Answer:
Signs of pregnancy
12 weeks - At this time you can place your hand under the does belly were the udder will be and gently palpitate the area and hold your hand very still and feel little kicks. It feels just like a human baby. Keep in mind you might not feel it every time but keep checking.
14 weeks - Around this time the vulva will start to get bigger and longer and the skin around this area will become smoother.
15 weeks - At this time if it is your doe's first kid you should see the udder start to develop. Keep in mind that some first time mommy's udders develop a little slower so don't freak out if the udder development is a little slow at this stage.
20 weeks - Right around this time the udder will fill out in preparation for the kidding.
As early as 9 days before kidding keep look out for the tail drooping and a hump rising right before the tail.
Signs that the doe is about to kid
24 hours before kidding you will notice that the ligaments around the tail disappear.
1. appears restless
2. eyes luminous
3. smells the ground
4. paws the bedding
5. looks behind her
6. stargazes
7. Hollows out.
8. tail lifts up
9. rises and lies down frequently
10. udder begins to fill
11. vulva becomes flabby
12. white discharge
13. real talkative and not in her normal tone "mamma talk"
Content source Reference: http://barnanimal.com
B. Progesterone Test
an early assay for progesterone can give an idea whether the goat is pregnant or not. High progesterone at 18-22 day post breeding usually indicate pregnancy. rapid assays like ubio quickVET progesterone assay is a useful tool for this.
http://www.ubio.in/animal-tests/bovine-rapid-tests/bovine-pregnancy-spot