Treatment of Nausea and Vomiting during Pregnancy
Did you know that 90% of women experience nausea and vomiting during pregnancy?
Even though we call it ‘morning sickness’ the symptoms can occur at any time of the day. Around weeks eight or nine of pregnancy you may begin to experience these symptoms and it will typically subside after weeks twelve to fourteen. However pregnancy symptoms may continue beyond twenty weeks and in 10% of pregnancies they may continue up until birth.
It is believed that nausea and vomiting during pregnancy is likely due to hormonal changes. Women who had suffered from nausea and vomiting during previous pregnancies are more likely to experience these symptoms again in subsequent pregnancies. Women carrying twins often experience these symptoms much more severely.
Does my morning sickness affect my baby?
No, we can reassure you that mild to moderate vomiting doesn’t affect your developing baby. It has actually been associated with lower rates of miscarriage, stillbirth, premature birth, intrauterine growth restrictions and birth defects. However unrelenting nausea can also affect a woman’s capacity to carry out her normal everyday tasks.
In less than one percent of pregnancies women experience a more severe form of nausea and vomiting. We call this Hyperemesis gravidarum and it often requires hospitalisation. It is characterised by dehydration, maternal weight loss (greater than five per cent) and electrolyte imbalance.
So how do we manage morning sickness?
Commonly practiced interventions
- Herbal teas (ginger or peppermint)
- It sounds obvious but try to eat at times when you are feeling less nauseous
- Eat small amounts of food often
- Avoid spicy or fatty foods
- Keep dry crackers and water with you (eat before getting up in the morning)
- Have food and drink at separate times
- Do not brush teeth straight after eating
- Drink small amounts of fluids often (approx. two litres a day)
- Identify and avoid known triggers
- Rest when possible because fatigue makes nausea worse
Drug treatments – current guidelines
- Pyridoxine – 25-50 mg orally, four times a day.
If symptoms persist continue Pyridoxine and add one of the following:
- Doxylamine – 12.5-25mg orally, 3-4 times daily
- Promethazine – 10-25mg orally, 3 times daily
- Metoclopramide – 10mg orally, 3-4 times daily
If symptoms still persist continue Pyridoxine with a different antiemetic from the three above. If after this there is still no satisfactory result, try
- Ondanestron tablet or wafer 4-8mg, 2-3 times a day.
Patients unable to tolerate wafers or tablets can use one of the following
- Metoclopramide – 10mg intramuscular/intravenous, every eight hours (most commonly prescribed however in many cases it has been found to be ineffective for treating nausea and vomiting)
- Ondansetron – 4-8mg intravenous, every eight to twelve hours (often prescribed for women with hyperemesis gravidarum but it is not recommended in the first trimester of pregnancy). It can cause constipation so use laxatives sparingly.
- Prochlorperazine – 25mg rectally, once or twice daily
- Prochloperazine – 12.5mg intramuscular, every eight hours
- Promethazine – 12.5-25mg intramuscular, every four to six hours
If vomiting persists, consider treatment in hospital with rehydration through intravenous fluids.
- Prednisolone – 50mg orally daily for three days, then 25mg daily and then reduce it to 5mg daily.
Other treatments such as antacids, ranitidine and proton pump inhibitors are often used to treat acid reflux and bloating.
Obstetric drug information services in Western Australia
- Women and children’s Health Services (Perth) – (08) 93402723
The important thing to note is that nausea and vomiting in pregnancy is very common. There is a wide range of interventions and treatments however dietary and lifestyle treatments should be implemented first. Pharmacological treatments should not be ruled out due to a fear of hurting the baby.