Nausea and Pregnancy

Nausea, vomiting or “morning sickness” are commonly experienced by women in early pregnancy affects approximately 70% of all pregnant women in the world. Severe vomiting occur in 3% of all women1. That means that 87% of pregnant women have nothing to worry about; this condition is more a norm than a deviation. In most cases, no treatment is needed; but you do need to monitor your water balance and avoid dehydration1.

Why does nausea occur during pregnancy?

The medical cause of nausea and vomiting during pregnancy is unknown. There are many theories, including a hormonal stimulus, evolutionary adaptation, and psychologic predisposition2.

First trimester

Nausea and vomiting, which can strike at any time of the day or night, often begins one month after you become pregnant. This might be due to rising hormone levels. This is often called “morning sickness,” but symptoms can occur at any time – not just in the morning. Usually, the symptoms are tolerable and do not interfere with everyday life3.

Second trimester

The second trimester of pregnancy often brings a new sense of well-being. The worst of nausea has usually passed and your baby isn’t big enough to make you too uncomfortable4

Third trimester 

If you’re feeling nauseated during the third trimester, it’s probably a gastrointestinal issue — everything is getting squished in there, causing your digestion to slow down. Your third trimester nausea could also be paired up with loss of appetite, persistent vomiting, and difficulty losing weight. In this case, you should contact your doctor5.

What is indomitable vomiting or toxicosis?

A very small number of all expectant mothers in the world (between 0.3% and 2%) have continual nausea and vomiting. Uncontrollable vomiting in pregnant women is called hyperemesis. Hyperemesis is often associated with nutritional deficiencies, maternal weight loss, and fluid and electrolyte imbalances; this might cause adverse perinatal outcomes6. In such cases, you should immediately contact your doctor.

What causes nausea and vomiting during pregnancy?

According to research, nausea and vomiting during pregnancy may appear because of the effects of a hormone produced by the placenta called human chorionic gonadotropin (HCG). Pregnant women produce HCG shortly after a fertilised egg attaches to the uterine lining. Women with severe morning sickness (hyperemesis gravidarum) have higher HCG levels than other pregnant women. Women who are pregnant with twins or multiples also have higher HCG levels and are more likely to experience morning sickness. Similarly, estrogen, another hormone that increases during pregnancy, is associated with an increase in the severity of nausea and vomiting during pregnancy7.  

However, high pregnancy hormone levels aren’t consistently associated with nausea and vomiting7.   

It is also possible that nausea and vomiting during pregnancy are signs of viable placental tissue7.  

Remember that an absence of nausea and vomiting during pregnancy is not rare.  Some women with healthy pregnancies never experience morning sickness7.

Management of Nausea During Pregnancy

Unfortunately, no hard and fast treatment will work for everyone’s morning sickness. Every pregnancy will be different. But there are some changes you can make to your diet and daily life to try to ease the symptoms8.

If your morning sickness is not too bad, your GP or midwife may initially recommend you try some lifestyle changes8:

  • get plenty of rest (tiredness can make nausea worse)
  • avoid foods or smells that make you feel sick
  • eat something like dry toast or a plain biscuit before you get out of bed
  • eat small, frequent meals of simple foods that are high in carbohydrates and low in fat (such as bread, rice, crackers and pasta)
  • eat cold foods rather than hot ones if the smell of hot meals makes you feel sick
  • drink plenty of fluids, such as water (sipping them little and often may help prevent vomiting)
  • eat foods or drinks containing ginger – there’s some evidence that ginger may help reduce nausea and vomiting 

If your morning sickness symptoms persist, your doctor may recommend vitamin B-6 supplements (pyridoxine), ginger and over-the-counter options. If you still have symptoms, your doctor may prescribe anti-nausea medications9.

Your doctor may ask how often you experience nausea, how often you have vomited, whether you can keep fluids down, and whether you have tried home remedies. There are a number of prescription medications that are safe to take during pregnancy for nausea and vomiting. Your doctor can recommend a safe option based on the severity of your symptoms9.

Check with your doctor before taking any over-the-counter medications or supplements during pregnancy9.


  1. Matthews A, Haas DM, O’Mathúna DP, Dowswell T. Interventions for nausea and vomiting in early pregnancy. Cochrane Database Syst Rev 2015; CD007575.
  2. Committee on Practice Bulletins-Obstetrics. ACOG Practice Bulletin No. 189: Nausea And Vomiting Of Pregnancy. Obstet Gynecol 2018; 131:e15.
  3. Pregnancy week by week. (Last access 16.06.2022). 
  4. Pregnancy week by week. (Last access 16.06.2022).
  5. When Morning Sickness Doesn’t Go Away: Third Trimester Nausea. (Last access 18.07.2022).
  6. Dodds L, Fell DB, Joseph KS, et al. Outcomes of pregnancies complicated by hyperemesis gravidarum. Obstet Gynecol 2006; 107:285.
  7. Is nausea during pregnancy a good sign? (Last access 16.06.2022)
  8. Vomiting and morning sickness. (Last access 16.06.2022). 
  9. Morning sickness. (Last access 16.06.2022).