Many biological agents categorised as hazard group 2, 3, and 4 can affect the unborn child if the mother is infected during pregnancy. These may be transmitted through the placenta while the child is in the womb, or during or after birth, for example through breast feeding or through close physical contact between mother and child.
Examples of diseases/agents where the child might be infected in one of these ways are Hepatitis B, HIV (the AIDS virus), herpes, TB, syphilis, chickenpox, shingles, listeria monocytogen and typhoid.
For most workers, the risk of infection is not higher at work that living within the community; but in certain occupations exposure to infections is more likely, for example laboratory workers, health care workers, those looking after animals and dealing with animal products.
Some biological agents are, however, known to cause abortion of the foetus or physical and neurological damage. Rubella (German measles) and toxoplasma can harm the foetus, as can some other biological agents, for example cytomegalovirus and Chlamydia in sheep. Where staff and students are likely to be exposed to such agents, this should be taken into account in risk assessments carried out under COSHH.
Account must first be taken of:
- the nature of the biological agent;
- how infection is spread;
- how likely contact is;
- what control measures there are.
The Control Measures may include:
- physical containment;
- hygiene measures;
- use of available vaccines (if exposure justifies this).
If there is a known high risk of exposure to a highly infectious agent, then it will be appropriate for the pregnant worker to avoid exposure altogether, e.g. pregnant women must not work with calving cows, farrowing sows, lambing ewes, or handle cat faeces.