Nutrition in relation to the endocrine regulation of preterm growth

In October 2016 the following changes were made:
- An additional reference group (n=100) of infants born between 32 and 42 weeks of gestation has been added for the analysis of endocrine parameters in cord blood;

In January 2017 the following changes were made:
- The intervention is stopped, because of insufficient number of formula-fed infants;
- The number of participants with a gestational age less than 32 weeks was reduced from 150 to 70.

Insulin-like growth factor I (IGF-I) is one of the key factors in the endocrine regulation of growth in preterm infants. After birth IGF-I levels quickly drop as the placental supply is suddenly disrupted, to then slowly be restored in preterm infants. We hypothesize that IGF I has to reach a threshold concentration before it can effectively influence growth. Furthermore it is expected that less energy- and nutrient-enrichment is required once IGF-I passes the threshold concentration. The maximum growth rate is then expected to be potentiated by IGF-I, reducing the need for extra nutrients and potentially leading to increased fat deposition if diet enrichment is continued.

During hospitalisation infants will be subjected to weekly anthropometric measurements and blood draws once every 2 weeks until a postmenstrual age of 36 weeks. Infants will be followed up at the outpatient department at term age and 3, 6, 12 and 24 months corrected age for continued anthropometric measurements, body composition and bone mineralization measurements, blood pressure registration, neuropsychologic assessment and a total of 2 blood draws.

In October 2016 the following changes were made:
- A food frequency questionnaire of maternal nutrition during pregnancy was added for participants with a gestational age lower than 32 weeks;
- The frequency of anthropometric measurements between 30 and 36 weeks postmenstrual age was reduced to once every 2 weeks instead of weekly.

Preterm infants (born < 32 weeks) fed limited energy- and nutrient-enriched preterm follow-up formula at a postmenstrual age of 32-33 weeks will be compared to preterm infants fed according to the standard regime. Formula fed infants will be randomized to either a full energy- and nutrient-enriched preterm starter formula until a postmenstrual age of 32-33 weeks (intervention group) or until term age (control group). In both groups the preterm starter formula will be followed-up by a limited energy- and nutrient-enriched preterm follow-up formula until 6 months corrected age. From 6 months onwards both the intervention as well as the control group will be fed regular follow-up term formula. The study will also include a breast fed reference group which will be fed fortified breast milk until term age, according to current practice.

In January 2017 the intervention is stopped, because of insufficient number of formula-fed infants;