Four out of five studies on PCBs reported an adverse effect on birth weight [ 13- 15, 19]; one did not[ 16].
Conclusions:Results suggest prenatal smoke exposure has a greater negative effect on birth weight for women endorsing co-occurring depressive symptoms.
It affects obesity indirectly via its effect on birth weight (B i ), which in turn affects subsequent obesity (arrow 1); it affects obesity directly (arrow 2); and, it affects obesity by modifying the relationship between birth weight and obesity (arrow 3).
Prenatal dietary treatment had no effect on birth weight or on metabolic endpoints when animals were 'lean' (1.5 years).
In conclusion, 24 common variants associated with adult adiposity did not have a strong effect on birth weight in the Danish Inter99 population.
There was no treatment or gender effect on birth weight, but a significant effect of fetal number (P = 0.004), with twins being born lighter than singletons (4.1 kg±0.2 [n = 12] vs. 5.3 kg±0.2 [n = 8], respectively).
However, by visual comparison of the effect on adult BMI with the effect on birth weight and ponderal index from the figure, no tendency in this direction seems to exist.
It could have been of interest if the alleles with the strongest effect on adult BMI also had the strongest effect on birth weight although not reaching statistical significance in this study sample.
Prenatal stress has been reported to either decrease [26], [27], [28], increase [29], or have no effect on birth weight [30], [31], although varying methods of prenatal stress induction and statistical analyses of birth weight [32] may have confounded the results.
Many trials have assessed the effect on birth weight of giving women micronutrient supplements during pregnancy.
Finally, we examined the intervention effect on birth weight at different levels of maternal compliance.
