[Frequency of hypotrophic births in the Warsaw population]

Newborn's reduced body mass and length are regarded as an important symptom. The diagnosis requires careful observation of the individual's course of growth and metabolic condition. Various criteria are used to diagnose hypotrophy; 3rd, 5th or 10th percentile body mass are the most common, although others recommend using a value of -2.0 SDS body mass and length.

To define the frequency of body mass and length deficiency in newborns in the Warsaw population.

4096 children born in single deliveries in 2009 at one Warsaw hospital. Body dimensions at birth were compared against the following standards, taking gestation period and sex into consideration: 1. Usher and McLean (UML). 2. A standard generally used in Warsaw maternity wards, drawn up by the Mother and Baby Institute (IMiD). 3. A standard drawn up in Wielkopolska (WLKP). Hypotrophy was diagnosed retrospectively on the basis of -2.0 SDS body mass and/or body length and 10th percentile body mass criterion.

Regardless of sex and the standard being applied, at least one of the analysed body dimensions fell at or below -2.0 SDS in approximately 1% of all children. In newborn boys hypotrophy was diagnosed significantly less frequently using the UML standard than using the national ones, while in newborn girls it was diagnosed less frequently using the IMiD standard than UML or WLKP. Birth mass below the 10th percentile was found in approximately 7% and in just over 3% of all newborns using the IMiD and WLKP standards respectively.

The absence of national standards for body length at birth makes the -2.0 SDS criterion difficult to use, while basing the diagnosis purely on evaluating body mass results in too few diagnoses of hypotrophy. Using the 10th percentile criterion allows for diagnosing hypotrophy in a few percent of newborns, while the Warsaw and Wielkopolska standards result in more diagnoses. Taking population trends into account, we postulate the need to prepare new national standards of body dimensions of newborns based on the gestation period.