Pregnancy and chemicals

These guidelines apply to pregnant employees and students who work with chemicals and gases. The guidelines also apply to the supervisors of these workers.

Norsk versjon - Gravide og kjemikalier

Topic page about HSE | Pages labelled with pregnancy


Information for pregnant employees/students

Pregnant employees/students have to be particularly aware of all labelling in the facilities in which they work, which chemicals/gases they will be working with and the properties these substances inherently have.

See also the general guidelines about pregnancy during work or studies, accommodation, leave and other issues

Information for supervisors

Some chemicals and working situations can damage an individual's reproductive ability or injure foetuses. This should be carefully considered in determining appropriate work assigments for women and men who are in their reproductive years.

The pregnant employee/student's own view of the situation should also be part of the assessment of the working conditions. If the pregnant employee/student wants alternative tasks or a relocation, the employer should comply with these wishes when possible.

See also the general guidelines about risk assessment, accommodation, leave, etc.

Chemicals and general recommendations

Before a pregnancy, both parents' working environment is important. Damage can occur if either the female's or male's reproductive cells are exposed to harmful chemicals before fertilization has taken place.

Working environment conditions rarely cause risk of damage to reproductive cells, but we know that certain chemical substances can cause damage to both female eggs and male sperm cells. Examples of such chemicals are n-hexane, benzene, toluene.

Additional information about this subject can be found on the facts page about pregnancy and working environment (in Norwegian).

Risk statements and danger statements that require extra attention

(Under construction)

H-statements and Description

H340May cause defects
H341Suspected of causing genetic defects
H350May cause cancer
H351Suspected of causing cancer
H360May damage fertility or the unborn child
H361Suspected of damaging fertility or the unborn child
H362May cause harm to breast-fed children


There is usually no grounds for special consideration for pregnant women with regard to agents that are not known to cause damage/problems for pregnancies or foetuses. These include chemical irritants and contact allergens.

Substances to be aware of

  • Substances that can be absorbed through the skin, including certain pesticides (e.g. organophosphates, chloric pesticides, certain fungicides)
  • Endocrine disruptors (e.g. bisphenol A, phthalates). These substances can disrupt the development of the foetus, including its reproductive organs.


At NTNU, pregnant women should generally be excused from work with cytotoxic substances, since this exposure to can harm the foetus.

Anaesthetic gases

Anaesthetic gases are suspected to cause harm to the foetus Use in closed systems does not cause risk for pregnant women. The risk of foetal harm is considered insignificant if the air concentration of anaesthetic gases is lower than 1/10 of the value for implementation of measures / boundary value (in Norwegian).

NTNU advises pregnant women against contact with anaesthetic gases. If work with such gases is necessary, the work must be performed under controlled conditions and in a manner that avoids exposure, for instance by distribution in a closed system, ventilation, and use of personal protective equipment.


The health effects of exposure to nanomaterials have not been fully studied. Consequently, the basic rule at NTNU is that pregnant women should not work with nanomaterials.

However, situations can occur where there is no reason to believe that pregnant women (or others) are subject to hazardous exposure. Examples include situations where the nanomaterials are handled in a closed system or as solids. Based on a risk assessment, pregnant women can in these situations perform tasks involving nanomaterials.

Mercury and mercury derivatives

The workplace and tasks must be adaptable, so that pregnant women can work with mercury / mercury derivatives without being exposed to a situation where the mercury can be absorbed through contact.

Carbon monoxide (CO)

Pregnant women and foetuses are more sensitive to the effects of CO than others. CO displaces oxygen from the blood's haemoglobin, and can cause a lack of oxygen to the foetus. The amount and duration of the exposure is very significant.

Chemicals and breastfeeding

Chemical substances that are taken up in the mother's blood can be transferred to the breast milk and reach the baby this way. A workplace that is unsuitable during pregnancy due to contact with chemical substances, will commonly also be unsuitable during the breastfeeding period.


NTNU regulations



Occupational Health Services


Approved by the Director of HSE – 29. august 2014 – HMSRV5101E – ePhorte 2014/.....