The information provided below is for readers based in the United States of America. Readers outside of the United States of America should seek the information from local sources.


There are very few human studies evaluating the safety of guaifenesin during pregnancy or breastfeeding. It is important to talk to your doctor before using guaifenesin during pregnancy. It may be recommended to avoid the use of guaifenesin during the first trimester of pregnancy unless any possible benefits to the mother outweigh risks to the developing baby.

What is Guaifenesin?

Guaifenesin is an expectorant currently available as a generic or brand name medication (Mucinex™, Robitussin™). Guaifenesin is available as granules, extended-release and immediate-release tablets, or liquid and is taken every four hours (or every 12 hours for extended-release tablets). Extended-release tablets are only recommended in children age over 12 years old. It is important not to exceed the recommended number of doses per day (see product labeling). It is available over-the-counter, without a prescription. 

What is Guaifenesin used to treat?

Guaifenesin is used to treat cough in children over 2 years old, adolescents, and adults. Studies suggest guaifenesin is one of the more commonly used over-the-counter medications during pregnancy. Acute upper respiratory tract infections caused by the common cold or flu can cause symptoms of cough, chest congestion, and sputum production.

How does Guaifenesin work?

Guaifenesin works by loosening mucus and thinning secretions in the lungs to help cough be more productive. Guaifenesin also suppresses cough receptors that are hypersensitive to acute upper respiratory tract infections. 

If I am taking Guaifenesin, can it harm my baby?

There are limited human studies evaluating the safety of guaifenesin in human pregnancy. Normal doses of guaifenesin recommended on the product packaging are considered safe in pregnant women; however, it may be recommended to avoid the use of guaifenesin during the first trimester. Guaifenesin may only be recommended by your doctor if you have significant need for this medication. Guaifenesin products containing alcohol should be avoided in pregnant women. It is recommended to weigh the benefits to the mother against the risks to the developing baby before using this medication while pregnant. Contact your doctor before using this medication during pregnancy. 

Evidence from animal studies with Guaifenesin:

Pregnant rats treated with high doses of guaifenesin (doses higher than what humans usually take) had an increased risk of developmental defects in offspring. Rates of developmental defects were lower with exposure to low and moderate guaifenesin doses.

Evidence for the risks of Guaifenesin in human babies:

The Collaborative Perinatal Project found no evidence of harm to the developing babies with 1336 instances of guaifenesin use any time during pregnancy; however, an increase in inguinal hernia was noted in a sample of 7/197 newborns exposed to guaifenesin during the first trimester and 20/1337 exposed any time during pregnancy. A study in 141 newborns born to mothers participating in the Michigan Medicaid program between 1985 and 1992 found no association between first trimester guaifenesin use and an increased risk of birth defects. Two studies found no strong association between first trimester guaifenesin exposure and neural tube defects. A case report published in 1981 noted possible development of fetal alcohol syndrome in newborns exposed to guaifenesin or other expectorants at any time during pregnancy. 

Bottom line: There is limited safety information on the use of guaifenesin during pregnancy. Recommended doses of over-the-counter guaifenesin are expected to be safe in pregnant women; however, consult your doctor before using this medication during pregnancy. It may be recommended to avoid first trimester use of guaifenesin unless benefits outweigh risks due to the lack of available safety information.

If I am taking Guaifenesin and become pregnant, what should I do?

If you are using guaifenesin and become pregnant, you should contact your doctor immediately. Your doctor will determine if your medication is medically necessary, or if it should be discontinued until after the birth of your baby.

If I am taking Guaifenesin, can I safely breastfeed my baby?

There is no information available on the effects of guaifenesin on the breastfed baby. It is recommended to weigh the risks and benefits of this medication before taking it while pregnant or breastfeeding. Contact your doctor for advice.

Bottom line: There is no evidence on the safety of guaifenesin exposure in nursing infants. Weigh the risks versus benefits before using this medication.

If I am taking Guaifenesin, will it be more difficult to get pregnant?

One case report suggests guaifenesin may increase sperm count and motility in males, making it easier to get a woman pregnant.

If I am taking Guaifenesin, what should I know?

There are very few human studies evaluating the safety of guaifenesin during pregnancy or breastfeeding. It is important to talk to your doctor before using this medication during pregnancy. Due to the lack of safety information on guaifenesin, your doctor may recommend avoiding first trimester use of this medication.

If I am taking any medication, what should I know?

This report provides a summary of the available information about the use of Guaifenesin during pregnancy and breastfeeding. Content is from the product label unless otherwise indicated.

You may find Pregistry's expert reports about the individual medications used to treat cough and cold symptoms here, and a report on having a cough during pregnancy here.   Additional information can also be found in the resources below. 

For more information about Guaifenesin during and after pregnancy, contact (800-994-9662 [TDD: 888-220-5446]) or check the following links:

National Institutes of Health:  Guaifenesin Prescribing Information

UCSF: Acute upper respiratory tract infection (cold)

Read the whole report
General information

It is very common for women to worry about having a miscarriage or giving birth to a child with a birth defect while they are pregnant. Many decisions that women make about their health during pregnancy are made with these concerns in mind.

For many women these concerns are very real. As many as 1 in 5 pregnancies end in a miscarriage, and 1 in 33 babies are born with a birth defect. These rates are considered the background population risk, which means they do not take into consideration anything about the health of the mom, the medications she is taking, or the family history of the mom or the baby’s dad. A number of different things can increase these risks, including taking certain medications during pregnancy.

It is known that most medications, including over-the-counter medications, taken during pregnancy do get passed on to the baby. Fortunately, most medicines are not harmful to the baby and can be safely taken during pregnancy. But there are some that are known to be harmful to a baby’s normal development and growth, especially when they are taken during certain times of the pregnancy. Because of this, it is important to talk with your doctor or midwife about any medications you are taking, ideally before you even try to get pregnant.

If a doctor other than the one caring for your pregnancy recommends that you start a new medicine while you are pregnant, it is important that you let them know you are pregnant.

If you do need to take a new medication while pregnant, it is important to discuss the possible risks the medicine may pose on your pregnancy with your doctor or midwife. They can help you understand the benefits and the risks of taking the medicine.

Ultimately, the decision to start, stop, or change medications during pregnancy is up to you to make, along with input from your doctor or midwife. If you do take medications during pregnancy, be sure to keep track of all the medications you are taking.