When is the fetus most vulnerable to the effects of teratogens and why?

Case Study: Cell Biology and GeneticsBelow are several case studies. Your instructor will either assign you a case study or have you select one. If all of the case studies have not been covered, your

Case Study: Cell Biology and Genetics
Below are several case studies. Your instructor will either assign you a case study or have you select one. If all of the case studies have not been covered, your instructor may assign a case study that no one has covered. Be sure to integrate your knowledge of advanced physiology and pathophysiology across the lifespan with the clinical implications for the advanced practice nurse.
Case Study Posting Requirements
1.    Make sure all of the topics in the case study have been addressed.
2.    Cite at least three sources; journal articles, textbooks, or evidenced-based websites to support the content.
3.    All sources must be within five years.
4.    Do not use .com, Wikipedia, or up-to-date, etc., for your sources.
CASE STUDY ONE
Felicity is a very busy 29-year-old woman in a professional career. She has diabetes mellitus, and is also pregnant for the first time. Due to her busy schedule, it took her three weeks to visit the family doctor to have the pregnancy confirmed. Felicity became very concerned when her physician asked whether she had been taking folic acid. It was all Felicity could do to remember to manage her insulin levels, and taking folic acid supplements was something she hadn’t even considered. Her doctor told her to take 600 μg of folic acid daily and advised Felicity to return later for maternal serum marker testing.
1.    Explain the potential teratogenic effect of folic acid deficiency on the developing fetus. What other risk factor is noteworthy in Felicity’s case?
2.    What is the benefit of maternal serum marker testing? What other test would be particularly useful to monitor the development of Felicity’s baby in this situation?
3.    When is the fetus most vulnerable to the effects of teratogens and why?
MUST BE FOUR PAGES LONG NOT INCLUDING TITLE AND REFERENCE PAGE THANK YOU! REFERENCES MUST BE WITHIN 5 YEARS OLD.