Tips for Breastfeeding a Baby with PKU

(from members of the PKU Listserv group)

Breastfeeding a baby with PKU can be a satisfying and successful feeding method, in combination with PKU formula. Blood phe levels can be well controlled using breast milk as a natural source of phenylalalnine to augment formula. There are many different approaches that can be successful. It is important for a breastfeeding mother to heed the advice of an experienced PKU clinic, and to find the method that works the best for her, perhaps with a little trial and error in the beginning. Here are some experiences from a professional as well as from mothers who have breastfed their infants with PKU.

óVirginia Schuett, Director, National PKU News

From a Professional:

Norway is one of the worlds leading country in breastfeeding, and therefore it has been naturally to treat our PKUās with formula and breastmilk. Since 1979, 97 PKU babies have been born, 88 ( 90%) have been breastfed. After admission and start of the diet s-phe were below 400 umol/l (6,5 mg%)as an average in 8 days (1-35). Aversion to the nipple of the bottle with phe-free formula is usually only at the first feeds (these are smart babies!). Infants have been breastfed from 1-16 months (mean 7 mo.). All babies are fed on demand. Mothers are encouraged to use electrical breast-pump or empty her breast by hand 3-5 times a day after breastfeeding in the beginning.

How to start? I had an article in Acta Pediatrica Vol. 88/December1999/suppl. 432, p.25 Breastfeeding in phenylketonuria. You will here find how to start diet with serum phe above 1200 umol/l ( 20 mg%) and serum phe less than 1200 umol/l (20 mg%) when the infant is diagnosed. I think the article will be of good help. Most important is that the baby is fed ad lib and on demand. The first day or three feed only phe-free formula ad lib, but count the amount. When time for breastmilk, divide the amount of formula the baby took the day before in 7-8 or more bottles; give this set amount of formula before each feed and then let the baby breastfeed on demand. The baby should be given formula first no matter how many feeds, and then breastfed. By following the serum phe you reduce the amount of formula and the baby take more from the mother. You donít need to know the total amount of breastmilk. The first 2 weeks we follow serum phe 3 times/week and weight check same day then the serum phe usually is where it should be. Follow up: serum phe once a week. And weight check same day, length and headcirumference once a month first year. One very important thing: Ask the mothers to drink a lot, it will help most mothers to have plenty of milk. My advice is, fill a bottle with at least 11/2 lit of water and drink between mealtimes (has to be empty by bedtime); fluids at mealtimes are in addition.

Kristina Motzfeldt
Metabolic dietition
Dept. of Pediatric Nutrition
Rikshospitalet University Hospital
0027 Oslo

One Motherís Problem with Breastfeeding and Helpful Responses

My son Dominic is 8 weeks old he has CPKU. We have had breastfeeding issues since day one. We have been instructed to give the formula first, then breastfeed. He didnít want to breastfeed after the bottle, so we went to breastfeeding first and then giving the formula for a few days. It was going better so we were told to try and go back to giving formula first. It worked and was going well for about ten days, then he started refusing the breast again. Now, it doesnít matter whether the formula is first, or the breast is first. He gets very agitated when offered the breast. It is a constant struggle. So far his levels have been good ( I donít know how) and he is growing and gaining weight appropriately. However, I dread feeding him because I am always wondering "how will it go this time". What can I do? I feel the breastfeeding is important and I donít want to give up. I know people have been successful. I would appreciate any advice and information.

(from a professional)

I know it can be difficult to find the right way to breastfeed an infant with PKU, and consequently very frustrating for the mom. Every clinic seems to have a different approach, and of course some have no experience at all and are not very interested in helping a new parent figure it out. I am not sure what your clinic's attitude or experience is, but I have not dealt with a breastfeeding mom for more than 16 years, so I don't feel up on the latest or best approach.

I do know that I was successful with at least half a dozen moms way back when I was in the clinic, some breastfeeding for a year or more but most for about 6 months. The blood phe levels were uniformly very good and I always felt the blood control was completely comparable to the usual approach of PKU formula plus an added source of phe from a source with a known phe content (such as an infant formula or milk).

My method back then was typically to alternate breast feeding with PKU formula feeding, allowing so many minutes at the breast and then following right away with formula at each feeding. I think this is optimal, as the baby then gets formula combined with some phe at each feeding, optimizing protein utilization and synthesis. The time allowance at the breast varied with the breast milk phe content, which we analyzed periodically (it is extremely variable from one woman to the next). We also did blood monitoring weekly for better control and advice to the mom for adding breast milk or adding more formula.

I think it might be helpful to you to speak with other moms who have breastfed relatively recently. I'm sure there are other ideas about how to manage breastfeeding. If you don't already belong to the PKU Listserv group, I suggest this is the place to start. You can simply post a question and hope to get responses from others with experience. It is a very supportive group for all kinds of issues related to PKU so it is good to join in any case.

To join the group, just e-mail Lin Gilbert at There are about 1300 families in the group so surely you will get some responses.

I hope this helps a little.
Virginia Schuett, MS, RD
Director, National PKU News

(from mothers)

* First, TAKE HEART!!! Babies can be very headstrong even at just a few weeks old. The problem is they aren't always clear about what they want which makes living with them tricky to say the least as I'm sure you have found already!! But I am SUCH a huge believer in breast feeding and it's importance I want to make a suggestion. I would suggest that you focus more on the breast feeding than the formula for a few days. When he is hungry, give him the breast first and foremost. Now I know he may balk and fuss but you just deep breathe and persist but my guess is that eventually he will settle down and eat. Then follow with the bottle once he's had a good start on the breast milk. Do that consistently at each feeding. Continue to keep an eye on his levels as you have been doing and my guess is things will settle down.

I do want to mention one other thing. I'm sure you'll receive other suggestions and I would encourage you to try the ones that make the most sense to you and appeal to you most in your situation. But if you do give it your best and it's still a battle then you can rest assured that you have given your son a great start with 2 months of breastfeeding so GOOD FOR YOU MOM!! That effort is to be celebrated and you are to be congratulated.

* I know this is a hard time for you with your new diagnosis and these feeding issues. I was fortunate not to have too many initial problems with breastfeeding my daughter, but I did have a few problems down the road with my daughter not eating as much when she breastfed and she ended up weaning herself at about 6 months (just refused breast milk all together). Trying to breastfeed is difficult especially when we must give those bottles of formula that are critical for our children. Have you tried pumping and giving the breast milk by bottle? In terms of your son getting the benefits of the breast milk and getting the bottle he apparently seems to prefer, it is a win-win.

I understand the strong desire to have the breastfeeding experience, but sometimes it just doesn't work, PKU or not. My sister-in-law was not able to breastfeed with any of her 3 children and my cousin is having a terrible time with her second child- is seeing specialists and everything- I'm sure some people are giving you advice to just keep trying, but if it's stressing you out, you can be sure it's stressing the baby as well and stress is also known to decrease milk production. Yes, giving breast milk to your son does have benefits, especially since he has PKU. THe alternative is a regular formula that is higher in phenylalanine than breast milk. There is an advantage of feeding your son breast milk or something like Similac by bottle, though- you know and can calculate exactly how much phenylalanine he is getting and it makes diet management (keeping those levels in check!. MUCH easier.

Again, I would strongly suggest to try pumping and giving the breast milk by bottle. If your son seems to prefer the taste of the formula, you could always mix the bottles, too, like give 2 oz. formula and 1 breast milk, in the same bottle.
I had the same problem with my daughter Katie when she was a newborn. I was also a big believer in the benefits of breast milk (I breastfed my non-pku daughter until she was 22 months old) so I ended up giving Katie breast milk through the bottle. We'd alternate feedings throughout the feeding breast milk, the next feeding formula. I was able to get her to breastfeed for the middle of the night feedings, which made things easier. I pumped an average of four times per day for six months (pumped more often at first til my supply was good) and froze the milk in a chest freezer, which I was then able to defrost and use til she was one year. Though I would have rather have just been able to breastfeed, it made it easier to keep track of her phe intake and it vastly reduced my stress of "will she breastfeed this time?" each feeding. Hope this helps, and good luck!

* Try massaging your breast just before feeding or try pumping to initiate the "let -down" (I could never feel it, but many moms do). You could also try a warm shower (when practical) or warm wash cloths.

* I know there is some kind of device that you can tape to your breast that his formula would come through at the same time that he is nursing. He would be getting formula and breast milk simultaneously. Check with Le Leche League. I know there is a device you can use to do this. I saw it. I just don't know what it is called.

I have nursed four children and know the frustration you are going through. When I nursed Andrew (PKU), I was told to rotate between nursing and formula. So, I would give him a bottle of formula and then the next time he needed to eat, I would nurse him. This worked out very well until I went back to work. It was too confusing for the day care mom and so I quit at four months. Andrewās levels were always good.

* I breastfed my son until he was 4 months. It went smoothly, then I ran out of milk. I think everyone should do what he/she thinks is important, but if it is a constant struggle, it is stressful for you and Dominic, and that's not healthy. I would try it till you feel you've done everything you can. You don't have anything to feel guilty about, you did what you could. There are many healthy babies raised without breast milk.

* I feel for you! When my son was diagnosed I strongly pushed to be able to breastfeed (and I HAD to if you know what I mean; pumps just don't work relieving the pain) the doctor was leery but since there had been a few successful cases they reluctantly agreed to let me continue. Zack was put on a VERY strict schedule of feeding every 3 hours day and night (ugh) was only about 10-15 ml of formula, topped off with the breast (which I had to time-not easy to do at 3 AM) He was allowed to nurse up until 1 hour before the next scheduled feed if he was still hungry after the first nursing set of about 15-20 min. As he got older of course his formula intake increased. I honestly cannot remember how many ml we went but I know it was never over 45mL for quite awhile... (and no-after he was about a month and WANTED to sleep through the night, I rearranged his daily intake so we could both sleep!)

I guess it all comes down to the proportions of formula he is having to intake each feeding...schedule, etc (and some kids just don't want to!) I had to continue to pump and finally gave up nursing about 7 months (as he had 4 teeth). Regardless, remember the formula is the most important part of your son's life now and if he is successfully drinking it-be VERY thankful!

* I was successful!!! Here's what I did: 3 breast feedings per day and 3 or four bottles. I would breastfeed in the middle of the night (SOOOO much better than the bottle at that point), midday and later I would also. I would work it so I could BF when I was out because I thought it was easier than the bottle. Also, I pumped 2 times when I did the bottle to keep my milk up. If my daughter's levels were too low, I would cut out a bottle and then add a breastfeeding.

My daughter's levels have always been great. A couple slightly high readings here and there and a few low ones but I think this method worked wonderfully!! I made sure when I did the blood test, I would do it after a bottle feeding so the breast milk wouldn't make the level skyrocket.

To me, the breast milk is healthier AND the BF is a wonderful bonding experience.

I have a daughter who is 2 years older than my PKU daughter so I had experience with BF so that made it easier.

When researching this whole issue, I talked to a lady who had done it this way also. It makes sense if you think about it. Of course your son doesn't want the breast after the bottle. It is so easy to get the milk out of a bottle. The breast makes the baby work hard.

Depending on your baby's phe tolerance, you can come up with how much breast milk to give him vs. how much formula. Your nutritionist will know how much phe (an estimate) is in one ounce of breastmilk.

* I told my PKU doctor I wanted to continue breastfeeding after my daughter, Annaliese, was diagnosed. As the Dr. suggested, she was breastfed every other feeding and her formula feedings were supplemented with my breast milk. At six months she weaned herself, probably because drinking from me required more energy than the bottle. I even weaned her from the bottle to a cup at that time. All went smoothly except that I wanted her to breast feed more. But her needs were more important that my desires.

* I have a five month old with PKU and a 3 year old; both were breastfed. I found that breastfeeding was one of the most un-natural natural things to do! In other words, it doesn't come easy. With both of my boys, I had difficulties and spent many days and nights in tears due to my frustration. So, please know that you are not alone.

Is Dominic gassy at all with the breastfeeding? Have you tried to eliminate things from your diet? Sometimes, eliminating dairy, broccoli, spicy foods, etc. will help. Even though he is 8 weeks old, he senses a lot. If you are nervous or frustrated when you try to breastfeed him, he will pick up on it. Have you tried different positions? He may prefer one position over another. Is he aligned right? Is there someone near you that has experience in breastfeeding that can help out?

You are right, breastfeeding is important. But, if it doesn't work out, that's okay too. You are not any less of a mother, and rest assured, Dominic will turn out just fine. If you can, try to take some deep breaths and relax before you try breastfeeding. Instead of getting worked up about "how it will do this time" think to yourself, "I am going to try this, but if it doesn't work this time, that's okay too." Breastfeeding is kind of like a dance -- both you and Dominic need to find the right rhythm between the both of you -- this takes time.

* I know so well the struggles you are facing. Our son is thirteen weeks old and for the first 10 weeks it was a HUGE struggle. I think my pediatrician thought I was crazy because one day I would call and say that Will refused to drink from the bottle and the next day I would say he ONLY would take the bottle and not breastfeed! Will was fickle at first and I donít think that it has anything to do with NIPPLE CONFUSION or the taste of the formula. I truly believe that Will got what he needed in those first weeks in spite of the drama I felt that I went thru in an attempt to balance his phe intake. His levels stayed within normal range and he is now 17 pounds strong and very happy. He did have reflux issues which are managed with medicine but, barring medical issues, I really think if you hang in there and just keep trying both at each feeding, in whatever order you are possessed to try that time, he will do fine. I now am back at work, so this is how we do it- WHEN I AM HOME...Will gets his phe-containing bottle first and then is breastfed if he is still hungry. If he doesnít want the bottle (like tonight) I just breastfed him to keep him from getting too hungry. He then slept a while, upon waking he was hungrier than usual because I donít have enough milk to be his "primary meal" so he ate a phe bottle happily and then breastfed some. Now we are back on track for the last feeding of the night. WHEN I AM AT WORK...the nanny feeds him the same thing at each meal, which is a combo 1.5oz breastmilk/2.5oz Phenex 1. He doesnít have the choice so he eats that or nothing. If he completely refuses then he must wait for the next feeding and usually eats.. it was a struggle but now is just fine. Hang in there and email me directly if you need advice. It gets better.

* I wasn't given the option to breastfeed. I was told off the breast the day after he was diagnosed with PKU. If that's what you want, don't give up, especially if your babyís levels stay good. If the levels start getting high and staying high, you may want to do what's best for his development. However, I will tell you what I did and I would do it again in a second.

I had a double automatic pump to express breast milk. I'd feed my son, then an hour or two later, pump. And start that cycle again. I would freeze my breast milk. Each day I would make a mixture of Phenex 1, thawed out breast milk, and water to feed him. I would feed him with an Advent brand bottle because that's what I thought was closed to a breast. We still got to snuggle up when I bottle fed him and I don't think I missed any bonding time because he wasn't at my breast. He's a huge cuddle bug now. Feeding should be a wonderful, loving time with your baby, not something to cause stress. You get enough stress with a baby as it is.

Pumping gets a lot easier and more routine as the months go on. By the end I would only pump 3/4 times a day. It didn't take long with a nice pump. I wanted him to have as much benefit as he could from the breast milk.

If you go this route, I have one tip. I learned this AFTER about 13 months of pumping. If you OR your baby get sick, give the milk you are currently expressing. Because your body knows it's sick or the baby is sick, it will produce extra anti bodies in the breast milk to help heal your baby quicker.

* I breastfed my daughter until she was nine months old. What I found was that I had to use the slower-flowing nipples. I used Avent bottles, and stayed with the stage 1 nipples for a long time. I know they tell you to switch, but in my experience, if they get used to not having to suck as hard, then they don't want to nurse anymore.

* This can be a tough one!. With our dietician's help, we worked out a number of ounces of formula that kept my daughter's levels good. It was basically trial and error and we needed periodic adjustments. Then the rest of the time she could nurse on demand. I never mixed breastfeeding and the bottle. I enjoyed nursing her at night so I only breastfed at night. Then I would alternate nursing and giving the bottle until I reached the number of ounces of formula required and then I would only nurse. It sounds quite complicated but actually it worked out well in the end and there were never any conflicts between nursing and bottles because I never did them at the same time. Each week we did blood levels and if her levels were climbing we might add an ounce of formula and if they were too low we would reduce the amount of formula. Hope this helps.

* I fed my son breast milk for his whole first year. I also tried nursing but eventually just started using my breast pump and just mixed the breast milk with the formula. I know this ends up defeating some of the advantages of breastfeeding like the convience of always having the breast milk ready and warm, etc. But for me it was better, for I then knew exactly the amount of breast milk he was getting and was able to keep his levels very good. I would pump up a bunch for the freezer for when I needed it, but mostly just tried to get the amount needed to mix with the formula each day. Each day I'd premix all his formula with breast milk and have in the fridge which was convenient. My company had bought the pump for me and it was a really nice dual pump which only took about 10-20 minutes to pump.

* I had to pump for awhile and give my daughter breast milk from the bottle. As she got used to the switch of the formula alternating with the breast milk, I gradually reintroduced my breast. Each night I would try and let her latch on though, so as not to have total confusion. When she was real sleepy seemed to be a good time for her to latch on and not get agitated. She is almost tem months old now and I am still able to breast feed three times a day while she gets to eat 8 separate exchanges daily. It is definitely worth the effort!

* I went through this with our first child (who is now 17 and about to start college!). What I found worked best for both her and I and Dad was to express (pump) the breast milk and freeze it ahead of time, then mix directly with the formula in a bottle. This way there was no "nipple" confusion for Jax, Daddy got to feed her too, and I still got to give her the advantage of mother's milk. I did this for about 6 months before we switched over to mixing Similac or Enfamil with the breast milk. Talk to your nutritionist about the amounts of phe per each, then you can measure appropriately. It also made it extremely easy to correlate blood levels with amounts of formula taken. We recorded how much was left in each bottle and how much we originally used of both breast milk and formula. It was a little more time consuming, but well worth the effort. I think I used to "de-stress" when I sat down to express the milk. It actually helped me to calm down with all the confusion and stress of a new, PKU positive child.

With our second child, now 13, I was able to breastfeed exclusively since he doesnít have PKU, and so enjoyed it that I did it for 2 years, mindful that the next child could have PKU. In fact, he did! Our next son, now 10, was given the same regimen as our daughter. All three are happy, healthy, and active.

* First of all...CONGRATULATIONS on the birth of your little bundle of joy! I can very easily remember the frustration at the beginning! I have 3 children (all were breastfed for over 1 yr.) My youngest, Vincent, has PKU. Admittedly, it was more of a challenge to breastfeed him, but I feel it was so worth it. Try to hang in there! Do you have a good support team? How is your son's dDietitian? Thank goodness, mine is absolutely wonderful. She totally supported my breastfeeding efforts. Most of the time my son only needed a very little amount of Phenyl Free 1. We would give him a little in the morning and a little at night. The rest of the time he could nurse. I would give formula first, when he needed it, because of the importance of getting that in them. Vincent nursed for 13 mos. and then still took breast milk from a cup for another month or so.

There is a booklet available from the public library..."Guide to Breastfeeding the Infant With PKU". I don't know if you have seen this website, but I found it pretty helpful.

* My son is 7 1/2 months old and he went through a period much like you are describing. I don't know why. In fact, I think I may have attributed it to gassiness and/or constipation(he was a VERY gassy newborn). One day he would suck down the bottle and refuse the breast, and the next day it would be the opposite. I remember one day where he didn't eat for approximately 7 hours! He had missed 2 feedings! I tried kind of stuffing my breast into his mouth and that only made it worse - both for me and for him - as he still refused. I called the clinic, and they referred me to my pediatrician (who knows next to nothing about PKU) who didn't have much to say. I was so frustrated as well. One thing my older son taught me with breastfeeding is that he can sense my agitation. So I then just tried playing with him and calming myself down. He did eventually eat.

How much formula do you have to give him? Could he be full from that???

Stick with it, keep offering him food. I now only offer the breast first if my ducts are clogged, just so I know he'll take his Phenex, although I think he would always eat it (he's a very hungry little boy)! Do your best to sing to yourself, relax, keep happy thoughts and don't freeze up when you offer him the breast or the bottle. I know the first couple of times I was offering, I was so tense about what he would do. Try to keep it out of your mind, smile a lot, and he'll get the cues (hopefully!). DON'T GIVE UP!!!! You can do it!

* I would just keep at it, especially since his levels are so good. Or you could try another approach. I pump every time I give my son a bottle (about three times) and then breastfeed the other feedings. That way he won't get as confused. You might try this, but be prepared that it might be difficult at first because of the change. It's a hassle to pump, but it's worked for us. Otherwise, you could pump and just put the breastmilk in his bottle of formula (mix it so he can't taste the difference). In any case, I would encourage you to keep up with it. Breastmilk is so good for him! Good Luck!

* This has happened with my first daughter who does not have PKU. What I wound up doing was pump (using a good quality double pump like Medela "In Style" for example) at the times when I would normally breastfeed and give breastmilk in a bottle. Yes, the intimacy aspect of breast feeding was lost, but we made up by cuddling, etc. My other daughter, who has PKU, somehow did not reject the breast but I was giving her bottle only 2-3 times a day when she was this young.

Last update: September 2006
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