Influence of sonographic fetal weight estimation in (suspected) fetal macrosomia on perinatal outcome

Objective To evaluate the influence of sonographic fetal weight estimation (EFW) in (suspected) fetal macrosomia on delivery mode and neonatal outcome (NO).

Methods This retrospective study evaluated the association between EFW, true birth weight (BW), mode of delivery and NO in 14,633 singleton pregnancies > 37+0 weeks of gestation with EFW within 7 days before delivery between 2002 and 2016. Study population was divided into four groups: Group 1: EFW < 4000 g/BW ≥ 4000 g, Group 2: EFW ≥ 4000 g/BW ≥ 4000 g, Group 3: EFW ≥ 4000 g/BW < 4000 g, Group 4: EFW< 4000 g/BW < 4000 g.

Results As expected, the highest secondary cesarean section (sCS) rate was found in Group 2 (30.62 %), whereas in Group 4 the sCS rate was only 17.68 %. With regard to Groups 1 and 3, surprisingly, the sCS rate in Group 3 was clearly higher (28.48 %) compared to Group 1 (21.22 %).

No significant differences were found regarding NO between Group 1 and 3 for the parameters “5-min Apgar < 7” (p = 0.75), “pH < 7.1” (p = 0.28) and “neonatal intensive care unit admission” (p = 0.54). However, there was a significantly higher probability for shoulder dystocia (SD) in Group 1 compared to Group 3 (Odds Ratio 4.58, 95 % CI 1.34, 24.30, p = 0.008).

Conclusion Underestimation by sonographic EFW in (suspected) macrosomia seems to have a greater impact on delivery mode than BW itself without impact on neonatal outcome but higher probability for SD.

Publication History

Article published online:
07 October 2020