Pollution and pregnancy: smaller babies
Living and breathing in a clean environment is ideal in pregnancy, but life in big cities does not make it possible. If we already knew that exposure to tobacco smoke had among other consequences a low birth baby, now new research reveals that maternal exposure to an atmosphere contaminated with nitrogen dioxide (NO2), which comes mainly from traffic pollution , in the early stages of pregnancy is associated with lower growth of the fetus.
This lower growth has been measured taking as a reference the measures during pregnancy and the size at birth, according to an international study in which researchers from CREAL (Center for Research in Environmental Epidemiology), an allied center ISGlobal, participated in a study of the INMA project (Childhood and Environment). The results of this work have been published in the June 26 issue of the scientific journal Environmental Health Perspectives.
Pollution delays fetal growth
The goal of this study was to investigate the impact of NO2 exposure on fetal and neonatal biometry within the Spanish INMA project. More than 2,400 women participated in this research, in particular 2,478 fetuses were evaluated, which were measured in each trimester of pregnancy, the biparietal diameter, which is the distance between the two parietal bones of the fetus' skull, the length of the femur, abdominal circumference and estimated fetal weight. These measurements, as well as the anthropometry at birth, were evaluated using specific growth-cohort curves at 12, 20 and 34 weeks of gestation. To estimate the exposure to NO2 in homes throughout the pregnancy process, measures of regression of land use were used.
Thanks to the results of this research, exposure to air pollution during pregnancy has been associated with fetal growth retardation. As an added value, it should be noted that few studies to date had measured fetal biometry longitudinally, in order to check areas of special vulnerability.
The researchers found that an increase of 10 g / m3 in the mean exposure of NO2 during the first twelve weeks of pregnancy was associated with lower growth in this period in the abdominal circumference and estimated fetal weight.
The study also revealed that the lowest growth due to exposure to contamination of the future mother occurs between week 20 and 34 in the biparietal diameter, abdominal circumference and estimated fetal weight, and femur length growth.
Problems that cause the baby to be born with low weight
Babies born underweight, usually less than 2 kilograms and 500 grams, need special care in the neonatal intensive care unit. Some of the medical problems that a low birth can present are:
1. Retinopathy of prematurity. It affects the blood vessels of the eye and babies born before the 32nd week of pregnancy.
2. Dyspnic syndrom. It is a breathing problem that affects babies born before the 34th week of pregnancy.
3. Bleeding in the brain. Intraventicular hemorrhages affect low birth weight premature infants during the first 3 days of life.
4. Persistent arterial duct. When the artery called "arterial duct" does not close to prevent blood from entering the lungs, as it did in pregnancy, it is necessary to use drugs or surgery.
5. Necrotic enterocolitis. It is a problem of the intestines and can be dangerous for the baby.
Other health problems for the baby related to low birth weight are the risk of diabetes, heart disease, high blood pressure and metabolic syndrome, among others
Marisol Nuevo Espín
