Premature babies and pyloric stenosis – perhaps rare but certainly risky

I was surprised to find recently that when a premature baby has infant pyloric stenosis (PS), there are some notable differences from the way full-term babies present with this condition.  It is important for general practice medical doctors and pediatricians to be aware of these differences, so I’ll pass on what I learnt for the interest and benefit of readers: survivors, parents, and medical workers.

What motivated me to research this subject?

A recent web chat with a fellow PS survivor who was born 3 months premature taught me that early arrival lowers the risk of PS.  However, because PS so often comes with stress and an increased incidence of other congenital abnormalities, I had assumed that prematurity would increase the incidence of PS.  Fair enough as an assumption, but apparently I was wrong: the medical literature I have read mostly (but not unanimously) tells me that premature infants have less chance than full-termers of having infant pyloric stenosis.  My research surprised me in several ways…

Pyloric stenosis in the premature infant is rather hazardous because it usually presents in a more deceptive way than in full-term babies.  In full-term babies, the diagnosis of PS is all-too-often delayed until the baby has almost expired.  Because prematurity comes with its own list of dangers and complications, the recognition of PS is even more often delayed.  In addition to this, compared with the PS symptoms of an average full-term baby, the premature infant with PS will usually present differently.

1        Vomiting is more likely to be more intermittent and less forceful.

2        As always, medical (drug) treatment is likely to reduce the condition’s severity, often making surgery unnecessary – but sometimes delaying surgery while the baby loses still more of its already more delicate condition.

3        Informed parents will look out for the rather dramatic PS symptoms of projectile non-bilious (without bile) vomiting, ravenous hunger after vomiting, severe weight loss, lack of bowel motions and even urination which are typical of the infant brought to the clinic or hospital from home: these are all likely to be less severe in premature babies.

4        Alert doctors will look for the visible signs of PS present in full-term babies: severe vomiting, seeing gastric peristalsis (waves of muscle action over the stomach) after feeding, and finding “the pyloric olive” (swollen pylorus): these are (or were once) valuable and often sufficient diagnostic tools.  But in premature infants these clinical symptoms are also typically unclear.  So barium and ultrasound tests may be needed, which take time – which is especially critical for a tiny sick baby.

5        Added to this, the pyloric measurements (pyloric wall thickness, length and width of the pyloric passage) as measured by sonography give a clear diagnostic indication in full-term babies but less so in premature infants.  (See also #7 below.)

6        The medical literature informed me that whereas the average age of the onset of PS symptoms in a full-term baby is 3 weeks, it averages 5 weeks in a premature infant.  However, the several reports I read included several pre-term babies whose PS developed earlier than 3 weeks!

7        At operation, the swollen pylorus of premature infants is softer, more pliable, less gritty and thinner than that found in full-term babies.

8        Several journal articles mentioned that the common practice of feeding tiny infants by a tube that passes past their pyloric muscle is suspected of both causing some PS cases and often delaying its diagnosis.

9        Findings about the incidence of PS in pre-term infants seem to vary somewhat.  A Taiwanese project reported on all the IHPS patients admitted to all the country’s hospitals between 1991 and 2004 enrolled 214 babies, 18 of whom were premature.  The average age overall at diagnosis was 40 days.  A significantly older age of symptom onset, a lower body weight at admission, more cases diagnosed by barium meal study and higher postoperative complication rates were noted in the preterm group versus full-term infants with IHPS.  Cases diagnosed before 3 weeks and pre-term infants had higher complication rates and longer hospital stays.
A 2009 Australian study however, reported in its Abstract:  IHPS occurs more frequently in male and ex-premature infants.  It commonly presents without the full spectrum of ‘classic’ symptoms and signs.  Given the availability of ultrasound diagnosis, IHPS should be considered in all babies with any one of the classic findings.
A 2012 U.S. study seemed to bear out these surprising findings!  Again in its Abstract, it reported:  The authors found pyloric stenosis to be significantly associated with male sex, age between 2 and 7 weeks, early study period, being first born, maternal smoking during pregnancy, preterm delivery, small weight for gestational age, Caesarean section, and congenital malformations.

Some conclusions

Nowhere have I read that premature babies with PS have been found to be less likely to survive the condition and its treatment.  The death rate from infant PS remains less than 1% in countries with a good standard of health care.  However, each of pre-maturity, PS and surgery carries its own risks.

One Report concluded:  A premature infant, 3 months of age or less who vomits gastric contents, fails to gain weight, and is constantly hungry, is likely to have pyloric stenosis.  Palpation of the pyloric tumor is certain evidence of the diagnosis.

18 thoughts on “Premature babies and pyloric stenosis – perhaps rare but certainly risky

  1. Wendy

    Fascinating! Isn’t it hard enough being a premie and then to have pyloric stenosis on top of it? Yikes! Your post is a definite eye-opener. It’s so great that you are informing us about this. It’s surprising that PS premies have such success given what you report about the presentation of PS symptoms being less dramatic than those in full-term babies. I wonder if there are any other places you could publish your post so that you could inform more parents. I think that PS in premies is a condition that parents of premies especially need to be aware of as well as parents in general and those thinking of becoming parents. In any case, thanks so much for waking us up to this issue.

  2. Fred Vanderbom Post author

    Yes, I am also very grateful to have been prompted to research and write about this aspect of PS: what I found was eye-opening to me and I do hope it will help a lot of people.
    There’s a regular trickle of people who find one of my posts relevant to them via search engines, but it’s a tiny percentage of those who could be helped by the material.
    Sadly, the medical establishment runs a very closed shop: the few forum and many medical information sites with information about PS are mostly superficial (less than a page of information), never deal with any of the many related issues that I write about, and are usually very establishment-oriented (they mention only the “party line”) – needless to say, they seem to be mostly written by doctors (very “safe” but…).
    Do you have any suggestions about how we could reach out better beyond our blogsites?

  3. Milton Pino

    Premature babies need a lot of care and attention after leaving the womb so this is why we give thanks to the world of modern technology and to all the life saving masters in the medical profession that nurture our before-time babies with their knowledge, thus increasing the odds for their survival. Hospitals today are well equipped to deal with emergencies like early births. The welfare of the premature baby is first and foremost in all hospital maternity wards. The reasons given behind why a woman may go into labour earlier than anticipated are all health related factors, e.g., smoking, poor diet, infections, twins, cervical ineptitude and other conditions that can be life threatening such as pre-eclampsia. All of these can speed up the process where premature baby births are likely.

  4. Sue Westcott

    I’ve found your website informative, interesting and helpful, thank you. I was born twelve weeks early in 1969. My mother was not allowed to see me at all for ten days, my father could only look through a window into the special care baby unit where I was being looked after, in those days parents weren’t allowed close contact with their premature babies. After five weeks, my mother was finally allowed to feed me for the first time and I was discharged from hospital a week later, having finally reached the magic weight of 5lb from my birth weight of 2lb 3oz.

    Within a few days I began to projectile vomit. Our family doctor suspected my mother was overfeeding me (I was, after all, quite small) and he suggested she cut down the amount of milk she fed me. It had no effect. The health visitor suggested thrush and I began treatment for that, but I was still being violently sick. Finally, in desperation, my parents rang the sister who’d headed the special care baby unit where I’d been treated and she arranged admission to hospital and pyloric stenosis was suspected. The hospital hadn’t seen a case in a premature baby girl before, so it wasn’t certain, but they proceeded with the operation.

    After the operation, my mother noticed a marked difference in the way I tolerated any form of handling. I’d never really liked being picked up and cuddled before the operation – having spent that long in intensive care where the nurses were far too busy looking after very sick babies and without any parental contact meant I simply wasn’t used to it. After the operation if I was held I would go rigid and not respond in any way. I’ll never know if it was a result of early isolation, with the added complication of the operation. It still doesn’t feel right, and the feelings you describe of anger and depression certainly echo with me.

    My own daughter was born prematurely six years ago. What potentially could have been a thirty three week birth, was thankfully held off until thirty five weeks and she was a good healthy weight, but I was still very frightened for her. She was with me throughout the nine days we spent in hospital, I was never separated from her, yet the twenty four hours she spent in an incubator receiving photo light treatment for jaundice, still reduce me to tears. She was right by the side of my bed, I could still touch her, change her nappy and feed her, but I couldn’t hold her. I wonder how my parents managed to cope with separation from me, seemingly so well.

    The pyloric stenosis scar continues to cause problems, forty three years later! I had my gall bladder removed last year and alerted the surgeon to the possibility of the internal scar tissue causing problems. His arrogance astounded me, I was told the procedure would still be keyhole and it was none of my concern. I awoke after surgery to discover that they’d had to convert to an open procedure and had reopened my original scar, extending it further, resulting in an eight inch incision. Infection and the problems of scar tissue healing meant it was three months before I didn’t have to visit the nurse every day for the dressings to be changed. Five months on and internally it’s still periodically painful and swells alarmingly on occasion.

    Your website helps enormously, it means that there are other people who have been through this too and that I’m not alone. Thank you.

  5. Fred Vanderbom Post author

    Hi Sue, I am so grateful that you found this blog!
    I remember how excited I was several years ago when I found an invitation to PS survivors from Mark (who Comments here from time to time) to establish contact. He and I soon found we’d had a very similar journey with the ongoing effects of PS. Then about 3 years ago Wendy (whose supportive Comments here are regular) started her blog – and again I found somebody who’d “been there, done that” and whose friendship helped me also to break out of my feelings of isolation and frustration.
    Since starting this blog I’ve had so much correspondence with folk like you: the details vary of course but the stories are the same: the condition, surgery, maternal deprivation and trauma of being a PS baby can all-too-often have ongoing effects. And as for adhesions… so many problems and so many doctors in denial.
    I have just taken up contact with somebody who wants to research this and very much hope that this results in a higher-profile Report than what I can produce.
    Thank you so much for telling us something of your story. You may well have little idea how important it is to have done this, as I find many PS survivors are inclined to pour cold water on what these blogs are chronicling.
    Please keep reading and interacting with us here!

  6. Patricia Samuel

    I have read your commentary on Premature Pyloric Stenosis and was very pleased with the information you captured and rendering the subject matter easy to understand. I am grateful for your own interest and concerns and your willingness to share your research on the subject. I am still very concerned but I feel better with the knowledge that you have armed me with.

  7. Fred Vanderbom Post author

    Patricia, I’m so glad that my research and writing efforts are so often and much rewarded with feedback like yours. I’ve been given several gifts which I want to use to help the pyloric stenosis and infant surgery communities of which I am very much a part.
    If you ever feel up to it, I and I’m sure our readers would very much value having a bit more of your experience chronicled here. What are your concerns and how has this post helped you?
    Keep well – and best wishes.

  8. Shihab rabh

    Good job, very interesting article, I am currently reading a lot of literature regarding pyloric stenosis in preterm, and actually most of the cases reported stated that it occurred at less than 3 weeks of age rather 5 weeks of age as known. I am a family medicine resident and I find this to be very important for me due to the atypical findings of PS in preterms as it will pass undiagnosed by many PCPs. Thank you for bringing up this topic.
    If you have good articles regarding preterm PS please let me know

    1. Fred Vanderbom Post author

      Thank you for your commendation, Shibab.
      I’ll review my material on IHPS in pre-terms and email you the links I have; you will most likely have read them already. Best wishes for your studies. I would of course value your sending me any material you assemble as part of your ongoing studies or as a report.

  9. sonya

    My 2 daughters had ps, they’re now 33 and 28. My oldest daughter’s 2 boys also had ps (now 5 and 1.5). Now we were fully prepared that our youngest baby would also have ps, he was a preemie at 29.5 weeks and is now 4.5 mths, 2 mths “corrected”. We do hope he will not get ps. At this age is there chance of him getting over it or not?

    1. Fred Vanderbom Post author

      It’s not possible to predict, Sonya, so stay prepared. Though it seems that premmies don’t have a higher risk of having ps, there are certainly many stories of premmy bubs with ps on the web. Also, the genes for ps seem to be very strong in your family, although they must have weakened over 3 generations of parents from outside your line. Sleep him on his back and try to feed him regularly rather than whenever he sicks up, as frequent feeding may raise one the risk factors for ps. Best wishes!

  10. Chris Holinde


    I am now a 31 year old male and I was born with PS and also a double hernia on top of the PS! I was full term and at birth was 6.5 pounds and 2 weeks later I was dropping into the 4 pound weight group. I had emergency surgery to fix my PS. I have had no complications at all with mine. I have 5 inch scar across my stomach from it. I have turned out to be very athletic and I am 6’5″ and weight 260 and have a very muscular build

    1. Fred Vanderbom Post author

      Chris, you went through a rough time in your first month or so and you are blessed and lucky that this doesn’t seem to have affected you since. Congratulations! Because there seem to be no significant studies of ongoing effects after PS and infant surgery it is impossible to know whether your experience was the rule or the exception, but I suspect and hope it’s the former. A quick search of the web reveals a small but significant number who have had trouble in a variety of ways.

  11. Aminta

    My husband was born with pyloric stenosis. We have three boys. Our two older boys were born full term and both developed PS at 3 weeks. Our baby was born at 34 weeks. His PS was diagnosed at 10 weeks (4 weeks corrected). My two older boys’ pylori were completely closed, with forceful vomiting. However, my baby’s pylorus was not, so his symptoms were milder. He was diagnosed after a 3rd ultrasound.

    1. Fred Vanderbom Post author

      Thank you Aminta for sharing your experience with PS. Although it is unusual for a father who had PS to have 3 children with all troubled by this condition, the early onset all shared and the small differences remind us to expect anything after we get PS into our genes.

  12. sharon seleb

    I gave birth to a boy at 28wks, he just had surgery for pyloric stenosi at 39 wks. He also has severe chronic lung disease. He experienced symptoms around 36wks. He just had the surgery 2 days ago and is now intubated. He was only intubated the day he was born for 12 hrs. He is given morphine almost every 2hrs because he is in so much pain. The pediatric surgeon told his neonatology team at Lurie Children’s that he can eat immediately after surgery, so they tried. He had residuals on 5ml feeds, when just a few weeks prior was eating 40mls fully fortified. He ate 5mls the 2nd day of life. The surgeons said it can take time to extubate because of his lung disease. Does anyone have any similar stories? Thoughts or suggestions?

    1. Fred Vanderbom Post author

      Thank you for sharing some of the story of your son’s struggle with life. I do hope you get some helpful feedback here, and that one day you’ll be able to look back at this difficult time with satisfaction and gratitude, as well as a bit older and wiser.
      I would also encourage you to consider posting your story on Facebook’s “Pyloric Stenosis Support Group” page. This is the largest of Facebook’s PS interest groups, a “closed” site (open to with registered members only) with more than 750 members, many of whom are quite active and interested in sharing and helping.
      Just yesterday I read the newly posted summary of a study which may also be of interest to you: you can find it at It is one of several studies that show that unfortunately infant PS comes more often than average with other conditions and can trigger them.
      Prayers and best wishes.


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