I can totally relate to your situation as I been through it too. My PILs are very traditional thinking, who think they are the eldest so they can do whatever they want. My fil is a heavy smoker that causes his own children to have asthma and still claim he has the right to smoke in his own house. Sadly, there is nothing you can do much especially if your husband side his parents and complain or conflict between his parents and you might cause a stress on your marriage relationship which happens to my case. If your husband is supportive of you and the two of you are financially stable you might want to consider to rent a small apartment while waiting for your BTO. Nevertheless, I will recommend you to relax and close one eye for your own health and your unborn baby. Sometimes it is really hard to change the thought of the old people especially those who are stubborn, all keep thinking about it will only make your life even more stressful. I know it as I did it all: talking calmly, fighting and planning to move to my sis' house but to no avail, and worse end up with postnatal depressions due to constant fight with my husband and my PILs doing more stuff to make me realise who is the "boss in their house".
Nisha Ferdinands