A mother should not fear or feel PND or depression post birth at all.
It's not a medical condition nor a mental health issue.
Giving birth and bringing up a baby is hard work the first 6-12 months.
PND is a 'label' given to a woman's feeling as a result of massive hormone changes taking place, a lack of sleep, afterall baby wakes you up when baby wants, not when you want, and the reality that mum still has to do all the same things she did before.
Depression if any occurs, and if it's clinical depression, is as a result of exhaustion and the negative feeling that mum is not 'keeping up' and meeting expectations.
ANYONE who makes a mum, be it first child or 6th child or more, feel bad because they are a mum should not only be ignored, but removed from your circle, at least till you can deal with people being negative.
Don't let the world around you bring you down and don't feel you aren't coping. If you are really struggling, you'll know and your friends and family will help, and if they don't, then you are stronger than them already!
Embrace the hormone changes that take place around 3 months, see it as a growth, rather than a trauma or negative, and simply look into bubs eyes and smile, maybe a soft blow of breath at babies face to make bub smile and react...
You don't have to 'suffer' PND or 'depression' you can turn it into a base line and simply reject it's dominance.
Enjoy being a mum, it's a time to grow yourself and your baby. Get over the wannabe's who think they know more and tell them to come back in a month or 6 :)