This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: General obstetrics, Subject name: Anatomy
Decidual space is obliterated by: 
Select and explain. 
A. 10 th week, B. 12 th week, C. 18 that week, D. 16 th week
D: 16 th week
Answer: D: 16 th week 
Explanation: Decidual space is the space between decidua capsularis and parietalis seen in early pregnancy because the gestational sac does not fill the uterine cavity. By 14-16 weeks the gestational sacred has enlarged to fill the uterine cavity completely by 4 th month (16 weeks). Ref: Datta Observe 9e pg 22.