There is a lot of research on most vaccinations out there. Some of it is valid research with a good study size, others are not so good (they all get rated). We asked our midwife about any effect on the baby compared to babies who don't have the Hep B and she said she personally hasn't noticed an effect. She mentioned there was one research paper that stated it can make breastfeeding more difficult but it was a small study and inconclusive. She also said that it has to be your informed decision, but if there is no high risk then it is up to you. Also, if you do choose to have your baby vaccinated straight away, they will get a total of 4 injections instead of the standard 3, not sure why, maybe something to do with a baby's immune system. Whatever decision you choose to make is the right decision for you and your child. Vitamin K again needs to be your decision, but is highly recommended as babies are born with low levels of this and it is needed to assist with blood clotting. It can prevent very serious complications that may not be picked up until it is too late. It has to be your personal decision. We are probably going to withhold Hep B as we are a low risk and baby won't be attending child care for a while, but we will defintitely be giving vit K - better to be safe than sorry.