Which coagulation change occurs in pregnancy?

Which coagulation change occurs in pregnancy?

• A. INR increases
• B. PT and aPTT decrease slightly
• C. Fibrinogen increases about 50% by the second trimester
• D. Bleeding time increases

Answer: (C)

Pregnancy deliberately shifts the coagulation system toward a hypercoagulable state to protect against heavy bleeding at delivery. A key part of this change is a marked increase in fibrinogen, a major clotting protein produced by the liver. Fibrinogen rises by about half of its normal level by mid-pregnancy, and this substantial increase helps quicken clot formation if placental or uterine bleeding occurs. At the same time, standard clotting times like PT and aPTT generally remain normal or may be slightly shortened because of higher levels of clotting factors circulating in the blood. INR tends to stay normal as well. Bleeding time isn’t increased in pregnancy and isn’t a sensitive indicator of these physiologic changes. So, the standout physiologic change is the roughly 50% rise in fibrinogen by mid-pregnancy, supporting hemostasis during delivery while contributing to a hypercoagulable state overall.

Pregnancy deliberately shifts the coagulation system toward a hypercoagulable state to protect against heavy bleeding at delivery. A key part of this change is a marked increase in fibrinogen, a major clotting protein produced by the liver. Fibrinogen rises by about half of its normal level by mid-pregnancy, and this substantial increase helps quicken clot formation if placental or uterine bleeding occurs.

At the same time, standard clotting times like PT and aPTT generally remain normal or may be slightly shortened because of higher levels of clotting factors circulating in the blood. INR tends to stay normal as well. Bleeding time isn’t increased in pregnancy and isn’t a sensitive indicator of these physiologic changes.

So, the standout physiologic change is the roughly 50% rise in fibrinogen by mid-pregnancy, supporting hemostasis during delivery while contributing to a hypercoagulable state overall.