Yes it is common to have a thick blood clot during confinement. I had it on my second but not first. Told my makcik urut to massage at my womb, abdominal area if there's any lump (indication of there might be still blood after birth) meaning dr did not clear it out properly before end of labour. If you feel cramp, pain and during confinement the clot keeps coming out it is good. This is also dirty blood. Sooner later, it will be just normal blood