The effect of biacromial and bideltoid distance on shoulder dystocia and birth weight in newborns

OBJECTIVE: To evaluate the relationship between neonatal biacromial and bideltoid diameter (BDD), birth weight and shoulder dystocia (SD). MATERIAL AND METHODS: This was a prospective observational study conducted on 161 pregnancies who applied to Private Lokman Hekim Hospital for follow-up between February 2021 and August 2021. Maternal height, weight, parity, and presence of SD in the second stage of labor were evaluated in the patients included in the study. The weight, height, head circumference, biacromial and BDD measurements of newborn babies were taken within the first two hours after birth. The primary purpose of the study was to evaluate the relationship between the biacromial and BDD and SD. The secondary purpose of the study was to evaluate the relationship between the biacromial and BDD and macrosomia. RESULTS: The mean age and post-pregnancy body mass index of the participants were 31.3±4.4 years and 29.0±4.0 kg/m(2), respectively, and 42.9% (n=69) delivered vaginally. The incidence of macrosomia was 6.8% (n=11) in all women and the incidence of SD was 7.2% (n=5) in women who had vaginal deliveries. The mean biacromial diameter (BAD) was 12.4±1.0 cm and the mean BDD was 18.2±1.7 cm. A correlation rate of 0.373 was found between SD and the BAD, and 0.484 between SD and the BDD. The correlation coefficients between macrosomia and the biacromial and BDD were 0.213 and 0.420, respectively. In cases in which the BDD was ≥21 cm, the sensitivity for SD was 100%, the specificity was 90.63%, and the accuracy was 91.30%. The cut-off point for the BAD was ≥14 cm, and the sensitivity and specificity for SD was 63.64% and 89.33%, respectively. The highest correlation for SD was obtained in cases in which there was a history of SD (0.648). CONCLUSION: The relationship between neonatal biacromial and BDD, and macrosomia and SD were significant. There was no difference between the correlation values of the two measurements in terms of SD. However, the correlation coefficient of the BDD was greater for macrosomia.