Introducing formula after ebf

[Quietlyalert]

My baby is 11 weeks old and has been exclusively breastfed other than in her first couple of days when she had some formula. I have a hen do this weekend but am having trouble expressing enough milk so my partner can give her breast milk throughout the day and evening (estimating she will need about 200ml per feed but have only managed a couple of hundred mls over two days). I'm therefore wondering about my partner giving her some formula to top up the expressed milk feeds. My concern is whether I will somehow be undoing the good work having ebf her fir so long. I've read conflicting info online and am a bit confused. A lot of my friends give the odd bottle of formula eg at night, but I'm wondering if adding even just the odd bottle of formula lessens some of the health benefits of ebf? Thanks

At this stage your breastfeeding is well established and the odd bottle of formula will not undo the hard work you have done in breastfeeding thus far. You've done really well, and the only thing is that you may need to express when you are out to avoid hard, achy and leaky boobs!

Why are you estimating 200ml per feed? That's on the (very) high end for an ebf 11 week old. Ebf babies don't take in as much volume as ff babies, because bm changes in content as your baby ages in a way formula does not, so it isn't a good idea to estimate a feed size of ebm from what a baby of that age takes in formula.

Kellymom has a good guide on how to estimate feed size of ebm. It depends on how often per day a baby feeds, but 90ml per feed would be an estimate if baby feeds 8 times per day, for example.

Thanks both for your replies. MissRatty that is encouraging and yes will definitely take a pump out with me! geekaMaxima I was guessing at 200ml as the one and only time we've been out I left the grandparents with 300ml for two feeds and she demolished it - we had to cut our evening short so I could come back and feed her! But I wonder if she just drank it as it was there rather than she was hungry. She does feed on average 8 times a day and is quite light. I'll check out Kellymom, thank you.

I think the guide is 1oz per hour you are leaving them for plus an oz.

Thank you, very useful - using both those methods it works out around 450-500ml or 90ml / feed.

There are ways to bottle feed a bf baby that are sympathetic to what they are used to and stops them accidentally guzzling too much. It's quite different to how many people might bottle feed, especially if they have previously only been used to fully ff babies.

The trusty Kellymom has info that's also available as a 1-page PDF you can hand to your dh if he likes how-to guides.