Canadian Paediatric Society Clinical Tool
Newborn Weight Loss & Hydration Assessment
Track physiologic weight loss against the 7% caution and 10% critical hydration thresholds with day-of-life diaper benchmarks.
Infant Weight Measurements
Standard range: 2500g – 4200g
Measured on pediatric scale
Early Diuresis / Nadir Phase
Day 1 (Birth)Day 4 (Expected Nadir)Day 10-14 (Birthweight Regained)Day 21
Expected Diapers on Day 3 (CPS Benchmark)
Wet Diapers (Urination)
At least 3 wet diapers
Soiled Diapers (Bowel Movements)
2–3 transitional greenish-yellow stools
Looser greenish-yellow transitional stoolCalculated Weight ChangeCaution: Borderline Weight Loss (7.4%)
-7.4%(-250g)
< 7% Normal7-10% Caution>= 10% Urgent
Weight loss of 7.4% on day 3 exceeds the average physiological nadir (5-7%). While acceptable if infant is clinically vigorous and transitioning on days 2-3, careful monitoring of feeding frequency and diaper output is warranted.
Pediatric Clinical Guidance
•Increase feeding frequency to minimum 8–12 times per 24 hours (q2-3h from start of feed).
•Encourage bilateral breast drainage with breast compression during active sucking.
•Monitor diaper output closely against CPS day-of-life benchmarks.
•Re-weigh infant within 24 to 48 hours to ensure weight nadir has stabilized.
Clinical Thresholds
- Average healthy loss: 5% to 7% (nadir typically day 3).
- Loss > 7% warrants lactation review and feeding frequency audit.
- Loss >= 10% requires formal clinical evaluation for hypernatremic dehydration.
- Birth weight should be fully regained by day 10 to 14.