Chapter 35, Ep 1 of 6: Pregnancy Physiology and Hyperemesis

Episode one of the GI in Pregnancy chapter sets the physiologic baseline that every later stem depends on. The organizing idea is that pregnancy shifts a predictable set of labs, so any deviation pregnancy does not itself cause is by definition pathologic. From there it walks the volume, CBC, and liver-test changes, the fetal-protective imaging menu, and the antiemetic sequence for nausea and hyperemesis. The through-line is that you interpret a pregnant patient against a moved reference range, and you treat vomiting on a mechanistic ladder that ends with an absolute safety rule.   Topics covered The shifted-baseline principle Volume expansion and hepatic blood flow CBC and creatinine dilutional shifts Liver tests and the ALP versus GGT rule Fetal-protective imaging menu Nausea and hyperemesis gravidarum defined The antiemetic treatment sequence Thiamine before glucose and Wernicke prevention   Key decisions AST, ALT, and bilirubin do not rise in normal pregnancy, so any elevation is pathologic and starts a workup, while an isolated alkaline phosphatase rise with a normal GGT is placental and needs only reassurance. A pregnancy creatinine is usually below zero point eight, so a value of one point zero is high for this patient and warrants a workup rather than a shrug. Ultrasound without doppler is first-line in all trimesters, MRI without gadolinium is preferred over CT, and CT is reserved for when diagnostic benefit clearly exceeds a fetal dose kept generally below fifty milligray. First-line therapy for nausea and hyperemesis is pyridoxine ten to twenty-five milligrams three to four times daily combined with doxylamine, escalating to ondansetron or metoclopramide as second-line. Any pregnant patient with prolonged vomiting who needs IV fluids gets thiamine one hundred milligrams before or with any glucose-containing fluid, because glucose loading in a thiamine-depleted patient precipitates Wernicke encephalopathy. Refractory hyperemesis escalates to methylprednisolone sixteen milligrams every eight hours, held until after ten weeks of gestation for the cleft palate signal, with total parenteral nutrition as the last resort. Hyperemesis liver abnormalities resolve with hydration, which distinguishes them from intrahepatic cholestasis and viral hepatitis, and elevated bile acids with palmoplantar pruritus point to cholestasis rather than hyperemesis.   For the full chapter with MCQs, tables, and primary-guideline references, visit www.boardpearls.com. Questions or feedback: [email protected]. (00:00) - Introduction and the shifted-baseline principle (00:51) - Volume expansion and hepatic blood flow (01:40) - CBC and creatinine shifts (02:17) - Liver tests and the ALP-GGT rule (05:07) - Imaging by fetal-protective logic (07:28) - Nausea and hyperemesis defined (09:03) - The antiemetic treatment sequence (10:47) - Thiamine before glucose