Getting a full feeding in a baby's first few days of life
This seems to be pretty important, especially for babies 2 days old. (see: Babies two days old are the most troublesome) On their second day of life, they tend to cluster feed. In particular, they get really hungry and want to eat, eat, eat. Throw out all notions of "feed once every 3 hours". Feed whenever you see The signs of a newborn hunger.
If breastfeeding is not going well, it's totally, like 100% ok to supplement with formula. Nobody ever said adding formula on top of breastfeeding was a bad idea. (BUT! Keep in mind that one should, in general, prioritize breast milk over formula milk.) If it gives the baby a full tummy so that she can go to sleep till the next feeding (typically in 3 hours from the start of the first feeding), be all for it.
How to decide how much to supplement? First off, we need an upper bound on the amount. 20 mL is what pre-made liquid formula comes in, so that's a good prior to start with. Look at her reaction. Babies that are 2 days old need (on avrage) 7-10 mL of milk, including the colostrum produced by the mother, but because during the cluster feeding phase an infant just wants to be fed, look out for The signs of a newborn hunger. (I personally find smacking of lips to be the most obvious to look for.)
Do not confuse the act of filling up a baby on the 2nd day cluster feeding phase with The goal after the first few weeks of a newborn life is full feeding each meal.
If there are signs of hunger, don't hesitate to top off with more pre-made formula. A good rule of thumb: 5 mL at a time. Don't do more. Roughly keep track of the total volume being fed; 15 mL feels like a good upper-bound for the first few days of life.
see also: How to feed a baby with a syringe
If baby is not completely full after each meal, this may extend the period during which she has issues with feeding.
How to feed a baby with a syringe
Prerequisites:
Firstly, get clean hands. Wash with mild soap, and don't apply anything after washing. (If you don't wash your hands... er, ok, use a pair of non-powdered, hypoallergenic nitrile gloves.)
Next up, lay the baby on a pillow on your lap, such that she is facing you. Have the oral syringe of milk formula handy.
Now, you can stick your pinky into the baby's mouth, soft side (i.e. not the nail) touching the upper gum of the baby's lips. Then, take the oral syringe, stick it just inside the baby's mouth touching your pinky finger, and start to squirt out liquid, 0.2 mL at a time.
FAQ:
Will the baby develop a dependency on the syringe, and be unable to breastfeed?
Apparently no, according to the nurses at MGH. The pinky finger simulates a nipple, and delivering milk onto the pinky finger simulates sucking on a nipple to get food.
How will this affect breastfeeding?
According to our experience, it reduces baby's frustrations while breastfeeding, especially in the first two days of life. If baby was still hungry from the last feeding, then they might end up particularly fussy while breastfeeding, possibly discouraging the mother. (Colostrum is produced in exceedingly small quantities, like 1 mL per feeding.)
A baby needs about 15 mL (max) during the first few days; on verage maybe about 7-10 mL. (see: Getting a full feeding in a baby's first few days of life)
Babies two days old are the most troublesome
Every nurse, doctor, midwife, staff at MGH has said this to us: babies at 2 days old are the most needy. New parents should not have any surprises here.
How to take care of a newborn baby
The goal after the first few weeks of a newborn life is full feeding each meal
This is an idea espoused by Growing Families, a ministry by Gary Ezzo and his wife Anne-Marie.
The idea here is that we ensure that by the 2nd week of life, we have an infant that is able to fully eat and then go to sleep after each round of feeding.
The signs of a newborn hunger
These are, in no order of priority: