You need a small amount of vitamin A to keep healthy.

http://www.patient.co.uk/health/planning-to-become-pregnant

Foods and drinks to avoid

You should not eat the following if you are pregnant or trying to become pregnant:

• Anything with a lot of vitamin A. You need a small amount of vitamin A to keep healthy. However, large amounts can harm an unborn baby. So, avoid:
  • Liver and liver products such as liver pâté and cod liver oil supplements.
  • Vitamin tablets or supplements which contain vitamin A.