What is the management of diarrhea in a pregnant woman at 36 weeks gestation?

Management of Diarrhea in Pregnancy at 36 Weeks Gestation

For a pregnant woman at 36 weeks with diarrhea, prioritize aggressive hydration with oral rehydration solutions or intravenous fluids if severely dehydrated, obtain stool cultures to identify infectious causes requiring specific treatment, and avoid antiperistaltic agents like loperamide during pregnancy. 1

Immediate Assessment and Hydration

Assess hydration status systematically by checking for orthostatic hypotension, decreased skin turgor, dry mucous membranes, and obtain accurate body weight before initiating therapy 1. At 36 weeks gestation, dehydration poses significant risks to both mother and fetus.

• Hospitalize immediately if severe dehydration is present for intravenous fluid replacement with 0.9% saline solution and close monitoring 1, 2
• For mild to moderate dehydration, initiate oral rehydration therapy with small, frequent volumes (e.g., 5 mL every minute initially) using oral rehydration salts 3
• Laboratory studies including serum electrolytes should be measured when clinical signs suggest abnormal sodium or potassium concentrations 1

Diagnostic Evaluation

Obtain stool cultures for enteroinvasive bacterial infections and Clostridioides difficile testing in all pregnant women with gastroenteritis 1. This is critical because certain pathogens require specific antimicrobial therapy during pregnancy.

• Take careful travel and contact history, with appropriate testing for amoebic or Shigella dysentery if relevant travel exposure exists 1
• If diarrhea persists beyond 5 days, high fever is present, or dysentery occurs, consider bacterial pathogens requiring antibiotic treatment 3

Antimicrobial Therapy When Indicated

For confirmed Salmonella gastroenteritis, treatment is mandatory during pregnancy to prevent extraintestinal spread to the placenta and amniotic fluid, which can result in pregnancy loss 1.

• Safe antibiotic choices include ampicillin, cefotaxime, ceftriaxone, or trimethoprim-sulfamethoxazole 1
• Fluoroquinolones must be avoided during pregnancy due to potential fetal risks 1
• Evaluate household contacts for asymptomatic carriage of Salmonella or Shigella to prevent recurrent transmission 1

Symptom Management

Antiperistaltic drugs are not recommended for pregnant women with diarrhea as they shift focus away from appropriate fluid and electrolyte therapy and can cause serious side effects including ileus 3, 1. This is a critical pitfall to avoid.

For nausea and vomiting accompanying diarrhea:

• Metoclopramide can be used with less drowsiness and dystonia compared to promethazine 1
• Ondansetron may enhance compliance with oral rehydration therapy, though at 36 weeks this concern about first-trimester exposure is not relevant 3, 1

Nutritional Support

Continue regular diet during diarrhea with foods including starches, cereals, yogurt, fruits, and vegetables, while avoiding foods high in simple sugars and fats 3.

• Replace excess fluid losses from vomiting or diarrhea with oral rehydration solutions as outlined above 3
• Give thiamine 100 mg daily for a minimum of 7 days to prevent refeeding syndrome and Wernicke encephalopathy if intake has been poor 1

Thromboprophylaxis Considerations

At 36 weeks gestation (third trimester), outpatients with active diarrheal symptoms should receive VTE prophylaxis unless contraindicated 1. This is particularly important given the hypercoagulable state of late pregnancy.

• Pregnant women hospitalized for gastroenteritis should receive anticoagulant thromboprophylaxis during hospitalization 1

Critical Pitfalls to Avoid

• Do not use loperamide or other antiperistaltic agents despite one study showing no increased malformations, as guidelines explicitly recommend against their use in pregnancy due to serious side effects 1, 4
• Do not delay necessary interventions solely because the patient is pregnant - if urgent evaluation or treatment is needed, proceed appropriately 1
• Do not rely solely on dietary modifications when infectious causes are suspected - obtain appropriate cultures and treat accordingly 1

When to Escalate Care

Return immediately or call if the patient develops:

• Decreased urine output or inability to maintain hydration orally 3
• Persistent high fever or bloody diarrhea 3
• Signs of preterm labor (given 36 weeks gestation) 1
• Mental status changes or severe weakness 1