Milk production starts when two hormones work together: prolactin triggers your body to make milk, and oxytocin pushes that milk out. For most people, this process begins during pregnancy and ramps up after birth, but it can also be induced without a pregnancy through hormonal preparation and breast stimulation. Either way, the core principle is the same: frequent removal of milk from the breast signals your body to keep making more.
How Your Body Makes Milk
Your breasts begin preparing for milk production midway through pregnancy. Rising levels of prolactin, a hormone from the pituitary gland, stimulate the growth of milk-producing tissue and prime your cells to synthesize milk proteins. But during pregnancy, high progesterone from the placenta blocks prolactin from doing its full job. Think of it as having the engine running but the brake on.
Once the placenta is delivered after birth, progesterone drops sharply. That sudden drop releases the brake, and prolactin floods your milk-producing cells. This is why conditions like retained placental fragments can delay milk coming in: leftover placental tissue keeps progesterone elevated, preventing prolactin from fully activating.
The second key hormone is oxytocin, which controls the “letdown” reflex. When your baby sucks at the nipple (or a pump creates suction), nerve signals travel to your brain and trigger oxytocin release. Oxytocin causes tiny muscles around the milk-producing glands to contract, squeezing milk into the ducts and out through the nipple. During lactation, these two hormones stop competing with each other and work in sync, with prolactin building milk supply and oxytocin delivering it.
What to Expect in the First Days
The earliest milk your body produces is colostrum, a thick, yellowish fluid packed with antibodies. The volume is small by design. In the first three hours after birth, expressed colostrum averages about 0.4 mL. By three to six hours, it rises to roughly 1 mL. These amounts stay low through the first 30 hours or so, then increase dramatically as your body transitions to producing mature milk, typically between days two and five.
Those tiny early volumes are normal and sufficient for a newborn whose stomach is about the size of a marble. Frequent feeding during this window is what drives supply upward. The CDC recommends that newborns nurse every one to three hours in the first days, working up to 8 to 12 feeding sessions per 24 hours in the first weeks. Each session sends a hormonal signal to produce more. Skipping or spacing out feedings in these early days is one of the most common reasons supply stalls.
Skin-to-Skin Contact and Early Supply
Holding your baby directly against your bare chest does more than promote bonding. Skin-to-skin contact raises oxytocin levels in both parent and baby while lowering cortisol, the stress hormone that can interfere with letdown. Research published in Breastfeeding Medicine found a direct, measurable relationship: for every minute of skin-to-skin contact, pumped milk volume increased by roughly 1.3 to 3.7 mL. Over the first postnatal month, infants who had skin-to-skin contact at least once a week consumed nearly twice as much breast milk as those who didn’t (about 4,132 mL versus 2,226 mL total).
If your baby can’t latch right away due to a NICU stay or other complications, skin-to-skin time still helps. Even without active nursing, the physical closeness stimulates hormonal pathways that support production. Combine it with pumping sessions to maintain the supply signal.
Building and Protecting Your Supply
Milk production works on a supply-and-demand loop. The more milk removed from the breast, the more your body makes. The less removed, the more your body slows down. This means the single most important thing you can do is empty your breasts frequently and thoroughly.
In the first weeks, aim for at least 8 to 12 nursing or pumping sessions in every 24-hour period, including at least once overnight. Prolactin levels peak during nighttime hours, so middle-of-the-night sessions are especially effective for building supply. If you’re exclusively pumping, try to mimic a newborn’s feeding pattern: pump for about 15 minutes per session (or until milk stops flowing), every two to three hours.
A few things that commonly interfere with this process:
- Supplementing with formula early on without also pumping reduces the demand signal your body receives.
- Pacifier use in the first weeks can satisfy a baby’s sucking urge without stimulating the breast.
- Hormonal factors like polycystic ovary syndrome (PCOS), thyroid disorders, or retained placental tissue can delay or reduce milk production at a biological level.
- Breast surgery history, particularly reductions that severed milk ducts, can limit how much milk reaches the nipple.
How to Know It’s Working
Since you can’t measure what your baby drinks at the breast, diaper output is the most reliable early indicator. In the first few days, expect at least one wet diaper and one stool per day of life (so one on day one, two on day two, and so on). After day five, your baby should produce at least six wet diapers daily, and the number of stools will vary. Steady weight gain after the initial newborn weight loss, which typically reverses by about two weeks, is the other key marker.
Your breasts will also give you signals. You may feel a tingling or tightening sensation when letdown occurs, notice your breasts feel fuller before feedings and softer afterward, or see milk leaking from the opposite breast during nursing. Not everyone feels letdown distinctly, though, so diaper counts and weight checks are more reliable than sensation alone.
Herbal and Dietary Galactagogues
Fenugreek is the most widely used herbal supplement for boosting milk production. A network meta-analysis of clinical trials found it significantly increased breast milk volume compared to placebo, by roughly 11 to 18 mL per feeding session on average. That’s a meaningful but modest boost. Interestingly, the same analysis found that certain less common galactagogues, including palm dates and a tropical herb called Coleus amboinicus, outperformed fenugreek substantially.
Galactagogues work best as a supplement to frequent milk removal, not a replacement. No herb or medication will build supply on its own if the breast isn’t being emptied regularly. Fenugreek can also cause digestive upset in some people and may lower blood sugar, so it’s worth discussing with a healthcare provider if you have diabetes or take blood-thinning medications.
Inducing Lactation Without Pregnancy
It is possible to produce breast milk without having been pregnant. This is relevant for adoptive parents, surrogacy situations, and transgender women. The process requires mimicking the hormonal changes of pregnancy, then withdrawing those hormones to trigger milk production, just as delivery does naturally.
The most widely referenced approach is the Newman-Goldfarb protocol. In its standard form, it involves taking a combination birth control pill (containing both estrogen and progesterone) alongside a medication that raises prolactin levels. The birth control pill simulates the hormonal environment of pregnancy, priming breast tissue for milk production. The person takes both medications for several months, ideally starting six months before the baby is expected.
About six weeks before the baby’s arrival, the birth control pill is stopped while the prolactin-raising medication continues. This mimics the progesterone drop that happens at delivery. At this point, pumping begins: sessions of 5 to 7 minutes, followed by breast massage, then another 5 to 7 minutes, repeated every three hours. In the final month, overnight pumping is added.
The amount of milk produced through induced lactation varies widely. Some people achieve a full supply, while others produce enough for partial feeding and supplement the rest. Starting the protocol earlier and pumping consistently tend to produce better results. An accelerated version of the protocol exists for situations with shorter preparation time, though it generally yields less milk.
For people over 35 or those who can’t take estrogen-containing birth control, modified versions of the protocol use progesterone-only medications instead. All versions require medical supervision, as the medications involved carry their own risks and are used off-label for this purpose.
Relactation After a Gap
If you stopped breastfeeding and want to restart, the same supply-and-demand principle applies. Frequent breast stimulation, either through nursing or pumping every two to three hours, can reactivate the hormonal cycle. The shorter the gap since you last nursed, the faster supply tends to return. People who stopped within the past few weeks often see milk return within days. Longer gaps may take weeks of consistent stimulation, and a galactagogue may help speed the process.
Getting a baby to latch again after a break can be its own challenge, especially if they’ve become accustomed to bottle feeding. A supplemental nursing system, which delivers formula or donor milk through a thin tube taped to the breast, lets the baby feed at the breast while supply rebuilds. This keeps the baby fed and the breast stimulated at the same time.