The leading cause of maternal death during the first trimester of pregnancy is: Select one: a. internal bleeding caused by a ruptured ectopic pregnancy. b. unrecognized or untreated supine hypotensive syndrome. c. massive brain damage secondary to a prolonged seizure. d. blunt trauma to the abdomen during a motor vehicle crash.

a. internal bleeding caused by a ruptured ectopic pregnancy.

Explanation:

An ectopic pregnancy is a medical condition in which the fertilized egg grows outside the lining of the uterus. Almost all the type of ectopic pregnancies occur in the fallopian tube. As the pregnancy grows, the fallopian tube ruptures and burst. The rupture of the fallopian tube causes internal bleeding. This is a kind of life-threatening emergency.  

The rupture ectopic pregnancy causes vaginal bleeding, hemorrhage, and abdominal pain. The patient with the ruptured ectopic pregnancy is treated with surgical procedures.

Thus the, rupture ectopic pregnancy in the first trimester can be the leading cause of maternal death.