Although with a certain variability, due to the essential assumption that each individual is unique and unrepeatable, the newborn emits the first urine within a few hours of birth. There follows a more or less long pause related to the time elapsed before being attached to the mother's breast or bottle. In some infants, however, the first urination occurs only after several hours, even 24-30 hours after birth; this phenomenon seems more common in boys.
The newborn's first urine often leaves a pink - orange - reddish sediment, which can color the diaper; this phenomenon, which is absolutely physiological, tends to disappear within 3-4 days.
In the first days of life, the newborn urinates two to six times a day, while subsequently the number of urinations tends to increase.
Once stabilized, more or less starting from the fourth - fifth day of life, the urination of the breastfed newborn is characterized by the emission of colorless and low specific weight urine, which on average wets five to six disposable diapers well. and throws within 24 hours. Scarce and yellowish urine, especially if accompanied by hard stools, drowsiness and dry mouth and mucous membranes, are an important sign of dehydration. In such circumstances it is therefore appropriate to put into practice the advice of the pediatrician; generally, water with a low fixed residue and low in sodium is administered through the bottle.
Many pediatricians recommend supplementing the baby's diet with water or herbal teas (provided they are very diluted and poorly sweetened), regardless of the presence or absence of signs of dehydration. This result is obtained by preparing a bottle every day with a quantity of water equal to 3-5% of the infant's weight, giving it from time to time without any forcing. This practice, contrary to common thought, does not interfere in the least with the acceptance of the mother's breast, since the newborn is perfectly able to distinguish the water and the bottle from the smell of the mother's breast and milk.
At the base of the poor production of urine there can be not only a poor supply of liquids through the mother's milk, but also an "excessive sweating due to overheating (fever, high ambient temperature) and general or localized infectious processes in the urinary tract. severe, fortunately rare, the scarce or absent production of urine in the newborn may be due to congenital malformations or bladder dysfunctions of neurological origin.
An excessive production of urine by the newborn can be the result of a "diet that is too rich in sodium (for example due to a milk that is too concentrated or due to the lack of fluids); absurdly, therefore, the newborn can be dehydrated even when urinating normally or abundantly. The baby's urine may be abundant even when he or she has a lot of fluids during the day or has difficulty concentrating urine due to very rare metabolic problems such as diabetes insipidus.
