This page has moved. Click here to view.
Significant bleeding from a variety of causes, such as placental abruption and placenta previa, may occur in the second trimester. The etiology of bleeding in many cases in the second half of pregnancy is unknown. However, among known causes of clinically significant bleeding, placenta previa and placental abruption are the two most common etiologies. The different degrees of placenta previa are as follows:
• Total placenta previa: The placenta totally covers the internal cervical os.
• Partial placenta previa: The placenta partially covers the internal cervical os.
• Marginal placenta previa: The edge of the placenta extends to the margin of the internal cervical os.
• Low-lying placenta: The placenta is within reach of the examining finger introduced through the cervix.
Placenta previa usually is associated with painless vaginal bleeding, although uterine contractions may be present. The diagnosis is best confirmed by an ultrasound scan. Factors associated with an increased risk of placenta previa include multiparity, advancing maternal age, previous cesarean deliveries, and induced abortion. Placenta previa may be associated with placenta accreta, especially if a patient has had a previous cesarean delivery. Management depends on the amount of persistent bleeding and the
Premature separation of the placenta, abruptio placentae, occurs in approximately 0.5-1.5% of pregnant women. Its clinical presentation varies from minimally painful vaginal bleeding and uterine irritability to less common severe separation with fetal demise, maternal hypotension, and disseminated intravascular coagulopathy.
In general, abruptio placentae must be managed with expeditious delivery and careful maternal and fetal monitoring. After physical examination, a complete blood count and laboratory test of coagulation function--including a platelet count, fibrinogen level, and determination of
If the fetus is alive after artificial rupture of membranes, FHR monitoring is undertaken. In the presence of a reassuring FHR pattern, vaginal delivery may be anticipated and is preferred. Cesarean delivery is used in the presence of a nonreassuring FHR pattern or failure to make adequate progress in labor. Blood replacement is directed at maintaining blood pressure and urinary output, as well as keeping the hematocrit above 25%. If a coagulopathy is present (ie, hypofibrinogenemia), component therapy based on the etiology may be required in addition to blood replacement. The use of heparin to prevent intravascular coagulopathy is contraindicated in the case of abruptio placentae because it may cause further hemorrhage.
After delivery, abnormalities of coagulation correct themselves spontaneously. These clotting factors of hepatic origin, such as fibrinogen, usually return to normal within