Boy, I remember this…. struggled with it with both of mine…. thought at one stage I had been attacked in the night by a swarm of killer bugs…was so itchy. I found that if I was exposed to heat… ie… hot bath, overheating etc it got worse. I did mention it to the doc at the time and all was fine in my case. But for your own peace of mind, I would mention it to your doc / midwife, as I know that in some cases it can be caused as a result of liver problems.
Don’t forget, your skin is stretching too….. which can also cause it to itch. Make sure you use a nice mild moisturiser to keep your skin hydrated….