I am an osteopath and have been successfully treating mums to be for sciatica. Thought I would share some advice. First of all i would find your local Osteopath. They can assess you and explain why it's occurring. Then importantly get you some treatment. I usually use a combination of medical acupuncture, massage and therapeutic exercise. Everyone is different but normally with my patients the sciatica is significantly reduced within two treatments and approx 7 days of daily prescribed exercise. I have written an article that you might find useful and there is a video of one of the exercises I often prescribe. www.osteopathypartnership.com/sciatic-pain-pregnancy-help-hand/