As a microbiologist and an expectant mother the question of 'How sterile an environment should we bring our babies up in?' is often asked of me.
Recently I have been thinking about this question more deeply because of my own pregnancy. Our baby's immune system is the key component to ensuring they have resistance to disease and this can be passed on from mother to baby through breastfeeding, but in addition babies need to be exposed to relatively harmless bacteria, viruses and allergens to build up their own immune systems. This will ensure they have resistance to certain infections for the rest of their lives.
The Hygiene Hypothesis, which was first explored in the late 80's by Dr Strachen, suggests that the reduction of early childhood exposure to disease through too clean an environment and increased use of antibiotics has actually led to increased allergies in children. In 2004 Dr Ferdman suggested that 'parental paranoia' where parents are too worried about exposure to minor infections such as the common cold is actually reducing our children's abilities to cope with infections and thus actually making them more susceptible to disease.
For instance prevention of bacterial diseases such as food poisoning can be and should obviously be avoided; the hygiene hypothesis is not implying that we should expose our babies to harmful diseases and thus bring them up in an unclean and unhealthy environment. But what it is suggesting is that an overly clean or sterile environment can do more harm than good. Children should be playing outside and exploring and being exposed to household pets: this will actually improve their immune systems and overall health.
Speaking of pets! I have a labrador cross which my husband and I rescued and nursed back to health a few years ago and is now a major part of our family. I have been contemplating how this will affect our child's health. However, recent studies by Licarrdi et al. have shown that increased exposure to our furry friends in particular cats, in early childhood may lower the risk of developing an allergic reaction to pet hair. Thus, once again greater exposure evokes greater resistance.
Therefore, overall a sensible approach is required by parent. Our children don't need to be brought up in sterile environments! They need to be exposed to everyday dirt and germs to enable them to build up their immune systems and have the ability to fight infections. I will certainly be encouraging our baby to play outside in the mud and build a forever bond with our doting Labrador!
Dr Katie Laird Senior Lecturer in Microbiology, De Montfort University and Mum-To-Be.