Morning Sickness

Morning sickness affects up to 70% of pregnant women, causing nausea and vomiting that can strike at any time of day—not just in the morning. While this common condition is usually harmless to both mother and baby, understanding its causes and knowing how to manage it can make the journey through pregnancy much more comfortable.

Table of contents

• What is morning sickness?
• Signs and symptoms
• What causes morning sickness?
• When does it start and how long does it last?
• Who is more likely to experience morning sickness?
• Is morning sickness harmful to the baby?
• Severe morning sickness: Hyperemesis gravidarum
• Managing morning sickness through diet
• Lifestyle changes that help
• Medical treatments
• When to contact your healthcare provider

What is morning sickness?

Morning sickness is the term used to describe nausea and vomiting during pregnancy. Despite its name, this condition can occur at any time of the day or night. Some women experience symptoms only in the morning, while others feel sick throughout the entire day^[1][2].

This is an extremely common condition. Around half to two-thirds of all pregnant women will experience morning sickness to some degree, with approximately 70% of women in the first trimester (the first three months of pregnancy) being affected^[2][3]. At least 7 in 10 pregnant women have morning sickness in early pregnancy^[5].

In most cases, morning sickness doesn’t harm the woman or the unborn child. It may even be a sign that all is well with the pregnancy, as it can be associated with a lower risk of miscarriage. The symptoms probably show that the placenta (the organ that supplies the baby with food and oxygen) is making all the right hormones for the growing baby^[3][14].

Signs and symptoms

Common signs and symptoms of morning sickness include an upset stomach (nausea), loss of appetite, and vomiting^[1][2]. Some women describe the feeling as similar to heartburn or reflux, seasickness or motion sickness, or as if something is stuck in their throat. Others experience what feels like hunger pangs^[2].

Morning sickness is often brought on by smelling certain odors or eating certain foods^[1]. The symptoms can also include psychological effects, such as depression and anxiety, especially when the nausea and vomiting are unrelenting and affect daily life^[3].

What causes morning sickness?

The exact cause of morning sickness remains a mystery, but healthcare providers believe it’s a mix of physical and chemical changes that pregnancy triggers^[2][3].

Several factors are thought to play a significant role, including:

• High levels of hormones, including estrogen (a female sex hormone) and pregnancy hormones like human chorionic gonadotropin or HCG (a hormone produced during pregnancy)
• Low blood sugar levels
• Blood pressure fluctuations, particularly lowered blood pressure
• Changes in metabolism (how the body processes food and nutrients)
• Altered metabolism of carbohydrates (sugars and starches)

Recent research has provided new insights into what causes morning sickness. A study published in the journal Nature found that a hormone called GDF15, produced by the fetus and placenta, is a key cause behind nausea and vomiting of pregnancy. Women who are exposed to lower levels of GDF15 before pregnancy tend to experience more severe symptoms when they become pregnant and are suddenly exposed to higher levels of the hormone^[4].

Morning sickness may be worsened by stress and anxiety, being overtired, eating or smelling certain foods, motion sickness, and heat or warm weather^[2].

When does it start and how long does it last?

Morning sickness typically starts early in pregnancy. It can begin as early as the fourth to sixth week of pregnancy, but most women experience signs of morning sickness before nine weeks of pregnancy^[2][3][5].

The symptoms usually peak (feel the worst) around eight to 10 weeks of pregnancy, although this timing varies from woman to woman^[2].

For most women, morning sickness improves or goes away by weeks 12 to 16 of pregnancy (around the end of the first trimester or beginning of the second trimester). However, about one in five women endures morning sickness into their second trimester. Some women experience lingering symptoms through the beginning of the second trimester (weeks 14 to 27), and an unfortunate few experience nausea and vomiting for the entire duration of their pregnancy^[2][3][5].

Who is more likely to experience morning sickness?

While morning sickness can affect any pregnant woman, certain factors may increase the risk or severity of symptoms:

• Being pregnant for the first time
• Being pregnant with twins, triplets, or more (multiple pregnancy). Being pregnant with more than one baby may increase the risk because there may be a larger placenta and increased pregnancy hormones^[5]
• Having had mild or severe morning sickness in a previous pregnancy
• Having a mother or sister who had severe morning sickness during pregnancy
• Having a history of motion sickness or migraine headaches (severe headaches that may make you sensitive to bright lights and sound)
• Being overweight or obese (having a body mass index or BMI of 30 or more)
• Having used contraceptives containing estrogen that caused nausea
• Being pregnant with a female fetus^[5][7][10]

Is morning sickness harmful to the baby?

In most cases, morning sickness doesn’t harm the woman or the unborn child^[3][6]. The baby is perfectly cushioned inside its sac of amniotic fluid (the fluid that surrounds and protects the baby in the womb). While vomiting and retching may strain the abdominal muscles and cause localized aching and soreness, the physical mechanics of vomiting won’t harm the baby^[3].

Mild morning sickness that doesn’t cause significant weight loss is not harmful to the baby. Mild weight loss during the first trimester is not uncommon when women have moderate symptoms, and is not harmful to the baby^[6].

However, severe morning sickness that includes significant weight loss and dehydration (not having enough water in the body) needs prompt medical attention, as it can pose risks to both mother and baby^[3].

Severe morning sickness: Hyperemesis gravidarum

Hyperemesis gravidarum is the term for the most severe form of nausea and vomiting during pregnancy. This condition affects up to 3 in 100 pregnant women (less than 1% to 3% of pregnancies)^[2][5][10].

Hyperemesis gravidarum is diagnosed when a woman has lost 5% or more of her pre-pregnancy body weight and has other problems related to dehydration. It can cause serious fluid loss and lack of enough nutrients from the diet (malnutrition)^[7][10].

Symptoms of hyperemesis gravidarum include:

• Vomiting more than three to four times a day
• Nausea that lasts several hours each day
• Becoming severely dehydrated, with signs including little to no urine production, dark-colored urine, and dizziness or faintness when standing up
• Losing 10 pounds (around 4.5 kilograms) or more
• Rapid or pounding heartbeat^[1][2][10]

Women with hyperemesis gravidarum need treatment, sometimes in a hospital, to stop the vomiting and restore body fluids. Treatment may include receiving fluids through a vein (IV fluids) to restore hydration, and medications to relieve nausea. Rarely, continuing weight loss might lead to the need for a feeding tube^[2][8].

Managing morning sickness through diet

Making small changes to your diet can go a long way in decreasing nausea^[2]. Here are some dietary strategies that may help:

What to eat:

• Eat bland, easy-to-digest foods such as bananas, white rice, applesauce, and toast. These foods don’t have an overwhelming flavor, so they’re less likely to upset your stomach^[6][13]
• Choose high-protein foods like chicken, peanut butter, beans, nuts, cheese, milk, cottage cheese, and yogurt. Protein-rich foods can help with nausea by increasing a hormone called gastrin, which aids digestion^[6][13]
• Eat high-carbohydrate foods such as bread, rice, crackers, and pasta^[7]
• Try cold foods or beverages like smoothies, almond milk, or cold sandwiches rather than hot meals if the smell of hot food makes you feel sick^[7][13]
• Eat fruits and vegetables high in water content, such as watermelon and cucumbers^[13]
• Foods or drinks containing ginger may help. Some evidence suggests ginger may help reduce nausea and vomiting. Try ginger tea, ginger candy, or ginger ale (check to see that they actually contain ginger rather than just ginger flavoring)^[7][8]
• Citrus fruits and peppermint may also provide relief^[13]

When and how to eat:

• Eat a few crackers, dry toast, or dry cereal in the morning to help settle your stomach. Keep a few crackers next to your bed and eat a couple before getting up^[2][6]
• Have a small snack at bedtime and when getting up to go to the bathroom at night^[2]
• Eat several small meals throughout the day (around 5-6 snack-sized meals) instead of three large meals. Avoid large meals, and instead snack as often as every 1 to 2 hours during the day. Try to eat before you get hungry and before nausea occurs^[2][6]
• Don’t let yourself get too hungry or too full^[2]

What to drink:

• Drink plenty of fluids, such as water. Sipping them little and often may help prevent vomiting^[7]
• Try to drink between meals rather than with meals so that your stomach does not get too full^[2]
• Seltzer, ginger ale, or other sparkling waters may help control symptoms^[2]
• Try herbal teas and broth^[13]
• Suck on ice cubes made from juice or water, or ice lollies^[7]

What to avoid:

• Avoid foods that are high in fat and low in nutrition^[2]
• Avoid foods or smells that make you feel sick^[7]
• Foods with strong smells, onions, garlic, spicy foods, and acidic fruits may trigger nausea^[2]

Lifestyle changes that help

Beyond dietary changes, several lifestyle adjustments can help reduce morning sickness symptoms:

Rest and stress management:

• Get plenty of rest. Tiredness can make nausea worse^[7]
• Keep your morning activities slow and calm. Give yourself a few extra minutes to wake up at a leisurely pace^[2]
• Lessen stress as much as possible. Remember to get enough sleep and keep your stress level in check with meditation or prenatal yoga^[13]

Environmental adjustments:

• Avoid poorly ventilated spaces that trap food odors or other smells^[2]
• Avoid smoking cigarettes or being in areas where people are smoking^[2]
• Keep air flowing through rooms to reduce odors^[1]
• Dress in loose clothing made of breathable fabrics to stay comfortable^[22]
• Check your screen brightness settings and turn on nighttime mode on devices, as bright or flashing lights can trigger nausea^[22]

Alternative therapies:

• Try acupressure. There’s some evidence that putting pressure on your wrist, using a special band or bracelet on your forearm, or by pressing with your fingers may help relieve symptoms. These acupressure wristbands can be found in drug stores, health food stores, and travel stores^[1][7]
• Acupuncture at acupoint P6 has been used with varying degrees of effectiveness. If you’re thinking about trying acupuncture, talk to your healthcare provider and look for an acupuncturist who is trained to work with pregnant women^[1][8]

Vitamin adjustments:

• Take your prenatal vitamins at night with a little food rather than on an empty stomach, since the iron they contain may irritate your stomach. At night, you might be able to sleep through any discomfort^[1][14]
• You may have to try several different brands of prenatal vitamins before finding one you can tolerate. You can also try cutting your prenatal vitamins in half—take half in the morning and the other half at night^[14]
• Increase vitamin B6 in your diet by eating whole grains, nuts, seeds, peas, beans, salmon, and avocados^[1][13]

Medical treatments

If lifestyle and dietary changes don’t provide enough relief, your healthcare provider may recommend medications to help manage morning sickness.

Over-the-counter and prescription treatments:

• Vitamin B6 supplements (also called pyridoxine), at 100 mg or less daily, have been shown to ease symptoms of morning sickness. Many healthcare providers recommend trying this first before trying other medicines^[8][14]
• A delayed-release combination of doxylamine (an antihistamine) and vitamin B6 is available. In Canada, this is sold as Diclectin; in the United States, a similar product called Diclegis has been approved by the FDA for treating morning sickness^[8][12][14]
• Antihistamines, which are usually used to treat allergies, also work as anti-sickness medicines. These will usually be given as tablets^[7]
• Other anti-sickness medicines (called antiemetics) that may be prescribed include phenothiazines, metoclopramide, and ondansetron^[8][12]
• For severe morning sickness (hyperemesis gravidarum), your doctor may suggest an injection or a type of medicine that’s inserted into your bottom (suppository)^[7]
• In severe cases, corticosteroids may be used^[12]

Hospital treatment:

Vomiting during pregnancy may cause dehydration and an imbalance of electrolytes (minerals in the body like sodium or potassium). For moderate to severe morning sickness, extra fluids and prescription medicine are recommended. If you have hyperemesis gravidarum, you may be given fluids through a vein (IV fluids) and anti-nausea medicine in a hospital^[8].

It’s important to check with your healthcare provider before taking any medicine or supplements during pregnancy^[8].

When to contact your healthcare provider

While morning sickness is usually not harmful, there are times when you should contact your healthcare provider. Call your midwife, doctor, or healthcare provider if^[1][6][7]:

• You produce no urine or only a little urine that’s dark in color, or have not had a pee in more than 8 hours
• You are unable to keep food or fluids down for 24 hours
• You feel very weak, dizzy, or faint when you stand up
• You have tummy (abdominal) pain
• You have a high temperature (fever)
• You vomit blood or material that looks like coffee grounds
• You have lost weight or have excessive weight loss
• You have a racing or pounding heartbeat
• Your nausea and vomiting continue beyond your 4th month of pregnancy (although this happens to some women and is often normal, you should have it checked out)
• Your morning sickness does not improve despite trying home remedies
• You vomit more than 3 times per day

Your healthcare provider will do a physical examination and may order urine or blood tests to check for dehydration or other complications^[2][6][8].

Remember, while morning sickness can be challenging and uncomfortable, it’s a common part of pregnancy for many women. With the right strategies and support from your healthcare team, you can find relief and focus on the exciting journey ahead.