Most women with a placental abruption have sudden-onset abdominal pain, vaginal bleeding, and uterine tenderness. In a prospective study, Hurd and colleagues (1983) reported that 78 percent with placental abruption had vaginal bleeding, 66 percent had uterine tenderness or back pain, and 60 percent had a nonreassuring fetal status. Other indings included fre quent contractions and persistent hypertonus. In a ifth of these women, preterm labor was diagnosed, and abruption was not suspected until fetal distress or death followed.
Importantly, the signs and symptoms of placental abruption can vary considerably. In some women, external bleeding can be profuse, yet placental separation may not be so extensive as to compromise the fetus. In others, there may be no external bleeding, but the placenta is suiciently sheared of that the fetus is dead-a concealed abruption. In one unusual case, a multiparous woman cared for at Parkland Hospital presented with a nosebleed. She had no abdominal or uterine pain, tenderness, or vaginal bleeding. Her fetus was dead, however, and her blood did not clot. he plasma ibrinogen level was 25 mg/dL. Labor was induced, and a total abruption was conirmed at delivery.
With severe placental abruption, the diagnosis generally is obvious. From the previous discussion, it follows that less severe, more common forms of abruption cannot always be recognized with certainty. hus, the diagnosis is one of exclusion. Unfortunately, no laboratory tests or other diagnostic methods accurately conirm lesser degrees of placental separation. Sonography has limited use because the placenta and fresh clots may have similar imaging characteristics. Glantz and Purnell (2002) reported only 24-percent sensitivity for sonography in 149 consecutive women with a suspected placental abruption.
Important, negative indings with sonographic examination do not exclude placental abruption. Conversely, magnetic resonance (MR) imaging is highly sensitive for placental abruption and should be considered if the diagnostic information would change management (Masselli, 2011).
With abruption, some degree of intravascular coagulation is almost universal. hus, elevated serum levels of D-dimers may be suggestive, but this has not been adequately tested. Preliminary data show that serum alpha-fetoprotein levels > 280 �g/L have a positive-predictive value of 97 percent (Ngai, 2012).
hus, in the woman with vaginal bleeding and a live fetus, it is often necessary to exclude placenta previa and other causes of bleeding by clinical and sonographic evaluation. It has long been taught-perhaps with some justiication-that painful uterine bleeding signiies placental abruption, whereas painless uterine bleeding is indicative of placenta previa. he diferential diagnosis is usually not this straightforward, and labor accompanying previa may cause pain suggestive of placental abruption. On the other hand, pain from abruption may mimic normal labor, or it may be painless, especially with a posterior placenta. At times, the cause of the vaginal bleeding remains obscure even after delivery.
Placental abruption is one of several notable obstetrical entities that may be complicated by massive and sometimes torrential hemorrhage. Hypovolemic shock is caused by maternal blood loss. In an earlier report from Parkland Hospital, Pritchard and Brekken (1967) described 141 women with abruption so severe as to kill the fetus. Blood loss in these women often amounted to at least half of their pregnant blood volume. Importantly, massive blood loss and shock can develop with a concealed abruption. Prompt treatment of hypotension with crystalloid and blood infusion is essential, and resuscitation steps are described later (p. 788).
onic fluid embolism-led to the initial recognition of di brination syndrome. his syndrome is currently referred to as lation, which later is described more broadly on page 782.