Substances of Concern during Pregnancy

Nutrition before and during pregnancy and lactation can have a significant effect on the long-term health of both infants and their mothers. The potential impact of nutrition is greater at this time than during any other stage of life. Contact The Nutrition Consultation Service at (617) 732-6054 if you have questions.


Drinking alcohol when you are pregnant is the cause of Fetal Alcohol Syndrome (FAS), a leading cause of birth defects and intellectual disability. Children born with FAS have facial deformities, are of low weight and height, have a smaller-than-normal head, and exhibit mental and physical disability.

Drinking alcohol during pregnancy can:

  • Damage the baby’s central nervous system.
  • Cause a miscarriage, premature separation of the placenta, and low birth weight.
  • Interfere with the body’s ability to absorb and use some vitamins and minerals (thiamin, folate, vitamin A, vitamin B6, zinc, phosphorus, calcium, and magnesium).

The Surgeon General and Secretary of Health and Human Services advised that the only completely safe choice is not to consume alcohol during pregnancy.

Cigarette Smoking

Cigarette smoking has been shown to decrease the weight of babies at birth and increase the risk of several complications during pregnancy. This may be caused by carbon monoxide, nicotine, or other things that are found in tobacco smoke. Smoking may also reduce blood flow to the baby and can decrease food intake by the mother. Exposure to second-hand smoke also increases these risks. Smoking should be avoided during pregnancy.


Drinking excessive amounts of caffeine has been linked to miscarriages, lowered birth weight, and other complications during pregnancy. Because caffeine may cause birth defects, the consumption of caffeine during pregnancy is discouraged.

The American Dietetic Association recommends that pregnant women consume no more than 300 mg caffeine per day. This is the amount typically found in one 10 oz cup of coffee.

Common sources of caffeine:

  • Instant coffee (10 oz) Amount: 100mg
  • Decaf coffee (10 oz) Amount: 4-10mg
  • Caffeinated tea (10 oz) Amount: 40-90 mg
  • Ice Tea (12 oz) Amount; 22-36mg
  • Milk Chocolate (1 oz) Amount: 1-15mg
  • Mountain Dew (12 oz can) Amount: 52-55mg
  • Diet Cola (12 oz can) Amount: 36-59mg
  • Cola (12 oz can) Amount: 35-46mg
  • Sprite (12 oz can) Amount: 0mg

Artificial Sweeteners

Artificial sweeteners are used to give food and beverages the sweet taste of sugar without all of the calories. Many different brands can be found in the supermarket. There is no nutritional need to consume artificial sweeteners. However, if you decide to include them in your diet, use the information below to choose one that is safe for your baby. Also, some people have reported sensitivities to many of the artificial sweeteners, even those deemed safe for pregnancy. If you feel that you have a reaction to an artificial sweetener, stop using it and consult your doctor or nutritionist for more information.

Aspartame (Equal, NutraSweet, Nutra-Taste)

The FDA and the American Academy of Pediatrics Committee on Nutrition consider aspartame to be safe for both the pregnant woman and the developing infant. The dietitians at the BWH Nutrition Consult Service/OB-GYN recommend no more than 1-2 servings/day of aspartame containing foods.

Saccharin (Sweet’N Low)

The use of saccharin is not recommended during pregnancy. It is a weak carcinogen that crosses the placenta.

Stevia (Pure Via, Sweet Leaf, Truvia)

Stevia is a sweetener from a plant native to South America. Stevia is safe to consume during pregnancy.

Sucralose (Splenda)

Sucralose is a low-calorie sweetener made from normal table sugar through chemical modification. Sucralose is safe to use during pregnancy as it does not cross the placenta.

Download pdf version of Brigham Obstetrics and Gynecology Group Substances of Concern During Pregnancy information sheet.

Learn more about Brigham and Women's Hospital

For over a century, a leader in patient care, medical education and research, with expertise in virtually every specialty of medicine and surgery.

About BWH