AFJOG

African Journal of Obstetrics and Gynaecology | Volume 2 | Issue 3 | 2024 | 27 ORIGINAL RESEARCH African Journal of Obstetrics and Gynaecology | Volume 2 | Issue 3 | 2024 | The role of foot length measurement to determine the gestational age in stillbirths Medical illness • Hypertension in pregnancy • Diabetes mellitus • Chorioamnionitis 25 (30.5) 18 (22) 1 (1.2) 6 (7.3 Method of dating pregnancy • Early ultrasound scan • Sure Dates (LNMP) • Symphysis fundal height 32 (39) 32 (39) 18 (22) * Values are given as mean ± SD or number (percentage) unless otherwise indicated. Method of dating pregnancy: EUS: Early ultrasound scan, SD: Sure dates (LNMP), SFH: Symphysis fundal height. Table 2. Determinants of stillbirths’ outcomes n (%) p-value* Mode of delivery • Normal vaginal delivery • Caesarean sections 78 (95.1) 4 (4.9) p= 0.07 Sex • Male • Female 50 (61) 32 (39) p= 0.78 Classification • Fresh • Maceration 20 (24.4) 62 (75.6) p = 0.04 Birth weight categories • < 2500 g • ≥ 2500 g 62 (75.6) 20 (24.4) p = 0.20 * Chi-squared derived p=value Table 3. Measured variables on the stillbirths Variable Overall n (SD)* EUS* SD* SFH* Pearson correlation** p-value Birth weight (g) • Overall weight • Fresh • Macerated 1719.5 ± 122.1 1410.0 ± 212.9 1819.0 ± 144.9 p= 0.13 Foot length (cm) • Measured foot length • Validated measured foot length 62.2 ± 13.8 61.8 ± 13.5 65.5± 14.0 65.4± 13.9 54.7± 12.4 58.6 ± 12.0 61.3 ± 15.5 60.8 ± 14.5 0.989 p= 0.18 p= 0.14 * Values are given as mean ± SD. ** Correlation is significant at the 0.01 level (2-tailed). Method of dating pregnancy: EUS: Early ultrasound scan, SD: Sure dates (LNMP), SFH: Symphysis fundal height Table 4. Comparison of the gestational age determined by foot length (GA FL ) to the best estimated gestational age (GA E ) by an EUS (GA EUS ), SD (GA SD ) and SFH (GA SFH ) Variable Overall* EUS* SD* SFH* Pearson correlation** p-value Best gestational age 31.7 ± 5.3 33.6 ± 4.9 30.4 ± 5.0 30.5 ± 5.9 0.908 p=0.000 Gestational age by foot length 30.9 ± 5.2 32.3 ± 5.4 29.1 ±4.8 30.4 ± 5.6 0.908 * Values are given in weeks ± SD. ** Correlation is significant at the 0.01 level (2-tailed). The EUS population has by far the least percentage of accuracy, 19 (54.3%), followed by SFH with 10 (28.6%). Among the EUS population, the gestational age derived from foot length was, on average, 1.2 ± 2.6 weeks smaller than the actual gestational age (Table 5). The Bland Altman plot of the EUS population showed no obvious linear relationship between the two methods. Figure 1. plots the difference between the EUS gestational age and foot length gestational age against their mean, which shows an explicit lack of agreement, as 19 stillbirths lie out of the 95% limits of agreement. The mean overall birth weight was 1719.5g. Fresh stillbirths had a smaller average weight, 1410g, compared to macerated stillbirths with an average weight of 1819.3g. Overall, there were 62 (75.6%) stillborn infants with low birth weight (< 2500g), while 20 (24.4%) had a normal birth weight (> 2500g). Among the EUS population (32 stillbirths), there were 6 (18.8%) stillbirths with a birth weight below the 3rd percentile for gestational age using the Fenton charts, Table 6. Table 5. Early ultrasound population mean difference Method Mean gestational age (weeks) Mean difference p-value Ultrasound GA 33.6 ± 4.9 1.23 p=0.01 Foot length derived GA 32.3 ± 5.4 Figure 1. Bland Altman plot of EUS population Mean difference (bias) (1.2313) (p= 0.01) 95% CI of mean difference (.2734, 2.1891) Line of no difference (0) Limits of clinically acceptable difference (-2, +2) Table 6. Fetal growth: Fenton charts, EUS population Growth pattern Frequency Percentage Appropriate for GA 22 68.8 Small for GA 6 18.8 Large for GA 4 12.4 Total 32 100% DISCUSSION A local study using the Merz model to determine the