As the nurse assessing miguel, what nursing diagnosis related to growth and development should be prioritized for this infant ?

Mr. and Mrs. Iglesias, both aged 30, bring their 6-month-old son, Miguel, to the pediatric clinic for a routine check-up. Miguel was born full-term with a normal birth weight but has been consistently below the 5th percentile for weight and height since birth. Mrs. Iglesias reports that Miguel has a poor appetite and often seems irritable. The family history is unremarkable for any genetic conditions or developmental delays.