What signs may indicate neonatal abstinence syndrome in a neonate with low birth weight?

Neonatal abstinence syndrome (NAS) is a condition seen in newborns who were exposed to drugs in utero, particularly opioids. One of the hallmark signs of NAS is irritability and restlessness. These symptoms are a result of the infant's withdrawal from the substances their mother used during pregnancy. Infants may exhibit a high-pitched cry, difficulty sleeping, and an overall state of increased sensitivity, leading to a general demeanor characterized by irritability.

The other options do not specifically correlate with NAS. Meconium ileus, while significant, is often associated with cystic fibrosis and not typically with withdrawal symptoms. Microcephaly and cleft palate are congenital anomalies that are more related to maternal use of substances such as alcohol or certain medications but not directly indicative of NAS. Stuffy nose and frequent sneezing may occur from various non-specific conditions in newborns and are not definitive signs of withdrawal. Thus, irritability and restlessness are the most directly relevant signs indicating NAS in a neonate with low birth weight.