17639
Women with a low PAH - DNA adduct level in concert with a high placental PAH level resulted in a 10 - fold elevated risk of having an NTD - complicated pregnancy .
 Chemical: PAH; Chemical: PAH
Given options, please tell me the categories of all the listed entity words.Output format is "type1: word1; type2: word2". 
Option: Chemical 
Text: {0} 
 Entities: PAH, PAH 
Answer:
 Chemical: PAH; Chemical: PAH