The spectrum of pregnancy sickness

Symptoms of pregnancy sickness vary dramatically from one person to the next. Mild pregnancy sickness is commonly known as ‘morning sickness’ and is characterised by bouts of nausea and occasional vomiting. At the other end of the spectrum is hyperemesis gravidarum (HG), a serious condition in which women can experience symptoms so severe that they need to be hospitalised for treatment. For most women the severity of the symptoms falls somewhere between the two extremes.

Scientists do not fully understand why some mums-to-be experience mild nausea while others develop HG, but there is evidence showing a link to genetics and hormones¹,². What we do know is that it has nothing to do with how different women cope with pregnancy, and nothing they have done (or not done) will cause pregnancy sickness.

What do we know about morning sickness?

While there is still a lot we don’t fully understand, here are some facts we do know:

• Around 70–80% of pregnant women will experience nausea and vomiting³. That means that while it’s normal to have some symptoms, it’s also normal not to have any.
• Pregnancy sickness is just as likely to strike after midday as it is before midday³.
• As long as you are still able to eat and drink normally, regular morning sickness won’t affect the health of you or your baby⁴.
• Even mild symptoms of nausea can make you feel miserable, particularly when they last for weeks and weeks.
• Pregnancy sickness and HG are not psychological conditions; they are physical illnesses. (Although moderate-to-severe pregnancy sickness can certainly take a toll on your mental health⁵,⁶!)

How long does morning sickness go on for?

At just six weeks pregnant, the 12-week milestone can feel an awfully long way off, but pregnancy sickness is usually limited to the first trimester. For most women, symptoms peak around weeks 9 to 11 and improve greatly between weeks 12 and 143. For some, pregnancy sickness goes on longer, until around 20 weeks, and acid reflux from the second trimester onwards can also cause nausea and vomiting.

If your symptoms are ongoing beyond 12 weeks, please see the information below about support and help for the more severe forms of pregnancy sickness and hyperemesis gravidarum.

Self-help for pregnancy sickness

When you feel sick day in and day out for weeks, you may be willing to try all sorts of things to help your symptoms – from aromatherapy to homeopathy. While it is unlikely that many of these alternative therapies are going to cause any harm, there is also little evidence that they help, and they can be very expensive.

UK charity Pregnancy Sickness Support offer evidence-based information on coping strategies and self-help. They say the best ways to manage pregnancy sickness are:

• Resting as much as possible. While it isn’t always easy, particularly if you have other children and perhaps work too, it’s important that you lie or sit down as often as you can when feeling sick.
• Keeping a symptom diary. Look for a pattern of symptom-free times of day and then aim to eat, drink and be active during these times. Although this doesn’t work at the far end of the spectrum where symptoms can be near-continuous, for regular ‘morning sickness’ most women will find their personal pattern if they keep a diary.
• Eating little and often. If you normally manage two slices of toast for breakfast, try half a slice every 15 minutes to spread it over an hour. This isn’t always practical if you’re working or busy, but with a bit of preparation, and perhaps a bag full of healthy snacks, it really can help.
• Avoiding spicy, oily or very sugary foods. These can often result in acid reflux, leading to an increase in nausea and vomiting.

We've also created a helpful video which includes tips on managing morning sickness throughout your day.

The main thing is to try to find what works for you. Don’t worry too much about what you’re eating and drinking (within current UK guidelines). For more tips and advice on eating with morning sickness, see the Pregnancy Sickness Support ‘Eating Advice’ page.

I think my symptoms are worse than normal. What should I do?

You should talk to your healthcare professional if you find you have any of the following symptoms as you may have HG and require medication:

• You are feeling very nauseous nearly all the time and it’s stopping you from eating and/or drinking
• You’ve lost more than five percent of your pre-pregnancy weight
• You are being sick more than three times a day for more than three days

If you are worried that your symptoms are worse than you were expecting, call the Pregnancy Sickness Support helpline on 024 7638 2020 or email support@pregnancysicknesssupport.org.uk for more information and guidance.