This sheet is about exposure to bimekizumab in pregnancy and while breastfeeding. This information is based on available published literature. It should not take the place of medical care and advice from your healthcare provider.

What is bimekizumab?*

Bimekizumab is a medication that has been approved to treat moderate to severe plaque psoriasis, ankylosing spondylitis, non-radiographic axial spondyloarthritis, psoriatic arthritis, and moderate to severe hidradenitis suppurativa. The brand name for this medication is Bimzelx®.

Sometimes when women find out they are pregnant, they think about changing how they take their medication, or stopping their medication altogether. However, it is important to talk with your healthcare providers before making any changes to how you take your medication. Your healthcare providers can talk with you about the benefits of treating your condition and the risks of untreated illness during pregnancy.

MotherToBaby has a sheet on psoriasis and psoriatic arthritis here https://mothertobaby.org/fact-sheets/psoriasis-and-pregnancy/ and a sheet on ankylosing spondylitis here https://mothertobaby.org/fact-sheets/ankylosing-spondylitis/ 

I am taking bimekizumab, but I would like to stop taking it before getting pregnant. How long does the drug stay in my body?

The time it takes the body to metabolize (process) medication is not the same for everyone. In healthy non-pregnant adults, it takes about 4½ months (around 138 days), on average, for most of the bimekizumab to be gone from the body.

I take bimekizumab. Can it make it harder for me to get pregnant?

Studies have not been done in humans to see if taking bimekizumab can make it harder to get pregnant. There was no effect on fertility in monkeys.

Does taking bimekizumab increase the chance of miscarriage?

Miscarriage is common and can occur in any pregnancy for many different reasons. Studies have not been done in humans to see if bimekizumab increases the chance of miscarriage.

Does taking bimekizumab increase the chance of birth defects?

Birth defects can happen in any pregnancy for different reasons. Out of all babies born each year, about 3 out of 100 (3%) will have a birth defect. Studies have not been done in humans to see if bimekizumab increases the chance of birth defects. A study in monkeys did not report an increased chance for birth defects with exposure to doses up to 38 times the maximum recommended human dose.

Does taking bimekizumab in pregnancy increase the chance of other pregnancy-related problems?

Studies have not been done in humans to see if bimekizumab increases the chance of pregnancy-related problems including preterm delivery (birth before week 37) or low birth weight (weighing less than 5 pounds, 8 ounces [2500 grams] at birth). A study in monkeys did not report an increased chance for poor growth with exposure to doses up to 38 times the maximum recommended human dose.

Since bimekizumab might suppress the immune system of the adult taking it, there is a theoretical concern that the same thing could happen to the baby if they are exposed during pregnancy. If someone has a weakened immune system they may be more likely to develop an infection from a live virus vaccine. Live vaccines contain a small amount of live virus. Inactivated vaccines do not contain live virus, so they cannot cause the disease they protect against. In the United States, rotavirus is the only live vaccine routinely given in the first year of life. Most babies can get inactivated vaccines in the first year of life. Talk with your child’s healthcare providers about your exposure to bimekizumab during pregnancy. They can talk with you about the vaccines your child should receive and the best time for your child to receive them.

Does taking bimekizumab in pregnancy affect future behavior or learning for the child?

Studies have not been done in humans to see if bimekizumab can increase the chance of behavior or learning issues for the child. A monkey study that followed the animals for 6 months after birth did not report an increased chance for changes in learning or behavior when exposed to doses up to 38 times the maximum recommended human dose during pregnancy.

Breastfeeding while taking bimekizumab:

Bimekizumab has not been studied for use during breastfeeding. Bimekizumab is a large protein molecule. Large protein molecules do not usually enter breast milk in high levels. Be sure to talk to your healthcare provider about all your breastfeeding questions.

If a man takes bimekizumab, could it affect fertility or increase the chance of birth defects?

Studies have not been done to see if bimekizumab could affect a man’s fertility (ability to get a woman pregnant) in humans or increase the chance of birth defects above the background risk. In general, exposures that men have are unlikely to increase risks to a pregnancy. For more information, please see the MotherToBaby fact sheet Paternal Exposures at https://mothertobaby.org/fact-sheets/paternal-exposures-pregnancy/.

*Updated August 2025

Please click here for references.

MotherToBaby is currently conducting a study looking at bimekizumab (Bimzelx®) and other medications used to treat psoriasis, psoriatic arthritis, ankylosing spondylitis, and non-radiographic axial spondyloarthritis, and moderate to severe hidradenitis suppurativa in pregnancy. If you are interested in learning more about this study, please call 1-877-311-8972 or visit https://mothertobaby.org/join-study/.

This sheet is about exposure to cephalexin in pregnancy and while breastfeeding. This information is based on available published literature. It should not take the place of medical care and advice from your healthcare provider.

What is cephalexin?

Cephalexin is an antibiotic medication that has been used to treat infections such as Staphylococcus aureus (Staph) and Escherichia coli (E. coli). Some brand names for cephalexin are Keflex® and Keftab®.

Sometimes when women find out they are pregnant, they think about changing how they take their medication, or stopping their medication altogether. However, it is important to talk with your healthcare providers before making any changes to how you take your medication. Your healthcare providers can talk with you about the benefits of treating your condition and the risks of untreated illness during pregnancy.

Having certain infections (such as a Staph or E. coli infection) during pregnancy can increase the chance of pregnancy-related problems or infections in a newborn baby. MotherToBaby has fact sheets on Staph and E. coli infections here: https://mothertobaby.org/fact-sheets/staphylococcus-aureus-pregnancy/ and https://mothertobaby.org/fact-sheets/e-coli-pregnancy/.

I take cephalexin. Can it make it harder for me to get pregnant?

Studies have not been done in women to see if cephalexin can make it harder to get pregnant. In animal studies, cephalexin did not affect fertility (ability to get pregnant).

Does taking cephalexin increase the chance of miscarriage?

Miscarriage is common and can occur in any pregnancy for many different reasons. In a study of 262 women who took cephalexin during pregnancy, there was no increase in miscarriages compared to a similar group of women who did not take cephalexin.

Does taking cephalexin 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. Information on the use of cephalexin in pregnancy is limited. In a study of 262 women who took cephalexin during pregnancy, there was no increased chance of birth defects.

Does taking cephalexin in pregnancy increase the chance of other pregnancy-related problems?

Studies have not been done to see if cephalexin can increase the chance of 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 taking cephalexin in pregnancy affect future behavior or learning for the child?

Studies have not been done to see if cephalexin can increase the chance of behavior or learning issues for the child.

Breastfeeding while taking cephalexin:

Cephalexin gets into breast milk in small amounts. In reports of 20 babies exposed to cephalexin through breast milk, 4 had diarrhea. There is one report of a baby getting a rash after being breastfed, due to a sensitivity to cephalexin. If you suspect the baby has any symptoms (such as diarrhea or rash), contact the child’s healthcare provider. Be sure to talk to your healthcare provider about all your breastfeeding questions.

If a man takes cephalexin, could it affect his fertility or increase the chance of birth defects?

Studies have not been done to see if cephalexin could affect a man’s fertility (ability to get a woman pregnant) or increase the chance of birth defects. Some infections, such as Staph or E.coli, might affect a man’s fertility. In general, exposures that fathers or sperm donors have are unlikely to increase risks to a pregnancy. For more information, please see the MotherToBaby fact sheet Paternal Exposures at https://mothertobaby.org/fact-sheets/paternal-exposures-pregnancy/.

Please click here for references.

This sheet is about exposure to paint in pregnancy and while breastfeeding. This information is based on available research studies. It should not take the place of medical care and advice from your healthcare provider.

What is paint?

In general, paint is made up of pigment particles (color) in a liquid base called the medium. There are two broad categories of paint: oil paints (oil/alkyd-based medium) and latex paints (water-based medium). Oil paints are thinned or cleaned with paint thinners including turpentine or mineral spirits. Latex paints are thinned or cleaned with soap and water. Most household paints are latex, vinyl, or acrylic compounds. Oil paints are sometimes used for trim work (such as around doors) in homes. There are many other mixtures of paints used for industry, the arts, and hobbies. In the past, lead and mercury were used in paint.

How could I be exposed to the chemicals in paint and what symptoms could they cause?

Exposure to paint can happen by breathing in dust or fumes (inhalation), direct skin contact (absorption) or swallowing paint chips or dust (ingestion). Painting in an area with poor or no ventilation (movement of fresh air around a closed space) for long periods of time could cause symptoms such as nausea, headaches, or loss of appetite. Some people might have allergic skin reactions or eye irritation. Ingestion of paint can lead to stomach irritation, nausea, or vomiting. Ingesting lead-based paint is toxic. Like other exposures, the amount (level) and duration (time) are important when thinking about an increased chance for problems. However, the exact level of paint exposure is usually not known. In general, ongoing exposure through a work setting would likely give higher total exposure than one-time household exposure. Smell is not a good measure of the level of exposure.

Does using paint increase the chance of miscarriage?

Miscarriage is common and can occur in any pregnancy for many different reasons. Household painting with proper safety precautions is expected to result in a low level of exposure and is not likely to increase the chance of miscarriage.

Does using paint increase the chance of birth defects?

Birth defects can happen in any pregnancy for different reasons. Out of all babies born each year, about 3 out of 100 (3%) will have a birth defect. We look at research studies to try to understand if an exposure, like paint, might increase the chance of birth defects in a pregnancy. It is not known if paint exposure can increase the chance of birth defects. Household painting with proper safety precautions is expected to result in a low level of exposure and is not likely to increase the chance of birth defects.

Does using paint increase the chance of other pregnancy-related problems?

It is not known if paint can increase the chance of 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).

Misusing paint (huffing):

Inhaling fumes from household substances to experience a “high” is called huffing. Some people huff paint or thinner containing toluene (a clear liquid with a unique smell that is used in making paints, paint thinners, and other products). There are older reports of babies born with problems after prenatal exposure to toluene-containing paint. In these cases, pregnant women were pregnant were directly huffing paint. Some of these babies were born preterm and had low birth weight, a small head size (microcephaly), and facial features similar to children exposed to alcohol during pregnancy. These children also had developmental delays. In these cases, the pregnant women were exposed to very high amounts of toluene and a much higher exposure than a hobby, painting a room in the home, or a professional painter would likely have.

How can I protect myself when painting?

Consider having someone else do the painting for you. If you plan to paint, reduce your exposure by:

• Selecting the correct paint, such as using paint for indoors only when painting a room in your house.
• Reading the product label and following all handling instructions for painting, cleaning, and storing.
• Working in a well-ventilated (fresh air) area with open windows and doors. Use fans in windows to help the air move. After painting, ventilate the room for another 2 to 3 days, and limit your time in this area.
• Wearing protective clothing such as long sleeves to cover your skin as well as gloves. If painting is part of your job, talk to your safety officer about wearing a respirator mask that filters vapors from paints and thinners.
• Not eating or drinking while painting.
• Washing your hands well after painting.

The Environmental Protection Agency (EPA) has a booklet with healthy tips for indoor painting at: https://www.cpsc.gov/s3fs-public/painting.pdf.

Walls, windows, or other surfaces might contain lead paint, especially in older homes. Be careful of exposure even if you are not preparing the walls. The dust you inhale might contain lead. MotherToBaby has a fact sheet on lead here: https://mothertobaby.org/fact-sheets/lead-pregnancy/.

I work as a painter. Can my work increase the chance of birth defects or other pregnancy-related problems?

Studies looking at professional painters have mixed results. These studies usually combine the outcomes of pregnancies of painters, printers, chemists, factory workers, and laboratory technicians, all with different chemical exposures. No consistent pattern of birth defects or increased chance of pregnancy complications has been reported.

Among professional painters, exposure levels will vary greatly based on paints and cleaners used, ventilation, wall preparation, protective gear used, handling and storage, and amount of time working. While there is no clear concern for painters, lowering chemical and fume exposure makes sense for both adult and pregnancy health. Each product has specific safety precautions on the label. An occupational health specialist or industrial hygienist might be able to offer specific ways to reduce your chemical exposure at work. More information and safety tips for working around chemicals can be found at: https://mothertobaby.org/fact-sheets/reproductive-hazards-workplace/.

I live in an old home, and I am concerned about lead paint.

The U.S. Federal Government banned lead-based paint from housing in 1978. However, lead-based paint might still be present in older homes. Paint chips can be tested for lead. Women who are pregnant should not remove old paint. Do not scrape, sand, or burn old paint because this puts higher concentrations of heavy metals (like lead), solvents, and other chemicals into the air.

If you need to remove lead paint from your home, have it done by someone who is certified in lead removal. Stay away from the area until the project is done, and the area is properly cleaned. For more information on lead, please see the MotherToBaby fact sheet at https://mothertobaby.org/fact-sheets/lead-pregnancy/.

Breastfeeding:

Exposure to paint during breastfeeding has not been well-studied. However, it is unlikely that low-level paint exposure in the breastfeeding woman would cause side effects in a nursing child. Be sure to talk to your healthcare provider about all your breastfeeding questions.

If a man is exposed to paint, can it affect fertility or increase the chance of birth defects?

It is not known if paint could affect a man’s fertility (ability to get a woman pregnant) or increase the chance of birth defects. In general, exposures that men have are unlikely to increase risks to a pregnancy. For more information, please see the MotherToBaby fact sheet Paternal Exposures at https://mothertobaby.org/fact-sheets/paternal-exposures-pregnancy/.

Please click here for references.

This sheet is about exposure to mold in pregnancy and while breastfeeding. This information is based on available published literature. It 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, particularly 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. However, 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, might be more sensitive to mold toxins. If you have any 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 chartarum mold is worse than common household molds. Should I be worried if I have it in my home?