Home › Pregnancy › Week 12 › Hyperemesis Gravidarum
Week 12 · First Trimestersevere

Hyperemesis Gravidarum at 12 Weeks Pregnant

Hyperemesis gravidarum (HG) is a severe form of pregnancy nausea and vomiting causing significant dehydration, weight loss, and malnutrition. It affects 0.3–3% of pregnancies and often requires medical treatment.

👶 What's Happening at Week 12

Your baby is now the size of a plum.

  • All organs and structures are formed — the rest of pregnancy is growth and maturation.
  • Reflexes develop: the fetus can open and close fingers, curl toes, and make sucking motions.
  • The kidneys begin producing urine.

🔬 Why You're Experiencing Hyperemesis Gravidarum at Week 12

  • Extreme sensitivity to hCG hormone — associated with high hCG levels (twins, molar pregnancy increase risk)
  • Genetic component — runs in families
  • Thyroid hormone fluctuations linked to high hCG levels
  • Helicobacter pylori infection possibly linked to HG severity
  • Psychological factors may influence severity but do not cause HG

💊 Relief Tips for Week 12

1
IV Fluids and ElectrolytesThe primary treatment for dehydration — typically administered in hospital or infusion clinic.
2
Anti-Nausea MedicationsOndansetron (Zofran), promethazine, metoclopramide, and doxylamine/B6 (Diclegis) are prescribed based on severity and individual response.
3
Thiamine (Vitamin B1) SupplementationEssential to prevent Wernicke encephalopathy from prolonged vomiting — almost always prescribed in hospitalized HG patients.
4
Nutritional SupportEnteral nutrition (via nasogastric tube) or parenteral nutrition (IV) may be needed in severe cases where no oral intake is tolerated.
5
Rest and Stress ReductionA supportive home environment and reduced demands are important for recovery.

📋 Other Week 12 Symptoms

Morning sickness (improving)Fatigue (improving)DizzinessIncreased appetiteSkin changes
See full Week 12 guide →

⚠️ Call Your Doctor If…

  • Vomiting more than 3–4 times per day with inability to keep fluids down
  • Signs of dehydration: dark urine, dizziness, confusion, dry mouth, not urinating
  • Weight loss of more than 5% of pre-pregnancy body weight
  • Vomiting blood or coffee-ground material

Frequently Asked Questions

How is hyperemesis gravidarum different from morning sickness?

Morning sickness involves nausea and some vomiting but allows adequate hydration and nutrition. HG is defined by persistent severe vomiting causing dehydration, weight loss (>5%), electrolyte imbalance, and inability to function.

Will my baby be affected by hyperemesis gravidarum?

With proper treatment, most babies born to mothers with HG do well. Severe untreated HG with significant malnutrition can affect birth weight.

When does hyperemesis gravidarum end?

For many women, HG improves by weeks 14–20. However, some women experience symptoms throughout their entire pregnancy.

Is Zofran (ondansetron) safe in pregnancy?

Ondansetron is widely used for HG. Current evidence does not confirm increased risk of birth defects, though some earlier studies raised concerns. The decision balances the risks of HG (dehydration, malnutrition) against any potential medication risk.

Medical Disclaimer: This content is for informational purposes only and does not constitute medical advice. Always consult your OB/GYN or midwife about symptoms during pregnancy.