Sunday, July 12, 2009

Morning sickness: Causes, concerns, treatments

Why do they call it morning sickness when I feel nauseated all day long?

"Morning sickness" is really a misnomer. (In fact, the technical medical term is "nausea and vomiting of pregnancy.") For some pregnant women, the symptoms are worst in the morning and ease up over the course of the day, but they can strike at any time and last all day long.

About three quarters of pregnant women experience nausea and sometimes vomiting during their first trimester. The nausea usually starts around six weeks of pregnancy, but it can begin as early as four weeks. It tends to get worse over the next month or so.

About half of the women who get it feel complete relief by about 14 weeks. For most of the rest, it takes another month or so for the queasiness to ease up, though it may return later and come and go throughout pregnancy.

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:

• Rapidly rising levels of the hormone human chorionic gonadotropin (hCG) during early pregnancy. No one knows how hCG contributes to nausea, but the timing is right: Nausea tends to peak around the same time as levels of hCG.

Estrogen, another hormone that rises rapidly in early pregnancy, is also considered a prime suspect, and it's possible that other hormones play a role 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, and that certain aromas instantly trigger her gag reflex. This may be a result of higher levels of estrogen.

• A tricky stomach. Some women's gastrointestinal tracts are simply more sensitive to the changes of early pregnancy.

You may have heard that morning sickness can be caused by a vitamin B deficiency. While taking a vitamin B6 supplement does seem to help ease nausea in many pregnant women, this doesn't mean they have a vitamin deficiency. In fact, at least one study has shown no significant differences in the levels of B6 in women with morning sickness and those without.

No one knows why B6 is helpful. There's also some evidence that taking a multivitamin at the time of conception and in early pregnancy helps prevent severe morning sickness, but again, no one knows why.

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 good 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 nauseated?

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. One study found that women with severe nausea and vomiting were 50 percent more likely to be carrying a girl.

Will my nausea affect my baby?

The mild to moderate nausea and occasional vomiting commonly associated with 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 aren't starving yourself. In most cases, your appetite will return soon enough and you'll start gaining weight.

If nausea keeps you from eating a balanced diet, make sure you're getting the nutrients you need by taking a prenatal vitamin. Choose one with a low dose of iron or no iron if that mineral makes your nausea worse.

Severe and prolonged vomiting has been linked to a greater risk of preterm birth, low birth weight, and newborns who are small for their gestational age. However, a recent study of women who were hospitalized with severe vomiting found that those who were able to gain at least 15.4 pounds (7 kilograms) during their pregnancy had no worse outcomes than other women.

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 were not developing properly, you'd have lower levels of pregnancy hormones in your system, so it follows that you'd have little or no nausea.)

But there are plenty of women with perfectly normal pregnancies who manage to escape nausea during their first trimester. Count yourself lucky and don't obsess about it 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, there are safe and effective medications you can take.) Not all the following suggestions are supported by hard evidence, but obstetricians and midwives commonly recommend them, and many women swear by them.

• 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 balanced diet.

It might also help to stick to bland foods. Try to eat food cold or at room temperature, because it tends to have less of an aroma than when it's hot.

• Keep simple snacks, such as crackers, by your bed. When you first wake up, nibble a few crackers and then rest for 20 to 30 minutes before getting up. Snacking on crackers may also help you feel better if you wake up nauseated in the middle of the night.

• Eat small, frequent meals and snacks throughout the day so that your stomach is never empty. Some women find that carbohydrates are most appealing when they feel nauseated, but one small study found that high-protein foods were more likely to ease symptoms.

• Avoid fatty foods, which take longer to digest. Also steer clear of rich, spicy, acidic, and fried foods, which can irritate your digestive system.

• Try drinking fluids mostly between meals. And don't drink so much at one time that your stomach feels full, as that will make you less hungry for food. A good strategy is to sip fluids frequently throughout the day.

Aim to drink about a quart and a half altogether. If you've been vomiting a lot, try a sports drink that contains glucose, salt, and potassium to replace lost electrolytes.

• Give yourself time to relax and take naps if you can. Watching a movie (preferably not one about food!) or visiting with a friend can help relieve stress and take your mind off your discomfort. Or try hypnosis — while 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 vitamins with 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, since this mineral can be hard on your digestive system.

• Try ginger, an alternative remedy thought to settle the stomach and help quell 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 see if ginger candies help.

A few studies found that taking powdered ginger root in capsules provided some relief, but be sure to talk to your provider before taking ginger supplements. There's no way to be sure how much of the active ingredient you're getting in these supplements, so some experts think it's best not to use them. (As with many other things that are helpful in small amounts, the effects of megadoses are unknown.)

• 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.

• Ask your provider about a device that stimulates the underside of your wrist with a mild electric current. This "acustimulation" device costs about $75 and is available by prescription only. It's safe, and research has shown that this technique works well for some women.

What about anti-nausea medications?

If the measures above don't provide you with enough relief, let your provider know so you can get the help you need. If your nausea and vomiting is getting worse, waiting too long to take appropriate medication may make it more difficult to treat.

Your provider will likely suggest that you try taking vitamin B6. No one knows why B6 eases nausea in some expectant mothers, but research indicates that it works for some women and it's consistently been shown to be safe when taken in commonly recommended doses.

The usual dose for treating morning sickness is 10 to 25 milligrams three times a day, but check with your provider before taking anything. She can tell you how much to take and whether the amount in your prenatal vitamin should count as one of the doses. (The amount of vitamin B6 in prenatal supplements varies by brand.)

Don't take more vitamin B6 than your caregiver recommends. Too much can cause numbness and nerve damage and may not be safe for your developing baby.

If vitamin B6 isn't enough to do the job, there are other anti-nausea medications that are considered safe and effective during pregnancy.

What if I just can't keep anything down?

Call your provider if you haven't been able to keep anything — including fluids — down for 24 hours. (If you're newly pregnant and don't yet have a doctor or midwife, go to the emergency room.)

You may have a condition called hyperemesis gravidarum — literally, "excessive vomiting in pregnancy." This condition can be difficult to manage, but the sooner you're diagnosed and begin treatment, the more likely you'll be able to avoid severe symptoms.

Your caregiver will probably want to give you some intravenous fluids right away, since you'll most likely be seriously dehydrated. Then she'll need to do some tests to check your electrolyte levels and make sure no underlying illness is causing your constant vomiting. Depending on your condition, you may need to be hospitalized for a few days so that you can continue to receive IV fluids and medication.

Many women feel much better after they're rehydrated and are able to control their symptoms with anti-nausea medication. In rare cases, you'll need to continue to receive intravenous therapy on and off either in the hospital or at home.

If inadequately treated, hyperemesis gravidarum can result in chronic dehydration, weight loss, malnutrition, and other complications for you and your baby. For more information, visit the Hyperemesis Education and Research Foundation website.

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