Hello. Welcome to hcm
The history seems rather different and the advice,never heard of.
Amnion is the fluid which makes the baby protected in womb. It is secreted by fetus only. When it is low,then we start to search for problems with fetus. It is very important and based on severity,we decide to do various procedures to increase the amniotic fluid
is one of the causes for structural damage caused to fetus and the cause for low amniotic fluid. Smoking causes the nicotine
and other various toxins to enter the fetus and cause various problems. I am really shocked at the advice. Your sister in law needs to be evaluated completly.
Also, delivering a pre mature baby has its own disadvantages. So be sure to find the cause for low amniotic fluid,please tell her to stop smoking and deliver only if the lungs of the baby have matured.
All the best