What helps reduce nausea in pregnancy?

Photo of a pregnant woman with nausea (PantherMedia / Wavebreakmedia ltd)

Common medications for nausea and vomiting are often used for this purpose in pregnancy too, as is ginger. But there is only little scientific research on their effectiveness in pregnant women.

Nausea and vomiting are common in early pregnancy: At least half of all women are affected by nausea in the first few months. It's often called morning sickness because it tends to be worse in the mornings, but it may last all through the day too. Although it can be difficult to deal with nausea and vomiting that lasts several weeks, these problems usually don't have any consequences for the mother and her child. In most cases they are even a sign that the unborn child is developing well.

It's not known why pregnancy is so often accompanied by nausea. Hormonal changes are believed to play an important role. It also isn't clear whether stress or psychological problems cause or worsen the symptoms.

Morning sickness typically starts between the sixth and eighth week of pregnancy and is gone by the end of 16 weeks. It lasts longer in some women, though. Nausea and vomiting become more of a problem if you feel extremely unwell and it becomes difficult to eat enough and follow a balanced diet. Severe nausea may also be a sign of other illnesses, such as gastroenteritis (stomach bugs), migraines, or gallbladder or pancreas disease.

About 1 out of 100 pregnant women experience an especially severe form of morning sickness with frequent and violent vomiting. This can lead to weight and fluid loss, which can also endanger the child. So it usually has to be treated at a hospital.

Which medication-free treatments can help?

Many women try to manage their nausea without using medication. Many react to triggers like certain smells and foods, stressful situations, heat or noise. It can help to pay attention to when you start feeling nauseous and whether triggers are identifiable, so they can be avoided.

Eating smaller meals more frequently throughout the day, drinking a lot of fluids and eating a low-fat diet are strategies that help some women. There is no good research testing different diets or changes in lifestyle to see whether they relieve nausea and vomiting in early pregnancy.

If women vomit a lot as a result of severe pregnancy-related nausea (hyperemesis gravidarum), they are given infusions (a drip) at the hospital to replace the fluids lost. They then typically stop eating solid foods for several days. There is hardly any research on whether a particular diet or other lifestyle changes could be effective against severe pregnancy-related nausea.

How effective are medications and herbal products?

Only very few studies have looked into the use of medication for nausea and vomiting in pregnancy. This is in part because hardly any clinical studies are done on pregnant women, as a precaution to prevent any harm to the child.

Common medications for nausea and vomiting include the following:

  • Dimenhydrinate: This drug is often used to treat nausea and vomiting. There has been little research on its effectiveness during pregnancy.
  • Metoclopramide: This drug stimulates the movement of the stomach and bowel, and is commonly used for nausea and vomiting. Whether or not it is also effective in pregnancy-related nausea hasn't been studied enough.
  • Vitamin B6: Can relieve nausea somewhat. It is not clear whether it prevents vomiting too.
  • Doxylamine: An older drug used to treat allergies (an antihistamine). Because it causes fatigue, it is mainly used as a sleeping pill. Studies have shown that – combined with other substances like vitamin B6 – it can relieve nausea and vomiting in pregnancy. These combinations are currently not available in Germany, though. Products that only contain doxylamine are available. There have been no studies on whether they too relieve the symptoms.
  • Promethazine: This drug is mainly used to treat restlessness and agitation, but it's also approved for the treatment of nausea and vomiting. Its effectiveness in pregnant women hasn't been tested well enough, though.

None of these medications have been explicitly approved for the treatment of nausea and vomiting in pregnancy, but they can be prescribed "off-label." It is then especially important to get professional advice about their effects, including possible side effects.

Herbal products containing ginger are an alternative. There is some evidence that certain ginger products can help relieve nausea in pregnant women. These include ginger capsules and ginger syrup (250 mg ginger per dose) that are taken three or four times a day. It's not clear whether drinking ginger tea or getting a lot of ginger in your diet helps.

There is no evidence that herbal products containing chamomile, raspberry leaves or peppermint relieve the symptoms.

Only a few studies have looked into how well some of the above-mentioned medicines can help against severe pregnancy-related nausea in particular. So it's difficult to say how effective they are. Herbal products like ginger haven't been tested in any studies.

How safe are medications and herbal products?

Some studies looked at whether drugs for nausea and vomiting increase the risk of miscarriages or malformations in children. To date there is no evidence for this, as long as the medications are taken only temporarily and as prescribed.

Depending on the product or medication in question, various side effects can occur. Ginger may cause heartburn, but it is usually well tolerated. Older antihistamines like doxylamine make people feel very tired, and sometimes drowsy or dizzy too. Metoclopramide affects the nervous system and might cause movement disorders. Because of this, in 2014 medications containing high doses of metoclopramide were taken off the market. Vitamin B6 is usually well tolerated.

How well do "alternative" treatments work?

Many pregnant women also try alternative or complementary medicine. Acupressure is commonly recommended, for example using acupressure wristbands that are supposed to apply gentle pressure to certain areas. Research on acupressure has produced conflicting results – some studies see an effect, others do not. There is no evidence that acupuncture helps. This is also the case for homeopathic remedies. There are no studies on the effects of alternative or complementary treatments for severe pregnancy-related nausea.