October 18, 2018

I’m 36 weeks pregnant Baby’s head measurements are showing a large discrepancy on ultrasound

Ask The Doctor > Questions & Answers > I’m 36 weeks pregnant Baby’s head measurements are showing a large discrepancy on ultrasound

Patient: I’m 36 weeks pregnant. Baby’s head measurements are showing a large discrepancy on ultrasound. Bpd is less than 1% and ofd is 96%. My doctor kinda blew it off, saying her head may have just molded that way due to positioning and they’ll check after birth. But this is a pretty concerning anomaly to us and would like more information.

Doctor: Hello,Thanks for the query to ATD,In specific pregnancies, it is important for the physician to predict fetal gr owth potential. This can be done in two ways. The first is by serial cephalometry and the second is by comparison of size to sibling weight.Concerning cephalic growth, Sabbagha and associates showed that 90% of fetuses normally maintain the same biparietal diameter (BPI) centile rank achieved by mid pregnancy.To determine cephalic rank, the BPD should be measured serially and classified into one of three categories: large, average, and small.Considering the fact that at 36 weeks the biparietal diameter is less than 1% and the of occipitofrontal diameter is 96%, this may indicate towards a dolichocephalic head.Dolichocephaly is a condition where the head is longer than would be expected, relative to its width. 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. 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. 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.So at 36 weeks if the metal growth parameters are normal and the overall growth is well and the level 2 scan didn’t show any soft tissue discrepancies then it is likely to be a holding defect which can easily get corrected after birth. So be patient and relax. Please follow your physician’s advise and have a positive attitude towards the outcome.I hope i have answered your concerns in detail,Wishing you safe delivery,Regards

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Dr. Jimmy Obaji M.D.

Dr. Jimmy Obaji completed his residency in Family Medicine at the University of Manitoba. He currently operates a walk-in-clinic in downtown Toronto.

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