Hanifah I Titisari and H. Risanto Siswosudarmo
Department of Obstetrics and Gynecology Faculty of Medicine
Universitas Gadjah Mada-Sardjito Hospital, Jogjakarta
Background: Estimated fetal weight (EFW) is used as a guidence for management of labor. Several methods are used including ultrasound and fundal height measurements. The usual method is using Johnson’s formula but Risanto’s formula is now developing.
Objective of study: To compare the accuracy of Johnson’s and Risanto’s formulas in determining estimated fetal weight based on maternal fundal height (FH).
Material and method: A cross sectional study was used, consisting of 655 pregnant women from Sardjito and affiliated hospitals at 37-42 weeks of gestation. Fundal height was measured from the symphisis to the top of uterine fundus, using inverted unelastic flexible tape. EFW based on Johnson’s and Risanto’s formulas were compared with the actual birth weight. Wilcoxon analysis was used for statistical analysis.
Result: Mean EFW of Johnson’s formula was 3136 ± 392.2 grams and EFW of Risanto’s formula was 3056 ± 322.5 grams and mean actual birth weight was 3021 ± 341.1 grams. The mean difference between EFW of Johnson’s formula and the actual birth weight was 156.1±107.3 grams, and mean difference between EFW of Risanto’s formula and the actual birth weight was 100.8±86.1 grams. Those two differences was statistically significant (p=0,001).
Conclusion: This study showed that Risanto’s formula was more accurate than Johnson’s.
Key words: Fundal height, Johnson’s formula, Risanto’s formula, Actual birth weight