Final answer:
The most important recommendation the nurse can make for a client at 30 weeks gestation reporting heartburn is to eat smaller, more frequent meals, which can help decrease heartburn by reducing stomach pressure and volume.
Step-by-step explanation:
The nurse should make the recommendation to eat smaller, more frequent meals (Option C). During pregnancy, especially at 30 weeks of gestation, the growing uterus can exert pressure on the stomach, leading to heartburn. Eating smaller, more frequent meals can help minimize this issue as it tends to decrease the volume and pressure on the stomach. Additionally, it is advisable for the client to avoid foods and beverages that could worsen GERD (Gastroesophageal Reflux Disease), such as chocolate, fatty foods, coffee, and alcoholic beverages, and to not lie down immediately after eating to help prevent the backflow of stomach contents into the esophagus.