In the letter, Dr. Cathy Baldwin-Johnson, of Anchorage, Alaska, described Palin's pregnancies, including the birth of her son, Trig, earlier this year at 35 weeks. Routine prenatal testing early in the second trimester of Palin's pregnancy determined that the fetus had the chromosomal condition known as Down Syndrome. The Alaska governor and her husband, Todd, decided to go ahead with the pregnancy.
The physician also said Palin had a breast biopsy in 1992 for what turned out to be a benign lesion. Her vital signs, including blood pressure at 96 over 61 and pulse of 77, have been normal. Palin has no close relatives with major medical problems.
"She is physically fit with a regular exercise regimen," Baldwin-Johnson wrote, adding that the 44-year-old Palin takes no routine prescription medications.
Palin recently promised in a nationally televised interview that she would release her medical records. Instead, the campaign issued the two-page letter from her physician on the eve of the election.
"In summary, Gov. Palin is in excellent health and has no known health problems that would interfere with her ability to carry out the duties and obligations of vice president of the United States of America," Baldwin-Johnson concluded.
The bulk of the letter described Palin's most recent pregnancy and Trig's health.
Trig was born in good health at 35 weeks and was able to go home two days after his birth. He had minor problems with jaundice that required therapy in the hospital and at home for several days.
"At the time of his last office visit, he was growing and developing normally for a child with" Down Syndrome, the doctor said.
The campaign's decision to release a brief summary letter is consistent with what Democratic presidential nominee Barack Obama did earlier this year.
Obama did not release records, but rather a letter from his personal physician attesting to the 47-year-old's good health. Obama has very good cholesterol levels, outstanding blood pressure and no sign of heart disease. He is a smoker who has quit but relapsed several times. He announced in February that he was quitting again with the aid of Nicorette gum. His doctor said only that Obama is using Nicorette "with success."
Last month, Democratic vice presidential candidate Joe Biden released medical records that showed the 65-year-old to be very healthy, with some routine aging issues. There was no evidence he's had a brain scan to completely rule out another aneurysm like the one that required emergency surgery 20 years ago.
The records showed no reason for concern about another aneurysm: Biden has no symptoms, has healthy blood pressure-120 over 78-and seems to have healthy heart arteries.
The records for John McCain, 72, showed him in generally good health, cancer-free and with a strong heart. He maintains a healthy weight and blood pressure and takes medicine for his cholesterol.
Critics raise lingering questions, however, about his melanoma, the worst kind of skin cancer. McCain's doctors performed extensive surgery that raised no concern that it had begun spreading, giving him a good prognosis. He undergoes regular skin exams.