Even with some variability, due to the unavoidable assumption that each individual is unique and unrepeatable, the newborn emits the first urine within a few hours of birth. This is followed by 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 first urine of the newborn often leave a pink-orange-reddish sediment, which can color the diaper; this phenomenon, 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 urine of low specific weight, which on average wets well from five to six diapers. and throws within 24 hours. Poor and yellowish urine, especially if accompanied by hard feces, drowsiness and dry mouth and mucous membranes, represent an important signal of dehydration. In such circumstances it is therefore appropriate to put into practice the advice of the pediatrician; generally water is administered with low fixed residue and low in sodium through the bottle.
Many pediatricians recommend supplementing the unborn child's diet with water or herbal teas (as long as 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 with a quantity of water equal to 3-5% of the newborn's weight every day, administering it from time to time without any forcing. This practice, unlike common thinking, does not interfere in any way 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 scarce production of urine there may be not only a scarce supply of liquids through the mother's milk, but also an excessive sweating due to overheating (fever, high environmental temperature) and general infectious processes or located in the urinary tract. Boundless in the most serious, fortunately rare, pathologies the scarce or absent production of urine in the newborn may be due to congenital malformations or bladder dysfunctions of neurological origin.
Excessive production of urine by the newborn may be the result of a diet that is too rich in sodium (for example due to too concentrated milk or due to a low fluid intake); absurdly, therefore, the newborn can be dehydrated even when urinating in a normal or abundant manner. The urine of the newborn can be abundant even when it takes a lot of fluids during the day or has difficulty concentrating the urine for very rare metabolic problems such as diabetes insipidus.