This post is about dolichocephaly, a form of positional molding which affects some breech babies – how it happens, why it may be important, and how to recognise it.
If you permanently link to this page, please use the new site: https://breechbirth.org.uk/2014/04/dolichocephaly-understanding-breech-head-molding/
Everyone is concerned about entrapment of the after coming head in a breech birth. And it seems so unpredictable. Many breech babies, even large ones, seem to just fall out. And then others, not so large, get stuck. RCOG guidelines suggest an estimated fetal weight above 3800 g is ‘unfavourable’ for vaginal breech birth, but goes on to say, “If the baby’s trunk and thighs pass easily through the pelvis simultaneously, cephalopelvic disproportion is unlikely.” (Easily is undefined, but in light of the evidence against augmenting breech labours, I interpret it as occurring spontaneously within about an hour of active pushing.)
Can we predict which babies’ heads are more likely to have difficulty passing through the pelvis? I don’t know, but I feel one phenomenon in particular deserves more attention – dolichocephaly.
Dolichocephaly developing due to positional pressures
Technically, dolichocephaly is a mild cranial deformity in which the head has become disproportionately long and narrow, due to mechanical forces associated with breech positioning in utero (Kasby & Poll 1982, Bronfin 2001, Lubusky et al 2007). This change in shape is more commonly associated with primiparity (first babies), larger babies, oligohydramnios, and posterior placentas, all of which result in greater forces applied to the fetal head.
(Note: Like all positional molding which occurs in utero, dolichocephaly does not in itself cause nor indicate abnormal brain development. The head shape is highly likely to return to completely normal in the days and weeks following birth, especially if baby receives lots of holding and cuddles to permit free movement of the head.)
Clinical Importance
Following the birth of the arms in a breech birth, the head will be in the anterior-posterior diameter of the pelvis. When the head shape has become abnormally elongated, the longest diameter of the fetal head will meet the shortest diameter of the maternal pelvis at the inlet. Unless the baby is still on the small side and the pelvic inlet very round, the chin may get stuck on the sacral promontory, preventing head flexion. A very experienced breech provider will have encountered this situation before, and should be able to assist, but it is quite a tricky place to be. The head may need to be rotated into the transverse diameter to safely enter the pelvis. A very elongated head can have difficulty passing through the lower pelvis as well, and can cause damage to the maternal pelvic floor, unless appropriate techniques are used to assist the head to flex.
Abnormal head molding in some breech babies
Estimation of fetal weight by ultrasound is notoriously inaccurate. However, a lack of proportionality between the head circumference and the biparietal diameter is more obvious to spot (e.g. HC=90th percentile, BPD=60th percentile; or a difference in correlating dates of two weeks or more), and may be a more relevant indication that this baby is too big for this particular woman. Dolichocephaly can be discerned on palpation as well, as the occiput is prominently felt above the fetal back, the head is not ballotable, and may feel unusually wide. I would suggest caution where estimated fetal weight is above 3500 g and a difference in HC and BPD, or careful palpation, indicates abnormal cranial molding has occurred, especially for women who are having their first baby, have a low amniotic fluid index, and/or a high posterior placenta; and in situations where imaging pelvimetry is not used to confirm an ample pelvic inlet.
Counselling Women
Women instinctively do not like weight limits used as ‘selection criteria.’ One woman (Ann, multip, 6’1”) looks at another (Carol, primip, 5’0”) and they both think – We can’t possibly be expected to have similar-sized babies. While Ann may carry a 4000 g baby with no abnormal head molding, and expect a straightforward birth, Carol’s baby may begin to show signs of dolichocephaly at 3300 g, especially if she has low levels of amniotic fluid and a posterior placenta. Carol may still have a successful birth, but it will more likely depend on the skill and experience of her attendant in assisting the aftercoming head to flex, rotate and negotiate the pelvic diameters, and the pelvic diameters themselves.
A ‘normal’ breech baby – well-flexed, with lots of room to move
We need to move away from the concept of ‘selection criteria,’ which are used by professionals to make decisions for women, and towards an understanding of what is ‘normal for breech.’ We need to understand more about which babies are more likely to experience those beautiful, often-easier-than-cephalic, dancing-into-the-world births, and which babies are truly being put at additional risk by their in utero conditions.
Then we will be able to explain to women the benefits of a caesarean section for pregnancies which have become ‘abnormal.’ Women will be able to approach this intervention with an open heart when they observe professionals are truly supporting ‘normal’ breech births and providing individualised care and screening to those which are not.
I would love to know what others think about this.
Shawn
Enjoyed reading . Makes sense . Am now thinking what are the skills I need as an attendant and how to know which way to turn baby if chin is wedged on coccyx .also palpations I find hard sometimes .
Indeed! I am still working on that one myself. Palpation will come with practice. Keep a self-audit of weights and positions. Give yourself permission to not be right all of the time. 75% of babies referred to my clinic for ?breech were cephalic on USS, and 30% of all breeches are missed. Clinical skills and technology should back each other up.
Once again you’ve clearly highlighted the importance of useful selection criteria rather than blanket rules, and asessing each case as unique . I’ve assisted a primip birth a 4.2 kilo baby with relative ease and had a primip with a much smaller baby get stuck at the sacral promontory. The flattened top to the baby’s head over the anterior fontanelle region is commonly seen after breech birth and may well increase the AP diameter. Thank you again for adding further knowledge to the breech birth arena. X
Thanks, Joy. I’m blessed to be doing this work in the company of such reflective people. x
This information will be an invaluable part of my practice
Good to know .. I would be keen to hear of your experiences using this information in practice.
Thank you, this was very informative and will greatly help my practice
Great, Clare. Please do share any experiences you feel have helped you, and will help others, as appropriate. We’re all learning from each other.
I can see how this situation can cause one to miss a breech presentation as the head would feel more like a bum.
Yes, great point Carly. Another midwife said this to me recently .. if it had not been for the scan, she would have thought it was a bum. To me, already knowing it was breech, it felt like an abnormally elongated head, sitting in transverse (and was).
This is brilliant Shawn. I had forgotten the term Dolichocephaly because I have not seen it for years due to lack of vaginal breech births.We need to share wider to inform students and recently qualified midwives! Well done on the great breech work. Jacque
Thanks, Jacque. We do indeed need to share and continue to learn as much as possible.
this is so very interesting
Thank you .. I will be interested to hear if you find it useful in practice.
I always say: the fat is on the bottom, not on the head. So a small baby has more risk to get stuck with the head than a bigger baby in breech position. If the baby is bigger, the head is not the bigger part, but the bottom is.
Thank you for this, Janke.
I agree that when bigger babies fit through a pelvis, it stands to reason their heads will, and of course a bigger baby will be more resilient in the case of a delay. However, as with a cephalic baby, fitting through the pelvis easily requires the head to be in an ideal position. I feel a misshapen head which becomes deflexed in cases of fetal compromise may have more potential to become caught at some stage in the birth process, and therefore become dependent on the birth attendant to help the head into a more ideal, flexed position to navigate the pelvis. But it’s just a theory!
If you have experience attending breech births, I would love for you to consider participating in my research!
Shawn
Only just seen this!!!! May explain an issue I had with a recent birth where the head didn’t engage at the same speed in previous births I’d attended. Baby did indeed have dolicocephaly and am now wondering if that was the issue rather than primiparity & syntocinon (I know, don’t even get me started on the synto part :-{). Issue resolved with turning to lithotomy & Mauriceau. All ended well (parents ecstatic) but this might well explain the delay 😉
Thanks for sharing that experience, Lisa. Would love to hear more about 1) how you diagnosed that the head had not engaged, eg. what you felt; and 2) whether you feel the change in position assisted the engagement at all. If it was not possible to perform Mauriceau with the woman upright, did it feel more possible after turning to lithotomy? 🙂
I’ll fill you in on the 13th!!! 🙂
I have a student who was described as having this condition. Does it have any negative effects on academic performance?
Hi, Alan. My thoughts around dolichocephaly end at birth. A paediatrician would be best placed to advise you on the consequences of childhood dolichocephaly. A cranial osteopath would probably have some thoughts as well. Best wishes, Shawn
My head is long I’m african too but I wanted to know how I can get it smaller if it’s possible. Does anyone have answers please ??
Sorry David. No answers.
Thanks for this post, it is really reassuring. I am currently pregnant 36w4d and baby is in breech position whole the time. And unfortunately baby head is abnormal like you described. I understand reasons why head shape is like it is but what constantly worrying me is will this shape of head will be changed after labor? It is scary for me to accept that this shape is permanent. I read a lot about operation to change head shape and I am hoping that won’t be neccesary for my little girl.
Hi Jelena — It is usually not necessary. Hold your baby a lot and give her an opportunity to move her head a lot rather than resting on one side. If you are worried, you can speak with a cranial osteopath or your GP for a referral. Best wishes, Shawn
This is a note I received from my OB today. I am 37w3d and my baby finally moved from a Frank to a Footling to a head down position last week. She still hasn’t rotated to face backwards-kind of sideways. Feet left, arm right. Her face looks squished in ultrasound-her nose & mouth look like a sucker fish. I am 43, went through ivf as well. Here’s the note:
I spoke with Bonnie regarding the question I had on the preliminary report.
I asked for clarification regarding “CI” listed under the measurements and it means “cranial index” which is a measurement of fetal head shapes. Your baby has a slightly longer and less wide head (most babies are this shape). The measurement from side to side in 14% while the entire circumference is 30%. This is an acceptable finding even though the CI is listed as low <2% or 71.4mm. The reference range is 73.90-82.70 thus only just over 2 mm short of normal. Please don't be alarmed since as a whole, your baby is measuring appropriately at 38%. You are going to meet this sweet little creature soon enough and wont have to worry about a large baby head to deliver!
Please let me know if you have any questions.
Julie
I’m glad it was reassuring Amber! And I’m glad your baby has found her way to a position that will hopefully give her more room. Most babies descend in the pelvis in a head-sideways position and then rotate to face your back when they are coming out. All the best. Shawn
Thank you so much for this article. My baby (first) was breech but we didn’t know until 36 weeks. Three different midwives had assured me that she wasn’t breech but the fourth caught it and we believe she had been for quite a while. No one ever mentioned the term Dolichocephaly, but I’m almost certain that’s what she had as her head was so elongated. It has since rounded out just fine. I had no option of a vaginal birth once we found out Baby was breech but I’d love the medical community to open its perspective to look into vaginal breech births as more of a possibility, keeping head shape and size in mind, rather than simply closing that door altogether, often unnecessarily, for lack of knowledge/research.
Wow! Thank you for sharing your story and perspective. When I speak to women who have had an unexpected breech birth, they often say they suspected their baby was breech but were reassured differently. Always listen to women …
Dear Shawn, thank You for this article. My baby boy is now 36 weeks and in frank breech position. Today we had an ultrasound: His belly circumference is now about 20 percentile and his head on 95 pc.
All of the ultrasounds before were fine, and head and belly were at the same percentile. Now there is a big discrepancy.
Is that normal that now the head is “flattened” due to his frank breech position?
Dominika
Hello Dominika —
Usually, even with breech babies, the head and body are on a similar percentile. We call this ‘symmetrical growth.’ A big discrepancy is called ‘asymmetrical growth.’ I can’t really comment on what this means for you and your baby because I am not providing clinical care. You should discuss these findings with your obstetrician and get her/his opinion.
Wishing you and your baby the best,
Shawn
Interesting! I’d always wondered if it was that shape to make the birth easier, because the larger occiput would “Catch” on the sacrum and be forced to remain flexed. But I suppose it would be Difficult if the neck wasn’t already flexed at that point of the birth…. fascinating. Thanks for your brilliant work on this.
Hi Heather. Thanks for this. One of the surprising finds from my early research about the principles of physiological breech birth was the consensus finding: “In a physiological breech birth, a healthy, uncompromised baby moves in ways which assist her/his own birth.” (100% consensus, https://www.midwiferyjournal.com/article/S0266-6138(16)30149-8/fulltext)
Although guidelines commonly say to look to ensure the neck is in a flexed position in utero, this changes as the baby progresses through the mechanisms of birth. A neurologically intact baby will continue to exhibit a full-body flexion recoil reflex (https://onlinelibrary.wiley.com/doi/epdf/10.1111/birt.12480), which helps her/him pull the aftercoming head through the pelvis, sometimes with a little rotation to oblique/transverse, which we may or may not observe externally.
My observation is that the biggest risk of head entrapment at the inlet results from fetal compromise, which inhibits this reflex.
Thank you for becoming involved!
Shawn
I am 23 weeks pregnant and my anatomy scan is showing the head is longer than wide so the nurse called and they are referring me to a specialist. Nurse said the word Dolichocephaly and said my fluids are low. I can find any readings on pregnant women finding this out this early. I am worried about his brain forming, trying not to stress.
Hi Miranda. I’m sorry this is causing you to worry. I really hope you are able to see the specialist soon, who should be able to explain what this means for your baby in your unique situation. As a midwife, I generally work with women who are at the end of their pregnancy and cannot offer you any advice. Wishing you and your baby well, Shawn
I’m a student midwife and mother of an 11-year-old daughter who was undiagnosed frank breech upon admission after SROM. In the confusion of realizing she was breech and with my own L&D experience, when the CNM called the OB in, and the OB poked her head in the door and said, “So, you want to have this baby vaginally?” I just assumed she was sympathizing with my disappointment, and I replied, “Yes, I did, but I guess it’ll have to be a C-section.” And off I went for a totally uneventful C/S. (Turns out she was the only OB in the hospital who did vaginal breech deliveries…I just didn’t understand what she was saying.) The disappointment was hard to contend with over the next several weeks, but I eventually made my peace as I realized how many cards were stacked against us for an uncomplicated outcome: she had dropped at 36 weeks, so the midwives’ exclamations that she must have turned in the past few days (had recently had an appointment) were certainly unfounded. She had a cord that was around 12 inches so ECV could have been disastrous. She had dolichocephaly (I never knew there was a term for it!), and bilateral hip dysplasia (frank breech) and needed a Pavlik harness for 2 months. I always imagined that this head shape would have dramatically complicated a vaginal breech delivery, but was never sure. Thought maybe the huge egg-shaped occiput would perhaps even help with flexion as the head entered the pelvic inlet…so it’s been helpful as I’ve studied more to have some clearer reading on this. Thank you. I hope I can get at least a few breech experiences in during my clinical rotations…but it just doesn’t look that likely these days. Only saw one with a CNM in the military, and I was so new I had no idea what was going on. Thanks for sharing knowledge!