For many women, morning sickness is one of the first and most recognizable signs of pregnancy. Despite its name, it does not only happen in the morning. Morning sickness refers to nausea and vomiting during pregnancy, not just in the morning. For some women, symptoms occur any time of day.
Nausea and vomiting can occur at any time of day and may range from mild to severe. Some women experience queasiness for just a few weeks, while others find it lingers well into the second trimester or beyond.
This article explains why morning sickness happens, what you can do to find relief, when symptoms might signal something more serious, and how your care team can help.
Why Morning Sickness Happens
The exact cause of morning sickness is not fully understood, but doctors agree that it is closely tied to the rapid hormonal changes of early pregnancy. During the first trimester, levels of human chorionic gonadotropin (hCG) rise quickly, peaking around 10 weeks. This hormone is thought to be a major trigger for nausea.
- Rapid hormonal shifts (especially hCG, estrogen, and progesterone)
- Slower digestion
- Heightened sense of smell
- Fatigue or stress
- Genetics (family history can increase risk)
Increased levels of estrogen and progesterone also contribute by slowing digestion, relaxing the muscles of the stomach, and making the gastrointestinal system more sensitive. These changes can make your body react strongly to food, smells, and even motion.
Other factors may play a role as well. Some women are more sensitive to odors and tastes during pregnancy, making everyday scents overwhelming. Stress, fatigue, and genetics may also influence symptom severity.
While most cases of morning sickness are mild and improve with time, severe or persistent symptoms require prompt evaluation to prevent complications for mother and baby.
What Is Considered Normal Morning Sickness?
Morning sickness typically begins around the sixth week of pregnancy and peaks between weeks nine and twelve. For most women, symptoms improve in the second trimester as hormone levels stabilize, though some continue to feel nausea later in pregnancy.
