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Nausea and vomiting

Some degree of nausea and vomiting affects most pregnant women starting from 4 – 7 weeks but often settles by 14-16 weeks. In most women symptoms are mild but some pregnant women have excessive nausea and vomiting. Excessive nausea and vomiting is known as hyperemesis gravidarum and treatment will need to be discussed with your GP.

Hyperemesis gravidarum is thought to be caused by pregnancy hormones , although it remains unclear why in some women symptoms are worse than others.

Most women have healthy pregnancies, however hyperemesis gravidarum is thought to be more likely if:

  1. You have had it in a previous pregnancy.
  2. You are having more than one baby (i.e. twins)
  3. You have a molar pregnancy. This is a rare condition and you will be advised on further management if there are any concerns with your pregnancy.

Excessive nausea and vomiting in pregnancy can be a difficult problem to cope with. If your mood is persistently low you should speak to a healthcare professional.

There is no evidence that hyperemesis gravidarum harms your baby but if it persists beyond 20 weeks you may be offered extra scans to check the growth of your baby.

Most women with nausea and vomiting can be managed at home with anti-sickness medication.You may need admission to hospital if you have significant amount of ketones in your urine which can indicate that you have severe dehydration. Likewise, if you are unable to keep any oral fluids down, you have abnormal blood tests or have any significant medical condition such as diabetes you may need to be treated in hospital.

Usual management in hospital includes:

  • Intravenous fluids (a drip in your arm)
  • Anti-sickness medicines
  • B vitamin called thiamine
  • Folic acid
  • Anti-embolic stockings

The most commonly used anti-sickness are cyclizine, metoclopramide and prochlorperazine which are considered to be safe in pregnancy. In severe cases that don’t respond to simple measures of fluids and anti-sickness drugs, steroids may be needed and this will be discussed with you by your doctor at the time. We sometimes need to use a stronger antisickness medicine called ondansetron. This is a very effective drug for most women, however has recently been shown to slightly increase the number of babies affected by cleft lip/palate with an extra 3 babies for every 10 000 women treated if used in the first trimester (up to the end of the first 12 weeks of pregnancy).

On discharge you will be given oral anti-sickness and if these become ineffective in the days to come you may need to see your GP.


Further sources of information