What are the causes and management of increased or decreased appetite during the first trimester of pregnancy?

Causes and Management of Appetite Changes in First Trimester Pregnancy

Both increased and decreased appetite during the first trimester of pregnancy are commonly related to hormonal changes, with decreased appetite being more common due to nausea and vomiting of pregnancy (NVP), which affects 30-90% of pregnant women and typically begins at 4-6 weeks, peaks at 8-12 weeks, and subsides by week 20.

Causes of Appetite Changes

Decreased Appetite

• Nausea and vomiting of pregnancy (NVP) is the most common cause of decreased appetite, affecting 30-90% of pregnant women 1
• Elevated levels of human chorionic gonadotropin and estrogen, along with changes in GI motility, contribute to NVP 1
• Progesterone can inhibit GI and small bowel motility, leading to delayed gastric emptying 1
• Hyperemesis gravidarum (HG), an intractable form of NVP affecting 0.3-2% of pregnant women, causes severe appetite reduction 1

Increased Appetite

• Hormonal changes may increase appetite in some women, though this is less common than decreased appetite 2
• Metabolic demands of pregnancy can stimulate hunger in some women, even in the first trimester 2

Assessment of Severity

• The Motherisk Pregnancy-Unique Quantification of Emesis (PUQE) score should be used to quantify severity 1, 3:
  • Mild (≤6 points)
  • Moderate (7-12 points)
  • Severe (≥13 points)
• Hyperemesis gravidarum is diagnosed when there is:
  • Intractable vomiting
  • Dehydration
  • Weight loss >5% of prepregnancy weight
  • Electrolyte imbalances 1

Management of Decreased Appetite and NVP

First-Line (Dietary and Lifestyle Modifications)

• Eat small, frequent, bland meals rather than large meals 1, 3, 4
• Follow the BRAT diet (bananas, rice, applesauce, and toast) 1
• Choose high-protein, low-fat meals 1, 3
• Avoid spicy, fatty, acidic, and fried foods 1, 3
• Identify and avoid specific food triggers and strong odors 1
• Maintain adequate hydration 1

Second-Line (Non-Prescription Supplements)

• Ginger (250 mg capsules four times daily) 1, 3
• Vitamin B6 (pyridoxine, 10-25 mg every 8 hours) as recommended by ACOG 1, 3

Third-Line (Prescription Medications for Persistent Symptoms)

• Doxylamine and pyridoxine combination (10 mg/10 mg or 20 mg/20 mg) - FDA-approved and ACOG-recommended 1, 3
• H1-receptor antagonists (promethazine, dimenhydrinate) if doxylamine is unavailable 1

Fourth-Line (For Moderate to Severe Symptoms or Hyperemesis Gravidarum)

• Ondansetron, metoclopramide, or promethazine 1, 3
• Intravenous glucocorticoids for refractory cases 1, 3
• Intravenous hydration and electrolyte replacement 1
• Hospitalization may be required for severe cases 5

Management of Increased Appetite

• Focus on nutrient-dense foods rather than calorie-dense options 2
• Maintain balanced nutrition with adequate protein, complex carbohydrates, and healthy fats 2
• Regular small meals can help regulate blood sugar and prevent excessive hunger 2

Important Clinical Considerations

• Early intervention is critical to prevent progression to hyperemesis gravidarum 1, 3
• Psychological factors such as stress, poor communication with partners, and inadequate information about pregnancy may exacerbate symptoms 4
• Early gestational age is associated with increased risk of ED visits for NVP 5
• Women with hyperemesis gravidarum may be at higher risk for adverse pregnancy outcomes 3

Monitoring and Follow-up

• More frequent prenatal visits may be needed for women with severe symptoms 3
• Monitor weight, hydration status, and electrolytes in women with persistent vomiting 1
• Consider additional ultrasounds (every 3-4 weeks) to document adequate fetal growth in women with persistent symptoms 1

By following this structured approach to managing appetite changes in the first trimester, clinicians can help improve symptoms and prevent complications while ensuring adequate nutrition for both mother and fetus.