Pregnant women should consume no more than 200mg of caffeine a day, the equivalent of two mugs of instant coffee, the guides say.
Babies under six months old should not be fed peanuts, although it is safe for expectant mothers to eat peanuts during pregnancy, they recommend.
The two books, Pregnancy and Birth to Five, are given free to all expectant women and new parents by midwives and health visitors.
A new step-by-step feeding guide is also included in books. This explains how to breastfeed and express milk and includes information for partners and answers to common questions.