Fetal bone strength and umbilical cord length

doi:doi:10.1038/jp.2009.64

Abstract

Objective:

Activity has been demonstrated in promoting bone mass in infants and adults. One of the major signs of fetal activity may be the length of the umbilical cord. We hypothesized that the fetus with a shortened umbilical cord may have low bone mineralization because of decreased movement or activity.

Study Design:

We investigated eight healthy term infants with shortened umbilical cords and 15 control term infants. Mothers with pre-eclampsia or hypertension, chorioamnionitis or prolonged ruptured of membranes were excluded from the study. Mother's age, parity, infants' gender, and birth and placenta weights were recorded. The umbilical cord length and diameter were measured as well as the newborn's tibial speed of sound (SOS). SOS measurements (Sunlight Omnisense 7000P instrument) were obtained at the tibial midshaft.

Results:

Measurement reproducibility was 0.8 plusminus 0.6% (means.d.) for repeat SOS measures. There were no differences between the two groups in mother's age (24.65.8 vs 25.83.3 years), parity (21 vs 21), infant's gender (25% females vs 47% females), birth weights (3320451 vs 3409452 g), or placental weights (52169 vs 588105 g). Umbilical cord diameters were also similar, 1.1 plusminus 0.3 vs 1.10.2 cm. However, there was a difference in the cord length between the two groups, 462 vs 574 cm (Mann–Whitney, P<0.001). The newborn infants with the shorter umbilical cord also had lower tibial SOS compared with controls, 3047107 vs 3194311 m/sec (Mann–Whitney, P<0.05). Tibial SOS was related to the infant's umbilical cord length (r=0.57, P<0.01) but not to infant's birth weight, gender, umbilical cord diameter, maternal age, or placenta weight.

Conclusion:

Infants with a short umbilical cord length have lower bone strength.

Keywords:

umbilical cord, fetal bone mineralization, term infant

Original Article