Breast is best. That much we know, and that's what women are told from the moment they enter motherhood. 

Breast feed for as long as possible. It’s best for you and it's best for the baby.

It’s a loaded and emotive issue. 

Breast-feeding doesn't come easy to some women. Some mothers and babies just never get the hang of it, and there are reasons for that. Mastitis is one reason. I had it when I was in London and Finn was a couple of months old. My midwife said feed through it, it will clear....and I did. But I don't think I’ll ever forget the pain. It was as if razor blades were passing through your breast. 

There are many other reasons. A baby may be tongue-tied which makes latching-on difficult, tiny babies often struggle to make it through a feed without falling asleep so they never get beyond the hydrating fore-milk and make it to the 'hind milk' - that's the second wave of milk that comes through that's high in fat and calories, and sustains the baby. So they don't get the milk that will sustain them. So they fall asleep and then wake up starving and crying again, and the pattern goes on. 

Some women simply don't produce enough milk. They’re exhausted. They’re stressed: motherhood in those early weeks and months can be enormously overwhelming. And yet the pressure goes on. Breast-feed your baby or you're failing your child and yourself.

I can't tell you how many mothers I’ve met who are distraught, or feel a failure, or are plunged into post-natal depression because of their struggles with breast-feeding.

And so today I read a study that says New Zealand children are not being breastfed for as long as international guidelines recommend. 

The study is in the New Zealand medical journal. It says only half of New Zealand babies are breast-fed exclusively for four months. 

The world health organisation recommends that children be fed exclusively for six months, and continue for two years and beyond. 

Well, those guidelines are designed with a one size fits all approach. 

Yes, those guidelines are great if you're south Sudanese. Women should be encouraged to breast-feed for up to two years in Africa because they don't have access to formula or clean water. In countries like India and Bangladesh and Bolivia it's the same. 

But here, tell a woman to breast-feed for up to two years and she'll probably ask you how she's going to contribute to the mortgage? Many women are back at work before their child is two.

And that's why I’ve never been a fan of guidelines. 

There is no 'one size fits all' for children. There really isn't. I had a big, robust baby who was in the top percentile for size. Finn was a big, round chubby bubba who fed with gusto, and my friend had a baby the same age as Finn, and he was a tiny little dot who could barely stay awake to feed and was in and out of hospital because he struggled for weeks to gain weight. In the end, his mother went against the advice of the hospital and gave him formula. And what do you know, he put on weight and life was much better for everyone. 

The thing is, advice is important. It really is. Give new mums the best support you can. But remember this too. Every mother does what she thinks is right for her and her baby. It’s called a mother's instinct, and no world body should make her feel guilty if she doesn't follow what academics believe to be 'best practice'.