ABSTRACT
Introdução - As elevadas taxas de mortalidade neonatal e a prevalência de bebês nascidos pequenos para idade gestacional (PIG) ainda apresentadas por regiões de baixa e média renda indicam a necessidade de investigação sobre fatores que influenciam o crescimento fetal. Medidas biométricas fetais
Introduction Elevated rates of neonatal mortality and small-for-gestational-age (SGA) babies in low- and middle-income regions indicate the need to investigate factors associated with fetal growth. Fetal biometric measurements below the 10th percentile for gestational age (GA) reflect failure in achieving growth potential and provide opportunities for prenatal interventions. Objective To investigate factors associated with fetal biometric measurements below the 10th percentile assessed at early third trimester among pregnant women in the MINA-Brazil study. Methods This was a prospective analysis of pregnant women living in the urban area of Cruzeiro do Sul (AC), followed up since the antenatal period. Screening of participants took place from February 2015 to January 2016. A sociodemographic and health history interview was carried out along with two clinical assessments, scheduled between the second and third trimesters of pregnancy, to collect data on lifestyle factors and complications during pregnancy, anthropometric evaluation, blood collection, and ultrasound scan assessing fetal biometric measurements of head circumference (HC), abdominal circumference (AC) and femoral length (FL). Poisson regression models with hierarchical selection of variables were fitted for factors associated with occurrence of fetal measurements below the 10th percentile at early third trimester. Prevalence ratios (PR) and 95% confidence intervals (95%CI) were estimated. Results Among 426 participants (mean age 25 years (SD 6.4) and gestational age 27.8 weeks (SD 1.7)), 11.3%, 8.9% e 9.4% had fetuses with HC, AC, FL below the 10th percentile at early third trimester. Fetal biometric measurements below the 10th percentile were negatively associated with higher maternal education level, which denoted over 50% of protection (HC: PR 0.47, 95%CI 0.28; 0.81; AC: PR 0.48, 95%CI 0.26; 0.87; and FL: PR 0.48, 95%CI 0.27; 0.86). Adjusted for maternal education level, nulliparity (PR 1.94, 95%CI 1.10; 3.43), higher pre-gestational body mass index (BMI) (PR 1.06, 95%CI 1.01; 1.11), and pre-gestational alcohol consumption (PR 1.80, 95%CI 0.98; 3.30) were associated with HC measurements below the 10th percentile. Maternal height (p for trend 0.039) and pre-gestational alcohol consumption (PR 2.55, 95%CI 1.31; 4.96) were also associated with AC measurements below the 10th percentile. Association between higher average screen time per day during antenatal follow-up and FL measurements below the 10th percentile were observed as well (p for trend 0.031). Higher maternal education level, which may provide better material and non-material conditions, seems to protect fetal growth from failure to reach potential fetal size for GA. Positive associations observed with obstetric and antenatal conditions may be mediated by biological factors or gestational dysfunctions to incur in fetal measurements below the 10th percentile. Conclusion The occurrence of fetal biometric measurements below the 10th percentile for GA and their associated factors corroborate pre-pregnancy and antenatal care improvements anchored in equity policies, and for new strategies prior to birth that optimize the window of opportunity in the first thousand days of life.