Biological samples included maternal bloods at 36 weeks pregnancy, umbilical cord, cord blood, and placental tissues at birth.
Additional biological samples include maternal and child DNA, as well as child testosterone, diurnal and reactive cortisol.
Detailed information on the geographical origin and ethnic background of the samples including the maternal region of was collected from all samples can be found in Figure 2 and Additional file 1: Table S1.
We analyzed a total of 182 (16-week), 78 (delivery), and 202 (cord) serum samples, including 71 maternal-infant dyads with mothers' PFASs concentrations available at both 16 week of gestation and delivery.
Plasma samples from women carrying euploid fetuses were recruited before amniocentesis for indications including maternal serum screening and advanced maternal age and compared with samples from women carrying Down syndrome fetuses sampling immediately as soon as possible after karyotype determination.
Although these findings are drawn from only 1 study, this was deemed high quality research boasting a vast sample size (n = 16,401), where a diverse range of covariates were included in statistical analyses, including maternal depression, a known risk factor for problematic behaviour and criminal activity in children [35 37].
The commonest fetal risk factor is macrosomia [23]; however, any maternofetal condition predisposing to fetal trauma including maternal obesity, maternal diabetes or instrumental delivery can be implicated [24].
Measures of maternal infection including maternal HIV, maternal HIV viral load (MVL), and maternal malaria were uniquely evaluated for association with CCR5 expression, also through linear regression.
A total of 1037 prenatal samples were studied, and the reason for referral of these samples included advanced maternal age, ultrasound findings, parental anxiety, and family history of a genetic condition or chromosome abnormality.
Thus, the target samples include 30 maternal chart reviews per facility in order to reach a total sample size of approximately 900 reviews.
