Maternal and placental risk factors for light-for-gestational-age births.

Aim: We conducted a cross-sectional study to investigate risk factors for births of light-for-gestational-age (LGA) infants.

Methods: A survey was conducted at the Department of Obstetrics and Gynecology at Sapporo Medical University Hospital in Sapporo, Japan from 2013 to 2014. LGA and appropriate for gestational age (AGA) are defined as having a birthweight below the 10th percentile and between the 10th percentile and 90th percentile for gestational age at birth in the population standard of gestational age, sex, and parity, respectively. An odds ratio (OR) and its 95% confidence interval (95%CI) for LGA were calculated by analysis using the logistic regression model.

Results: In total, 307 inpatients (94.2%) participated in the study out of 326 consecutive post-partum inpatients. Among them, 37 infants and 237 infants were classified into the LGA and AGA groups, respectively. As a result of multivariable analysis, prevalence of gestational hypertension (OR = 8.96, 95%CI 1.81-44.35) and the presence of placental infarction (OR = 9.65, 95%CI 1.76-53.01) were significantly associated with an increased risk of LGA. Placentas weighing 510-603 g and ≥604 g were significantly associated with reduced risk of LGA (OR = 0.04, 95%CI 0.01-0.29 and OR = 0.03, 95%CI 0.01-0.32, respectively), and higher placental weights were significantly observed in the trend for reduced LGA risk (P for trend < 0.001).

Conclusion: We found that the prevalence of gestational hypertension, lower placental weight, and the presence of placental infarctions were all independently associated with the risk of LGA. Placental abnormalities may be etiologically important for LGA risk, though further research is necessary.