The actual blood is blood, there is actually fairly little blood, most of what you see is endometrial lining.
this is the soft lining that builds up ready for a fertilised egg to implant into if you become pregnant.

As this thin layer is shed the uterus contracts to help shed it - this is part of the cramping.
the uterus is a muscle and as it contracts it cramps.
as the lining and blood pass through the cervix the cervix will often contract and release - which is another source of cramping.
It is common to feel cervical cramps when passing clots.

Many women find the surrounding muscles also cramp - ie their abdomen, back, thighs.

It's not likely that you'd feel pain in your ovaries at this time - more like achy, cramping in the general pelvic area.

cheers, yeah like all over cramps, but i just overies caz yeah i dunno, so when you go into labour n have a baby its just like servere cramping, i know thats not all it is is servere cramps but is that mainly like...what the pain is from?

pain in child birth is from contractions - which are uterus cramps but they are a different kind to period cramps.

when you are pregnant the uterus has grown and stretched a lot.
when you are not pregnant and having a period the uterus is about the size of a lady's fist or a small pear (upside down).
so the amount of muscle is far greater.
also during childbirth the uterus is trying to push the baby out and with that comes some "twisting" too.

Then there are the other labor pains - often felt in the back and legs.
Really it isn't possible to imagine how childbirth is going to feel until after it has happened.

Im 35 weeks pregnant. I've been getting pains in in vaginal area. I dont really get many pains in my stomach , a few but there rare. Does this mean im in labour?