Hair dye
(Date: October 2017. Version: 2)
This factsheet has been written for members of the public by the UK Teratology Information Service (UKTIS). UKTIS is a not-for-profit organisation funded by the UK Health Security Agency (UKHSA) on behalf of UK Health Departments. UKTIS has been providing scientific information to health care providers since 1983 on the effects that medicines, recreational drugs and chemicals may have on the developing baby during pregnancy.
Hair dye and pregnancy
There are many different types of hair dye. If pregnant, it is sensible to avoid using hair dyes from unknown suppliers, such as unbranded products sold on the internet and products for which the ingredients are not clearly listed, as these products may not go through safety and quality control checks and could contain harmful substances.
If you are a hairdresser and have questions about working with hair dyes when pregnant you may wish to read our bumps leaflet on ‘working as a hairdresser during pregnancy’.
Is it safe to dye my hair if I am pregnant?
There is very little scientific information about the pregnancy outcomes of women who occasionally use hair dyes during pregnancy. The small amount of evidence that is available does not suggest that dying your hair in pregnancy will harm a baby in the womb.
The few studies that have been done are summarised below. These studies looked at pregnancy outcomes of women who used many different types of hair dyes, and will therefore not tell you about potential effects of a particular type of hair dye.
When using hair dyes during pregnancy, it is important to follow the directions of use on the product leaflet. This may include carrying out a ‘patch test’ to rule out an allergic and/or skin reaction, and to minimise exposure by wearing gloves and ensuring that the room is well ventilated to reduce inhalation of fumes.
Can using hair dye in pregnancy cause my baby to be born with birth defects?
A baby’s body and most internal organs are formed during the first 12 weeks of pregnancy. It is mainly during this time that some medicines are known to cause birth defects.
The amount of hair dye that is likely to enter the mother’s bloodstream (either via the skin or from inhaled product fumes), and therefore potentially reach the baby in the womb, is expected to be very small.
Two studies have provided no proof that use of hair dye in pregnancy causes heart defects in the baby. No studies have investigated links with any other type of birth defects.
Can using hair dye during pregnancy cause miscarriage, preterm birth, low birth weight or stillbirth?
No links between dyeing your hair in pregnancy and having a miscarriage, a stillbirth, a preterm baby (born before 37 weeks of pregnancy) or a baby with a low birth weight (<2500g) are known about. However, no scientific studies have been carried out that have specifically investigated these pregnancy outcomes.
Can using hair dye during pregnancy cause other health problems in the child?
Learning or behavioural problems
There is no known link between using hair dye in pregnancy and learning or behavioural problems such as attention deficit hyperactivity disorder (ADHD) or autism spectrum disorder in the child. There are, however, no scientific studies that have specifically investigated a link with these problems.
Childhood cancer
There is no scientific proof that dyeing your hair before or during pregnancy will cause the child that you are carrying to develop cancer
A number of studies have investigated whether using hair dye during or before pregnancy increases the chance of the baby in the womb developing cancer in childhood. When thinking about the results of these studies (see below) it is important to understand problems with how some of the studies were done. Childhood cancers are generally rare. This makes it very difficult to find enough children with the specific cancer to do a reliable study. Also, the studies summarised below often relied on information about hair dye use that was collected from women many years after their pregnancies (in one study as long as nineteen years after). It has been shown that mothers of children with health problems such as cancer are more likely to remember doing something (like dyeing their hair) in pregnancy that they think may be related than mothers of healthy children. As a result, hair dye could be falsely linked to childhood cancer. These factors may explain why one study finds a link but another doesn’t.
• Three studies have all shown no link between use of hair dye in pregnancy and a brain tumour developing in the child.
• Two very small studies of children with a type of kidney cancer called Wilms’ Tumour found opposite results. While one study showed a possible link, the other study showed no link to use of hair dye in pregnancy.
• One study of children with a type of cancer that develops from cells in the testes or ovaries (germ cell tumours) showed a possible link with use of hair dye before pregnancy but not during pregnancy.
• Two studies showed that mothers of children who developed a type of cancer called neuroblastoma were more likely to have dyed their hair during their pregnancies, while a further more recent study did not agree with this finding.
None of these studies provides good enough scientific evidence to show a link between using hair dye in pregnancy and childhood cancer.
Will my baby need extra monitoring during pregnancy?
Using hair dye during pregnancy is not expected to cause any problems that would require extra monitoring of your baby.
Are there any risks to my baby if the father dyes his hair?
We would not expect any increased risk to your baby if the father used hair dye before or around the time your baby was conceived.
Who can I talk to if I have questions?
If you have any questions regarding the information in this leaflet please discuss them with your health care provider. They can access more detailed medical and scientific information from www.uktis.org.
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General information
Up to 1 out of every 5 pregnancies ends in a miscarriage, and 1 in 40 babies are born with a birth defect. These are referred to as the background population risks. They describe the chance of these events happening for any pregnancy before taking factors such as the mother’s health during pregnancy, her lifestyle, medicines she takes and the genetic make up of her and the baby’s father into account.
Medicines use in pregnancy
Most medicines used by the mother will cross the placenta and reach the baby. Sometimes this may have beneficial effects for the baby. There are, however, some medicines that can harm a baby’s normal development. How a medicine affects a baby may depend on the stage of pregnancy when the medicine is taken. If you are on regular medication you should discuss these effects with your doctor/health care team before becoming pregnant.
If a new medicine is suggested for you during pregnancy, please ensure the doctor or health care professional treating you is aware of your pregnancy.
When deciding whether or not to use a medicine in pregnancy you need to weigh up how the medicine might improve your and/or your unborn baby’s health against any possible problems that the drug may cause. Our bumps leaflets are written to provide you with a summary of what is known about use of a specific medicine in pregnancy so that you can decide together with your health care provider what is best for you and your baby.
Every pregnancy is unique. The decision to start, stop, continue or change a prescribed medicine before or during pregnancy should be made in consultation with your health care provider. It is very helpful if you can record all your medication taken in pregnancy in your hand held maternity records.
www.medicinesinpregnancy.org