“Morning sickness” is a misnomer. For some pregnant women, the symptoms are worse in the morning and ease up over the course of the day, but they can strike at any time and, for many women, last all day long. The intensity of symptoms can also vary from woman to woman too.

The medical term for morning sickness is “nausea and vomiting of pregnancy.” Up to three quarters of pregnant women have at least some nausea or vomiting during the first trimester, and about half have only vomiting. The nausea usually starts around 6 weeks of pregnancy, but it can begin as early as 4 weeks. It tends to get worse over the next month or so.

About half of the women who get nausea during pregnancy feel complete relief around 14 weeks. For most others, it takes another month or so for the queasiness to ease up, though it may return later and come and go throughout pregnancy. A small percentage of women have symptoms that persist continually (or nearly so) until delivery.

What causes nausea and vomiting during pregnancy?

No one knows for sure what causes nausea during pregnancy, but it’s probably some combination of the many physical changes taking place in your body. Some possible causes include:

• Human chorionic gonadotropin (hCG).This hormone rises rapidly during early pregnancy. No one knows how hCG contributes to nausea, but it’s a prime suspect because the timing is right: Nausea tends to peak around the same time as levels of hCG. What’s more, conditions in which women have higher levels of hCG, such as carrying multiples, are associated with higher rates of nausea and vomiting.
• Another hormone which rises rapidly in early pregnancy, estrogen is also a possible cause (along with other hormones as well).
• An enhanced sense of smell and sensitivity to odors.It’s not uncommon for a newly pregnant woman to feel overwhelmed by the smell of a bologna sandwich from four cubicles away, for example. Certain aromas instantly trigger the gag reflex. (Some researchers think this may be a result of higher levels of estrogen, but no one knows for sure.)
• A sensitive stomach.Some women’s gastrointestinal tracts are simply more sensitive to the changes of early pregnancy. Also, some research suggests that women with a stomach bacterium called Helicobacter pyloriare more likely to have nausea and vomiting. Not all studies confirm this link, though.
• Some researchers have proposed that certain women are psychologically predisposed to having nausea and vomiting during pregnancy as an abnormal response to stress. However, there’s no conclusive evidence to support this theory. (Of course, if you’re constantly nauseated or vomiting a lot, you certainly may begin to feel more stressed!)

Are some pregnant women more likely than others to feel queasy?

You’re more likely to have nausea or vomiting during your pregnancy if any of the following apply:

• You’re pregnant with twins or higher multiples. This may be from the higher levels of hCG, estrogen, or other hormones in your system. You’re also more likely to have a more severe case than average. On the other hand, it’s not a definite thing – some women carrying twins have little or no nausea.
• You had nausea and vomiting in a previous pregnancy.
• You have a history of nausea or vomiting as a side effect of taking birth control pills. This is probably related to your body’s response to estrogen.
• You have a history of motion sickness.
• You have a genetic predisposition to nausea during pregnancy. If your mother or sisters had severe morning sickness, there’s a higher chance you will, too.
• You have a history of migraine headaches.
• You’re carrying a girl. Multiple studies have found that about 55 percent of women with severe nausea and vomiting in the first trimester give birth to a girl.

Will my nausea affect my baby?

Mild to moderate nausea and occasional vomiting from morning sickness won’t threaten your baby’s well-being. If you don’t gain any weight in the first trimester, it’s generally not a problem as long as you’re able to stay hydrated and can keep some food down. In most cases, your appetite will return soon enough and you’ll start gaining weight.

If I don’t have morning sickness, does that mean I’m more likely to have a miscarriage?

Not necessarily. It’s true that a number of studies have shown that women who have miscarriages are less likely to have had nausea. (If your baby or your placenta was not developing properly, you’d have lower levels of pregnancy hormones in your system. So if that’s what causes nausea, it follows that you’d have less.)

But there are plenty of women with perfectly normal pregnancies who have little or no nausea during their first trimester. Count yourself lucky and don’t worry if you’re not suffering!

What can I do to get relief?

If you have a mild case of nausea and vomiting, some relatively simple measures may be enough to help. (If not, safe and effective medications might help settle your stomach.)

Eat small, frequent meals and snacks throughout the day so your stomach is never empty. High-protein foods and complex carbohydrates might be especially helpful. Whatever you eat, eat it slowly.

• Avoid lying down after eating (especially on your left side) because this can slow digestion.
• Try to avoid foods and smells that trigger your nausea. If that seems like almost everything, it’s okay to eat the few things that do appeal to you for this part of your pregnancy, even if they don’t add up to a perfectly balanced diet.
• Try to eat food cold or at room temperature because food tends to have a stronger aroma when it’s hot.
• Avoid fatty foods, which take longer to digest. Also steer clear of spicy, acidic, and fried foods, which can irritate your digestive system. It might help to stick to bland foods.
• Brush your teeth and rinse your mouth after eating.
• Try drinking fluids mostly between meals. You might find cold, carbonated beverages easiest to keep down. (Some women also find sour drinks, such as lemonade, easier to handle.)If you’ve been vomiting a lot, try a sports drink that contains glucose, salt, and potassium to replace lost electrolytes. (The color of your urine indicates whether you’re getting enough fluids: It should be clear or pale yellow. If it’s dark yellow, that’s a sign you need to drink more.)
• Don’t drink so much at one time that your stomach feels full because that will make you less hungry for food. A good strategy is to sip fluids throughout the day. Try using a straw if sipping isn’t going well.
• Be aware of nonfood triggers too: A warm or stuffy room, the smell of heavy perfume, a car ride, or even certain visual stimuli, like flickering lights, might trigger your nausea. So might changing positions too quickly. Avoiding such triggers can become an important part of your treatment.
• Get fresh air. Taking a walk or opening a window might ease your nausea.
• Nausea can become worse if you’re tired, so give yourself time to relax and take naps when you can. Watching a TV show (preferably not one about food!) or visiting with a friend can help relieve stress and take your mind off your discomfort.
• Try hypnosis. Although there’s no definitive evidence that it helps with morning sickness, it has been shown to be effective in combating nausea during chemotherapy.
• Try taking your prenatal vitaminswith food or just before bed. You might also want to ask your healthcare provider whether you can switch to a prenatal vitamin with a low dose of iron or no iron for the first trimester because this mineral can be hard on your digestive system. If the prenatal vitamin still makes you nauseated, ask if you can stop taking it until your nausea gets better, but ask your doctor about taking a folic acid supplement to reduce the risk of neural tube defects.

• Try ginger, an alternative remedy thought to settle the stomach and relieve queasiness. See if you can find ginger ale made with real ginger. (Most supermarket ginger ales aren’t.) Grate some fresh ginger into hot water to make ginger tea, or try ginger candies or crystallized ginger.

  Taking powdered ginger root in capsules also may provide some relief. Unfortunately, there’s no way to be sure how much of the active ingredient you’re getting in these ginger supplements, so talk to your provider before taking them. (As with many other things that are helpful in small amounts, the effects of megadoses are unknown.)

  Some women find similar relief from sipping peppermint tea or sucking peppermint candies, especially after eating.

• Try an acupressure band, a soft cotton wristband that’s sold at drugstores. You strap it on so that the plastic button pushes against an acupressure point on the underside of your wrist. This simple and inexpensive device, designed to ward off seasickness, has helped some pregnant women through morning sickness, although research suggests that it may be largely a placebo effect.
• Consider seeing an acupuncturist who has experience treating nausea during pregnancy.

• Ask your provider about a device that stimulates the underside of your wrist with a mild electric current. This “acustimulation” device is safe, though it can cause local skin irritation. (Use the gel that comes with it to help prevent this.)

  Though acustimulation isn’t widely used, there is some research showing that it may help. That said, there’s certainly no guarantee it will work for you, and these devices are generally not covered by insurance.

• Experiment with aromatherapy. Some women find scents such as lemon, mint, or orange useful. You can use a diffuser to dispense an essential oil, or you can carry a drop or two of an essential oil on a hanky to smell when you start to feel queasy. (Essential oils are very strong, so use only one or two drops.)

What about anti nausea medications?

If you’ve been unable to find relief from your nausea, talk with your provider about medication. There’s no need to continue to suffer, and waiting too long to take appropriate medication may make your condition more difficult to treat. See our articles on vitamin B6 and other nausea medications that are considered safe and effective during pregnancy.

By the way, while it won’t help you now, if you plan to get pregnant again, make sure to be taking a multivitamin at the time of conception and in early pregnancy. It may help prevent severe morning sickness, though no one knows why.