Morning Sickness During Pregnancy: Why It Happens and What May Help

A pregnant woman sitting on a sofa and drinking a glass of water.

If morning sickness has taken over more than just your mornings, you’re probably wondering why it happens—and what might help.

If you're reading this with crackers and ginger chews within reach, you already know the standard advice for morning sickness. Eat small meals, try ginger, and wait for the second trimester.

What most of us were never told is why morning sickness happens. The science has changed a lot in the last few years, and it points to a bigger picture involving a hormone from your baby, your gut, your nutrients, and your support system.

In this article, you'll learn what's really behind pregnancy nausea, why some people get hit so much harder, and which gentle strategies are worth trying.

This article provides general information. Talk with your prenatal care provider about pregnancy symptoms and before starting or changing supplements or medications.

Why "Morning Sickness" Is Misleading: Pregnancy Nausea Often Lasts All Day

For most people, morning sickness is not limited to mornings at all.

About 70% of pregnancies involve some degree of nausea and vomiting (1).
In a study where women tracked their symptoms daily, only 1.8% had nausea just in the morning, while 80% had it all day (2).
Only half felt relief by 14 weeks, and 90% by week 22 (2).
The nausea was similar in intensity to the nausea caused by chemotherapy (2).

If your nausea feels bigger than the word "morning sickness" suggests, the research agrees with you.

You might like this article, too: Preconception Supplements for a Healthy Pregnancy

What Causes Morning Sickness? The GDF15 Hormone Discovery

The biggest breakthrough in years centers on a hormone called GDF15, which acts on the part of the brain that controls nausea and vomiting (1). A genetic study first linked GDF15 to severe pregnancy nausea in 2018 (3).

Then a 2024 study in Nature found that (1):

Most of the GDF15 in your blood during pregnancy comes from the baby and placenta.
Higher levels are linked to more vomiting and to hyperemesis gravidarum, the severe form.
Low GDF15 before pregnancy raises the risk of severe nausea, while women with beta-thalassemia, who naturally have high GDF15, report very little nausea.

In short, how sick you feel often depends on how much GDF15 your pregnancy makes and how sensitive your body is to it (1). Severe nausea has a real, measurable biological basis, and it is not simply "all in your head."

You might like this article, too: Caffeine Consumption During Pregnancy and Lactation

Is Morning Sickness Protective? Food Aversions and Pregnancy Outcomes

Some evolutionary biologists believe pregnancy nausea may help protect both you and your baby.

Nausea often occurs during early pregnancy, when a baby's developing organs are particularly sensitive to harmful substances (4).
The strongest aversions are often to meat, fish, poultry, and eggs, foods that commonly carried pathogens before refrigeration (4).
In a study of women with one or two prior losses, nausea was associated with approximately a 50% lower risk of pregnancy loss, and nausea with vomiting with approximately a 75% lower risk (5).

These findings support the idea that pregnancy nausea and food aversions may be part of an evolutionary protective response. However, researchers have not established that nausea itself prevents pregnancy complications.

Many people have healthy pregnancies with little or no nausea. And if you have experienced a loss, the presence or absence of nausea does not mean you did anything to cause it.

You might like this article, too: Why Do You Wake Up Hungry at Night? Possible Reasons and What to Do

Small snack of yogurt, granola, and fresh fruit.

The Gut Connection: Why Protein May Help Pregnancy Nausea

Pregnancy hormones, mainly progesterone, can change the way your digestive system moves (6).

Your stomach normally runs on a steady rhythm of about three waves per minute. In one study, pregnant women whose rhythm was too fast or too slow had nausea, while those with a normal rhythm had almost none (7).
That rhythm tends to get more disrupted on an empty stomach (8).
In a small study, protein-rich meals eased nausea more than carb-heavy or fat-heavy meals with the same calories (8).

Crackers still have their place, but research suggests that pairing them with a little protein may work better.

You might like this article, too: Dr. Green Mom’s Guide to Healthy Eating During Pregnancy

Prenatal Vitamins, Iron, and Vitamin B6 for Morning Sickness

Nutrient intake before and during early pregnancy can make a difference.

Start early. ACOG notes that taking a prenatal vitamin for one month before conception may reduce how often and how severely nausea happens (9). An earlier study also linked skipping a multivitamin before six weeks of pregnancy to more vomiting (10).
Make your prenatal vitamins easier to take. If your prenatal is hard to get down on queasy days, try taking it with a snack or at the time of day you feel best.
The form of iron matters. Some forms of iron are easier on the digestive system than others. Iron bisglycinate, for example, is often better tolerated and may cause fewer digestive side effects, such as nausea and constipation, than traditional forms of iron. Choosing a prenatal with a gentle, well-tolerated form of iron can make a difference, especially when you're already dealing with morning sickness (11).
Ask about B6 and ginger. ACOG recommends vitamin B6, alone or with doxylamine, as a first-line treatment and considers ginger a reasonable option (9).

To learn more, read this article: A Guide to Iron Supplementation

The Emotional Side of Morning Sickness

Weeks of nausea take a real toll on mood.

More severe nausea is linked to symptoms of depression, while having support from three or more people is associated with fewer symptoms (12).
Women with hyperemesis gravidarum have significantly higher depression and anxiety scores (13).
ACOG notes that pregnancy nausea is often minimized and undertreated, and that your own sense of how bad it feels should guide treatment (9).

Accept help with cooking and errands, and tell your provider if you feel persistently low or anxious.

You might like this article, too: What Is Postnatal Depletion Syndrome?

A man prepares his pregnant wife a healthy meal.

Hyperemesis Gravidarum: When It's More Than Morning Sickness

Over one-third of people with pregnancy nausea have symptoms that may need fluids, vitamins, or medication (14). The most severe form, hyperemesis gravidarum (HG), is a leading reason for hospitalization during pregnancy (15).

Contact your healthcare provider if you notice any of these warning signs:

You can't keep liquids down for most of the day.
You notice signs of dehydration, like dark urine, very little urine, or dizziness when standing.
You're losing weight or can't eat enough to function.
You're vomiting blood, or you have belly pain or a fever.
Your nausea started for the first time after nine weeks of pregnancy (9).

Severe dehydration, vomiting blood, or significant abdominal pain warrants urgent medical attention.

Medication or IV fluids, when you need them, can absolutely be part of a holistic approach.

A pregnant patient talking with a healthcare provider during an office visit

Natural Ways to Ease Morning Sickness

Here are the simplest science-informed steps to try.

Don't let your stomach get empty. Stomach rhythms can become more disrupted when you're fasting, so try keeping a snack by your bed (8).

Add protein. Pair crackers with cheese, nut butter, or egg (8).

Sip when you can't chew. Try smoothies or other nourishing drinks when solid food feels difficult. One small study found that liquid meals improved stomach rhythm patterns, although they did not relieve nausea more effectively than solid meals (8).

Choose foods you can tolerate. Mild, low-odor foods may be easier to manage on queasy days.

Stay consistent with your prenatal, as much as possible. Take it at the time of day you feel best, ideally with a little food. If it consistently makes you sick, ask your provider about alternatives.

Ask about B6 and ginger. Both are recognized options for pregnancy nausea (9).

Let people help. Strong social support is associated with fewer nausea symptoms (12).

You might like this article, too: What to Look For in a Prenatal Vitamin

Summary

Morning sickness rarely sticks to mornings (2), and research has identified an important biological driver: a hormone from your baby and placenta called GDF15, combined with how sensitive your body is to it (1). Those sudden food aversions may even be part of an evolutionary protective response, although that theory is still being studied (4)

The most helpful steps can be simple. Don't let your stomach get empty, add protein when you can (8), talk to your provider about starting a prenatal before conception (9), and lean on the people around you (12). If you can't keep fluids down or feel dizzy and dehydrated, seek medical care promptly.

Be gentle with yourself this season, because small, steady nourishment and a good support team can go a long way.