15 Reasons for a Sudden Drop in Milk Supply

Are you concerned about the sudden drop in milk supply? This blog post will provide 15 reasons why this has happened. We’ll look at both short-term and long-term causes, so you can have a better understanding of what is happening and what you can do if you’re seeing a drop in supply.

One day your child is nursing like a champ, and the next day, it’s like your milk completely disappeared.

A sudden drop in your milk can be startling and even depressing – especially when you aren’t sure why it’s happening!

It’s important to know some of the “hidden” causes of a decrease in breast milk, why it happens, and if it’s a problem. As an International Board Certified Lactation Consultant – this is one of the most common issues I see new moms encounter.

The good news is that you can almost always recover when you’ve identified the issue – it might just take a little time and patience. In this article, I will discuss possible causes for a sudden milk supply drop.

Why is My Milk Supply Decreasing

bags of milk

1 – Stress

While stress in and of itself may not decrease milk supply, the effects of stress can make it more difficult to nurse/pump on demand, and decreased stimulation can lead to decreased milk supply.

However, the biggest issue is that stress can inhibit the oxytocin of the body, which is what triggers the letdown reflex. If your letdown is impacted, this will definitely lead to less milk being produced.

2 – Mint

Mint or peppermint is a known substance that can cause a decrease in supply…though there’s some debate on how much it actually takes to cause problems. There isn’t a lot evidence that supports it, beyond informal surveys like this one.

With that said, many parents have reported to me that they experienced a drop in milk supply after consuming larger amounts f mint, so it’s something to be aware of. I would avoid any herbal supplements or teas that contain peppermint.

3 – Fenugreek


“What? I thought fenugreek was supposed to help your supply!”

Ah yes…Fenugreek. It’s often the first thing mothers turn to when struggling with their breastmilk supply. I did, too!

And for some, it can help. However, it can have the opposite effect – especially with women who have a thyroid problem. Fenugreek can “influence the active thyroid hormone your body uses. This [can] make hypothyroidism worse and reduce milk production.” (source)

If Fenugreek is going to work, you will typically see results in 24-72 hours…so if you aren’t feeling like it’s helping or hurting after that…I would probably just stop. It’s not worth smelling like maple syrup or causing you and/or your baby gastric distress!

It has some other unsightly side effects, which I don’t love. According to Mosby’s Handbook of Herbs and Natural Supplements, by Linda Skidmore-Roth, it may also cause reduced absorption of medications.

Supplements should be prescribed for use under the care of an herbalist, but here are some of the best lactation supplements to help guide a discussion with your care provider.

4 – Parsley

Parsley is another herb that is thought to decrease milk supply…so just be careful eating too much parsley in your meals! If you are experiencing a decrease in the pumping session for a long period of time, the best way of reviving would be to cut out the parsley.

5 – Birth Control


Birth control is one of the more common issues when it comes to milk supply – but the primary focus is typically on forms that have been estrogen and progesterone.

This is why the mini pill is often prescribed to breastfeeding mothers because it doesn’t typically affect breast milk supply. If it does, you can generally stop it quickly without too many negative results.

Many new parents are recommended an Intrauterine Device (IUD) as birth control. However, many mothers report having a drop in supply while using the Mirena IUD.

An article I read a while back discussed this topic, though the website seems to be down. The author suggested that more moms have their milk negatively impacted by it than we may realize, simply because they don’t realize Mirena is the culprit. I have personally worked with several moms who have had this happen.

There are plenty of mothers who can use the Mirena IUD with no effects whatsoever…but it’s impossible to know if it will affect your body or not until you try (and I’m not sure it’s worth the risk).

The copper IUD is non-hormonal and should not impact your milk supply. It can cause increased cramping and bleeding, so it’s important to talk with your doctor about your options.

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6 – Sage

Sage is yet another herb to be careful with. A small amount shouldn’t do too much harm, but a significant amount will have negative consequences. This is a common ingredient in herbal teas, so be on the lookout!

7 – Decongestants

Decongestants are designed to dry up your sinuses….and unfortunately, they can dry your milk supply alongside them.

Mothers trying to dry up their milk supply are often told to use a decongestant because it does a pretty darn good job. But when you need more breast milk to nurse your baby, you better avoid decongestants.

Here is some good advice on cold and cough remedies compatible with breastfeeding.

8 – Pregnancy

While it is possible to breastfeed while pregnant, most expectant moms experience a huge drop in milk supply – especially around the 12-week mark. If you experience a drop out of nowhere, you may want to take a pregnancy test and look for other early signs of pregnancy.

10 – Not Nursing on Demand

Scheduled feedings instead of feeding on demand can lead to a decrease in supply, especially in the early weeks of establishing your milk supply.

When you try, and schedule feeds or limit when baby is eating – especially in the beginning – it goes against the natural process of milk production and your body may not make milk when it needs to. Feedback Inhibitor of Lactation (FIL) is a process that occurs when you nurse less frequently, and it tells your body to stop making milk if there isn’t the correct amount of stimulation.

The best advice I can give new moms is to stop watching the clock and feed their baby when they want it (while, of course, knowing the signs that their baby isn’t getting enough).

12- Not Pumping When You Miss a Feed

breast pump

Breast milk production is a supply and demand process – if you miss a feeding or a pump session, you are telling your body you don’t need to make milk then.

Now, if you miss one pump session, it *probably* won’t affect things too much (though I do know some women where it has). However, it’s important to ensure you regularly stimulate the breast to keep up your supply.

I recommend you don’t go for more than three hours daily without nursing or pumping.

And if the baby gets a bottle instead of nursing, it’s important to pump around the same time. Even if your baby is eating from a bottle, your body doesn’t know that. You have to pump to tell your body, “Yes! Baby needs milk still!”

13- Wrong Size Flanges

So many mothers use the wrong-sized flanges, and as a result, the pump can’t remove milk as efficiently as it could be. As a result, if your body isn’t removing the milk as it should, it will think you don’t need as much milk.

Here is some more information on finding a proper flange fit.

14- Oregano

Yet another herb that’s associated with decreasing milk supply. Don’t go too crazy with your next Italian meal! This is also an essential oil to make sure you avoid while breastfeeding.

15- Low Milk Supply During Period

woman with flower and menstrual cup

This is probably the most common reason I see women seeing a sudden drop in milk supply. However, in my experience, it is more an issue of your letdown being impacted.

Per Kelly Mom: “For women who have this problem, calcium/magnesium supplements may be helpful. This practice has also been reported to eliminate most uterine cramping and some premenstrual discomfort such as water retention.

The recommended calcium supplement dosage is between 500 mg calcium/250 mg magnesium and 1500 mg calcium/750 mg magnesium (the higher dosage is generally more effective).

Calcium dosages this high should not be taken alone but as a calcium/magnesium (or calcium/magnesium/zinc) combination. Otherwise, the calcium will not be adequately absorbed into your body.”

It is recommended to start this regimen when you ovulate through the end of your cycle (source). Of course, please consult with your doctor before starting any new vitamins.

Here is some more information: Breastfeeding and Your Period: Everything You Should Know.

16 – Lack of Hydration

There are a lot of misconceptions about breastfeeding and hydration. You actually don’t need to drink a ton more – just to thirst. Around 64 ounces (plus a little more) can help.

However, a lack of water intake decreases the amount of liquid in your body. And it could be partially responsible for the decrease in supply.

Here is some more information about hydration and breastfeeding.

17 – Not Eating Enough Calories

It is suggested that breastfeeding mothers eat 300-500 extra calories a day. I recommend figuring out your BMR (the number of calories you burn just being alive) and adding extra calories to that amount.

With a lot of the lactation cookies and other lactation foods out there, I also think that the main benefit of these just comes from them adding more calories.

Here are a few helpful resources:

18 – Too much exercise

running lady

This goes hand in hand with not drinking enough water or eating enough calories.

Often, when a new mother starts a new exercise regimen, it can be hard to know if you are eating and drinking enough. Moderate exercise shouldn’t affect your supply too much – make sure you keep up those calories and drinking – and read these tips about exercise and breastfeeding.

I see exercise affecting a mother’s milk the most when it’s a sudden change, and it’s a lot of intense exercises (such as Cross Fit).

Many breastfeeding mothers do these exercises and do just fine, but you have to ensure you are eating enough and not losing all your extra water through sweat!

19 – Illness

When you are sick, it can be hard to eat and drink enough, and, quite frankly, even want to nurse. It can be common to see a drop in supply during this time. One thing to remember is that with most illnesses, you can still nurse your baby – in fact, it’s recommended so you can create the antibodies they need to fight it!

20 – Solids

I’ve observed that many mothers see a drop in supply around the 8-9 month mark. As I’ve thought about it, I have suspicions about why. The first one is that solids are becoming more a part of the baby’s diet.

I believe it’s vital to introduce solids and encourage them (and I don’t love the phrase “food before one is just for fun), however, breast milk must remain the primary source of nutrition. If the baby starts to replace too much milk with solids, your supply will take a hit.

If a mom has a drop around this time, I typically recommend cutting back on solids until you can regain your supply. Always offer breast milk first and then solids shortly after.

We always do baby-led weaning with our children, which I feel was a pretty natural transition to eating more solids without hurting my milk supply.

Signs Your Milk Supply is Decreasing

down red arrow

If you notice any of the following signs, your milk supply may decrease. Keep in mind that it may also just be your supply regulating to what your child’s needs are – which isn’t necessarily a bad thing!

  • Your baby is fussier than usual and seems unsatisfied after feedings
  • Your baby is gaining weight more slowly than usual
  • You feel like you have less milk than before
  • Your breasts feel softer than they used to
  • It takes longer than usual to get your milk flowing
  • You don’t feel the let-down reflex as often as you used to
  • You aren’t producing as much milk as you did in the early weeks of postpartum
  • Your baby is suddenly sleeping through the night and isn’t waking up for feedings anymore

If you suspect your supply is dropping, I recommend working with a lactation consultant as soon as possible.

Milk Supply Drop Overnight

Rarely a mom will experience a large drop in milk supply overnight. The most common culprits for this are:

  • Menstrual cycle-related changes
  • Pregnancy
  • Stress
  • Something you ate

One Breast Producing Less Milk Suddenly

You may experience a sudden decrease in one side – how strange! When this happens, it is likely due to the following:

  • Less stimulation on that breast – this may have been over time or all of the sudden
  • This can happen due to a breast preference (either mom or baby)
  • Incorrect block feeding

If this happens, I would encourage you to start each nursing session on that side and possibly add in a power pump session.

Ages Milk Supply Drops are Common

A sudden dip in milk supply can happen at any age. Some times seem to be more associated with them:

  • 6-8 weeks: This is when many mothers have their milk supply regulated, and as such, it seems like a drop when it’s just their body adjusting to their child’s needs
  • 6-7 months: The introduction of solid foods can certainly decrease milk supply, especially when food is introduced quickly and breastfeeding sessions are dropped.
  • 9-10 months: This is where babies tend to be distracted, go through nursing strikes, or a mother’s period begins to return.

How do I Know if My Milk Supply is Low?

stressed out mom

I think every mom worries about their milk supply at one time or another – it’s only natural to wonder if you are making enough (especially if you can’t know without looking

I’ve written about this topic in-depth in this post – The Ultimate Guide to Increasing Breast Milk Supply – but in general, here are a few basic tips for knowing if your milk supply has dropped:

  • Baby is upset at the breast and can’t seem to get a letdown
  • Lower weight gain (this does not always mean your supply is low – my boys had low weight gain because of reflux. But it’s certainly worth looking into)

I often see that when a mother’s supply starts to regulate, it seems like her supply has dropped. Many mothers have a larger supply when their milk first comes in, and if they are pumping (generally not recommended until about 4-6 weeks), and suddenly go from making tons of milk to a lot less, they will think they are losing their milk.

This is not usually the case. The goal is to produce enough milk for your baby – an oversupply is not as glamorous as you think. In general, a mother who is pumping and breastfeeding full time an expect to produce .25-2 ounces TOTAL from a pump session.

In place of a nursing session, the average is about an ounce or so an hour.

This is also why it’s essential to practice paced feeding and keep bottles to 1-1.25 ounces per hour. I often see mothers who unknowingly “overfeed” their babies because they give their baby all the milk they pump…and then when their supply regulates more, they worry because they can’t keep up.

Keeping to the 1-1.25 ounces per hour rule helps prevent this (and you can freeze that extra milk!)

When Does Milk Supply Regulate?

Most women see that their milk regulates around 4-6 weeks.

In conclusion, there are many potential reasons why a mother may experience a sudden drop in her breast milk supply. These include illness, stress, lifestyle changes, dehydration, insufficient rest or nutrition, hormonal imbalances, and medications.

Mothers need to be aware of these factors so that they can take steps to manage them if necessary. Working with a qualified health professional such as a lactation consultant, can also help ensure that the mother receives the support she needs to maintain her milk supply.

I hope that this was helpful to anyone worried about a sudden drop in milk supply.

Please feel free to leave a comment if you have any questions or concerns!


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