Literature Review - Systematic Research 4 Pages

The topic is ( The impacts of Caffeine on Spontaneous Abortion in Makkah, Saudi Arabia ) - its about comparing between researchers.

Research question: Is there an impact of caffeine consumption abortion in Makkah, Saudi Arabia ?   

Type of research ( Quantitative ) -  I need some of statistics in Literature review And End the end i need schedule with all results that you finds. 

 https://www.ncbi.nlm.nih.gov/pubmed/20306287

https://academic.oup.com/aje/article/182/12/1023/2195415

https://www.cambridge.org/core/journals/public-health-nutrition/article/maternal-caffeine-intake-during-pregnancy-and-risk-of-pregnancy-loss-a-categorical-and-doseresponse-metaanalysis-of-prospective-studies/F3FC2934E398D3C7B80C3F3DBC9BFEC2

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3625078/

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3500353/

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2812592/