This happens when a fat bitch has a baby. Usually caused by a rift in the fatbitchtonic plates.
Nurse: That 'birthquake' measured a 9.8 on the richter scale,
by gjkuol09 December 27, 2006
An earthquake that occurs on one's birthday.
Danny: Holy cow, did you feel that? It's like the earth knows it's my birthday!
by juggleboy January 08, 2010
When someone has many, many, (too) many children.
"Wow...she really had a birth quake"
by BJCE September 10, 2006
The contractions a woman feels when giving birth.
Woman: Dayum, when I had Chewbacca I thought I was going to explode with the birthquakes!
by BananaBurguer August 20, 2014