When should new parents contact the baby's physician?

The correct choice highlights a critical situation that requires immediate medical attention for a newborn. More than 8 diarrhea stools in 8 hours can indicate a serious problem, such as a gastrointestinal infection or a significant disruption in the baby's hydration status. In newborns, dehydration can progress rapidly and lead to serious health concerns, making it essential for parents to reach out to the baby’s physician in such instances.

Monitoring the frequency and consistency of a baby's stools is an important part of assessing their health. Diarrhea in infants, especially at that volume, can signal issues that may require evaluation and potentially treatment, ensuring that the baby's nutritional needs are being met and that they are not losing critical fluids.

In contrast, while a temperature of 99°F in a newborn may warrant monitoring, it is not typically considered a fever, and generally, anything under 100.4°F (38°C) does not require immediate contact with the physician. Similarly, having fewer than 4 wet diapers in 24 hours or excessive crying during feeding can be concerning depending on the context, but these issues are not as urgent as the possibility of high stool frequency and the risk of dehydration.