Parity Conditions the Risk for Low Birth Weight after Maternal Exposure to Air Pollution

ABSTRACT

Multiparous mothers have greater umbilical blood flow and thus more efficient transport of pollutants than primiparous mothers. We tested a hypothesis that multiparous mothers are more prone to have an infant with low birth weight (LBW) after prenatal exposure to air pollution. A study was conducted on a representative group of more than 74,000 singleton, live, full-term infants. Birth data were obtained from the birth registry, while pollution data were from an environmental monitoring system (Poland). Multiple comparisons were controlled by the false discovery rate procedure (FDR). After standardization, the harmful effect of carbon monoxide (CO) on the odds ratio (OR) for LBW was seen among the multiparous mothers (OR = 1.28; 95% CI 1.06–1.54), while in primiparous mothers it was nonsignificant. The effect of CO on the OR for LBW differed according to parity, which was confirmed by the test for interaction (FDR-adjusted p = 0.03). The interaction between parity and sulfur dioxide (SO₂) was statistically nonsignificant (FDR-adjusted p = 0.08). Multiparous mothers may be more vulnerable to CO than primiparous mothers. Parity may be the modifier of the association between pollutants and the risk of LBW.

Disclosure of potential conflicts of interest

The authors declare that they have no conflict of interest. This article does not contain any studies with human participants performed by any of the authors.

Funding

This study was carried out within the Framework of a Project No. N N404 055 136, financed by the Ministry of Science and Higher Education.

Additional information

Funding

This study was carried out within the Framework of a Project No. N N404 055 136, financed by the Ministry of Science and Higher Education.