Causes of Pancreatitis in Pregnancy
Gallstone disease is the leading cause of acute pancreatitis in pregnancy, accounting for 56-100% of cases, followed by hypertriglyceridemia (which is amplified by pregnancy's physiologic hyperlipidemia), and alcohol abuse. 1, 2, 3
Primary Etiologies
Gallstone-Related Pancreatitis (Most Common)
- Gallstones cause 56-100% of acute pancreatitis cases during pregnancy, making biliary disease the predominant etiology 3, 4, 5
- The estimated incidence of gallstone-related disease complicating pregnancy is 0.5-0.8% 2
- Pregnancy creates a lithogenic environment through gallbladder stasis and increased cholesterol secretion due to elevated estrogen levels 6, 7
- Risk factors include preexisting gallstones, obesity (high prepregnancy BMI), and elevated serum leptin levels 2
- Acute pancreatitis most commonly occurs during the third trimester or early postpartum period when biliary stasis is maximal 3, 5
Hypertriglyceridemia-Induced Pancreatitis (Second Most Common)
- Pregnancy induces a "physiological hyperlipidemia" with 2-fold increases in triglyceride levels during the third trimester due to enhanced lipolytic activity 2
- Women with baseline triglyceride levels ≥500 mg/dL may develop severe hypertriglyceridemia during the third trimester, creating substantial pancreatitis risk 2
- Both insulin resistance and hyperestrogenemia amplify hypertriglyceridemia during pregnancy 2
- Maternal mortality from gestational hypertriglyceridemic pancreatitis approaches 20%, making early recognition critical 2
- Serum triglyceride levels >11.3 mmol/L (>1000 mg/dL) indicate hypertriglyceridemia as the causative etiology 8
Alcohol-Related Pancreatitis (Less Common in Pregnancy)
- Alcohol abuse accounts for 16-20% of cases in some series, though it is unusual compared to nonpregnant women 5, 7
- This represents a significantly lower proportion than in the general population where alcohol causes 20-25% of cases 8
Other Causes
- Post-ERCP pancreatitis: Pregnancy is an independent risk factor with rates of 12% versus 5% in nonpregnant women 1
- Hereditary pancreatitis (4% of cases) 5
- Hypercalcemia: Should be investigated in all cases, especially when gallstones and alcohol are excluded 8
- Drug-induced causes: Statins are contraindicated in pregnancy, but other medications may contribute 1
- Idiopathic: Should represent no more than 20-25% of cases after thorough investigation 8
Diagnostic Approach
Initial Laboratory Evaluation
- Measure serum amylase or lipase together with liver function tests 8
- Early elevation of aminotransferases or bilirubin strongly suggests biliary (gallstone) etiology 8
- Obtain fasting lipid panel and serum calcium to evaluate metabolic causes 8, 4
- Serum triglyceride levels >11.3 mmol/L confirm hypertriglyceridemia as the cause 8
Imaging Strategy
- Ultrasound of the gallbladder is the first-line imaging modality and should be performed immediately 1, 8
- Repeat biliary ultrasound if initial study is negative, as it remains sensitive for detecting missed gallstones 8
- MRCP (without contrast) has 97.98% sensitivity and 84.4% specificity for choledocholithiasis when ultrasound is nondiagnostic 8
- Endoscopic ultrasound can detect microlithiasis in recurrent cases when other imaging is negative 8
- CT scanning should be reserved for cases where malignancy needs exclusion or when assessing pancreatic necrosis in severe disease 8
Clinical Pearls and Pitfalls
High-Risk Screening
- Women with poorly controlled diabetes should have triglyceride levels checked once every trimester 2
- Do not delay intervention until pancreatitis develops in women with triglycerides ≥500 mg/dL 2
Common Diagnostic Errors
- The diagnosis of idiopathic pancreatitis should not be accepted without at least two good quality ultrasound examinations 8
- Do not use low-fat, high-carbohydrate diets without carbohydrate restriction, as excessive carbohydrates are converted to triglycerides 2
- The goal is to identify a definitive etiology in 75-80% of cases 8