Decreased neonatal tibial bone ultrasound velocity in term infants born after breech presentation.
OBJECTIVE
Fetuses found to be in the breech presentation have limited motion of their lower limbs. The aim of this study was to test the hypothesis that bone speed of sound (SOS) would be lower in infants born after breech presentation than in those born after vertex presentation.


METHODS
We studied 127 singleton, appropriate for gestational age, term infants delivered by a scheduled cesarean delivery at approximately 38 weeks of gestation because of breech presentation or repeat elective cesarean section with vertex presentation. We used the Sunlight Omnisense 7000p device to measure axially transmitted SOS of the right tibia within the first 96 h of life.


RESULTS
Fifty-three infants studied (42%) were born by cesarean section after breech presentation compared to 74 vertex controls. Bone SOS was significantly lower in the breech presentation group, even after taking into account the effect of gender and parity (as well as gestational age at birth and birth weight).


CONCLUSIONS
Bone SOS is lower in infants born after breech presentation than in those born after vertex presentation. We speculate that limited motion of lower limbs in fetuses found to be in the breech presentation leads to a decrease in bone mineralization and strength.
Tshorny
M
M
Department of Neonatology, Lis Maternity Hospital, Tel Aviv Sourasky Medical Center, Tel Aviv, Israel.
Mimouni
F B
FB
Littner
Y
Y
Alper
A
A
Mandel
D
D
D000328:Adult; D001724:Birth Weight; D015519:Bone Density / Q000502:physiology; D001846:Bone Development / Q000502:physiology; D001946:Breech Presentation / Q000503:physiopathology*; D002585:Cesarean Section; D005260:Female; D005324:Fetal Movement / Q000502:physiology; D005865:Gestational Age; D006801:Humans; D007231:Infant, Newborn; D008297:Male; D011247:Pregnancy; D012016:Reference Values; D013977:Tibia / Q000000981:diagnostic imaging*; D014463:Ultrasonography