Air pollution exposure during pregnancy, ultrasound measures of fetal growth, and adverse birth outcomes: a prospective cohort study.
BACKGROUND
Air pollution exposure during pregnancy might have trimester-specific effects on fetal growth.


OBJECTIVE
We prospectively evaluated the associations of maternal air pollution exposure with fetal growth characteristics and adverse birth outcomes in 7,772 subjects in the Netherlands.


METHODS
Particulate matter with an aerodynamic diameter < 10 μm (PM10) and nitrogen dioxide (NO2) levels were estimated using dispersion modeling at the home address. Fetal head circumference, length, and weight were estimated in each trimester by ultrasound. Information on birth outcomes was obtained from medical records.


RESULTS
In cross-sectional analyses, NO2 levels were inversely associated with fetal femur length in the second and third trimester, and PM10 and NO2 levels both were associated with smaller fetal head circumference in the third trimester [-0.18 mm, 95% confidence interval (CI): -0.24, -0.12 mm; and -0.12 mm, 95% CI: -0.17, -0.06 mm per 1-μg/m3 increase in PM10 and NO2, respectively]. Average PM10 and NO2 levels during pregnancy were not associated with head circumference and length at birth or neonatally, but were inversely associated with birth weight (-3.6 g, 95% CI: -6.7, -0.4 g; and -3.4 g, 95% CI: -6.2, -0.6 g, respectively). Longitudinal analyses showed similar patterns for head circumference and weight, but no associations with length. The third and fourth quartiles of PM10 exposure were associated with preterm birth [odds ratio (OR) = 1.40, 95% CI: 1.03, 1.89; and OR = 1.32; 95% CI: 0.96, 1.79, relative to the first quartile]. The third quartile of PM10 exposure, but not the fourth, was associated with small size for gestational age at birth (SGA) (OR = 1.38; 95% CI: 1.00, 1.90). No consistent associations were observed for NO2 levels and adverse birth outcomes.


CONCLUSIONS
Results suggest that maternal air pollution exposure is inversely associated with fetal growth during the second and third trimester and with weight at birth. PM10 exposure was positively associated with preterm birth and SGA.
Generation R Study Group, Erasmus Medical Center, Rotterdam, the Netherlands. e.vandenhooven@erasmusmc.nl
Edith H
EH
van den Hooven
Frank H
FH
Pierik
Yvonne
Y
de Kluizenaar
Sten P
SP
Willemsen
Albert
A
Hofman
Sjoerd W
SW
van Ratingen
Peter Y J
PY
Zandveld
Johan P
JP
Mackenbach
Eric A P
EA
Steegers
Henk M E
HM
Miedema
Vincent W V
VW
Jaddoe
D000393:Air Pollutants / Q000633:toxicity*; D000397:Air Pollution; D005260:Female; D047109:Fetal Development / Q000187:drug effects*; D005317:Fetal Growth Retardation / Q000139:chemically induced* / Q000000981:diagnostic imaging; D006801:Humans; D018811:Maternal Exposure; D009426:Netherlands; D011247:Pregnancy; D011256:Pregnancy Outcome; D011446:Prospective Studies; D018570:Risk Assessment; D016216:Ultrasonography, Prenatal
D000393:Air Pollutants