The biggest risk factor is an infection called toxoplasmosis.
Toxoplasma gondii is a parasite that can be present in the soil through cat faeces. Toxoplasmosis is quite common and is not dangerous to healthy adults, who may have no symptoms or mild flu-like symptoms; however, it can cause abnormalities in unborn children, so it is important to avoid if you are pregnant.
NHS does not screen for it, because it is considered to be a very low risk, however you should take all of the steps you can to avoid it. If you have contracted toxoplasmosis in the past then you will have developed immunity and it is of no concern to you or your baby, but you do not want to contract it for the first time while pregnant.
You have probably already read advice that you should not be the one cleaning out your litter tray if you have a cat and you are pregnant, that you should wash all vegetables and fruit thoroughly before eating, and that you should avoid eating cured or raw meats as well as unpasteurised goats cheese or milk – these are all in order to avoid toxoplasmosis.
In terms of gardening, there are a few easy steps you can take to minimise your risk.