration in hot weather because its composition adjusts to the infant’s needs and feeding frequency increases with demand. The infant’s 7 wet diapers per day with pale yellow urine are strong clinical indicators of adequate fluid intake and normal renal concentrating ability. This objective evidence should anchor the nurse’s response.

Response option	Clinical reasoning	Appropriateness
1. Boiled water after feeds	Introduces unnecessary fluid that can displace breast milk, reduce suckling stimulation, and lower milk supply; also carries contamination risk if preparation is imperfect	Incorrect
2. Oral rehydration solution on hot days	ORS is for managing dehydration or diarrheal losses, not for routine supplementation in a well-hydrated breastfed infant	Incorrect
3. Expressed breast milk by cup between feeds	Safe in principle, but unnecessary when the infant breastfeeds effectively; adds maternal workload and introduces a potential route for microbial contamination	Incorrect
4. Reassure using wet diaper evidence and support cue-based feeding	Aligns with exclusive breastfeeding guidance and uses the infant’s own output to confirm hydration; promotes demand feeding that protects milk supply	Correct

Key point! Hydration in a breastfed infant is assessed primarily through urine output, not through thirst or ambient temperature. Frequent, effective milk removal from the breast is the physiologic driver of a robust milk supply, so any unnecessary supplementation threatens lactogenesis. The guideline emphasizes that nurses in primary care must understand lactation physiology and support effective milk removal during early well-child encounters ^[1].

Watch out! A common distractor is offering expressed milk by cup because it seems “safe.” However, for an infant who is already breastfeeding well and showing normal urine output, adding cup feeds between breastfeeds can reduce direct suckling time and undermine the very mechanism that maintains milk production ^[1]. The best nursing action is not to add a task, but to reassure the mother using the infant’s own clinical signs and to encourage feeding whenever the infant shows hunger cues.