Five-dimensional long bones biometry for estimation of femur length and fetal weight at term compared to two-dimensional ultrasound: a pilot study

Abstract

Background/objective: This study aimed to evaluate accuracy of five-dimensional long bones (5D LB) compared to two-dimensional ultrasound (2DUS) biometry to predict fetal weight among normal term women.

Methods: Fifty six normal term women were recruited at Ain Shams Maternity Hospital, Egypt from 14 May to 30 November 2015. Fetal weight was estimated by Hadlock’s IV formula using 2DUS and 5D LB. Estimated fetal weights (EFW) by 2DUS and 5D LB were compared with actual birth weights (ABW).

Results: Mean femur length (FL) was 7.07 ± 0.73 cm and 6.74 ± 0.67 cm by 2DUS and 5D LB (p = .02). EFW was 3309.86 ± 463.06 g by 2DUS and 3205.46 ± 447.85 g by 5D LB (p = .25). No statistical difference was observed between ABW and EFW by 2DUS (p = .7) or 5D LB (p = .45). Positive correlation was found between EFW by 2DUS, 5D LB, and ABW (r = 0.67 and 0.7; p < .001). There was strong agreement between FL measured by 2DUS and 5D LB (ICC = 0.78), and perfect agreement between EFW by 2DUS and EFW by 5D LB (ICC = 0.918). 2DUS and 5D LB showed mean absolute percentage error for EFW of 10 ± 7% and 8 ± 7% compared to ABW (p = .15).

Conclusions: 2DUS and 5D LB had same accuracy for fetal weight estimation at normal term pregnancy.

Keywords:

• 2DUS
• 5D LB
• fetal femur
• fetal weight
• five-dimensional long bones

Acknowledgements

Special thanks go to the patients and their families for the great support of our work. Also, the authors highly appreciate the support from feto-maternal unit of Ain Shams University Maternity Hospital for the outstanding support during the entire experiment.

Ethical consideration: Institutional review board (IRB) approval: The protocol was discussed by the ethical scientific committee and informed consent was taken before participation.

Consent procedure: The investigator made a great concern that a correct informed consent process was in place to make sure that potential research subjects were fully addressed about the nature and objectives of this clinical trial, the potential hazards and gains of study participation, and also their rights as research subjects. The investigator took the written, signed an informed consent of each participant before performing any study-specific technique on the participant. The investigator retained the forms of original signed informed consents.

All data and materials are available on request with agreement for publication.

Subject confidentiality: All evaluation forms, reports, laboratory specimens, and other records that leave the site would not comprise unique personal data to maintain subject confidentiality.

Disclosure statement

All the authors declare no conflict of interest.