The PREWEAN Study. Weaning of Preterm Infants During the First Year of Life.

In this Austrian observational study preterm infants born with a birth weight \<1500 g and a gestational age \<32 weeks will be investigated at the neonatal outpatient clinic. Infants will be stratified according their feeding regimen (breast, formula and combined feeding) and their introduction of solid foods (early complementary feeding group: \<17th week of life corrected for prematurity, late complementary feeding group: ≥17th week of life corrected for prematurity). Nutrient intakes and anthropometric parameters will be assessed at term, 6 weeks, 12 weeks, 6 months, 9 months and 12 months - all corrected for prematurity and with 40, 54 and 66 months.

Introduction: Evidenced-based guidelines for the introduction of complementary feeding in preterm infants are not available so far. In comparison to full-term babies, there is strong evidence that babies less than 1500 grams have increased nutritional needs starting with the time of birth up to the second year of life to establish catch up growth and to reach the main milestones in neurological development.

Evidence based data on feeding practices after discharge of the hospital, weaning and the quantity and quality of complementary food are missing. With this prospective observational study the investigators intend to close this knowledge gap in weaning of former preterm infants.

Methods: In this prospective observational study preterm infants born with a birth weight \<1500 g and a gestational age \<32 weeks will be recruited at term corrected for prematurity at the neonatal outpatient clinic. Infants will be stratified according their source of milk intake (breast milk, formula and mixed feeding) and their introduction of solid foods (early complementary feeding group: \<17th week of life corrected for prematurity, late complementary feeding group: ≥17th week of life corrected for prematurity).

Nutritional intake will be estimated based on 24h Recalls at term and after 6 weeks of age corrected for prematurity. Furthermore, 3-days dietary records, an average dietary record and the introduction of the main food categories will be queried at 4 different time points (3 months, 6 months, 9 months and 12 months - all corrected for prematurity) by food questionnaire.

Within these visits anthropometric parameters (height, head circumference and weight), data on body composition (Pea Pod®, BodPod ) \& bio-impedance measurements will be collected. Atopy will be determined by the clinical scoring system SCORAD. For follow up anthropometry and the neurodevelopmental outcome will be assessed by the Bayley Scale at 12 \& 24 months corrected for prematurity and at 40 months of age. Furthermore, K-ABC II (Kaufmann assessment battery for children) will be performed at 66 months of age.

Goals: With this observational study the investigators aim to identify current feeding practices in premature infants and their impact on growth, body composition, atopy and neurodevelopmental outcome.

Eligibility Criteria:
Inclusion Criteria:

* Preterm infants born with a birth weight \<1500g and a gestational age \<32 weeks
* Informed consent

Exclusion Criteria:

* Gastrointestinal diseases: e.g. Hirschsprung disease
* Congenital heart diseases
* Major congenital birth defects
* Chromosomal aberrations