TTHM constituents (chloroform, bromodichloromethane and dibromochloromethane) analysed as categorical variables showed a slight excess risk of SGA during the entire pregnancy as well as trimester-specific periods.
The women were not asked for their motivation for having an abortion and it is possible that some women having second trimester abortion as well as first trimester abortion did not use family planning at the time of conception because they wanted to become pregnant.
The additional 4 comprehensive signal functions are more consistent with hospitals' capacity and include surgery and blood transfusion as well as second trimester abortion care.
However, the finding of higher vulnerability amongst girls is consistent with our previous follow-up of this cohort up until age 7 years and the association remained robust even after adjusting for postnatal environmental risk factors as well as first trimester exposure [ 18].
For each birth, we calculated averages for the time periods corresponding to the 9 months of pregnancy as well as for each trimester; trimester-specific exposures were examined to identify potentially critical times during pregnancy when pollutants may affect birth weight.
Chloroform analyzed as continuous variable (increase of 0.1 μg/d) was also associated with an increase in risk for LBW ORR 1.10, 95% CI 1.01-1.19) for the entire pregnancy, as well as for trimester-specific time windows.
Insulin-resistance of the group with preeclampsia was higher in first trimester prior to diagnosis as well as the third trimester after diagnosis compared to natural pregnancy under similar conditions.
This relation was statistically significant for first trimester exposure and for both birth length and head circumference, as well as for second trimester exposure and head circumference.
Direct dose measurements or calculations/estimates of fetal dose in chest CT are difficult to perform and in the literature a variety of doses is reported, most probably due to the background that fetal dose in chest CT is dependent on the position and size of the fetus as well as on the trimester of pregnancy [22].
We also estimated average concentration for the entire pregnancy, as well as for each trimester.
However, Pereira et al. (2012) reported a positive association between preeclampsia and NO2 exposure during the entire pregnancy as well as the third trimester.
