As a result of ongoing pain from the surgery, the musician, 33, has canceled the first four November dates of her scheduled tour.
"I was diagnosed with an ectopic pregnancy, or in my case it was a fallopian pregnancy (the embryo settled in my tube, which is the width of a straw)," the A Thousand Miles singer wrote.
"This is not considered a viable pregnancy because the fetus cannot develop and it is a high risk situation for the mother because of the potential for tubal rupture and internal bleeding."
As a result, Carlton was treated with Methotrexate, a mild chemotherapy, rather than surgery, in hopes that the treatment would shrink the pregnancy and save her fallopian tube.
"Despite our best efforts, my tube started to rupture and I was experiencing internal bleeding," Carlton revealed. "My doctor performed a successful surgery and removed my entire right fallopian tube."
Despite the health scare and having to cancel part of her tour due to intense pain, Carlton has retained a great sense of humor.
"It is also very important to note that this is the second time I ended up in the ER without underwear!" she wrote. "However, upon waking up the next morning in the hospital, and as my doctor was explaining to me what happened the night before, my fiancé showed up. He had flown all night. He had my underwear. My hunter green lace ones:-) I realize I am a lucky woman on many levels here."
This is a note about about what went down. See you soon guys, real soon Xx https://t.co/34644Blmsn— Vanessa Carlton (@VanessaCarlton) November 5, 2013