Hyperemesis gravidarum is best described as severe and persistent vomiting during pregnancy that leads to significant dehydration, electrolyte imbalances, and weight loss. Unlike mild morning sickness, it requires medical intervention due to risks of maternal and fetal complications. The condition often necessitates hospitalization for intravenous fluid replacement and antiemetic therapy. Recognition and timely treatment are crucial to prevent adverse outcomes.

Reference: Williams Obstetrics, Cunningham et al., 26th Edition.