1) Babies whose mother were exposed to air pollution while pregnant may have their growth affected. The air pollution exposure had the most effect during early and late pregnancy.
2) Researchers found that newborn babies from mothers who were exposed to air pollution during the early months of pregnancy had lower levels of thyroid hormones. They found the opposite when pregnant mothers were exposed to air pollution during the later months of pregnancy — the newborn babies had higher levels of thyroid hormones. Thyroid hormones are essential for regulating growth and metabolism.
3) The researchers monitored air pollution in pregnant mothers on a weekly basis. Newborn babies underwent a heel prick test after 48 hours to measure thyroid hormone levels.
Summary: Air pollution, especially during early and late pregnancy in mothers, may affect the levels of thyroid hormones in newborn babies, and thus their growth.
Journal source: Environmental Research
Association between prenatal exposure to air pollutants and newborn thyroxine (T4) levels