(a) Maternal age
    Organochlorine pesticides (OCPs)
        New POPs
        
    
    
        DDT group
        
    
    
    
        
Polychlorinated biphenyls (PCBs)
        Indicator congeners
        
        
    
    
        
Mono-ortho congeners
        
        
    
    
        
Non-classified
        
    
     
    (b) Parity
        Organochlorine pesticides (OCPs)
        New POPs
        
    
    
        DDT group
        
    
    
    
        
Polychlorinated biphenyls (PCBs)
        Indicator congeners
        
        
    
    
        
Mono-ortho congeners
        
        
    
    
        
Non-classified