Understanding Morning Sickness

What Is Morning Sickness?

Morning sickness — medically called "nausea and vomiting of pregnancy" (NVP) — is nausea and/or vomiting that occurs during pregnancy, most commonly in the first trimester. Despite the misleading name, it can happen at any time of day and, for many women, lasts throughout the day.

NVP is one of the most common conditions in medicine. It affects approximately 70-80% of all pregnant women to some degree. It is not a sign that something is wrong with your pregnancy — in fact, some research suggests that women who experience NVP have a slightly lower risk of miscarriage, though this should never be used to dismiss someone's suffering.

What Causes It?

The exact cause of pregnancy sickness is not fully understood, but it's believed to be related to several factors:

• Human Chorionic Gonadotropin (hCG): This pregnancy hormone rises rapidly in early pregnancy and peaks around weeks 8-12 — exactly when NVP tends to be worst. Women with higher hCG levels (such as those carrying twins) often experience more severe sickness.
• Oestrogen: Oestrogen levels rise dramatically in early pregnancy and may contribute to nausea, particularly by affecting the gastrointestinal tract.
• Progesterone: This hormone relaxes smooth muscle throughout the body, including the digestive system, which can slow digestion and contribute to nausea.
• Heightened sense of smell: Many pregnant women develop an extremely sensitive sense of smell in early pregnancy, and strong odours can trigger nausea.
• Evolutionary theory: Some researchers believe NVP evolved as a protective mechanism to prevent pregnant women from eating potentially harmful or toxic foods during the critical first trimester of foetal development.
• Genetic factors: NVP tends to run in families. If your mother or sisters experienced significant pregnancy sickness, you're more likely to as well.

Timeline

Understanding the typical timeline helps you know what to expect, though every pregnancy is different:

Week	What to Expect
Weeks 4-5	Symptoms may begin. Often just mild nausea, particularly in the morning or when hungry.
Weeks 6-7	Nausea typically intensifies. Vomiting may begin. Food aversions and smell sensitivity develop.
Weeks 8-10	Peak severity for most women. This is often the hardest period. Hang in there.
Weeks 10-12	Many women begin to notice gradual improvement. Some good days appear alongside bad ones.
Weeks 14-16	Significant improvement for the majority. The second trimester often brings relief.
Weeks 16-20	Most women are feeling much better. About 10% still have lingering symptoms.
Beyond 20	A small percentage of women experience nausea throughout pregnancy. HG can persist to delivery.

Risk Factors

Some women are more likely to experience NVP than others:

• First pregnancy (though it can occur or worsen in subsequent pregnancies)
• History of NVP or HG in previous pregnancies
• Family history of pregnancy sickness (mother or sisters)
• Multiple pregnancy (twins, triplets)
• History of motion sickness or migraine
• History of nausea while taking oestrogen-containing contraception
• Younger maternal age
• Obesity (BMI over 30)
• Female foetus (slightly increased risk, though this is not reliable for sex prediction)

What's Normal and What's Not

Normal (Common) Experiences

• Feeling nauseous most of the day, especially on an empty stomach
• Vomiting once or twice a day
• Strong aversions to certain foods, smells, or textures
• Difficulty eating balanced meals — surviving on limited foods
• Feeling exhausted alongside the nausea
• Emotional distress — crying, frustration, anxiety about the sickness
• Some weight loss in the first trimester (up to 5% of body weight)

Signs You Need Medical Help

• Vomiting more than 3-4 times daily
• Unable to keep fluids down for 12-24 hours
• Very dark or concentrated urine
• Weight loss of more than 5% of pre-pregnancy weight
• Dizziness or fainting
• Rapid heartbeat
• Blood in vomit
• Sickness so severe you cannot care for yourself or existing children
• Feeling depressed or hopeless about the pregnancy due to sickness

Morning Sickness vs. Hyperemesis Gravidarum

There's a significant difference between typical morning sickness and hyperemesis gravidarum (HG). Here's how to distinguish them:

Feature	Morning Sickness	Hyperemesis Gravidarum
Nausea	Intermittent, often triggered by food/smells	Constant, relentless, may not have triggers
Vomiting	Occasional (0-3x daily)	Frequent and severe (3-10+ times daily)
Eating	Can eat some foods, though limited	Unable to keep most food or fluids down
Weight	Minimal weight loss or stable	Weight loss >5% of pre-pregnancy weight
Hydration	Can maintain fluid intake	Dehydrated, may need IV fluids
Daily life	Uncomfortable but manageable	Unable to work, care for self/children
Duration	Usually resolves by week 14-16	May persist throughout pregnancy
Treatment	Lifestyle changes, sometimes medication	Requires medication, may need hospitalisation

If your symptoms match the HG column, please read our detailed HG guide and seek medical help promptly.

Impact on Mental Health

Pregnancy sickness doesn't just affect your body — it takes a significant toll on mental health. Research shows that women with NVP have higher rates of anxiety and depression during pregnancy. This is not surprising when you consider that:

• You may feel unable to enjoy your pregnancy
• You may feel guilty for not feeling "happy" about being pregnant
• Social isolation increases when you can't leave the house
• Relationships can be strained
• Work performance may suffer, adding financial stress
• Feeling dismissed or not believed by healthcare providers is deeply frustrating
• Some women consider termination solely because of the severity of their sickness

These feelings are valid and understandable. If you're struggling emotionally, please talk to your midwife, GP, or contact the Pregnancy Sickness Support helpline. Mental health support is just as important as physical treatment.