A 26-year-old women in the first trimester of pregnancy has been admitted with retching and repeated vomiting with large hematemesis. Her pulse rate is 126/minute and blood pressure is 80 mm Hg systolic. The most likely diagnosis is:

Upper gastrointestinal bleeding: “Occasionally, persistent vomiting may be accompanied by worrisome upper gastrointestinal bleeding. The obvious concern is that there is a bleeding peptic ulceration, however, most of these women have minute linear mucosal tears near the gastroesophageal junction. Women with these co called Mallory-Weiss tears usually respond promptly to conservative measures.” Ref. Williams 23/e, p 1053 With persistent retching the less common but more serious oesophageal rupture – ‘Boerhaave syndrome' may develop.