RESUMEN
<p><b>OBJECTIVE</b>To investigate the relationship between pathological abnormalities of placenta and small-for-gestational-age neonates.</p><p><b>METHODS</b>One hundred placentas of small-for-gestational-age (SGA group) and 200 appropriate-for-gestational-age (AGA group) with single living birth in third trimester were investigated by gross and microscopic examination. The AGA placentas were collected from 2 cases following every SGA placenta. All cases were collected from Shanghai Changning District Maternity and Infant Health Hospital from January 2010 to December 2011.</p><p><b>RESULTS</b>The gestational week, neonatal birth weight, full-term neonatal birth weight, the preterm birth rate and vaginal spontaneous delivery rate were significantly lower in SGA group than that in AGA group (P < 0.002). Full-term placental volume, placental weight and fetal placental weight ratio were lower in SGA group than that in AGA group (P < 0.05). Unusual insertion and torsion of umbilical cord were more common in SGA group (P < 0.05). Syncytial knots increase, avascular villi and villous infarcts were significantly higher in SGA group (P < 0.005), but there were no significant difference between SGA group and AGA group in intervillous thrombi, chronic villitis and chorangiosis (P > 0.05). Gestational hypertension disease and abnormality of fetal monitoring were more common in SGA group (P < 0.05).</p><p><b>CONCLUSIONS</b>Gestational hypertension disease is the main clinical cause of SGA. Some placental abnormality can affect the growth and development of intrauterine fetus.</p>