Factors influencing the occurrence of small for gestational age at different degrees

Abstract

To investigate the factors influencing the occurrence of small for gestational age (SGA) at different degrees and provide a basis for early identification of severe SGA cases. Neonatal and maternal prenatal information were retrospectively collected from January 2018 to December 2022 at Peking University People's Hospital. The neonates were divided into three groups: severe SGA group (birth weight below the 3rd percentile for gestational age and sex), mild SGA group (birth weight ≥3rd percentile and <10th percentile), and non-SGA group (birth weight ≥10th percentile). An ordered multinomial logistic regression model was used to analyze the factors influencing the occurrence of SGA at different degrees. A total of 14 821 neonates were included, including 258 cases (1.74%) in the severe SGA group, 902 cases (6.09%) in the mild SGA group, and 13 661 cases (92.17%) in the non-SGA group. The proportions of preterm births and stillbirths were higher in the severe SGA group compared to the mild SGA and non-SGA groups (P<0.0125). The proportion of neonatal asphyxia was higher in both the severe SGA and mild SGA groups compared to the non-SGA group (P<0.0125). Ordered multinomial logistic regression analysis showed that maternal pre-pregnancy underweight (OR=1.838), maternal pre-pregnancy obesity (OR=3.024), in vitro fertilization-embryo transfer (OR=2.649), preeclampsia (OR=1.743), connective tissue disease during pregnancy (OR=1.795), nuchal cord (OR=1.213), oligohydramnios (OR=1.848), and intrauterine growth restriction (OR=27.691) were all associated with a higher risk of severe SGA (P<0.05). Maternal parity as a multipara (OR=0.457) was associated with a lower likelihood of severe SGA (P<0.05). Maternal pre-pregnancy underweight, maternal pre-pregnancy obesity, in vitro fertilization-embryo transfer, preeclampsia, connective tissue disease during pregnancy, oligohydramnios, nuchal cord, and intrauterine growth restriction are closely related to the occurrence of more severe SGA. Maternal parity as a multipara acts as a protective factor against the occurrence of severe SGA.