Khoote do you know Quran!! The Ayat in the Holy Quran 2:228 is specific to waiting for the 3 periods to make sure that woman is not pregnant. Women who are above the age of giving birth , that Question does not arises.
2:228 Divorced women shall keep themselves in waiting for three menstrual courses and it is unlawful for them, if they believe in Allah and the Last Day, to hide whatever Allah might have created in their wombs. Should their husbands desire reconciliation during this time they are entitled to take them back into wedlock. Women have the same rights against their men as men have against them; but men have a degree above them. Allah is All- Powerful, All-Wise.
Read it , it is purely for the purpose of pregnancy in the Holy Quran. Bushra due to her age , probably was beyond the age of menstrual cycles. Thus the Islamic decree was not even applicable. Secondly she says that she passed her Idaat period while still at his house. How such sentence is acceptable in a Islamic country!!