Why Do Babies Suck So Much?

I recently attended a webinar with the subtitle, “Why Do Babies Suck So Much?” This tongue-in-cheek description of newborns is a great way to begin a discussion about what happens for mothers and infants during the first days and weeks of breastfeeding.

Normal full-term babies are born with a strong instinct and need to suck. They display a number of instinctual behaviors including rooting, putting their hands to their mouths, sticking out their tongues, and crying when they want to suck. Healthy newborns display these behaviors most of the time they are awake, particularly in the first few days to a week of life. Many parents assume that these behaviors mean that their baby is constantly hungry and is not getting enough to eat. This assumption can lead parents to lose confidence that breastfeeding will nourish their baby.

A newborn wants to suck for many reasons, and most babies are not very hungry their first few days of life. Babies are born with their bowels full of meconium, their first bowel movements. The motion of suckling and swallowing gets a baby’s intestines moving and helps the baby pass these first sticky poos. Once their digestive tract has emptied out much of this meconium, babies begin to feel more hungry. Fortunately, if breastfeeding is proceeding normally, this timing coincides with the mother experiencing an increase in the volume of milk her body makes.

This increase in volume often called the milk “coming in” (or called lactogenesis II by lactation professionals) can happen as early as 24 hours after birth, or as late as many days after. It is a result of many hormonal processes in the mother’s body after the placenta is delivered. The vocabulary of milk “coming in” is deceptive because it implies that a mother’s milk was somewhere else and then arrives, which is absolutely not the case!

Pregnant mothers develop milk in their breasts from about 10-14 weeks of pregnancy. Some mothers notice it leaking and can express some while pregnant, while others don’t see it. In either case this first milk - colostrum - is present when the baby is born and mothers don’t have to wait for it to arrive. Colostrum is the ideal nutrition, first immunization, and perfect opportunity for newborns to practice breastfeeding. The small volumes of colostrum allow babies to practice the combination of suck-swallow-breathe that they must master to breastfeed effectively, without needing to manage a heavy flow of milk. Once the baby has had time to practice breastfeeding with colostrum, the mother’s body begins making larger volumes of breastmilk.

During the last weeks of pregnancy and shortly after delivery, the mother’s levels of breastfeeding hormones including prolactin are as high as they will ever be. Every time her baby suckles, her body builds receptors to respond to these hormones. With each passing day, the hormone levels drop, but the receptors a mother has built respond to the hormones and her milk supply rises to meet her baby’s needs.

The more frequently the baby suckles during those early days of breastfeeding, the more hormone receptors the mother will have, and the easier it will be for her body to build a full milk supply. By several weeks after the birth, the mother’s hormone levels are much lower than they were during the first week after birth, and it can be much more difficult to build an adequate supply when mothers have a low supply after a few weeks of breastfeeding.

What can go wrong?

When a mother has not experienced an increase in milk volume by 72 hours after the birth, this is considered a delay in lactogenesis II. Up to 44% of U.S. mothers, particularly first time mothers, experience such a delay. By 72 hours newborns need their mother’s milk to increase to keep their energy up and to keep their weight from dropping too much. For mothers and babies in this situation, supplementation with donor milk or formula can become necessary.

Why the delay?

Many birth practices common in the U.S. contribute to mothers experiencing a delay. Many mothers receive large volumes of IV fluids during their labors either because of inductions or epidurals. Excess fluid in the mother’s body is linked both with excess weight loss in newborns, and with a delay in lactogenesis II. This excess IV fluid can cause a mother’s ankles, hands, face, breasts, and other parts of her body to swell. Many mothers who experience this find that once the swelling subsides (normally between days 3 and 5) their milk supply increases to meet their baby’s needs. In cases like this it is crucial to keep breastfeeding and/or pumping to keep the breastfeeding hormones and receptors going. It is also important to keep the baby nourished, which is why supplementation can be appropriate.

The main risk factors for a delay in lactogenesis II are being a first time mother, being over 30 years old, having a BMI in the overweight or obese range, giving birth to a baby weighing over 8 lbs (3600 g), having a stressful labor or birth, an unscheduled cesarean, gestational diabetes, few successful feedings in the first 24 hours, polycystic ovarian syndrome (PCOS) or excessive blood loss during or after the birth. When mothers have long epidurals or other medications for pain during labor, their babies are often born sleepy and may not breastfeed effectively for many hours or even days. This can put mothers at risk of low milk supply and babies at risk of excess weight loss and jaundice.

What can I do to avoid a delay?

Many risk factors are out of a mother’s control, but there are many steps she can take to encourage her milk to increase in volume within a normal time frame after birth.

  • Taking childbirth classes and hiring a doula can decrease the use of inductions and epidurals which likely contribute to a large proportion of delays.
  • Breastfeed early and often. A recent study found that only 10% of mothers in Peru experience a delay in lactogenesis II compared with 44% of mothers in the U.S. The main factor was breastfeeding frequency during the first 3 days of life. In the U.S. mothers breastfed an average of 8 times each 24 hours. In Peru the average was 13-18 times in 24 hours. Remember, it is normal and good for newborns to want to suckle every waking moment during the first few days!
  • Spend as much time as possible skin-to-skin with your baby. The mothers in the Peru study spent almost all of the first 3 days skin-to-skin with their newborns who slept in bed with their mothers. The U.S. babies slept swaddled in hospital bassinets beside their mothers’ beds.
  • Hand express after feedings and feed the expressed colostrum to your baby with a spoon or cup. Breastfeeding works on a supply and demand basis. Hand expressing gives your body the message to make more milk faster, and the extra colostrum gives your baby nutrition and calories.
  • If your baby cannot breastfeed right after the birth for any reason, begin hand expressing and pumping as soon as possible. Maintain a regular schedule of hands-on pumping with a hospital grade pump at least once every three hours until your baby is breastfeeding effectively.
  • Get help early! If you have any questions or concerns about how breastfeeding is going, ask to see a lactation consultant or specialist as soon as possible.

    Newborns suck a lot and this is normal and beneficial! Breastfeeding is most likely to get off to a good start if mothers allow and encourage their newborns to breastfeed early and often during the first several weeks of life. Over 80% of U.S. mothers plan to breastfeed for at least the first several months of their babies’ lives, but many times unrealistic expectations of newborn behavior, difficult births and lack of support make it difficult for mothers to realize their breastfeeding goals. Mothers can advocate for themselves and their babies by educating themselves and asking for support early and often. The investment of time and energy during the early days and weeks of breastfeeding usually pays off with mothers and babies enjoying the physical, emotional and nutritional benefits of a satisfying breastfeeding experience.