More tired than ever before, with a huge new set of responsibilities, plus a load of confusing hormones... it can be a recipe for arguments and tears!
Dummy or no dummy? Routine or no routine? If a couple has different ideas on how to bring up their baby there may be a lot of issues to work through.
An interfering mum or mother in law can cause more trouble between new parents if one partner feels bullied and unsupported by their other half.
The bond between a mother and child is a beautiful thing to see, but it can sometimes lead to new dads feeling a little pushed out.
Some mums feel a pang of envy at all the attention their baby receives, especially after being made such a fuss of while pregnant.
With all the new work that babies bring, if one worn-out partner feels that the other is not pulling their weight in the home, frustrations can boil over.
Couples may disagree over how much their lifestyle has to change. What if dad wants to have his regular Friday evening boys' night out but mum wants him to stay in?
If one new parent secretly still feels like a little kid themselves, having a baby can be a shock, finally forcing them to be mature and grow up.
With mum on maternity leave, and with the family living on a reduced income, dad may find the task of supporting his family financially a heavy burden.
There's not much time for any sort of fun in the bedroom for the first few weeks, and couples often find this lack of intimacy difficult.
