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Pregnancy Nutrition Guidelines

Foods to Avoid During Pregnancy

Any drugs taken during pregnancy can harm the child.
Any drugs taken during pregnancy can harm the child.
Publications International, Ltd.

Just as with the good foods you eat, the harmful substances you consume can get passed directly on to your unborn child. While some of the substances are obvious, like alcohol, some of them might surprise you.


Caffeine is a substance naturally found in coffee, tea, cola drinks, and chocolate. It is also in some medications. Read labels carefully to identify those products that contain caffeine. Caffeine readily finds its way to the fetus, and the concentration of caffeine in fetal blood will be about the same as in maternal blood. Studies have not shown an association between caffeine consumption and fetal abnormalities, but caffeine is a powerful stimulant. It also increases production of stress hormones, causing constriction of uterine blood vessels, which lessens the blood flow to the uterus and may temporarily decrease the amount of oxygen reaching the fetus.


Large amounts of caffeine cannot be good for your baby or you. However, caffeine consumption in small amounts (one to two cups of coffee per day) is considered safe during pregnancy.

Artificial Sweeteners

Although aspartame (found in NutraSweet and Equal) appears to have no effect on a developing fetus, pregnant women are advised to consume it in moderation. Pregnant women who have phenylketonuria (PKU) -- a rare, inherited disease in which the body cannot metabolize phenylalanine (an amino acid) -- or high levels of phenylalanine in their blood must avoid aspartame altogether. Aspartame contains phenylalanine, and an excess of phenylalanine in the body damages the central nervous system and can cause mental retardation.

Saccharin (found in Sweet 'N Low) should be avoided by all pregnant and breast-feeding women. Although studies linking saccharin to bladder cancer have been dismissed, it has been shown that it crosses into the placenta and may remain in fetal tissue.

Herbal Tea

Some herbs and herbal teas contain drugs. Ginseng tea contains a small amount of estrogen. Chamomile tea contains ragweed, which can cause severe allergic reactions in some people. Teas made from juniper berries may cause stomach irritation. Just because herbal teas are considered to be natural does not mean they are safe for pregnant women. So, in general, avoid herbal teas except for those teas known to be safe for pregnancy such as peppermint and raspberry leaf.


Cigarette smoking poses a serious threat to the well-being of your baby. Mothers who smoke usually have babies with a lower birth weight than mothers who do not smoke, and low birth weight is the leading cause of infant death. Smoking is also associated with a greater incidence of miscarriage, prematurity, stillbirth, and death of the baby soon after birth. Smoking by mothers has also been associated with impaired intellectual and physical development in their children.

If you have smoked for many years, it may be difficult to stop during pregnancy. However, for the health of your developing baby, you should quit. If you cannot stop entirely, just cutting down is helpful since the harmful effects of smoking are related to the amount you smoke.

These tips may help you quit or cut down:

  • Enter a program designed to help you quit. The American Lung Association can help you find one. Smoking cessation programs especially for pregnant women and new mothers are available in some areas.
  • Cut down on the number of cigarettes you smoke each day. Try to continue to reduce the number a little more each week. (Keep plenty of low-fat snacks and chewing gum on hand, and reach for those instead of a cigarette.)
  • Cut each cigarette in half and smoke only the half with the filter.
  • Take fewer puffs on each cigarette you smoke.
  • Use a water filter, available at drugstores, which attaches to the cigarette's filter.

If you quit or cut down on your smoking during your pregnancy, try not to resume the habit after having your baby. Children of smokers have been shown to have a greater susceptibility to respiratory diseases, such as colds, bronchitis, and asthma; ear infections; and other, potentially serious, medical problems. Cigarette smoke is also a known risk factor for sudden infant death syndrome (SIDS).


Studies on the effects of marijuana use are far from conclusive. There is some evidence that marijuana use is associated with lung cancer. It has been shown to impair short-term memory and cause menstrual irregularities. Studies in animals have shown that the active ingredient in marijuana crosses the placenta and accumulates in the fetus. Some studies suggest marijuana use is associated with precipitate labor (rapid expulsion of the fetus), prolonged labor, low birth weight, prematurity, and a greater risk of fetal distress. Although there is much researchers don't know about the long-term effects of marijuana use, marijuana is a drug, and you should avoid drug use during pregnancy.


Cocaine has profound effects on the mother and her fetus. It causes an increase in maternal heart rate; constriction of the blood vessels of the placenta, allowing less blood to reach the fetus; increased secretion of stress hormones, which causes constriction of uterine blood vessels; and increased uterine contractility.

It has been difficult for researchers to isolate the effects of cocaine since so many users take other drugs as well. However, cocaine use is also thought to be related to a high incidence of spontaneous abortion and to placental abruption (separation of the placenta from the uterine wall). Infants whose mothers used cocaine have a difficult time adjusting to environmental stimuli after birth and may be addicted to the drug.


Heavy drinking during pregnancy (more than five or six drinks daily) puts the baby at risk for fetal alcohol syndrome. Affected babies are born with physical malformations, including microcephaly (abnormally small head), certain heart defects, and, often, mental retardation.

Moderate (one or two drinks per day) and social (three to four drinks per day) drinking are also associated with problems. Some research points to a higher miscarriage rate among women who drink moderately. Other studies associate this level of drinking with a more frequent occurrence of birth defects and lower birth weights. No safe level of alcohol consumption has been established. As a result, it is best to take a cautious approach during pregnancy by abstaining from alcohol.

Other Medications and Drugs

Pregnancy is a time for prudent use of all drugs. Since few drugs have been proved safe for the fetus, and some drugs have been proved unsafe, you will want to be cautious about the medications you take. Drugs and medications include any over-the-counter remedies you may buy as well as prescriptions authorized by your doctor. Your doctor can help you to decide when medications are indicated for you during pregnancy.

Remember that good health during pregnancy is not just about avoiding harmful foods and drugs, it's about taking a proactive approach toward good nutrition, and making sure that you gain enough weight to benefit the baby growing inside of you.

This information is solely for informational purposes. IT IS NOT INTENDED TO PROVIDE MEDICAL ADVICE. Neither the Editors of Consumer Guide (R), Publications International, Ltd., the author nor publisher take responsibility for any possible consequences from any treatment, procedure, exercise, dietary modification, action or application of medication which results from reading or following the information contained in this information. The publication of this information does not constitute the practice of medicine, and this information does not replace the advice of your physician or other health care provider. Before undertaking any course of treatment, the reader must seek the advice of their physician or other health care provider.

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Dr. Elizabeth Eden, M.D. is a practicing obstetrician with her own private practice in New York City. She serves as an attending physician at the Tisch Hospital of the New York University Medical Center, as well as a Clinical Assistant Professor at the New York University School of Medicine.