Saturday, July 21, 2012

The Trouble with Calma and the Quest for the Perfect Bottle Nipple

When breastfeeding moms either want or need for their baby to have expressed milk from a bottle, the question they usually ask is, “What bottle/nipple is most like the breast? Which bottle/nipple is best for breastfeeding babies?”

The simple truth is that the correct answer is, “None.” There is no nipple that is like the human breast. Some may be better or worse for a baby who is going back and forth between breast and bottle, but there is no “best." What matters much more in avoiding baby developing a bottle preference is how the baby’s caregiver feeds baby with the bottle.

The problem with marketing nipples as "most like breastfeeding," or with similar claims is that it undermines breastfeeding. This is why part of the purpose of the WHO CODE (World Health Organization's International Code of the Marketing of Breastmilk Substitutes) is to prevent the aggressing marketing of bottle nipples. 

One of the first bottle nipples to be marketed as “most like mother’s nipple” is the Nuk. Their claim, “Orthodontic design shaped like a mother's nipple during breastfeeding." The marketing claims are pretty convincing:

The NUK® Orthodontic bottle makes baby's transition from breast to bottle and back a seamless one. Every nipple has unique features to make it easier to move back and forth from breast to bottle. These bottles have been scientifically designed to make feeding easier.

I was working with a mom who was wanting to transition her baby off of bottles of expressed milk on to the breast. I asked her what nipples she was using and she told me Nuk. I mentioned that she may want to switch to a different bottle and nipple that would encourage baby to use his mouth more like he would on the breast. I explained to her that the Nuk nipples tended to encourage sucking that could interfere with breastfeeding. She was shocked. “But is says right on the package that it is most like mother’s nipple and good for breastfeeding babies!”. She fell for the marketing hook, line and sinker.

Independent research, summarized on,  has shown the problems with these “orthodontic” nipples:
  • Ultrasound studies by Smith revealed that round nipples with a broad base, as opposed to the "orthodontic nipples" with flattened tips, best facilitate tongue and jaw motions similar to sucking at the breast(1)
  • Although orthodontic nipples such as the Gerber Nuk are frequently recommended for use by nursing mothers, they seem to teach the baby to retract his tongue and hump it up in the back of his mouth during feeding.
  • This creates problems with breastfeeding, since babies must flatten their tongues and extend them forward to get milk from the breast. In addition to reducing milk transfer, this type of tongue movement can cause severely abraded nipples.(1), (2)

Newer nipples are getting much more sophisticated and have even bigger claims. The Breastflow bottle, by The First Years claims:

Works like mom

The only bottle with a 2-in-1 nipple that lets your baby use the same natural motions as breastfeeding.

Soft outer nipple

mimics the feel of the breast and allows baby's tongue to stay in the same position as breastfeeding.

Inner nipple

allows your baby to control the flow naturally like breastfeeding whether you use breast milk or formula.

While I can’t find any independent research on how much these are or are not “just like” the breast, the fact is it is impossible. Moms report trying these to avoid “nipple confusion” but the fact remains that anything other than moms breast has the potential to cause nipple confusion or bottle preference, particularly if baby is being overfed with them. There are no shortage of complaints about this somewhat complicated system with multiple parts being difficult to clean, or the nipple frequently leaking, or collapsing while baby is feeding. This is a lot of extra effort and work for moms who believe the marketing that this nipple is somehow best for their breastfed baby.

The mimijumi bottle is designed to look like the breast:

With natural colors, textures and forms, the mimijumi baby bottle provides the perfect complement to breastfeeding and the best possible transition to bottle feeding.

The innovative nipple design replicates a mother’s breast, creating a natural feeding and latching experience for a happier and healthier bottle fed baby. Bold colors and soft textures are combined to give the Not So Hungry bottle a distinctive, eye-catching appearance.

I want moms to understand that “the best possible transition to bottlefeeding” is a marketing ploy! They want you to buy their bottle. Even if they tried to make it most like the breast with the best of intentions, that does not make it so.

Looks don't make a difference when you are wanting to avoid a flow preference with your baby and make an easy transition from breast to bottle and back. Users of the mimijumi have reported a fast flow rate and a stiff nipple:

"I ordered this bottle thinking that it would be closest to a breast, but I was very mistaken. My husband filled the bottle with breast milk and turned the bottle upside-down over the sink to show me that the milk just comes streaming out of the nipple. The baby was practically choking when he fed her using this bottle."
"Not only is the nipple extremely hard and inflexible, it also lacks control over the flow rate. My baby was permanently choking with this bottle, even with the "slow flow" nipple." 
The new kid on the block comes with great marketing claims. Produced by the heavily marketed Medela brand comes the Calma:

Introducing Calma: Designed exclusively for breastmilk feeding.

Switching from bottle back to breast has never been easier. Calma was developed using evidence-based research on babies' natural feeding behavior so you can enjoy your breastfeeding bond longer.

With Calma, the milk will only flow if your baby works and creates vacuum to remove the milk. This enables the feeding behavior learned at the breast to be used with Calma.

I decided to do some more research after the comment from a breastfeeding mom on an on-line forum. Other moms on the breastfeeding forum were suggesting that her baby was being overfed with the bottle, and this was the underlying cause of the problems she was having. The amounts her baby was getting from the bottle exceeded what research suggests a breastfed baby should get. She responded that it was not possible that her baby was being overfed with the bottle because she was using the Calma, which is just like the breast. She would not even begin to listen to the possibility that baby was getting too much milk because she did not think it was possible with this specially designed nipple.

The truth is it is easy to overfeed with any bottle and just like the other contenders, the Calma does not replicate the human breast and deliver milk in the same way. It was not too hard to find the following information, right on the Medela website:

INTERVIEW: Conquering Breastfeeding Challenges with Calma (As if a bottle can solve breastfeeding problems, sigh.)

On the comments of this article on the Medela website several IBCLCs reported a consistent problem with fast flow, and babies choking on the surge of milk flowing into their mouths. A Medela representative responds to these complaints by explaining that a baby cannot suck on the Calma nipple the same way they do at the breast because it will cause too fast of a flow.

Wait a minute. Let’s all stop here right now. Didn’t Medela claim that this new wonder nipple, “enables the feeding behavior learned at the breast to be used with Calma.” Now they are saying baby needs to suck differently on the Calma than they do at the breast? The Medela rep further explains:

"We’ve found sometimes that Calma takes a little getting used to. Typically, babies suck vigorously at the beginning of a feeding to stimulate let down. With Calma, relaxed sucking, similar to the middle of a feeding, works best. Many moms found that after a few tries, babies adjust their sucking at the beginning of the feed with Calma and that Calma helped immensely with the transition from bottle to breast."

An IBCLC, who was complaining about the fast flow she had seen with the bottle poiints out:

"If babies have to adjust their suck to be LESS vigorous to adapt to a bottle, then they will not be sucking in an appropriate manner for the breast. Effectively you are admitting to what I have found with 100% of the clients I have seen who have tried this bottle — babies suck worse on the breast. So while you may have found some resilient babies who are highly adaptable (because most babies WILL eventually take the breast when mothers maintain their supply through pumping) the babies who are having significant problems that comprise my clientele will not. Furthermore, aspiration from choking is a health risk. The degree of choking I observed among my clients was severe — not mild — and much worse than with other bottles."

What really matters when choosing and using a bottle with a breastfed baby?

One of the main reasons a baby may prefer the bottle to the breast is due to flow preference. Baby likes the fast and immediate flow from the bottle. They come back to the breast and don’t want to “work” for the let down. Medela has basically just said that babies need to learn to not suck to trigger let down when using this bottle.

What do breastfeeding moms need to know about bottle feeding expressed milk?

Suggested Bottle Nipples

A few bottle nipples which have been tested and rated by lactation consultants come out at the top when it comes to a good slow flow rate and a shape that baby may be able to take with a wide latch like the breast. Always buy the slowest flow nipple:

Evenflo Classic: Pros: You can purchase glass or plastic bottles. No disposable liners, no extra pieces to clean, very inexpensive. Cons: slightly higher flow rate than the other 3 listed here, but still slow.

Playtex VentAire (standard, not wide) Pros: Middle price range, easy to find and purchase. Cons: Angled bottle is less than ideal as you want to hold the bottle horizontal to pace baby's bottle feeding. Extra parts to wash as the bottom needs to be taken apart to wash.

Dr. Brown's Standard Bottles Preemie Flow (or Level One Flow would be next best): Pros: No disposable liners needed. Available in both plastic and glass. Cons: several extra parts to clean including a vent inserts and straw-like vent reservoirs.

Playtex NaturaLatch: Pros: Easy to clean with no extra parts. Cons: need to purchase disposable linters for the bottles. Some babies will only latch onto the end of the nipple and use it like a straw.


(1) Smith, W., Erenbert, A., Nowak, A. Imaging evaluation of the human nipple during breast-feeding. Am J Dis Child 1988; 142:76-78.
(2) Nowak, A., Smith, W., Erenberg, A. Imaging evaluation of artificial nipples during bottle feeding. Arch Pediatr Adolesc Med 1994 Jan; 148:40-2.

© Teglene Ryan

Are There Differences Between Breastfeeding Directly and Bottle-feeding Expressed Milk?

From the breast or from the bottle, fresh or frozen, your milk provides all of the nutrition your baby needs for normal growth and development and much more. The nutritive and health-supportive properties of breastmilk can be bottled, making it the next best alternative when breastfeeding is not possible or feasible. Mothers may need or choose to offer their milk by bottle for a variety of reasons as individual as each mother and baby pair, and as a result of this need, there are many solutions for expressing milk. It is easier than ever before to provide a baby with breastmilk long-term, even when a mother cannot or chooses not to breastfeed directly. Exclusive expressing and breastmilk-feeding can be necessary and even life-saving, especially for fragile premature babies. In most societies, the value of breastmilk is well-known, but the value of breastfeeding is not. Breastmilk is a wondrous living fluid that cannot be replicated, and breastfeeding is the normal and optimal way to deliver it.

Antibodies are blood proteins produced in response to substances that the body recognizes as alien, such as bacteria and viruses. Close physical contact with your baby helps your body create antibodies to germs in his environment. When you breastfeed directly, your body creates antibodies in response to cues from your baby’s saliva and other secretions. After exposure to new germs, your body can make targeted antibodies available to your baby within the next several hours (Chirco 2008) (Cantini 2008). While a bottle of milk from a previous date will provide your baby with immune factors, it will not contain antibodies to germs he was exposed to today.

Breastfeeding supports the normal development of a baby’s jaw, teeth, facial structure, and speech. The activity of breastfeeding helps exercise the facial muscles and promotes the development of a strong jaw and symmetric facial structure. Breastfeeding also promotes normal speech development and speech clarity. An increased duration of breastfeeding is associated with a decreased risk of the later need for braces or other orthodontic treatment. One study showed that the rate of misaligned teeth (malocclusion) requiring orthodontics could be cut in half if infants were breastfed for one year (Palmer 2008). Bottle-feeding requires a different tongue action than breastfeeding does, and over time may affect the growth and development of oral and facial tissue. Sucking on bottle nipples, pacifiers, and even thumbs and fingers can eventually affect the shape of a baby’s palate, jaw, teeth, and facial structure. In this presentation, Position and action of the tongue during breastfeeding, dental expert Dr. Brian Palmer shows how breastfeeding promotes normal facial development and provides illustrations showing what happens inside the mouth during bottle- and breast feeding (Warning: Slide 2 of the presentation shows a picture of a cross section of the mouth of a human cadaver for illustrative purposes).

When breastfeeding on cue (as your baby shows signs of hunger), you produce milk in response to your baby's demand: your body makes milk to replace the milk your baby removes from the breast. When exclusively expressing, you produce milk according to how much milk you are able to remove with the pump and/or your hands. Some mothers find it is more difficult to maintain milk production long term with a pump for a variety of reasons including difficulty scheduling time to express (frequency of milk removal) and the overall effectiveness of the pump at removing milk. Understanding how long term milk production works can help mothers who are dependent on their pumps for milk-removal maximize both the amount of milk they are able to remove and the length of time they are able to continue producing milk.

Bottle-feeding expressed breastmilk is more time-consuming than breastfeeding directly because you have to spend additional time expressing milk, washing pump and bottle parts, and shopping for necessary equipment: this time might have been spent enjoying your baby or taking care of yourself. When your breastfed baby is hungry or needs to be comforted, you simply put him to the breast. When bottle-feeding breastmilk, you must first attend to preparing a bottle before you are able to meet your baby's needs.

Skin-to-skin contact (also known as “kangaroo care”) is important to your baby’s development (Bigelow 2010). Babies held skin-to-skin stay warmer, cry less, and have better-coordinated sucking and swallowing patterns. Mothers who hold their babies skin-to-skin enjoy increased milk production, increased oxytocin release, improved mother-baby bonding, and more confidence in their mothering abilities (Moore, Anderson & Bergman 2009). When you are breastfeeding, you will naturally be in a position to offer skin-to-skin contact to your baby. When you are bottle-feeding, it is important to find additional time each day to hold your baby this way. 

Research has shown that breastfeeding directly correlates with a positive mood in mothers. One study examined the effects of breastfeeding and bottle-feeding on maternal mood and stress. After breastfeeding, the mothers in the study were found to have both a reduction in perceived stress and a more positive mood. In contrast, after bottle-feeding, mothers were found to have an increase in negative feelings. The researchers suggested that the higher levels of oxytocin released by breastfeeding may contribute to both reduction in stress and better mood (Mezzacappa & Katkin 2002).

Bottle-feeding gives your baby less control over his milk intake. Milk flows easily from a bottle nipple even when the baby is not actively sucking, and the faster flow can cause a baby to continue feeding after he is full. When bottle-fed, babies may drink more than they need because the care-provider may encourage the baby to finish the bottle rather than waste the milk inside. While breastfeeding, your baby can control the flow of milk by the way he feeds. You are not able to see how much milk your baby consumed, but you can watch for signs that your baby is satisfied, and you will be less likely to coax your baby to continue eating after he is full. Research suggests that infants who are breastfed, rather than bottle-fed breastmilk, are better able to self-determine fullness as children and may have a lower risk of overeating and obesity later in life (Isslemann 2011). Recent research suggests that it is the act of breastfeeding that helps prevent rapid weight gain (Li and Magadia et al 2012).

There are some variations between milk that is obtained directly from the breast (or that has been freshly expressed) and milk that has been stored. For example, freezing has been found to decrease the effectiveness of some of the antibodies and kill some of the living cells in milk (Orlando 2006) (Buckley & Charles 2006). In order for your baby to get the most anti-infective properties from your milk, it is best to offer it fresh whenever possible.

Getting the most out of breastmilk-feeding
  • Spend time in skin-to-skin contact with your baby to help your baby grow, improve milk production, and promote breastfeeding behaviors. 
  • Build and maintain milk production by expressing milk at least as often as your baby would breastfeed and draining your breasts well with “hands on” pumping
  • Use a paced bottle-feeding technique that promotes breastfeeding behaviors and respects your baby’s natural suck, swallow, and breathe patterns 
  • Beware of marketing claims. There is no such thing as a bottle or nipple that is “just like” the breast. Choose a bottle and nipple that fits your goals and your baby’s individual feeding style. 
  • Always hold your baby to feed. Bottle-propping is a choking and aspiration hazard. Eating is a naturally social experience; propping is isolating. 
  • Feed your baby when he shows hunger cues rather than on a schedule and let your baby determine when he is full (applies to healthy, full-term babies that are feeding well) 
  • Store breastmilk in smaller quantities to reduce waste 
  • Offer freshly-expressed milk whenever possible. 
  • If your baby is hospitalized, and you are unable to nurse or hold him, spending time in his environment (including touching equipment and even shaking hands with staff) will help you produce antibodies to germs to which he has been exposed. 
  • Baby-wearing and co-sleeping (room sharing) promote bonding, attentiveness to your baby’s hunger cues, and production of antibodies to germs in his environment 
  • If you are bottle-feeding due to low milk production, consider the option of using an at-breast supplementer so that your baby can receive supplemental feedings while nursing at the breast.
If you are bottle-feeding your baby exclusively or partly, and you would like to increase his feedings from the breast, or if you need more information about exclusively expressing your milk, an International Board Certified Lactation Consultant, WIC Peer Counselor, or volunteer breastfeeding support counselor would be able to offer information and support. The same holds true if you are feeling pressured to provide your milk by bottle even when it is not absolutely necessary; the often-suggested solutions for daddy- or grandparent- bonding time or feeding in public is “just pump.” Remember, whether by breast or by bottle, every ounce of breastmilk matters! You are doing something very special for your baby, your family, and your community.

More information:

It’s Not Just About Breastfeeding

Weaning from formula supplements

Help-My baby won't nurse!

It's Not Really About the Milk

Bottle Vs Breast, A Mother's Story

Milk Sharing, Good or Bad?

Buckley, K. Charles, G. (2006) Benefits and challenges of transitioning preterm infants to at-breast feedings International Breastfeeding Journal 1:13

Cantini, A. (2008) Pediatric Allergy, Asthma, and Immunology. Heidelburg, N.Y. Springer.

Chirico, G. et al (2008) Antiinfective Properties of Human Milk Journal of Nutrition 138, 1801S–1806

Isselmann Disantis, K. (2011) Do infants fed directly from the breast have improved appetite regulation and slower growth during early childhood compared with infants fed from a bottle? The international journal of behavioral nutrition and physical activity 17;8 (1):89

Li R, Magadia J et al (2012) Risk of bottle-feeding for rapid weight gain in the first year of life Arch Pediatr Adolesc Med 166(5):431

Moore ER, Anderson GC, Bergman N. (2009) Early skin-to-skin contact for mothers and their healthy newborn infants Cochrane Summaries

Mezzacappa, E. Katkin. E (2002) Breastfeeding is associated with reduced perceived stress and negative mood in mothers Health Psychology 21(2), 187-193

Orlando, S (2006) The immunologic significance of breast milk. J Obstet Gynecol

Neonatal Nurs 24(7), 678-83

Palmer, B. (2008) The Influence of Breastfeeding on the Development of the Oral Cavity: A Commentary Journal of Human Lactation, 14(2), 93-98

St. Francis Xavier University: Dr. Anne Bigelow. Enhancing Baby’s First Relationship: A Parents’ Guide for Skin-to-Skin Contact with Their Infants

© Jolie Black Bear, IBCLC, Serena Meyer, IBCLC, Teglene Ryan, IBCLC, and Adrienne Uphoff, IBCLC--All Rights Reserved

Thursday, July 19, 2012

Preparing for Your Return to Work: The Breastfeeding Mother’s Guide

When a family is expecting a baby, it’s a time full of wonder and happy expectation. For months, a mother feels fluttering and quickening, the soft movements of her baby. For many families, it is also a time for making plans to welcome a new family member. Parents may also use the time of pregnancy or the waiting period for adoption to investigate how to support the breastfeeding relationship in the workplace or in school. This article addresses some common questions breastfeeding mothers have about preparing for a return to work and includes the concerns that mothers who do not have a pro-breastfeeding workplace or school may face.

Talk to your employer

This article, Pumping 9 to 5, provides some information on how to talk to your employer about breastfeeding and how to make a plan for expressing your milk at work. Being ready for this conversation, with an idea of what you will need in terms of space and time, will help make your points clear and concise. Take the time you need to make a plan before you speak with anyone at your school or job. Other workplaces, tribes, and many places of higher education have set up lactation rooms; think about bringing them up in your conversation to support your requests. It may also be important to mention the ways your workplace or school will benefit from setting up a lactation room for other families. This booklet explains some of the possible concerns that a business or institution may have about setting up a lactation program for individuals that either work in or attend the facility.

Know your rights

There are State and Federal Laws in place to support breastfeeding mothers. For example California Labor Code 1030-1033 stipulates:
Every employer, including the state and any political subdivision, shall provide a reasonable amount of break time to accommodate an employee desiring to express breast milk for the employee's infant child. The break time shall, if possible, run concurrently with any break time already provided to the employee.
Additionally, the IHS and many Government agencies provide pumping breaks for their employees, and many institutions already have supportive programs in place for breastfeeding mothers. The Affordable Care Act of 2010, states that:
Effective March 23, 2010, the Patient Protection and Affordable Care Act amended the FLSA to require employers to provide a nursing mother reasonable break time to express breast milk after the birth of her child. The amendment also requires that employers provide a place for an employee to express breast milk.
Consider all of your options

Are you able to change your work schedule or delay returning to work or school? Some mothers have worked out job shares or found other ways to minimize separation from their babies. Talk to your employer about what might work for you.
  • Some companies offer on-site day-care or allow a mother to bring her baby to work with her so that she may continue to breastfeed. This arrangement eliminates the need to express milk because the mother can breastfeed her baby throughout the work day. Plan ahead: many on-site day-care facilities have long waiting lists.
  • Working from home part or full time is an option in some situations.
  • If you are not able to bring your baby with you or visit him during the day, consider a day-care situation that would allow a care-provider to bring him to you.
  • Split the work week with a co-worker who is looking for extra hours or a partial shift.

When should I start expressing milk? 

Babies grow so fast! They are newborns for only a few weeks, and before you know it, they are smiling, cooing, and reaching for your face while you are nursing. In the first several weeks after birth, take all the time you can to relax, get to know your baby, and just enjoy being his mom. Unless you have to return to work right away, it is recommended that mothers wait until breastfeeding is well-established before they begin expressing milk for returning to work: for most mothers, somewhere between 3-4 weeks. If you have to return to work earlier than 4-6 weeks, you might wish to begin pumping milk two weeks before you plan to return to work.

Learn how to express your milk

Preparing for your return to work or school can begin with learning to express your milk.
  • You can express milk by hand, with a breast pump, or by using a combination of the two. 
  • Learning how to remove milk without your baby requires both developing your own expression technique and conditioning your milk ejection reflex (MER) or “let down” to respond to it. 
  • Most mothers experience MER in response to the sensation of their babies suckling as well as other stimuli like the sound of a baby crying. If you are having trouble eliciting MER during expression, try visualizing your baby at the breast or listening to a recording of your baby's cry. Looking at pictures of your baby or smelling your baby's clothes or a blanket may also be helpful. If you have a video feature on your phone, try recording your baby breastfeeding so you can play it back while expressing. One study indicated that mothers who replicated their babies’ sucking patterns by adjusting the cycle settings on their pumps expressed more milk (Meier, et al, 2012). 
  • Warming the breast before expressing and gentle breast massage (working from the armpit towards the nipple with a soft kneading touch or in a circular motion with flat fingers) has been effective at increasing the amounts of milk removed during expression (Jones, Dimmock & Spencer, 2001). 
  • Combining hand expression and massage with a pumping routine has been shown to assist with increasing milk production and output (Morton, Hall & Wong, 2009).

How do I hand express?

Hand expression requires no special equipment and can be an effective way for you to remove milk when separated from your baby. Some mothers find that hand expression is more effective for them than pumping because it is more comfortable, and they can feel for areas of fullness and apply pressure with their fingers exactly where it is needed. Once you have success with a method of hand expression, you may feel that you are able to meet your baby’s needs without a pump.

What type of pump should I use?

A high-quality, full-size, double-electric pump is recommended for a mom who plans to pump milk every day. A pump that is made by a manufacturer specializing in breastfeeding equipment will be of higher quality than cheaper pumps made by a company whose primary products are bottle-feeding equipment or baby food. A breast pump is an item for which the old adage, “You get what you pay for,” often rings true. Another option for many mothers is renting a multiple-user pump from a trusted source such as a Hospital, Tribal Health Clinic, or local IBCLC. Most WIC offices provide pumps to moms who are returning to work or school; contact your local WIC office to see if you qualify. Many families have health insurance that is willing to cover the cost of renting a hospital-grade pump. If you are able, call your insurance provider for the details of your own coverage when you are pregnant. Recent 2011 news from the IRS states that electric pumps are now tax deductible, so keep your receipts for your tax records.

In our opinion, the top single user pumps on the market today are:

Pump Brand/Model
Cost range
Spectra S1 or S2
2 year
Closed system
Hygeia Enjoye*
3 year
Closed system
Ameda Purely Yours
1 year
Closed system
Medela Pump in Style
1 year
Open system

*Sold in the category commonly referred to as single-user pumps; Hygeia is the only pump company that has sought and received FDA approval for their pump to be used by more than one person.

What is the difference between an open and closed system pump? 

With an open system, if milk or condensation makes its way into the tubing, it is possible for mold to begin to grow in the motor. There is no way to clean the pump motor, and any mold spores present could come through the tubing and possibly into contact with the expressed milk. Furthermore, if the pump is second-hand or was used by another mother, germs from one mother or her milk could contaminate the milk in the same way. An open system is built to be a single-user system only.

Closed system pumps are just what they seem: there is no way for the milk to come into contact with the motor. Theoretically, any closed system pump could be safely used by more than one person (each with her own tubing and other external pump parts). 

What is the WHO CODE, and why is it important to consider when buying a breast pump?

The “WHO CODE” is short for the World Health Organization’s International Code of the Marketing of Breastmilk Substitutes. Part of the purpose of the WHO CODE is to protect breastfeeding by preventing aggressive marketing of breastmilk substitutes and artificial nipples. Many people prefer to purchase a breast pump from a company that is supportive of and compliant with the WHO CODE.

More information on both the breast pumps, the WHO CODE, and open and closed systems can be found at: The Problems with Medela

How often should I express milk?

Once a day is usually plenty at the beginning. Most moms find that they are able to express the most milk in the morning hours. You can nurse your baby on one side while expressing milk on the other side. Or you could pump both sides about one hour after your baby’s first morning feeding. Don’t worry if you don’t get very much milk at first. It takes practice, and your body needs to “learn” to make milk for that extra “feeding.” When milk is removed, your body responds by making more milk at a faster rate. It can take a few days for your body to increase production (Daly, Kent, Owens et al.,1996). Any milk collected during these practice sessions can be stored in the freezer.

How much milk should I have stored in my freezer?

Many mothers find that they feel less stress if they to know that they don't need to create a large freezer stash of milk before they return to work. Instead, they can use their maternity leave to focus on being with their babies and getting breastfeeding well-established. If you have enough milk to send with your baby on your first day, then you have enough in the freezer.

It is important to express as much milk while you are at work as your baby needs during that time. If your baby needs 10 ounces while you are away at work, then you need to pump at least 10 ounces each day.
For example:
If you were to only pump 8 ounces and send 2 ounces from the freezer each day, you would not be expressing the amount of milk your baby requires. Your body will “think” that your baby needs 2 fewer ounces each day than he really does, and your production will not match his demand. If you start to run out of milk in your freezer, you may face the difficult decision of how to meet your baby’s needs. Many mothers learn too late that increasing their milk supply to meet their baby’s demands is more complex than it seems. Meeting your child’s daily needs for expressed milk during separation is the best way to avoid difficulties later.

Using the simple system described, you pump each day what your baby would need the next day. This way you only use the small freezer stash for emergencies, such as dropping and spilling a day’s worth of milk, or other milk-related calamities.

If you need information about returning to work or expressing your milk, a Breastfeeding Counselor La Leche League LeaderNursing Mother’s Counsel or International Board Certified Lactation Consultant may be able to help. Accessing a community support system can help you reach your breastfeeding goals.

You may also be interested in these articles:
Returning to Work: The Breastfeeding Mother’s Guide
Are There Differences Between Breastfeeding Directly and Bottle-Feeding Expressed Milk?
Breast versus Bottle: How Much Should Baby Take?
Facts Every Employed Breastfeeding Mother Needs to Know
I’m Worried My Milk supply is Drying Up, What Can I Do?

Black Bear, J. (2011). Breastmilk Storage and Handling Guidelines.

Daly, S., Kent, J., Owens, R. & Hartmann, P. (1996). Frequency and degree of milk removal and the short-term control of human milk synthesis. Exp Physiol, 81(5), 861-75.

Easy Steps to Supporting Breastfeeding Employees. (2008). U.S. Department of Health and Human Services, Health Resources and Services Administration (HRSA), Maternal and Child Health Bureau. Produced in contract with Every Mother, Inc. and Rich Winter Design and Multimedia.

Forbes, B. (2011). What is the WHO-CODE? Website:

Internal Revenue Bulletin. Lactation Expenses as Medical Expenses. (2011). Website:

Jones E., Dimmock, P. W. & Spencer, S. A. ( 2001). A Randomised Controlled Trial to Compare Methods of Milk Expression After Preterm Delivery. Arch Dis Child Fetal Neonatal Ed, 85, F91–F95

Meier, P. Engstrom, J. Janes, J. Jegier, B. & Loera, F. (2012). Breast pump suction patterns that mimic the human infant during breastfeeding: greater milk output in less time spent pumping for breast pump-dependent mothers with premature infants. Journal of Perinatology, 32, 103-110

Morton J., Hall, J., Wong, R., Thairu, L., Benitz, W. & Rhine, W. (2009) Combining hand techniques with electric pumping increases milk production in mothers of preterm infants. Journal of Perinatology, advance online publication,29, 757-764

Shebala, M. (2012, January 26). Benefits of breastfeeding in workplaces touted. Navajo Times,

Silver, B. (2010). College and University Lactation Programs, some Additional Considerations. The Elsevier Foundation, University of Rhode Island Schmidt Labor Research Center.

Simmance, A. (2011). Why You Shouldn't Buy, Sell, or Borrow a Second Hand Medela Swing Pump. Website:

State of California, California Labor Code § 1030.
2002: Chapter 3.8, Section 1030, Part 3 of Division 2 of the Labor Code

West, A. (2011). The Problems with Medela. Website:

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