2.5 Nausea, Vomiting & Gastrointestinal Discomforts of Pregnancy

Rising hCG and estrogen, and the smooth-muscle relaxation produced by progesterone, account for most of the gastrointestinal complaints of pregnancy. The midwifery approach is to validate the experience, treat it in evidence-based steps, and stay alert for the point at which a common discomfort has become a pathology — most importantly, the transition from ordinary nausea and vomiting to hyperemesis gravidarum.

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Nausea and Vomiting of Pregnancy (NVP) & Hyperemesis Gravidarum

Nausea and vomiting of pregnancy affects up to 70–80% of pregnant individuals. Symptoms characteristically commence between 4 and 6 weeks gestation, peak between 8 and 10 weeks, and resolve spontaneously in over 85% of patients by 16 to 20 weeks.

Pathophysiological Drivers

• Rapidly rising levels of human chorionic gonadotropin (hCG) and estrogen, which stimulate the chemoreceptor trigger zone in the brainstem.
• Elevated progesterone, which relaxes gastrointestinal smooth muscle, prolongs gastric emptying time, and impairs gastrointestinal motility.
• Genetic factors involving the growth differentiation factor 15 (GDF15) gene and vestibular hypersensitivity.

Clinical Severity: PUQE Score vs. Hyperemesis Gravidarum

Midwives quantify symptom severity using the validated Pregnancy-Unique Quantification of Emesis (PUQE) score, evaluating: (1) hours of nausea per day, (2) daily vomiting episodes, and (3) daily retching/dry-heaving episodes.

• PUQE Score: Mild (≤6 points), Moderate (7–12 points), Severe (≥13 points).

Stepwise Management of NVP

NVP Stepwise Management Pathway
├── Step 1: Dietary & Lifestyle Modifications
│   ├── Small, frequent meals q1-2h (high protein, dry carbohydrates)
│   ├── Acupressure wristbands at Neiguan (P6) point + Ginger (250 mg PO QID)
│   └── Discontinue prenatal vitamins containing iron; substitute folic acid alone
├── Step 2: First-Line Pharmacotherapy (ACOG Level A)
│   └── Pyridoxine (Vitamin B6) 10-25 mg PO TID/QID + Doxylamine 10-12.5 mg PO TID/QID
├── Step 3: Second-Line Antiemetic Escalation
│   ├── Add Promethazine (12.5-25 mg PO/PR q4-6h) OR Prochlorperazine (5-10 mg PO/PR q6-8h)
│   └── OR Metoclopramide (5-10 mg PO/IV q8h - dopamine antagonist with prokinetic action)
└── Step 4: Third-Line & Refractory Hyperemesis
    ├── Ondansetron (4-8 mg PO/IV q8h - serotonin 5-HT3 antagonist)
    └── Inpatient IV rehydration: D5LR/D5NS + IV THIAMINE (100 mg) BEFORE DEXTROSE

[!CAUTION] Wernicke Encephalopathy Prevention: In patients with prolonged vomiting or hyperemesis gravidarum, maternal thiamine (Vitamin B1) stores are rapidly depleted. Intravenous infusion of glucose/dextrose without thiamine triggers acute cerebral pyruvate accumulation, causing Wernicke encephalopathy (triad of ataxia, ophthalmoplegia, and acute confusion). Always administer 100 mg IV thiamine prior to or concurrent with dextrose infusions.

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Gastrointestinal Discomforts: GERD, Constipation & Hemorrhoids

Gastroesophageal Reflux Disease (GERD / Pyrosis)

• Etiology: Progesterone decreases the resting basal tone of the lower esophageal sphincter (LES) and slows gastric transit. In the late second and third trimesters, the expanding gravid uterus elevates intra-abdominal pressure, displacing the stomach cephalad and promoting acid reflux.
• Midwifery Interventions:
  1. Non-Pharmacologic: Small, frequent meals; avoid eating within 2 to 3 hours of recumbency; elevate the head of the bed 6 inches using a wedge pillow; eliminate trigger foods (caffeine, chocolate, peppermint, citrus, acidic, and high-fat foods); avoid tight, restrictive abdominal clothing.
  2. First-Line Pharmacologic: Calcium carbonate antacids (e.g., Tums; provides both symptom relief and bioavailable calcium). Avoid sodium bicarbonate (risk of systemic metabolic alkalosis and fluid retention) and high-dose magnesium trisilicate.
  3. Second-Line Pharmacologic: Histamine-2 receptor antagonists (H2RAs): Famotidine (20–40 mg daily or BID).
  4. Third-Line Pharmacologic: Proton pump inhibitors (PPIs): Omeprazole (20 mg daily) or pantoprazole for refractory erosive symptoms.
  5. Mucosal Protectant: Sucralfate (1 g PO TID/QID; minimally absorbed systemically, highly safe).

Constipation

• Etiology: Progesterone inhibits gastrointestinal motilin and reduces colonic smooth muscle contractility, doubling colonic transit time and maximizing mucosal water reabsorption. Ingestion of supplemental elemental iron and mechanical rectosigmoid compression by the fetal head compound the issue.
• Midwifery Interventions:
  1. Lifestyle: Increase dietary fiber intake to 25 to 30 grams/day (legumes, whole grains, fruits, vegetables, prunes); increase daily oral hydration to 2.5 to 3.0 liters/day (8–10 glasses); engage in daily moderate physical exercise.
  2. First-Line Laxatives: Bulk-forming laxatives (psyllium husk, methylcellulose) and surfactant stool softeners (docusate sodium 100 mg PO BID).
  3. Second-Line Laxatives: Osmotic agents such as polyethylene glycol (PEG 3350 / MiraLAX) 17 g daily, lactulose, or magnesium hydroxide (Milk of Magnesia).
  4. Contraindicated / Avoid: Stimulant laxatives like castor oil (provokes violent uterine contractions and diarrhea) and mineral oil (impairs fat-soluble vitamin A, D, E, K absorption).

Hemorrhoids

• Etiology: Progesterone-induced venodilation combined with mechanical obstruction of the inferior vena cava and iliac veins markedly increases hemorrhoidal venous plexus pressure, exacerbated by chronic straining during defecation.
• Management: Prevention of hard stools; warm sitz baths for 15–20 minutes twice daily; application of cold ice packs; topical astringents (witch hazel pads / Tucks); topical hydrocortisone 1% cream combined with pramoxine for acute pruritus and inflammation; gentle manual reduction of prolapsed external hemorrhoids.

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