Which breast to start on sounds like a tiny question, but it affects both your supply and your comfort. The rule itself is simple. Remembering it when you're running on no sleep is the hard part, so here are some ways to make that easier.

TL;DR: Start each feed on the breast you finished on last time (or the fuller one). Alternating keeps your supply even and both sides comfortable. Use any system that helps you remember, a hair tie, a note, or an app that tracks the side for you.

Why which side matters

  • Even supply. Milk production runs on demand. If one breast gets used more, it tends to make more, and you can end up lopsided.
  • Comfort. Regularly draining both breasts helps avoid engorgement and lowers the risk of a clogged duct.
  • A fuller feed. When a breast gets properly emptied, your baby reaches the richer, higher-fat hindmilk later in the feed.

The simple rule

Start the next feed on the breast you ended on. Because that side got less time and is fuller, beginning there evens things out over the day. If you're not sure where you ended, just start on whichever breast feels fuller.

One breast or both per feed?

Both are normal. Let your baby finish the first side before you switch, so they get the richer milk toward the end. Then offer the second breast; if they take it, great, and if not, start there next time. Newborns often want both sides, while older, efficient babies are sometimes happy with one.

Low-tech ways to remember

  • The hair-tie trick. Wear a hair tie or bracelet and move it to the wrist on the side you'll start with next.
  • A safety pin or clip moved to the bra strap of the next side.
  • A nursing necklace slid to one side.
  • A quick note on your phone or a notepad by the chair.

These all work, right up until you're exhausted and forget to move the hair tie. Every one of them depends on you remembering to update it, which is a lot to ask when you're this tired.

The easier way

This is exactly the problem we built MilkMode to solve. When you finish a feed, it remembers which side you used. Next time, it tells you which breast to start on and starts the timer with a single tap (one-handed, in the dark, and without a hair tie in sight), so all you have to do is glance down.

Don't aim for perfection. Missing the "right" side occasionally won't hurt your supply or your baby. Roughly even use over time is plenty, so you don't need flawless alternation at every feed.

Want the companion question answered too? See how long to breastfeed on each side, and our overview of how to track breastfeeding without losing your mind.

Keep reading

Never wonder which side again

MilkMode remembers the last side for you and starts the timer with one tap. $4.99 once, no subscription, works one-handed in the dark.

Download on the App Store

Related reading

This article is general information, not medical advice. If you have concerns about your baby's feeding, weight, or hydration, contact your healthcare provider or a lactation consultant.