The “Letdown Response” is slang for the term “Milk Ejection Reflex” (MER), which is the initial contraction of milk from the alveoli, from which the milk supply is stored prior to use. The grape-like clusters contract and squeeze milk down the milk ducts, or channels, when the body receives stimuli, such as nipple stimulation, baby crying, pumping, breast massage, etc. Read more on how overactive letdown works.
Foremilk vs. Hindmilk
This fast letdown of foremilk gets the feeding started, and the contractions calm after 1-3 minutes of the feeding, in which the baby sets the pace, and breastfeeds to their fullness. A mother may notice this letdown response with a tingling sensation or even a pulling from the inside of the breast. Some may not feel it.
- Foremilk: Foremilk is the milk that your baby drinks at the beginning of a feeding. Typically, foremilk is mostly water combined with other nutrients, carbohydrates (lactose), protein and vitamins.
- Hindmilk: Hindmilk is the milk that follows the fore, usually quite fatty.
Completing a feeding and not prematurely stopping allows the baby to get the perfect combination of nutrients and calories needed.
Occasionally, the letdown can feel overactive or too strong for the baby to handle. Another common term for this experience is called “forceful letdown,” and is commonly connected to an oversupply. This is not always the case, as sometimes the flow of milk is also controlled by how well the baby is latched and swallowing.
It's important to determine whether your nursling needs assistance controlling the flow, if there is an oversupply, or if the force can be attributed to the body releasing pressure from the milk supply. A latching difficulty can also lead to engorgement, and those symptoms can mimic an oversupply.
How Do You Know?
We see breast engorgement the first couple of weeks postpartum, as baby learns to feed and mother gets comfortable with positioning, hunger cues, and frequency needs. Also the body is still regulating and determining how much milk to make. After 4-6 weeks, the milk supply should be regulated accordingly and milk flowing at an appropriate rate.
Signs of an Uncontrolled, Forceful Letdown
- Your baby chokes and/or gags during the first 1-3 minutes of the feeding.
- You see milk dripping on the sides of their cheeks when feeding.
- Your baby clamps down on the nipple at the start of the feed (if unsure, observe the nipple before and after the feed for creasing or “lipstick” shape").
- Baby is gassy.
- Loud, sporadic gulping sounds.
- Baby has green stools (an exception is day 2-3 of life).
- Spitting up frequently.
- Develops reflux or colic.
- Fussy or irritated while feeding, may even frequently let go and re-latch.
What can we do about this? We need to address whether or not there is an oversupply and assess how well the baby feeds.
If the baby is struggling with the fast flow, we assess the latch and positioning, their mouth, and weight gain before and after a feed. Ankioglossia, or “tongue tie”, can mimic these issues of clamping, clicking and gulping, spit up, and fussiness at latching or staying latched. If they do not have full range of motion of their tongue, a vacuum seal cannot be formed and they rely on clamping to stay attached. Milk pools in their mouth and they gag or choke since the tongue is not controlling the movement down their throat.
This can absolutely lead to engorgement, or perceived oversupply if unaware. If not addressed in a timely way, it can cause the opposite, a low milk supply due to inadequate milk removal, causing the body to back off producing altogether. An IBCLC familiar with ankioglossia should rule this out, assessing for tethers that are too restrictive under the tongue, lips, and cheeks. They can refer accordingly to a healthcare professional who can address or provide therapy for ankioglossia: ENT, a dentist with specialization, and SLP for corrections and therapy.
Is it Oversupply?
Oversupply, or an overabundant milk supply, can be due to a number of reasons, including overdoing feeding + pumping regimens, PCOS, and the body simply not regulating to what your baby needs. Typically, supply is based on the “orders placed” by baby, or your pumping regimen. Milk is released or breasts stimulated, and the body replaces what is used and produces more if the stimulation calls for it.
Occasionally mothers who are unsure of their supply or anxious to have enough milk will feed their baby full time and pump additionally to either store for a stash or increase their milk supply. This can be overdone, though, and create more milk than what is comfortable or necessary. The build-up of pressure can cause a forceful letdown to prevent engorgement or mastitis but can be hard for your baby to handle. In this case, limit pumping sessions to 1-2x a day if feeding full time. Hand express at the start of a feed to lessen the initial letdown force, catch to store, and let the baby finish the feed.
Positions can help using gravity to slow things down, too. Opt for reclined or leaned-back cradle positions, with baby tummy-to-tummy and in control of the flow rate. Side lying is also quite helpful.
Block feeding may be recommended, feeding only from one breast each feeding, while using a cold compress in between, and really scheduling out feedings. However, this can also be done too much and create the opposite problem in too little milk, so this should be done only for a week and preferably with the help and guidance of a breastfeeding professional, or a lactation consultant. (IBCLC, CLC). Do not try to limit feedings during the first 4 weeks of life or slow weight gain. Wait for milk regulation goals at 4-6 weeks.
- Burp the baby after feedings, and keep them upright for a few minutes after feeding, allowing the breast milk to settle.
- Allow the letdown reflex to happen before bringing the baby’s mouth to feed while the overactive letdown is too difficult to handle, and catch the milk in a bowl or bottle to save for stashing.
- Use your breast pump on a gentle setting to collect the letdown.
- Apply cold compresses on days that the oversupply feels on the verge of engorgement.
- Try a different nursing position to slow the milk flow and use the weight of baby’s head and gravity to help them stay latched and drink comfortably.
- Listen for clicking sounds and struggling gulps, and have a lactation consultant assess if necessary. They can provide resources to correct things if needed, but also ways to nurse and protect milk production in the meantime.
- Nipple shields should be used sparingly and as a “band-aid” until latch is improved and milk flow slowed to a manageable rate. This can protect the nipples from further damage and may help the baby latch.