Tuesday, June 28, 2011

Questions for our Readers: Rolling Over

Back in April, we started a new series where we ask our readers to share their experiences watching their babies achieve various milestones. In the first post, we asked for stories about one of the first (and, in my opinion, most exciting) major milestones, smiling!

For the second installment of our Babies’ Firsts series, we want to know about rolling over! Specifically, we’d like to know:

  1. How old was your baby when he or she rolled over for the first time?
  2. Did your baby roll from back-to-tummy or tummy-to-back first and how long did it take before he or she could roll both ways?
  3. What kind of adjustments or modifications did you have to make in your baby's environment to accommodate his or her new skill?
So, if you’d like to share what it was like when your baby started rolling over, please send us a comment! Keep in mind that all babies are different. We are not trying to encourage competition about whose baby rolled over earliest; we simply want to provide an opportunity for parents to share their experiences with each other. Next time, we’ll describe what the research shows about how and when babies start rolling over and share tips to help parents make sure that their newly mobile little one stays safe.

Friday, June 24, 2011

The Active Mommy Conundrum: Can Exercise Harm Breastfeeding? Part 2.

By Taryn Barrette, RD

In this short series, we’re sharing the research about the effect of exercise on breastfeeding. Last time, I explained that exercise does not reduce milk supply but what about lactic acid? Does lactic acid get into breast milk and affect the baby in any way? In today’s post, we will discuss the effect of exercise on the lactic acid content of breast milk.

What is Lactic Acid?

Lactic acid is found naturally in the blood and muscles and is a byproduct of normal metabolism. During high intensity (anaerobic) exercise, oxygen intake is decreased and CO2 is increased resulting in an excess of lactic acid. The high concentration of lactic acid eventually dissipates to normal levels after intense exercise is stopped and the lactic acid is recycled back during the normal metabolic process.

Lactic Acid in Breast milk

It is known that lactic acid produced from exercise is present in breast milk up to 90 minutes post-exercise; however, research shows that the concentration of lactic acid is only significantly higher after bouts of high intensity exercise. In one study, “High intensity” was determined by each participant’s “Rate of Perceived Exertion” (RPE) – meaning that the degree of difficulty was determined by the exerciser’s perception.

Thus, when an individual exerts themselves for 30 minutes of what is perceived to be highly intense exercise, there is a significant increase in lactic acid in their breast milk compared to breast milk expressed prior to exercise or during moderate exertion.

There was only an increase in lactic acid after an ‘intense’ (anaerobic) workout. When mothers engaged in moderate (aerobic) exercise that was 50% or 75% of maximum exertion (which is a more typical level of exercise for most people) there was not a significant or noticeable increase in lactic acid concentration in their breast milk.

Infant Acceptance of Breast Milk

Though all of the studies analyzing the contents of post-exercise breast milk showed that intense exercise was related to increased lactic acid concentration, we don’t have consistent evidence that lactic acid affects infant acceptance of the milk. Most of the studies of infant acceptance of breast milk required the mothers to offer expressed milk to their babies rather than feeding them directly from the breast.

One study with 12 mothers involved collecting breast milk samples before exercise and then 1 hour after intense exercise. The mothers then fed their infants the expressed breast milk (blinded as to whether they were feeding the pre- or post-exercise milk). They, along with a lactation consultant, then judged whether they felt their child accepted the milk well or not. This study found that there was no difference in infant acceptance of the breast milk despite there being significantly higher concentrations of lactic acid in the post-exercise milk.

In another study from 1992, breastfeeding mothers were asked to collect breast milk samples at 10 and 30 minutes post-high intensity exercise. The mothers then fed their infants the expressed breast milk with a dropper and rated the infant’s acceptance. These mothers reported that their infants rejected the post-exercise milk more often than the pre-exercise milk.

What’s a Mom to Do?

So can you still be the active mommy that you want to be? The answer is Yes! Moderate exercise does not affect the flavor, taste or nutritional quality of your breast milk at all. Intense exercise (completely based on your own perception) does alter the lactic acid concentration of your milk, but this change is not likely to be an issue with your infant. After all, the best evidence comes from longer term studies that included measurements of infant growth and findings from those studies did not show that exercise interfered with breastfeeding. Of course, talk to your doctor before you start any exercise program.

If you find a link between bouts of strenuous exercise and breast milk refusal, you can decrease the intensity or wait 30 minutes for the lactic acid to disappear but it may be more likely that your infant is distracted or there is another reason for the refusal.


1. Wright KS, Quinn TJ, Carey GB. “Infant acceptance of breast milk after maternal exercise.” Pediatrics. 2002;109(4):585-9.

2. Wallace JP, Inbar G, Ernsthausen K. “Infant acceptance of postexercise breast milk.” Pediatrics. 1992; 89(6 Pt 2):1245-7.

3. Dewey KG, Lovelady CA, Nommsen-Rivers LA et al. A randomized study of the effects of aerobic exercise by lactating women on breast milk volume and composition. N Engl J Med. 1994; 330: 449-453.

Tuesday, June 21, 2011

The Active Mommy Conundrum: Can Exercise Harm Breastfeeding? Part I

By Taryn Barrette, RD and Jane Heinig

I don’t have children yet, but I’ve always imagined that one of my favorite things to do with my new baby would be to take him for a jog. I lead a pretty active lifestyle and feel that it is important to share my love for fitness with my children – but I also plan to breastfeed and I was concerned about the potential for exercise to affect my milk supply. I had also heard that lactic acid can build up in breast milk.

So, I began to wonder: Does exercise reduce milk supply? Does exercise lead to lactic acid in breast milk? And if so, can the baby actually taste it? If lactic acid is present in the milk, will the baby refuse to drink it? How am I ever going to be the active mommy that I’ve always dreamed of? In today’s post, we will discuss the effect of exercise on breast milk volume. Next time, we’ll talk about breast milk and lactic acid.

Exercise and Breast Milk Volume

In many countries around the world, the idea that physical activity would interfere with breastfeeding would be considered crazy or a joke. Most women in the world must maintain very active lives despite having young children in tow. Many women have physically demanding occupations and many more must walk great distances for food or water. Women with access to their children (not separated for many hours with no way to express their milk) are able to breastfeed despite their activity levels. The challenge comes when a woman’s occupation prevents her from being able to feed her baby. Her body will make less milk if less milk is removed. But exercising, especially in short to medium bouts, even at very high levels does not reduce milk supply. A series of important studies looking at this phenomenon where conducted here, at UC Davis. In the first of the studies, the researchers followed small groups of women who were either sedentary or extremely active (marathoners, masters swimmers, triathletes) and they found no difference in the women’s milk supply or in their infants’ growth. In fact, they found that the athletes tended to have higher milk volumes and greater energy content in their milk. In a follow-up study, the researchers took a group of sedentary women and increased their activity by putting them on a supervised exercise program (some of these women were also put on low-calorie diets). Once again, they found that there was no effect of the exercise on the mothers’ milk supply or their infants’ growth. Other studies have indicated that exercise did not interfere with lactation among women who were overweight when they began exercising. All of this research shows that going out for a jog (when you’re ready and the doctor says it’s ok) is a great idea!


Lovelady CA, Lonnerdal B, Dewey KG. Lactation performance of exercising women.Am J Clin Nutr. 1990 Jul;52(1):103-9.

Lovelady CA, Garner KE, Moreno KL, Williams JP. The effect of weight loss in overweight, lactating women on the growth of their infants. N Engl J Med. 2000 Feb 17;342(7):449-53.

Lovelady CA, Nommsen-Rivers LA, McCrory MA, Dewey KG. Effects of exercise on plasma lipids and metabolism of lactating women. Med Sci Sports Exerc. 1995 Jan;27(1):22-8.

Friday, June 17, 2011

Fathers and Baby Behavior: The Father's Day Edition

First, we’d like to say Happy Father’s Day to all of our readers! We are so appreciative of all that fathers do for their children and hope that you get the celebration you deserve!

Research has shown that fathers play an important role in the cognitive, emotional, and physical development of their children. Over the last few years, several of our posts have focused specifically on fathers, so in honor of Father’s Day, we’d like to highlight these previous posts.

It Takes Two Baby: How Babies and Parents Learn about Each Other
(December 2009) – This post focuses on how various caregivers can build relationships with newborn babies. It explains that fathers are often an important source of stimulation and fun, provide variety and security, and can be the first caregiver to learn to read the infant’s cues. It also highlights how important fathers can be in ensuring that the new baby doesn't get overstimulated by their new and exciting surroundings.

Parenting Roles Change: The Rise of the Stay-at-Home Dad (August 2010) - With more women working outside the home than ever before, it isn’t surprising that the number of stay-at-home dads has nearly doubled in the past 10 years. This post features 5 tips for stay-at-home dads with information about how to make caring for themselves and their babies a little easier.

New Dads on the Block (August 2010) – In this post, we describe how the father’s role has changed over the last 40 years, highlighting the increase in paternal involvement and understanding of their babies.

And Baby Makes 3: The Realities of becoming a dad (October 2010) - This post, the fourth in a series about how couples transition into parents, describes recent research on experiences shared by new fathers, including feeling lost in the shuffle, dealing with reality, and bonding with baby.

Baby Behavior Around the World: Key Caregivers of Babies (Part 2) (May 2011) - In the second part of our first Baby Behavior Around the World post, we describe how fathers’ roles vary in different cultures and countries.

We hope that the posts that we’ve written so far have been useful, and we are eager to provide more information for all of our male readers. So, we have a special request of our female readers: share this post with the fathers in your life! If you are a dad reading this post, share it with other dads you know. Understanding Baby Behavior can make parents' lives less stressful and make them feel more confident in knowing what their babies needs.
Have a great Father's Day weekend!

Tuesday, June 14, 2011

Friday, June 10, 2011


We have a lot to celebrate this month!

The Secrets of Baby Behavior Blog is turning 2...

...and yesterday, Jen G graduated from UC Davis with a Master's Degree in Maternal and Child Nutrition!

We are very proud of how much we've been able to share over the last 2 years and look forward to what we have planned in the future! If you have any questions you'd like us to answer or suggestions for future topics, please let us know.

Tuesday, June 7, 2011

Part 2: Tips to Ease the Transition of Baby into Her Own Room

Charlotte, 5 1/2 months
In our last post, we wrote about current practices and recommendations for sleeping locations of infants. It doesn't matter if you are a first time mom or an experienced mom, or how old your baby is, transitioning your baby into her own room will be an adjustment for the whole family Today, we have a few tips that may help make the process easier!
  • As with any transition, change takes time. Don’t expect your baby to fall asleep easily in your room one night and just as easily in his own room the next night. Being patient as your baby gets accustomed to his new space is important!
  • Take small steps toward a gradual transition into the new location. For example, if your baby sleeps on a sleep surface other than a crib, like in a bassinet, start by moving your baby’s crib into your bedroom and having him sleep there. After your baby gets used to sleeping in his new crib in your room, then move the crib into his room. Another option is to start the transition by having your baby sleep in his new room for daytime naps only. After that is going well for a while, try having him sleep in his room for bedtime too.
  • Keep in mind that any change in routine (and transitioning to a new room is a big one!) can affect your baby’s sleep patterns, potentially causing more night awakenings for a short time.
  • Be consistent; older babies like routines! It’s important to be consistent with your baby’s bedtime setting as well as his bedtime routine. For more about routines, click here.
  • While you are trying to be consistent, it’s also important to be realistic. Things will happen that will be out of your control. Your baby may get sick and be in your room for a few days until she is feeling better. That’s okay! You can get back to your usual routine when she is back to feeling better.
  • It’s not unusual for older infants to wake more than usual once in a while. She may have separation anxiety or be conquering a new physical milestone. For a list of reasons why older babies may wake more sometimes, click here.
  • It’s not uncommon for some older babies to resist being placed back to sleep in their cribs after awakening during the night. For an explanation of why this happens, click here. For solutions, click here.
  • Wait until your baby is in quiet (deep) sleep before transitioning her from one sleeping place to another, such as from your bed or your arms to a crib. Older babies can enter deep sleep more quickly than younger babies, but always look for signs of deep sleep before lying your baby down to sleep.
We hope this information has been helpful! Making a big change, like moving your baby into her own room, is a big milestone and it is important to do what is best for your family. We’d love to hear your stories and tips about how YOU transitioned your babies into their own rooms too!

Friday, June 3, 2011

Reader Question: "At what age do you transition babies to sleep in their own rooms?"

This week we will be answering a reader question that we received a couple of weeks ago. Here is what she asked:

“I am a first-time mom of a 4 ½ month old and have been trying to find information about when it’s best to transition my daughter into her own room. She’s currently sleeping in her own, safe space in my room. I’ve seen a lot of recommendations to transition her between 2 and 4 months of age, but I couldn’t find any research-based support for those recommendations. I was glad to see in your post on January 4, 2011 titled “Can Little Changes Lead to a Little More Sleep?” that you offered a recommendation from the AAP. I spent a few minutes trying to find the reference you used for that recommendation and haven’t been able to find it. Would you please provide me with the AAP reference you used? I would really appreciate it.”

We thought this was a great question and that other readers might appreciate hearing the latest recommendations about transitioning babies into their own rooms to sleep. We realize that this is a very personal and individual decision for every family. However, we hope to provide you with enough evidence that you can make an informed decision. Let’s look at current practices related to infant sleep location and then compare those to what experts recommend. We'll also take a look at new government safety precautions for infant cribs.

Current Practices
Currently, parental practices for transitioning babies into their own rooms are similar across the United States, but this hasn’t always been the case. Recent trends in increased room sharing among parents and babies challenge long held Western cultural beliefs about the need to get infants to sleep independently, in their own rooms (and cribs), at an early age. (Morgan 2006) In a 2005 study among parents NOT planning to co-sleep, researchers found that most infants were moved into their own rooms gradually over the first several months of life, with 68% sleeping in their own rooms by 6 months of age and 76% by 12 months. (Burnham 2005) Another study, this one from 2008, showed that 15% of 3-month-olds and 29% of 12-month-olds slept in their own rooms.(Hauck 2008) Room sharing not only promotes breastfeeding, it also decreases the risk of Sudden Infant Death Syndrome (SIDS), and the AAP also endorses room sharing for parents and infants.

Recommendations for the Infant Sleep Setting
The American Academy of Pediatrics, in their 2005 policy statement on SIDS, concluded that placing babies to sleep in their parents’ room, on a separate sleep surface, reduced the risk of SIDS. Evidence referenced by the AAP in that statement included several large trials concluding that babies should sleep in their parents’ rooms, on a separate sleep surface, for the first 6 months of life. This recommendation is also endorsed by the United Kingdom Department of Health. Data from a study by Blair 1999 (referenced in Morgan 2006) also showed that chance of death from SIDS was cut in half when the mother slept in the same room as the baby. For the full AAP report on infant sleep safety recommendations, click here:

Choosing a Safe Sleep Surface: NEW Safety Guidelines
There are brand new government safety standards required for all cribs sold in the United States (new and resale). Starting June 28, 2011, all cribs sold in the United States must meet new federal requirements. For the specifics of this new law, click here. I was surprised to read that safety standards have not been established for “Cosleepers” (infant beds that attach to the parent’s bed). Also, the CPSC has recalled a few popular co-sleeper models. For more information about the latest product recalls and safety information, visit the CPSC website.

Making the decision to transition your baby into his own room is only the first step in making this change happen. Even after a successful transition, you aren’t completely off the hook; your baby may still need your help during the night. Just because she is in the other room doesn’t necessarily mean she is going to sleep in there all night long without waking. Older babies are more likely than younger babies to sleep longer stretches but many still wake occasionally and they often need their parents help to get back to sleep. (Burnham 2005)

Next time we’ll share tips to ease the transition of your baby into his own room and review older infant sleep patterns so you will know what to expect during the transition!


The Changing Concept of Sudden Infant Death Syndrome: Diagnostic Coding Shifts, Controversies Regarding the Sleeping Environment, and New Variables to Consider in Reducing Risk. Task Force on Sudden Infant Death Syndrome. Policy Statement, Published online November 1, 2005. Pediatrics Vol. 116 No. 5 November 2005, pp. 1245-1255.

Burnham MM, Goodlin-Jones BL, Gaylor EE, Anders TF. Nighttime sleep-wake patterns and self-soothing from birth to one year of age: a longitudinal intervention study. J Child Psychol Psychiatry. 2002; 43(6): 713–725.

Morgan KH, Groer MW, Smith LJ. The Controversy About What Constitutes Safe and Nurturant Infant Sleep Environments. JOGNN. Nov/Dec 2006.

Hauck FR, Signore C, Fein SB, Raju TN. Infant sleeping arrangements and practices during the first year of life. Pediatrics. 2008 Oct;122 Suppl 2:S113-20.