How do you do it?

Question
You told me that the pelvis bone will spread to an obvious 1.5 inches but how do you feel  out the pelvis bone?
And also is there any way at this stage i can try to feel out the babies?
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The text above is a follow-up to ... Im confused

-----Question-----
I was quite sure that my guinea Pig was pregnant because of all of the signs. drinking less, rounder appearance. but when i took her to the vet they said it could just be constipation. But now im confsed because i was so certain she was pregnant. And i still think shes pregnant because her personality is chaning she a lot more tranquil and calm and she lays down a lot more and she's getting heavier. but there still that doubt in my mind. How can i be 100% certain she's prenant?
-----Answer-----
There are very many vets out there who dont know what they are doing so never rely on what they say. As far as telling if she is pregnant, other than inactivity and excessive water drinking, her belly will become obviously pregnant because it will be twice her size, and bouncing around with active babies by 60 days. The only indication of birth is around 70 days, 48hrs before she gives birth, her pelvis bone (between her legs) will spread to an obvious 1.5 inches. From that point on it is close to show time. If she is pregnant, make sure to take extra good care of her. Give the mommy veggies high in vitamin C such as parsley and cabbage. Pellets and timothy hay should always be available for the piggies. Good foods are romaine lettuce, parsley, cucumber, carrots, cabbage, green bell pepper, cilantro, turnip greens, collard greens, broccoli, and a whole lot more. Broccoli, cauliflower, and cabbage can cause gas so should be sparingly. Fruits are good also like strawberries, blueberries, oranges, seedless grapes, watermelon, apples, and much more. Fruits should only be given once or twice a week because they can cause diabetes. SEEDS CAN BE TOXIC AND SHOULD BE AVOIDED. Iceberg lettuce is not healthy for a piggy because it has zero nutritional value. When choosing foods, lean towards greens and veggies with high vitamin C.
She will give birth on her own, and involvement by you is a bad idea. The only time you should get involved is if she is screaming or pushing for over 10 minutes without the result of a baby. In these cases she should be rushed to a local vet. Cesarean sections are not healthy and very dangerous. The babies stay with mommy for 3 weeks.  At this time, mommy, baby girls, and baby boys should be separated from each other. The baby boys are sexually mature at age 3weeks, so they are able to get mommy or sissy pregnant, so separation is important. They should stay in your care for another 3-4 weeks before finding a home.
Good luck.

Answer
You will know it when you feel babies. you will feel and even see her belly jumping in all different directions within two weeks of birth. You can stick two or three fingers from behind her to inbetween her legs. There will be many times you will think "Its seperated !" but it wont. When it happens, you wont believe how obvious it feels. The two bones go outward from both sides of her ..."pee hole" i guess u would say:) Good luck. Keep me posted