Contractions with rectum pressure

Summer • Teen Mom Alert!!!! Haha I'm 17 engaged and happily expecting ! Can't wait for our bundle joy to get here 💕🍼
Why is it that everytime I have a contraction I feel ALOT of pressure in my rectum (as if I need to pass gas or poop) but when my contraction ends the urge goes away (as in I couldn't poop if I tried) just wondering if anyone else has or is experiencing this ?! Thanks in advance!