Night milk also contains higher levels of certain DNA building blocks, which help promote healthy sleep. Day milk, by contrast, has more activity-promoting amino acids than night milk. Iron in milk peaks at around noon; vitamin E peaks in the evening.
Breast milk pumped at night has more melatonin — the hormone of drowsiness — and higher levels of nucleotides thought to promote sleep. By contrast, breast milk pumped in the morning features higher concentration of cortisol, a stress hormone that makes babies more alert.
Feeding pumped breastmilk
For nighttime bottles, give your baby milk that has been pumped at night and the same for during the day. In this way, your baby naturally gets milk to keep their body in sync the same as if they were directly feeding at the breast/chest.
Overnight, your prolactin levels – the hormone designed to support milk production – are at their highest. So, when your baby feeds frequently at night, the message to your body to boost milk supply is even stronger.
While the exact time that prolactin levels peak seems to differ from person to person, it most often occurs somewhere between 11 pm and 7 am. High prolactin levels at these times could lead to higher levels of milk production at these times.
Despite views to the contrary, breasts are never truly empty. Milk is actually produced nonstop—before, during, and after feedings—so there's no need to wait between feedings for your breasts to refill.
Human milk changes over the course of lactation in order to perfectly suit the infant's nutritional and immunological needs. Its composition also varies throughout the day.
Ultimately, if your baby has reached its birth weight and you're pumping enough milk during the day, it's okay to sleep eight hours without pumping at night. Keep in mind there is an adjustment period for your body as it begins to acclimate to the decrease in overnight milk removal.
The longer the time between feeds, the more diluted the leftover milk becomes. This 'watery' milk has a higher lactose content and less fat than the milk stored in the milk-making cells higher up in your breast.
These sessions don't need to be evenly spaced, but you should be nursing/pumping at least once during the night in the first few months or anytime you notice a decrease in supply. Avoid going longer than 5-6 hours without pumping during the first few months.
Can I mix freshly expressed breast milk with older breast milk? Mixing freshly expressed breast milk with already cooled or frozen milk is not advised because it can rewarm the older stored milk. It is best to cool freshly expressed milk before combining it with older, previously cooled or frozen milk.
This is different for every mother, but typically, the overall fat in breast milk is highest in the evening and at night. If your baby is sleeping when your breasts are full, that would be a good time to pump in order to store your breast milk for later, especially if it's higher in fat during this time.
Trying not to go more than 4 hours without pumping/nursing is a general breastfeeding rule while breastmilk is being established. It's best to wait until after the first 12 weeks to start eliminating pumping sessions.
Interestingly, prolactin levels have a typical 24-hour cycle — just like the human body's circadian rhythm. Prolactin peaks in the early morning hours around 2-5 a.m., while the lowest prolactin levels happen in the late afternoon to early evening.
The overall amount of fat in breast milk is highest in the evening and at night, compared with milk produced during the day. However, multiple factors contribute to the amount of fat in breast milk, especially the frequency of feeding. More frequent emptying of the breast increases the fat content in breast milk.
Is watery breast milk good for your baby? In a word, yes. Both fatty milk and watery/less fatty milk are good for your baby, and it's important that your baby gets both.
To collect hindmilk for your premature baby, you should use a breast pump and separate the foremilk from the hindmilk as you pump. When you begin pumping your breast milk, it will be thin and watery. Pump for about 2 minutes, then remove the collection container from the pump.
Know, however, that consuming too much fluid (or having colorless urine) can actually harm your milk supply. When over hydrated, your body works to restore its electrolyte balance by dumping excess water in your urine, which diverts water away from your breasts and can actually decrease your milk supply as a result.
If you don't nurse (or pump) that often, your body will assume you need to produce less milk, and your milk supply may decrease.
Your healthcare provider would likely recommend that you continue to pump until your baby is able to breastfeed effectively and once you have a sufficient milk supply. Once this has happened, they will likely advise you to stop pumping and just breastfeed - and, of course, get plenty of rest in between.
If You Miss a Night Pumping Session
If you accidentally miss a pumping session now and then, there is no need to fret, as it most likely will not harm your supply — especially if you can squeeze in another session at a different time of the day.
You make more watery or thirst quenching milk in the morning, and less volume but fattier milk in the evening. This is why your baby may want to cluster feed or fuss feed in the evenings. Your milk producing hormone prolactin is highest in the middle of the night.
Most women do not need to pump during the period of time that their baby is sleeping at night. However, some women may find that long stretches without breastfeeding or pumping can result in a lower milk supply.
Newborns have a strong sense of smell and know the unique scent of your breastmilk. That is why your baby will turn his or her head to you when he or she is hungry.