Nausea and vomiting are symptoms of pregnancy and affects most women in between 4-7 weeks of pregnancy. It usually resolves by 12-14 weeks but in some, it may last until 20 weeks. This condition is often called as ‘morning sickness’ but it can occur at any time of the day.
The causes of morning sickness is a complex interaction of many factors. Several theories that has been purposed are:
1.Physiological factors – hormonal changes
During pregnancy, the pregnancy hormone (hcG) will increase and this can cause pregnant women to feel nausea or vomiting.Other than that, the increase of gut hormone also contributes to the nausea and vomiting.
2. Psychological factors
Some expectant mothers cannot adapt to the physiological changes during pregnancy, or excessively worry about the growth of the fetus, leading to poor mental condition and emotional instability, thus causing nausea and vomiting.
3. Genetic
In many studies, data suggests that genetic plays a role in determining the severity of nausea and vomiting in pregnancy. Women who are born from pregnancy with severe nausea and vomiting had 3% chance of developing the same during their own pregnancy.
It is unclear why some women had worse than the others but it is more likely to happen if:
- You have had it before in previous pregnancies
- You are pregnant with more than one baby (twins or triplets)
- You have thyroid problem
- You have molar pregnancy (presence of pregnancy-like symptoms but there is no fetus seen during ultrasound)
It is also important to take into account other causes of nausea and vomiting which include gastritis (gastric), appendicitis or food poisoning if you started having thesymptoms after 10 weeks of pregnancy.
What is hyperemesis gravidarum?
When nausea and vomiting become severe which leads to dehydration and significant weight loss. In this case, you might experience persistent nausea and vomiting, weakness, dizziness, thirst, excessive salivation. You are advised to visit a doctor as this condition may need you to be admitted to a hospital.
Will it harm my baby?
There is no evidence that nausea and vomiting have harmful effects on the baby. In fact, studies have shown that women who had nausea and vomiting were less likely to have miscarriages.
However, in severe nausea and vomiting, you may have a baby with low birthweight. Doctor will monitor on the baby’s growth throughout the pregnancy if the nausea and vomiting persists.

What can I do to ease the symptoms?
You should:
- Eat in small amount often.
- Eat food that are high in carbohydrates and low in fat like potato, porridge, rice or pasta. You can also try plain biscuits or crackers.
- Avoid food that trigger the symptoms.
- Avoid caffeine and spicy food as they can cause heartburn which will worsen the morning sickness.
- Avoid smells that trigger symptoms.
Some women find eating or drinking ginger products helps but these may irritate your stomach.
If the symptoms persists, go to a doctor for anti-sickness medication. This medication is safe for pregnancy.
What if the symptoms persist despite these measures?
You must be assessed at a hospital and admission may be required if you cannot tolerate any fluid without vomiting.
What to expect during hospitalization?
You will be given drip through your arm until the you are hydrated. This will be continued until you are able to drink without vomiting. Each day, your fluid intake and urine will be measured to make sure you had enough intake.
You might also be offered anti-sickness medication through drip.
After discharge
You will be given anti-sickness tablets to take home. If you feel better, you can cut down the number of tablets. If your vomiting gets worse, stop eating but try to continue sipping fluids and take the anti-sickness tablets until you start to feel better. Ask your GP for a repeat prescription before your tablets run out.
Your symptoms may return and you may become dehydrated. If this happens, go to the hospital to be assessed again.
This can be a difficult situation for you and may affect you throughout your pregnancy. However, the symptoms usually resolve or improve after your baby is born.