What causes morning sickness in early pregnancy

Morning sickness is probably caused by pregnancy hormones. The levels of hCG (human chorionic gonadotropin) hormone in your body rises quickly during the first few weeks of pregnancy. 

Pregnancy sickness is often at its worst when you first wake up, which is why it’s called morning sickness. However, feeling sick or being sick (vomiting) can happen at any time of day during pregnancy.

Morning sickness is usually worse during the first 12 weeks (first trimester). It usually clears up by weeks 16 to 20 of your pregnancy, although it can go on for longer for some people. 

Morning sickness does not put your baby at any increased risk. 

Some people worry because they don’t have morning sickness. They may think that their pregnancy is somehow not strong enough or that they are more likely to miscarry. This is not true.  

Pregnancy symptoms are different for everyone. Not everyone will feel sick or vomit. 

“During my first viable pregnancy, one month after a 12-week miscarriage, I experienced no sickness at all. This made me always worry I was going to miscarry again. Thankfully it did not happen, and I have a very healthy and active 18 month old now! My second viable pregnancy was completely the opposite and I still get waves of nausea at 37 weeks.”

Kristina

How can I manage morning sickness? 

Unfortunately, there is no magic cure for morning sickness. But there are some things that many people have found helpful. You could try:

• eating little and often – eating 6 small meals a day instead of 3 big meals
• resting – pregnancy sickness may feel worse when you’re tired, so try to rest if you’re not feeling well
• avoiding foods with lots of sugar or saturated fats – this includes sweets, chocolate and red meat
• eating carbohydrates – things like bread, rice, potatoes and pasta can be easier to eat when you’re feeling nauseous
• keeping away from sickness ‘triggers’ – you may find that eating or even smelling certain food makes you feel sick 
• having a small snack before getting up in the morning – something like dry toast, crackers or a plain biscuit is great for lining your stomach before you begin your day
• having foods or drinks that have ginger in them – there is some evidence that things like ginger biscuits, crystallised ginger or ginger tea can help you feel a little less queasy 
• wearing plastic acupressure bands throughout the day – these are available in most pharmacies and have a plastic button that presses on the acupressure point on the wrist, which may help reduce your nausea.

“I felt sick for most of my pregnancy, which was tough. I had some obvious triggers, like the smell of mincemeat, that were easy to avoid. But finding something to ease the nausea was a bit more trial and error. Strangely, eating helped, so I avoided big meals and ate small amounts throughout the day instead.”

Alison

What should I do if I get morning sickness at work?

Having morning sickness during work hours can be challenging, especially if you’re not ready to tell anyone about your pregnancy. 

Some people decide to tell their employer about their pregnancy earlier than planned because symptoms like morning sickness may be too difficult to hide. Although this may not have been when you wanted to share the news, it does mean that your employer can now help you. 

All employers must do a risk assessment with you to see if your job poses any risks to you or your baby. If there are any risks, they must make reasonable adjustments to remove them. This can include changing your work hours.

For example, you could ask about working slightly different hours to avoid times when you feel worse. Or you could ask about working from home on days when the morning sickness is bad.

Once your employer knows you’re pregnant, you’re protected against unfavourable treatment because of pregnancy-related discrimination. Your employer must record any pregnancy-related sickness separately so that it isn’t used against you in any disciplinary, redundancy or dismissal decisions. 

Find out more about pregnancy and work.

Hyperemesis gravidarum

Sometimes, pregnancy sickness is severe. You may be sick several times a day and be unable to keep food or drink down. This is known as hyperemesis gravidarum (HG) and often needs hospital treatment. 

HG is thought to affect around 1 to 3 in every 100 pregnancies. 

Causes of hyperemesis gravidarum

No one knows exactly what causes HG, although some experts believe it’s due to pregnancy hormones. There is some evidence that you are more likely to experience HG if:

• you have a mother or sister who has had it
• you have suffered with HG in a previous pregnancy.  

Symptoms of hyperemesis gravidarum

HG causes extreme nausea and sickness and weight loss. You may also be dehydrated, which can cause:

• thirst
• tiredness
• not weeing very much
• dark yellow and strong-smelling wee.  

You may also have low blood pressure (hypotension) when standing. Symptoms include:

• lightheadness or dizziness
• blurred vision
• generally feeling weak 
• fainting.

Some pregnant people have also experienced: 

• changes to their sense of smell
• producing more saliva 
• headaches and constipation (from dehydration).

If you’re being sick a lot or can’t keep your food or drink down, tell your midwife, doctor or contact your local maternity unit as soon as possible. They can make sure you get the right treatment so you don’t get dehydrated.

Treating hyperemesis gravidarum 

There are several medicines that are safe to use in pregnancy, including anti-sickness drugs (anti-emetics), vitamins B6 and B12, steroids or a combination of these. Do not take any medication for HG without speaking to a midwife or doctor first. 

You may need to go into hospital for treatment if your sickness is severe and it can’t be controlled. Your doctor will assess your condition and work out the best way to manage it for you and your baby. If needed, they can give you fluid and medicines directly into a vein (intravenously) to help you stay hydrated.  

Hyperemesis gravidarum and blood clots

Because HG can cause dehydration, there's also an increased risk of having a blood clot (deep vein thrombosis), although this is rare.  

There is treatment to prevent blood clots if you are dehydrated and are not able to move around. 

Will hyperemesis gravidarum harm my baby?

It’s unlikely that having HG will harm your baby if you receive the right treatment. However, if it causes you to lose weight during pregnancy, there is an increased risk that your baby may be born smaller than expected (have a low birthweight). 

Manage symptoms of hyperemesis gravidarum

Having HG can affect you both physically and emotionally. You may feel that it takes away any enjoyment of being pregnant, when you expected to feel happy. 

Having severe sickness can be exhausting and hard to cope with. You may feel isolated if you have to stay at home, or anxious about how long you will feel bad for. These feelings can make it hard to manage your mental health and could lead to more serious issues such as anxiety and depression. 

Talk to your midwife or doctor if you are struggling to cope with either your symptoms or your feelings. They will understand and won’t judge you.

Pregnancy can be a very emotional experience and mental health difficulties are very common during pregnancy. 

Your healthcare professional will talk to you about how you feel so they help you find the right treatment and support.

More information and support

• Pregnancy Sickness Support is a charity who have tips to help you cope with morning sickness and HG.
• Hyperemesis Gravidarum (HG) Support by HER Foundation have a private Facebook group you can join. 

What causes morning nausea in early pregnancy?

How can I stop morning sickness in early pregnancy?