How Milk Is Made

During pregnancy the breasts develop and begin to produce milk (lactate). The timing of this varies between different women. Most mothers are ready to produce milk halfway through pregnancy. During the last 3 months of pregnancy, they may notice that their breasts are making colostrum. This yellow or straw-coloured fluid is low in volume but high in protein and antibodies to protect the new baby after birth.

The breasts start making mature breastmilk from about 30–40 hours after the placenta is delivered. For many mothers the milk ‘comes in’ slowly, but for some it happens quite quickly. Most mothers notice their breasts feeling full and even tight and sore around this time. The milk appears whether or not the baby has suckled at the breast.

Because the body gets ready for breastfeeding well before the baby is due to be born, you will make milk even if your baby dies. The placenta makes hormones to stop the mature milk being made until after the baby is born. When the placenta is gone, the hormone levels drop and the breasts start making milk. This can happen as early as the 16th week of pregnancy and is common from about 18 weeks. A woman is more likely to produce milk early if she has been pregnant before, and even more so if she has previously breastfed a baby.

The let-down or milk-ejection reflex is important in breastfeeding because it allows the baby to get the milk stored in the breasts. A hormone called oxytocin acts to push milk along the ducts from the milk glands towards the nipples. This happens when a baby sucks at the breast. However,  seeing or hearing another baby, or even thinking about your own baby, may trigger your let-down and cause your breasts to leak. Very full breasts can also do this.

You may find your milk lets down at times, even if you don’t know the reason. In the early days after your baby’s death, the let-downs can be frequent and sometimes painful. Other factors are also known to cause a let-down in some cases. These include warmth, breast massage, touching the nipples, lovemaking and orgasm. Oxytocin also causes the womb to contract during labour and after the baby is born. This can be painful but helps the womb to return to its pre-pregnant size.

To stop making milk you will need to reverse the milk-making process.

To do this, you will need to limit milk removal. You may want to express the milk because your breasts feel tight and sore and because they remind you of your loss. However, to give them the message to stop making milk, it is best to express only enough to keep them comfortable. The fuller you leave them, the sooner they will stop making milk. However, they don’t have to be left painfully full for this to happen.

There are also medications and herbal supplements that may help the process work faster. You might like to discuss the pros and cons of using these with your doctor.

The more milk that is removed from the breast, the more milk it will make.