Increased incidence of fetal growth restriction in association with breech presentation in preterm deliveries < 32 weeks

Breech presentation and fetal growth restriction (FGR) are each related independently with preterm delivery. This study was designed to assess the possible relationship between breech presentation and FGR in deliveries at < 32 weeks' gestation. From an established database of 465 consecutive deliveries at < 32 weeks of non-hypertensive, nondiabetic patients with singleton nonanomalous fetuses, those in whom birth weight, body length, fetal presentation (vertex or breech), and amniotic fluid volume (AFV) had been assessed were studied. Fetal growth restriction (defined as symmetric if both birth weight and body length were < 10th percentile and asymmetric if only the birth weight was < 10th percentile) was studied in relation to maternal age, parity, tobacco use, fetal presentation, AFV, membrane status, and gestational age at delivery. Statistical analyses included contingency tables and analysis of variance, with p < 0.05 considered significant. Two hundred ninety-eight patients met the inclusion criteria. In these patients 85 (28.5%) fetuses were breech and 213 (71.5%) cephalic. A total of 56 (19%) fetuses were growth restricted. Of these, 31 (10.4%) were symmetrically and 25 (8.3%) asymmetrically growth restricted. The incidence of symmetric growth restriction in the breech-presenting fetuses was 16% (n = 14) versus 8% (n = 17) in the cephalic-presenting fetuses, and of asymmetric growth restriction 12% (n = 10) versus 7% (n = 15), (overall p = 0.03). Fetal growth restriction was not associated with significant differences in maternal age, parity, smoking, AFV, membrane status, or gestational age at delivery (each p > 0.10). In preterm deliveries at < 32 weeks' gestation, breech presentation is associated with an increased incidence of intrauterine growth restriction, independent of clinical confounders.