We love Dr. Brown’s Natural Flow Bottles. In fact, we use nothing but these bottle with our infant. They fight colic, discourage ear infections, and preserve vitamins. That’s a lot of good from a baby bottle. (See our full review of the bottles here.)
But when our daughter was about six weeks old, the bottles started leaking whenever we used them. At first we thought we had somehow broken the bottles, but as it turns out, a lot of parents have leaky bottles. So what’s the deal? Did the makers of the bottle just forget that leaking is awful?
We decided it was time to do some research. And the answer, of course, was that we were just using the bottles incorrectly. Whoops! So we adjusted how we used the bottles and we haven’t had any problems with them since. And given all the benefits of these bottles, we really did not want to switch brands. So solving this problem was a huge relief.
Why Do the Bottles Leak Sometimes?
Dr. Brown’s bottles work so well because they have a patented air vent that redirects air bubbles from the nipple to the back of the bottle as a baby feeds. This is why the bottles are so good for gassy babies; they reduce the air that your baby swallows as she feeds. But the air vent that makes the bottles so great comes with a small downside: milk or formula can exit the bottle through the vent if the bottle is not handled properly.
To be clear, the bottles do not typically function this way, and most consumers never see a leak occur at all. After the leaks began, we contacted Blake’s sister who had used the bottles multiple times as a nanny. And unsurprisingly, she had never had a single leak with the Dr. Brown’s bottles. The leaks are pretty rare.
But small errors can occasionally cause milk to leak out the vent. So let’s take a look at how to keep that from happening.
Don’t Overfill the Bottles
Do not exceed the fill-line of these bottles. If the bottles are advertised to hold eight ounces, then you should never put more than eight ounces in the bottles. Otherwise the extra fluid may just escape into the vent (and onto your hands as you feed the baby).
Keep in mind that if your use formula, eight ounces of water plus some powdered formula equals more than eight ounces of total fluid. So if you put that combination into an eight ounce bottle, you could be looking at some leaking. So be cautious. Overfilling is easy to do but annoying to clean up.
Don’t Heat the Milk With the Vent in Place
Parents often desire to heat milk up for their infants. But as milk is heated it expands. If you keep the Dr. Brown’s vent in place as you heat milk or formula, the liquid will be forced up into the vent. And as we have already covered, that leads to leaking.
So to avoid this problem, either heat your bottles without the vents (the preferred option) or loosen the nipple collar after heating the milk so that the pressure can equalize and the milk can leave the vent. Then when it is time to feed your baby, re-tighten the collar.
Be sure though not to ever place the vent in milk heated above body temperature. If you place the vent into milk that is overheated, the milk may rise into and condense inside of the vent. So always wait until the milk is cool enough for your baby to actually use before placing the vent inside.
Don’t Shake the Bottle With the Vent Inserted
If you shake your bottles to mix formula while you still have the vent inserted, you are likely causing liquid to enter the vent and leak out later. There are a couple ways to avoid this problem.
First, you could mix the baby formula by stirring the liquid instead shaking it. This method has the added benefit of reducing air bubbles (which can further reduce infant gas).
However, many parents (us included) find that shaking the bottles is a lot easier. So if you prefer shaking your bottles, use Dr. Brown’s storage caps. The caps are super affordable and easy to use. Shake with the cap in place, and when the formula is properly mixed you can remove the cap and insert the full vent assembly.
Don’t Submerge the Reservoir Tube
When feeding your baby, avoid keeping the bottle perfectly level. More specifically, you should avoid submerging the reservoir tube (the long part of the vent) under liquid as you feed your infant. If the bottle isn’t held properly and the tube is submerged in the milk, then you might end up with some leakage. The ideal angle is 45 degrees during feeding. This should consistently keep the end of the tube out of the the liquid.
But if you do mess up and liquid ends up inside the reservoir tube, don’t worry. All you need to do is stop the feeding, turn the bottle upright, and loosen the nipple collar a bit to release the built-up pressure. The milk will fall back into place at the bottom of the bottle, and you can then re-tighten the collar and resume feeding.
Don’t Over-Tighten or Under-Tighten the Nipple Collar
Both over-tightening or under-tightening the nipple collar can cause leakage. Over-tightening causes too much pressure to build up, and under-tightening the collar doesn't allow the bottle to form the seal that holds back the liquid during feeding.
This may seem frustrating, but it really isn't. The reality is that most people naturally tighten the nipple collar correctly; it's not hard to get correct. But if you struggle here, just follow this rule: twist the collar onto the bottle until you feel a small amount of resistance, then give it one more half-turn.
Use an Age-Appropriate Nipple
If your baby is sucking on the nipple too hard, the baby could cause the nipple seal to break. If this happens to you, you likely to need to move up to a faster-flow nipple. On the other hand, if your baby tries to block the flow or slow down the milk, the infant can cause fluid to be forced backward into the vent. If that happens to you, then you probably need to move to a slower-flow nipple. Thankfully, Dr. Brown's bottle nipples are very affordable.
We consider Dr. Brown’s Natural Flow Bottles to be the best on the market. However, we do understand why some parents become frustrated with the leaking. So follow these tips, and you’ll likely never have anything but good experiences with these bottles.