Blockfeeding or"Staying on the same breast": the advice that can reduce your lactation

Imagine a 15-day-old baby. Weight gain is insufficient and the baby is sleepy at the breast. Stools have been green for several days. Worried, the mother turns to an online breastfeeding group. Within minutes, responses pile up: "It's a foremilk/hindmilk imbalance", "You have too much milk at the start of the feed", "Stay on the same breast so the baby gets the fatty hindmilk."

She follows the advice. And breastfeeding continues to deteriorate.

This is a situation I see regularly in consultations.

Green stools at 15 days: a signal that must be read in context

A breastfed baby's stools follow a very precise pattern in the first days of life:

• Day 1–2: meconium : black and sticky

• Day 3–5: transitional stools: brown-green

• From Day 5 onwards: yellow, seedy stools, at least 2 to 3 per day

A 15-day-old baby should have had several yellow stools every day for some time. If stools are still green and weight gain is slow ( or the baby has gone several days without a stool) =>this is not a mysterious "milk imbalance": it is a sign that breastfeeding is not yet established.

Green stools in this context are late transitional stools: they indicate that the baby is not yet receiving enough milk by volume. The digestive system is still in a phase that should have resolved well before now.

This is not a question of milk type, but a question of quantity.

Green stools: almost always normal, very rarely pathological

Outside of the early newborn period, green stools in a breastfed baby who is gaining weight well are, in the vast majority of cases, perfectly normal. They can appear occasionally with no clinical significance whatsoever, as I explain in my article on breastfed baby stools.

There are many common, transient causes: a cold or gastro virus, teething, a recent vaccination, an antibiotic course (in mother or baby), phototherapy for jaundice, or simply a high intake of green vegetables in the mother's diet.

Truly pathological causes of green stools ( cow's milk protein allergy with blood in the stool, gastrointestinal infection) are rare, and are generally accompanied by other clearly identifiable clinical signs: visible blood, foul-smelling stools, eczema, intense crying, reflux, poor weight gain. A medical consultation is warranted in those cases, but there is no need to jump to conclusions for occasionally green stools in a baby who is growing well and thriving.

"Hindmilk": a concept that needs serious qualification

We often hear about the "thin" milk at the start of a feed and the "rich, fatty" milk at the end. This distinction, while not entirely wrong, is widely misunderstood and leads to harmful advice.

Here is what physiology actually tells us: the fat content of breast milk is not linked to the duration of a feed, or to whether the breast has been "emptied". It is linked to the degree of fullness of the breast. The fuller the breast, the lower the fat content. The more regularly the breast is drained through frequent feeding, the naturally richer the milk. Fat content is therefore a continuous and dynamic phenomenon.

In practice, this means that pushing a baby to "finish" one breast does not mechanically guarantee fattier or more caloric milk. What it does guarantee, however, is a feed that is less well adapted to the baby's satiety cues ,and in some situations, a disruption of milk production.

Staying on the same breast ("blockfeeding") is an advice reserved for one specific situation

The recommendation to keep feeds on a single breast does exist: but it is reserved for one very specific context: true oversupply.

When a mother is producing an excessive volume of milk, with persistently engorged breasts and forceful letdowns, the baby may have explosive, liquid, greenish stools in large quantities, feed very frequently, gain weight very rapidly, and be uncomfortable during feeds (coughing, releasing the breast, crying and wriggling) and after each feed (regurgitation, gas, significant crying) ,all due to lactose overload. During lactose overload, the lactase enzyme in baby's gut is overwhelmed: lactose goes undigested in the colon and baby will have flatulence and tummy pain.

In this context, keeping feeds on one breast (or the same breast for several feeds in a row) can be a relevant strategy to gradually reduce production. It is a clinical technique that I guide in consultations, one that requires proper assessment and careful monitoring.

But applied to a 15-day-old baby with slow weight gain, this advice is the exact opposite of what is needed.

In that situation:

• The baby needs more milk, not less.

• Milk production is still being established — it depends entirely on adequate stimulation and effective drainage of both breasts.

• Systematically staying on one breast reduces lactation by halving the signal sent to both breasts.

• Weight gain, already slow, risks stalling or worsening.

• Breastfeeding can be seriously compromised as a result.

What is actually recommended in this case is precisely the opposite: offering both breasts at each feed (switch nursing), increasing feeding frequency, reviewing positioning and latch, ensuring the baby is feeding effectively, and considering transitional supplementation if needed, under professional supervision.

Online breastfeeding communities: a valuable source of support, but not always of tailored advice

Online breastfeeding groups have real value: they offer presence, solidarity, a space to feel less alone at 3am : and that matters.

But solidarity cannot replace clinical assessment. Advice that is perfectly appropriate in one situation may be contraindicated in another. Information about "hindmilk" and "block feeding" circulates widely online, often without the clinical nuance that should accompany it.

When weight gain is slow, when wet and dirty nappies are not where they should be, when stools are giving information that deserves proper interpretation: a consultation with a trained lactation professional, whether a specialist midwife or an IBCLC or an NDC practitioner, provides a full clinical picture of the situation, identifies what is actually happening, and tailors advice to your baby, not a baby in general.

In summary

Green stools at 15 days with slow weight gain signal that breastfeeding is not yet well established :they are a warning about the volume of milk being received, not its composition. Outside this early period, green stools are in the vast majority of cases normal and unremarkable.

The advice to "stay on the same breast" (blockfeeding) is a clinical tool reserved for true oversupply. Applied to a situation of slow weight gain, it can seriously undermine breastfeeding by slowing a production that needs, on the contrary, to be supported.

Elise Armoiry — IBCLC, NDC practitioner, founder of My Baby Moon Over 2,000 families supported since 2014. 📞 07.49.50.67.82 | 📧 info@mybabymoonibclc.com

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References

• Armoiry E. Les selles du bébé allaité. My Baby Moon IBCLC, 2024. mybabymoonibclc.com

• Douglas P. It's normal for babies to have green stools and mucous in the stool. Possums / NDC Breastfeeding & Lactation Foundations Program. possums.org

• Douglas P. Encouraging baby to drain your breast doesn't increase baby's fat intake and can worsen breastfeeding problems. Possums / NDC Breastfeeding & Lactation Foundations Program. possums.org

• Mohrbacher N. Breastfeeding Answers, 2022.