This sheet is about exposure to mold in pregnancy and while breastfeeding. This information should not take the place of medical care and advice from your healthcare provider.

What is mold?

Molds are fungi that are able to live almost anywhere, indoors and outdoors. They grow best in warm, damp, and humid places, including water-damaged areas. Molds can be different colors and can have a musty, earthy smell. They spread by releasing spores that can pass through the air and be carried on the clothing or on animals. Four common household molds are Cladosporium, Penicillium, Alternaria, and Aspergillus.

Can mold make me sick?

Molds themselves do not make people sick. Some molds produce toxins that can cause symptoms such as stuffy nose, eye irritation, rash, wheezing, fever, or shortness of breath. Not everyone who is exposed to mold will have symptoms. People who have a weakened immune system or a chronic (ongoing) respiratory condition, such as asthma, may be more sensitive to mold toxins. If you have any of these symptoms, talk to your healthcare provider.

Mold exposure has not been well studied in pregnancy. If you are pregnant or breastfeeding and you have found mold in your home, have it removed as soon as possible since it could affect your health or the health of your baby after delivery.

I have heard that Stachybotrys chartarummold is worse than common household molds. Should I be worried if I have it in my home?

Stachybotrys chartarum is a greenish-black mold. It is less common in homes, but not rare. If you think your home may have Stachybotrys chartarum, you do not need to have it tested to find out what kind of mold it is. Since all molds can cause health problems, any mold should be removed from the home as soon as possible. Stachybotrys chartarum should be removed in the same way as any other type of mold.

Can exposure to mold make it harder for me to get pregnant?

Based on the studies reviewed, it is not known if exposure to mold can make it harder to get pregnant.

Does exposure to mold increase the chance of miscarriage?

Miscarriage is common and can occur in any pregnancy for many different reasons. Based on the studies reviewed, it is not known if exposure to mold increases the chance of miscarriage.

Does exposure to mold increase the chance of birth defects?

Every pregnancy starts out with a 3-5% chance of having a birth defect. This is called the background risk. Based on the studies reviewed, it is not known if exposure to mold increases the chance for birth defects above the background risk. Animal studies have shown that mold can increase the chance of birth defects when it is eaten in large quantities, but there is no proven risk to a pregnancy from exposure to airborne mold during pregnancy.

Does exposure to mold increase the chance of other pregnancy-related problems?

Based on the studies reviewed, it is not known if exposure to mold can cause other pregnancy related problems, such as preterm delivery (birth before week 37) or low birth weight (weighing less than 5 pounds, 8 ounces [2500 grams] at birth).

Does exposure to mold during pregnancy affect future behavior or learning for the child?

Based on the studies reviewed, it is not known if exposure to mold during pregnancy can cause behavior or learning issues for the child.

How can I reduce my exposure to mold?

• Keep the moisture levels in the house as low as possible; on average lower than 50%.
• Use an air conditioner or dehumidifier during humid months.
• Use exhaust fans in kitchens and bathrooms.
• Clean bathrooms with mold killing products. Wear non-porous gloves and eye protection and have good air ventilation while cleaning.
• Do not put carpet in bathrooms or basements.

How can mold be cleaned up after a water leak or a flood?

• Wear a mask that can keep mold spores out of the air you breathe, such as an N95 respirator. For the mask or respirator to work properly, make sure to follow all instructions on the packaging.
• Wear non-porous gloves made from natural rubber, neoprene, nitrile, polyurethane, or PVC.
• Wear eye protection, such as goggles without air vents in them.
• Increase air ventilation while cleaning by keeping doors and windows open, air vents and fans turned on.
• Remove all items that have been wet for more than 48 hours if they cannot be thoroughly cleaned and dried. This includes carpeting, upholstery, wallpaper, drywall, floor and ceiling tiles, insulation material, clothing, leather, paper, wood, and food.
• Remove mold growth from hard surfaces by using commercial mold cleaning products or a bleach solution (1 cup bleach in 1 gallon of water). Do not mix bleach with ammonia or other household cleaners. Always follow use and storage directions on the labels.
• If you are sensitive to mold or cleaning products, consider asking someone else to clean for you, especially in areas with poor ventilation.
• Professional companies can be hired to clean up flooded basements or other household areas.

Breastfeeding and exposure to mold:

Studies have shown that breastfeeding can help protect infants against developing asthma and allergies, including those related to mold exposure in the home. If you are breastfeeding, mold should be removed from the home as soon as possible. If you suspect the baby has any symptoms related to mold (frequent sneezing, stuffy nose, watery, itchy eyes, coughing, wheezing, or shortness of breath), contact the child’s healthcare provider. Be sure to talk to your healthcare provider about all of your breastfeeding questions.

If a male is exposed to mold, could it affect fertility (ability to get partner pregnant) or increase the chance of birth defects?

Based on the studies reviewed, it is not known if exposure to mold could affect male fertility or increase the chance of birth defects above the background risk. In general, exposures that fathers or sperm donors have are unlikely to increase the risks to a pregnancy. For more information, please see the MotherToBaby fact sheet Paternal Exposures at https://mothertobaby.org/fact-sheets/paternal-exposures-pregnancy/.

Selected References:

• Agache I, et al. 2010. Risk factors and asthma phenotypes in children and adults with seasonal allergic rhinitis. Phys Sportsmed 38(4):81-86. [PubMed: 21150146]
• Cao S, et al. 2020. Changes in children’s asthma prevalence over two decades in Lanzhou: effects of socioeconomic, parental and household factors. J Thorac Dis 12(10):6365-6378. [PMC free article: PMC7656413] [PubMed: 33209475]
• Centers for Disease Control and Prevention. 2020. General Information about Mold. Available from URL: https://www​.cdc.gov/mold/basics.htm.
• Centers for Disease Control and Prevention. 2004. Investigation of acute idiopathic pulmonary hemorrhage among infants – Massachusetts, December 2002-June 2003. MMWR 53:817-820. [PubMed: 15356457]
• Centers for Disease Control and Prevention. 2020. Natural Disasters and Severe Weather. Mold after a Disaster. Available from URL: https://www​.cdc.gov/disasters/mold/.
• Centers for Disease Control and Prevention. 2000. Update: pulmonary hermorrhage/hemosiderosis among infants – Cleveland, Ohio, 1993-1996. MMWR 49:180-184.
• DiPaolo JA, et al. 1967. Teratogenic response by hamsters, rats and mice to aflatoxin B1. Nature 215:638-9. [PubMed: 6058319]
• Etzel RA, et al. 1998. Acute pulmonary hemorrhage in infants associated with exposure to Stachybotrys atra and other fungi. Arch Pediatr Adolesc Med 152:757-762. [PubMed: 9701134]
• Gallant MJ, et al. 2020. Prenatal and early-life exposure to indoor air-polluting factors and allergic sensitization at 2 years of age. Ann Allergy Asthma Immunol 124(3):283-287. [PubMed: 31765814]
• Hayes AW, et al. 1974. Teratogenic effects of ochratoxin A in mice. Teratology 9:93-7. [PubMed: 4204660]
• Korpinen E. 1974. Studies on Stachybotrys alternans: effect of low doses of stachybotrys toxins on pregnancy of mice. Acta Path Microbiol Scand 82:457-464. [PubMed: 4528746]
• Lee E, et al. 2020. Prenatal mold exposure is associated with development of atopic dermatitis in infants through allergic inflammation. J Pediatr (Rio J) 96:125–31. [PMC free article: PMC9432247] [PubMed: 30243937]
• Loth EA, et al. 2015. Experimental Paracoccidioiomycosis in pregnant rats. Rev Inst Med Trop San Paulo 57(6): 515-518. [PMC free article: PMC4727139] [PubMed: 27049707]
• Magoha H, et al. 2014. Association between aflatoxin M1 exposure through breast milk and growth impairment in infants from Northern Tanzania. World Mycotoxin J 7(3): 277-284.
• Magoha H, et al. 2014. Fumonisin B1 contamination in breast milk and its exposure in infants under 6 months of age in Rombo, Northern Tanzania. Food Chem Toxicol 74:112-116. [PubMed: 25280923]
• Martyny JW, et al. 2005. Aerosolized sodium hypochlorite inhibits viability and allergenicity of mold on building materials. J Allergy Clin Immunol 116:630-635. [PubMed: 16159635]
• Reddy CS, et al. 1981. Teratogenicity of secalonic acid D in mice. J Toxicol Environ Health 7:445-55. [PubMed: 7288897]
• Strina A, et al. 2014. Risk factors for no-atopic asthma/wheeze in children and adolescents: a systematic review. Emerg Themes Epidemiol 11:5. [PMC free article: PMC4068161] [PubMed: 24963333]
• US Environmental Protection Agency (EPA). 2020. Mold and Health. Available at URL: https://www​.epa.gov/mold/mold-and-health.
• US Environmental Protection Agency (EPA). 2018. Mold and Your Home. Available at URL: https://www​.epa.gov/mold​/mold-and-your-home.

“OTIS/MotherToBaby encourages inclusive and person-centered language. While our name still contains a reference to mothers, we are updating our resources with more inclusive terms. Use of the term mother or maternal refers to a person who is pregnant. Use of the term father or paternal refers to a person who contributes sperm.