What Causes Lack Of Sensation While Having Intercourse/masturbation?

Hello i am 23 weeks pregnant and during my second ob visit i mentioned vaginal itching to my doctor he said it was fine i didnt have a yeast infection so i didnt seek treatment. Now for the past month or so i havent felt any sensation when recieving oral sex from my boyfriend or when masturbating. What could cause this problem and is there any way to fix it?