Morning sickness is nausea or vomiting that affects over two-thirds of pregnant women. Morning sickness can happen at any time of day. It usually starts around weeks 8–10 and decreases by week 13. Causes include:
- Blood pressure fluctuations or low blood sugar.
- Metabolic changes.
- High pregnancy hormone levels.
- It can get worse with stress, fatigue, certain foods, smells, or heat.