yes
Preggies usually wear tunics and some other not tight shirts or wardrobe....
Water-filled fat suit (she can be seen playing around with it in the Series 5 blooper reel and Doctor Who Confidential).
If you're asking how it detects pregnancy, it does so by having a chemical dye that reacts with the hormones that are present when pregnant. If you're asking how it gives a negative result and then...
four months earlier. So if you are 16 weekd now you had sex in december.