If you’re tandem nursing a toddler (or preschooler) and newborn, congratulations on your new arrival! I’m sure a lot of your attention is focused on your youngest child, but you definitely have an adjustment with your relationship with your toddler too.

And if your older nursling is breastfeeding a lot, you might notice their face getting a little fuller and those chubby thighs getting chubbier. It’s not just your imagination! But don’t worry.

And if you’re feeling guilty for even worrying about your toddler’s weight, don’t feel guilty either. It’s okay that you want to make sure you’re taking care of your little one. Just don’t take any of those insecurities out on your child.

Read on to learn about the effect of newborn breast milk on your toddler’s health and weight.

What happens when your milk comes in while tandem breastfeeding

In the first few days of tandem nursing (or even if you’re nursing while pregnant), you may be afraid that you won’t produce colostrum, the thick “liquid gold” substance full of antibodies and perfect for newborns.

RELATED: Tandem nursing – Breastfeeding while pregnant or nursing two kids at once

RELATED: Will I still make colostrum if I’m nursing my toddler?

But your body is programmed to make colostrum for the first 2-5(ish) days postpartum, and after that, your full milk will come in.

This mature milk has lots more volume and flavor than what you were producing during pregnancy and during the early days of your newborn’s life. It’s richer and sweeter than colostrum, which tends to taste salty.

Tandem nursing mother with newborn baby boy and toddler baby girl

And your breastfeeding toddler will likely be super excited about it. You’ll notice that they want to nurse a lot, probably much more frequently than they did before the baby came.

NOTE: If it’s bothering you when your toddler breastfeeds, like, you’re feeling a sense of skin-crawling or rage, you’re not alone, and it’s not because you’re a bad mom. You’re likely dealing with breastfeeding aversion and agitation. Get more info and help here.

Some toddlers will continue eating solids like they did before, but others may become much less interested in solids once your milk comes in. Don’t worry, it won’t last forever.

Will my tandem nursing toddler steal milk from my newborn?

You may initially be afraid that your toddler will “steal” milk from your newborn. But since your milk production works on supply and demand, you’ll simply produce more milk to keep up with the two of them.

In fact, I find it really useful to have a nursing toddler around for when I’m feeling engorged during those first few weeks of breastfeeding. They help take the edge off, get milk flowing, and make it easier for a newborn to latch.

While some people suggest you always let your newborn nurse first before your toddler, I can see it both ways. Generally, the first milk that comes out, the foremilk, is less fatty and filling. In fact, too much foremilk (like when you’re engorged) can upset your baby’s tummy, causing gas and a greenish, frothy poop.

RELATED: Engorgement relief for breastfeeding

The milk from the end of a feed, the hindmilk, tends to have more fat and is satiating. So don’t worry if you let your older child nurse first. The most nutrient-dense milk is what comes at the end anyways.

Is it okay if my tandem nursing toddler gains weight?

If you’ve noticed that your toddler’s enthusiasm for your newly increased milk supply has caused their cheeks to look a little chubbier, you may be worried. Is it a dangerous amount of weight gain?


And on top of it, you may feel guilty for even asking the question. I shouldn’t care about my child’s weight, right? Am I a bad mom for worrying about this?

First off: You’re not a bad mom. You’re an awesome mom because you care enough to nurse two children at the same time, and because you pay enough attention to your child to care about their physical health.

Secondly: This is totally normal and not a problem. It might be that your child was about to go into a growth spurt anyways. And even if that’s not the case, it will still be okay.

Within a few months, your toddler will probably lose their single-minded interest in breastfeeding constantly.

And truth be told, this is one of those many things in parenthood that seems like a big deal at the time, but eventually becomes irrelevant.

In fact, I saw someone in a support group the other day asking if it was okay that her tandem nursing toddler was filling out a bit since her baby came. It suddenly reminded me that I had the same fears too when my oldest was tandem nursing.

I asked the pediatrician about it at her two-year checkup, and she said not to worry about it. We kept an eye on her growth chart, and although it did bump a little bit at the time, it evened out after a while.

The thing is, that phase didn’t last long. She’s 7.5 years now, and I had totally forgotten about my angst over her weight gain (and accompanying angst over my angst) until I read this other mom’s concern.

Should I set boundaries on my toddler’s tandem nursing?

That’s up to you and your child. Remember, breastfeeding is a two-way street, especially for older nurslings.

If your toddler is breastfeeding so much that it’s bothering you or setting off nursing aversion, there’s nothing wrong with setting gentle, respectful limits.

If you don’t have a problem, though, there’s no reason you have to set boundaries on your child’s nursing (except maybe if your newborn is hungry and your older child isn’t wanting to take turns).

If you want to night wean your toddler, get help from this post, and check this out for a great way to help your toddler feel special even when you’re night weaning.

Conclusions on worry over tandem nursing toddler

If you’ve been worried about your toddler nursing extra after your new milk supply came in, breathe easy. In a few months or a few years, you likely will have forgotten this whole situation, and everything will be fine.

Keep offering solids, support your child, and make sure that you have a support group yourself.