Management of Acute Gastroenteritis at 22 Weeks Gestation
For a pregnant woman at 22 weeks with acute gastroenteritis, prioritize aggressive oral or intravenous rehydration, obtain stool cultures for bacterial pathogens and Clostridioides difficile, initiate thromboprophylaxis if hospitalized, and treat confirmed bacterial infections (especially Salmonella) with pregnancy-safe antibiotics while avoiding fluoroquinolones and antiperistaltic agents. 1
Initial Assessment and Hydration Strategy
Assess hydration status systematically by checking for orthostatic hypotension, decreased skin turgor, dry mucous membranes, and obtain accurate body weight before initiating therapy. 1 Laboratory studies such as serum electrolytes are rarely needed but should be measured when clinical signs suggest abnormal sodium or potassium concentrations. 1
Rehydration Protocol
For mild to moderate dehydration: Initiate oral rehydration therapy with small, frequent volumes using oral rehydration salts or half-strength apple juice followed by preferred liquids. 1, 2
For severe dehydration: Hospitalize immediately for intravenous fluid replacement and close monitoring, as severe dehydration poses significant maternal and fetal risks. 1
Continue regular diet during diarrhea with foods including starches, cereals, yogurt, fruits, and vegetables, while avoiding foods high in simple sugars and fats. 1
Diagnostic Evaluation
Obtain stool cultures for enteroinvasive bacterial pathogens and test for Clostridioides difficile in any pregnant woman presenting with acute gastroenteritis. 1, 3 This diagnostic approach is critical because bacterial infections may require targeted antimicrobial therapy to prevent maternal-fetal complications.
Review travel and contact history carefully, with appropriate testing for amoebic dysentery or Shigella species in patients with relevant exposure history. 1, 3
Consider bacterial pathogens requiring antibiotic treatment if diarrhea persists beyond 5 days, high fever is present, or dysentery occurs. 1
Thromboprophylaxis—A Critical Safety Measure
Administer anticoagulant thromboprophylaxis with low-molecular-weight heparin (LMWH) to all pregnant patients hospitalized for gastroenteritis, as pregnancy itself increases VTE risk and acute illness compounds this danger. 1, 3 LMWH is preferred over unfractionated heparin due to better safety and efficacy in the obstetric population. 1
For outpatients in the third trimester with active gastroenteritis, initiate VTE prophylaxis unless contraindicated (e.g., active bleeding or heparin allergy). 1
Antimicrobial Therapy
When to Treat
Do not prescribe antibiotics for viral gastroenteritis, as they provide no benefit and may cause harm. 1 However, specific bacterial infections require treatment:
For confirmed Salmonella gastroenteritis, treatment is mandatory to prevent extraintestinal spread to the placenta and amniotic fluid, which can result in pregnancy loss. 1, 3 This is a critical distinction from non-pregnant patients, where uncomplicated Salmonella gastroenteritis is often managed supportively.
Pregnancy-Safe Antibiotic Choices
Appropriate antibiotics for Salmonella include:
- Ampicillin
- Cefotaxime
- Ceftriaxone
- Trimethoprim-sulfamethoxazole (TMP-SMZ)
Fluoroquinolones must be avoided during pregnancy due to potential fetal risks, despite their effectiveness in non-pregnant populations. 1, 3 This is a common pitfall—always verify pregnancy status before prescribing quinolones for gastroenteritis.
Symptom Management
Antiemetics
Ondansetron may enhance compliance with oral rehydration therapy and decrease hospitalization rates by controlling nausea and vomiting. 1, 4, 5 However, consider its use on a case-by-case basis, particularly noting that some guidelines suggest caution before 10 weeks of pregnancy. 1
Metoclopramide can be used for nausea and vomiting with less drowsiness, dizziness, and dystonia compared to promethazine. 1
Nutritional Support
Supplement with vitamin B6 (pyridoxine) for mild cases of nausea. 1
Give thiamine 100 mg daily for a minimum of 7 days, then 50 mg daily maintenance, to prevent refeeding syndrome and Wernicke encephalopathy until adequate oral intake is established. 1
Critical Medications to Avoid
Do not use antiperistaltic agents (loperamide) in pregnant women with acute gastroenteritis. 1 These agents shift focus away from appropriate fluid and electrolyte therapy and can cause serious side effects, including ileus. 1 The FDA label for loperamide notes that while animal studies showed no teratogenicity, there are no adequate well-controlled studies in pregnant women, and it should only be used if potential benefit justifies potential risk. 6
Avoid gadolinium-based contrast agents for MR imaging during pregnancy, as gadolinium crosses the placenta and its safety profile is not established. 1, 3
When to Escalate Care
Return immediately or call if the patient develops:
- Decreased urine output or inability to maintain hydration orally
- Persistent high fever or bloody diarrhea
- Signs of severe dehydration
Do not delay urgent interventions solely because the patient is pregnant—necessary diagnostic or therapeutic procedures should proceed with appropriate fetal safety modifications. 1, 3
Prevention of Recurrent Transmission
Evaluate household contacts of pregnant women with salmonellosis or shigellosis for asymptomatic carriage to prevent recurrent transmission back to the patient. 1, 3
Special Consideration for Inflammatory Bowel Disease
If the patient has known IBD and a suspected flare, flexible sigmoidoscopy or colonoscopy may be performed if results will affect antenatal management. 7 For pregnant women with IBD who have a disease flare on optimal maintenance therapy, treat with systemic corticosteroids or anti-TNF therapy to induce symptomatic remission. 7