If you’ve ever noticed that one breast is producing significantly more milk than the other while expressing, you’re not alone! It’s actually quite common for one side to be a “super producer” while the other lags behind. But when the difference becomes more noticeable—especially if one side has slowed down over time—it can be frustrating and leave you wondering what’s going on.
So, let’s talk about why this happens, how to encourage better output from the slower side, and what to do if your pump settings suddenly need adjusting.
Why Is One Side Producing Less?
There are a few possible reasons why one breast may be slacking off while the other is still going strong:
1. Natural Differences
Most people have a dominant side when it comes to milk production, just like we have a dominant hand. It could be that the right side has always been your powerhouse, and the left side has always been a bit slower, but the difference wasn’t as noticeable before.
2. Pump Flange Fit & Suction
If you’ve recently had to increase the suction on your pump to get a full drain, it might mean that your pump parts need checking:
• Flange Size: If your flanges aren’t fitting correctly, it can affect how efficiently your milk is being removed. Engorgement, weight fluctuations, or simply prolonged pumping can change how your breast fits in the flange over time.
• Worn-Out Pump Parts: If your pump has been working hard, the valves and membranes may need replacing. If these parts are stretched or worn out, suction efficiency drops, leading to incomplete milk removal.
3. Letdown Reflex Differences
The stronger-producing side may simply have a faster letdown, making it easier to empty fully during each session. The slower side may need a bit more encouragement to trigger letdowns.
4. Latch History
If you breastfed before transitioning to exclusive pumping, your baby may have preferred one side over the other, naturally encouraging higher production in that breast.
5. Hormonal Shifts & Fatigue
Hormonal changes (like your cycle returning or postpartum hormonal shifts) can temporarily affect supply. Stress, dehydration, or lack of sleep can also impact one side more than the other.
How to Boost the Slower Side
The good news? There are plenty of things you can try to help your left side catch up!
1. Start with the Slower Side
When you begin pumping, always start on the left side first. Your first letdown is often the strongest, and this can encourage better milk removal from the slower side.
2. Power Pumping
Power pumping is a great way to stimulate supply on one side. Try adding an extra pump session just for the left side or mimic a cluster feeding session:
• Pump for 10 minutes, rest for 10 minutes
• Pump for 10 minutes, rest for 10 minutes
• Pump for 10 minutes again
Doing this once or twice a day for a few days can help stimulate an increase in production.
3. Massage & Compression
While pumping, use breast massage to encourage better milk flow. Massaging in circular motions or applying gentle pressure to different areas of your breast can help trigger additional letdowns.
4. Heat & Relaxation
Applying warm compresses before pumping can help relax the milk ducts and improve milk flow. If you find yourself tensing up while pumping, taking deep breaths or listening to calming music can help release oxytocin, which plays a key role in milk letdown.
5. Switch Up Your Pumping Routine
• Try Different Pump Settings – If you’ve increased the suction level, you might need to experiment with going back down to see if gentler suction works better for full drainage. Too much suction can sometimes cause nipple swelling, making milk removal harder.
• Check Flange Fit Again – If one side isn’t draining well, the fit might need adjusting. You could even try a different size for each side.
• Try Hand Expression After Pumping – Sometimes, the pump doesn’t fully empty the breast, but a bit of hand expression at the end can remove leftover milk and signal your body to produce more.
6. Increase Milk-Boosting Foods & Hydration
Even if you’re getting good overall volume, small tweaks to your diet can help encourage better production in both breasts. Foods like oats, flaxseed, and almonds are known to help milk supply, and staying well-hydrated is key.
When to Seek Help
If your slower side suddenly drops dramatically in production and nothing seems to help, or if pumping becomes painful, it might be worth checking in with a lactation consultant to rule out any underlying issues like a clogged duct or mastitis.
Final Thoughts
Milk supply naturally fluctuates, and it’s completely normal to have one side that produces more than the other. By starting your sessions on the slower side, using massage, adjusting your pump settings, and adding a power pumping session, you can help balance things out. But most importantly—be kind to yourself! Your body is doing amazing work, and even if your supply is uneven, your baby is still getting all the incredible benefits of your milk.
Have you experienced uneven milk production? What worked for you? Let’s share tips and support each other—drop your experience in the comments!
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