Occupational exposure to chemicals and fetal growth: the Generation R Study.
BACKGROUND
Developmental diseases, such as birth defects, growth restriction and preterm delivery, account for >25% of infant mortality and morbidity. Several studies have shown that exposure to chemicals during pregnancy is associated with adverse birth outcomes. The aim of this study was to identify whether occupational exposure to various chemicals might adversely influence intrauterine growth patterns and placental weight.


METHODS
Associations between maternal occupational exposure to various chemicals and fetal growth were studied in 4680 pregnant women participating in a population-based prospective cohort study from early pregnancy onwards in the Netherlands (2002-2006), the Generation R Study. Mothers who filled out a questionnaire during mid-pregnancy (response: 77% of enrolment) were included if they conducted paid employment during pregnancy and had a spontaneously conceived singleton live born pregnancy (n = 4680). A job exposure matrix was used, linking job titles to expert judgement on exposure to chemicals in the workplace. Fetal growth characteristics were repeatedly measured by ultrasound and were used in combination with measurements at birth. Placental weight was obtained from medical records and hospital registries. Linear regression models for repeated measurements were used to study the associations between maternal occupational exposure to chemicals and intrauterine growth.


RESULTS
We observed that maternal occupational exposure to polycyclic aromatic hydrocarbons, phthalates, alkylphenolic compounds and pesticides adversely influenced several domains of fetal growth (fetal weight, fetal head circumference and fetal length). We found a significant association between pesticide and phthalate exposure with a decreased placental weight.


CONCLUSIONS
Our results suggest that maternal occupational exposure to several chemicals is associated with impaired fetal growth during pregnancy and a decreased placental weight. Further studies are needed to confirm these findings and to assess post-natal consequences.
The Generation R Study Group,  Erasmus MC, PO Box 2040, 3000 CA, Rotterdam,  The Netherlands.
Claudia A
CA
Snijder
Nel
N
Roeleveld
Egbert
E
Te Velde
Eric A P
EA
Steegers
Hein
H
Raat
Albert
A
Hofman
Vincent W V
VW
Jaddoe
Alex
A
Burdorf
D000328:Adult; D004785:Environmental Pollutants / Q000633:toxicity*; D005260:Female; D047109:Fetal Development / Q000187:drug effects*; D006801:Humans; D016014:Linear Models; D018811:Maternal Exposure; D016273:Occupational Exposure; D010575:Pesticides / Q000633:toxicity; D010795:Phthalic Acids / Q000633:toxicity; D010920:Placenta / Q000187:drug effects* / Q000473:pathology; D011084:Polycyclic Aromatic Hydrocarbons / Q000633:toxicity; D011247:Pregnancy; D016216:Ultrasonography, Prenatal
D004785:Environmental Pollutants; D010575:Pesticides; D010795:Phthalic Acids; D011084:Polycyclic Aromatic Hydrocarbons