In which trimester is pregnancy-induced pancreatitis most commonly seen in a female patient of childbearing age with a history of pancreatic divisum and recurrent acute pancreatitis?

Pregnancy-Induced Pancreatitis: Trimester of Occurrence

Pregnancy-induced pancreatitis occurs most commonly in the third trimester of pregnancy. 1, 2, 3

Epidemiologic Pattern by Trimester

The overwhelming majority of acute pancreatitis cases in pregnancy present during the third trimester:

• Third trimester accounts for 56-78% of cases, representing the highest risk period 1, 4, 2, 3
• Second trimester accounts for approximately 24-56% in some series 4
• First trimester cases are relatively uncommon 1

The incidence increases progressively with advancing gestational age, though severity is not necessarily correlated with trimester 3.

Pathophysiologic Basis for Third Trimester Predominance

Several pregnancy-related physiologic changes peak in the third trimester, explaining this temporal pattern:

• Triglyceride levels increase 2-fold during the third trimester due to enhanced lipolytic activity in adipose tissue 5
• Women with baseline triglycerides ≥500 mg/dL may develop severe hypertriglyceridemia during the third trimester, creating substantial pancreatitis risk 5
• Both insulin resistance and hyperestrogenemia amplify hypertriglyceridemia during late pregnancy 5

Clinical Context for Pancreatic Divisum Patients

For patients with pancreatic divisum and recurrent acute pancreatitis, the third trimester represents the highest-risk period due to:

• Compounding anatomic vulnerability from the divisum with pregnancy-induced metabolic changes 5
• Peak triglyceride levels occurring in late pregnancy 5
• Gallstone formation risk, which affects 0.5-0.8% of pregnancies and represents 56-100% of pancreatitis cases 5, 1, 2

Risk Stratification Approach

High-risk women should have triglyceride levels checked once every trimester, particularly those with poorly controlled diabetes mellitus 5. Additional risk factors include:

• Preexisting gallstones 5
• Obesity (high prepregnancy BMI) 5
• Elevated serum leptin levels 5

Do not delay intervention until pancreatitis develops, as maternal mortality from gestational hypertriglyceridemic pancreatitis approaches 20% 5.

Management Implications by Trimester

The timing of pancreatitis occurrence dictates management strategy:

• First trimester: Conservative treatment preferred; bridge to second trimester for definitive intervention if needed 1
• Second trimester: Optimal window for laparoscopic cholecystectomy if indicated 6, 1
• Third trimester: Conservative treatment or ERCP with sphincterotomy, with cholecystectomy deferred to early postpartum period 1

For biliary pancreatitis specifically, recurrence rates reach 70% with conservative treatment alone, making definitive intervention critical 1.