How to ask for HL

Hi. I'm in my 32 weeks and still working. I was recently posted to a division quarter for my workplace and it is located very far from my home. I find it hard to travel everyday to work, thus i was wondering if doctor could give me HL if I ask for it? And how many days can they give? Anyone knows what I can tell the doctor in order to get HL? I'm currently subsidised in NUH.