Background
In South Asia, a third of babies are born small-for-gestational age (SGA) accounting for a quarter of all neonatal deaths. The risk factors are well described in the literature, but many studies are in high-and-middle income countries or measure SGA on facility births only. There are fewer studies that describe the prevalence of risk factors for large-for-gestational age (LGA) in low-income countries. We aim to describe the factors associated with SGA and LGA in a population-based cohort of pregnant women in rural Nepal.
Methods
This is a secondary data analysis of a community-based trial where women were assessed for pregnancy approximately every five weeks. Demographic, socio-economic status (SES), medical/obstetric history, and timing of last menstruation were collected on pregnant women at enrollment. Vital signs, illness symptoms, and antenatal care (ANC) attendance were collected throughout the pregnancy and neonatal weight was measured for live births. We conducted multivariate analysis using multinomial logistic regression. Outcomes were SGA, LGA compared to appropriate-for-gestational age (AGA) and were multiply imputed using birthweight recalibrated to time 0, at delivery.
Results
In the adjusted analysis, SGA was associated with lower SES, zero parity, interpregnancy intervals less than 18 months, poor appetite/vomiting in the second trimester, and swelling of hands/face in the third trimester. Parity greater than five, male fetal sex, and increased weight gain were protective for SGA. Many of these factors were inversely associated with LGA. Additionally, four or more ANC visits and respiratory symptoms in the third trimester were negatively associated with LGA, and maternal age <18 years and respiratory symptoms in the second trimester were positively associated with LGA.
Conclusions
Our findings are in line with known risk factors for SGA. Because the prevalence and mortality risk of LGA babies is low in this population, it is likely LGA status does not indicate underlaying illness. High quality antenatal care, monitoring for appropriate gestational weight gain and increased monitoring of women with high-risk pregnancies may reduce prevalence and improve outcomes of SGA babies.
Trial Registration
The study used in this secondary data analysis was registered at Clinicaltrials.gov NCT01177111.