Kp. Williams et N. Nwebube, Abdominal circumference: a single measurement versus growth rate in the prediction of intrapartum Cesarean section for fetal distress, ULTRASOUN O, 17(6), 2001, pp. 493-495
Objective The fetal abdominal circumference is the most sensitive ultrasoun
d biometric measurement for predicting intrauterine growth restriction, whi
ch is associated with an increased risk of intrapartum fetal distress. We s
ought to evaluate and compare whether a third-trimester ultrasound measurem
ent of abdominal circumference made within I week prior to delivery better
Predicts operative delivery for fetal distress when compared with the growt
h velocity of the abdominal circumference in the third trimester.
Methods Retrospective analysis was carried out of prospectively collected u
ltrasound data on 117 patients with singleton gestations who had had at lea
st two ultrasound assessments performed less than 6 weeks apart in the thir
d trimester, with the last ultrasound performed within 1 week prior to deli
very. The abdominal circumference value of the last ultrasound prior to del
ivery was placed into one of three categories: less than or equal to 5% cen
tile, < 5 to less than or equal to 10% centile and > 10% centile for gestat
ional age. The growth velocity of the abdominal circumference per week tc,a
s placed into one of three categories: > 5 mm/week, 6-10 mm/week and greate
r than or equal to 11 mm/week. The chi-squared test was used to compare dif
ferences between the incidence of fetal distress between the groups.
Results The incidences of Cesarean section for fetal distress in relation t
o a single measurement of the abdominal circumference were: less than or eq
ual to 5% centile, 8/23 (35%); > 5 to less than or equal to 10% centile, 3/
12 (2.5%); > 10% centile, 8/81 (10%) (P < 0,05). The incidences of Cesarean
section for fetal distress with the three abdominal circumference growth v
elocities were: less than or equal to: 5 mm/week, 9/55 (16%); 6-10 mm/week,
4/11 (36%); greater than or equal to 11 mm/week. 8/51 (16%) (P=0,9401).
Conclusion A single measure of the fetal abdominal circumference made withi
n 1 week prior to delivery is superior to an assessment of growth rate of t
he fetal abdomen in the third trimester in discriminating patients who requ
ire Cesarean section for fetal distress.