INTRODUCTION
This is part of the emergency Labour Ward protocols that I wrote on behalf of Iaso Maternity Hospital in Athens a few years ago. It is addressed to colleagues but is also well understood by non-medical readers.
Placental abruption refers to a normally located placenta that separates after the 20th week of pregnancy and before delivery. It occurs in 1% of pregnancies and is a major cause of perinatal morbidity and mortality.
The classification distinguishes extent of detachment (partial or complete) and point of detachment (peripheral or central). Based on clinical picture it is classified into:
0- Asymptomatic
1-Mild (in 48% of cases) with no or minimal bleeding, mild uterine tenderness, normal BP and palpitations, absence of coagulation disorder, no fetal distress.
2- Moderate (in 27%) with no to moderate bleeding, moderate or severe uterine contractions (up to tetanic spasms), maternal tachycardia with orthostatic response to BP and palpitations, hyponodonemia/coagulopathy, fetal distress.
3- Severe (represents 24% of cases) with no to severe bleeding, painful tetanic contractions of the uterus, maternal shock, hyponodogenemia and coagulation disorder, fetal death.
Clinical presentation includes vaginal bleeding (80%), abdominal or lumbar pain and uterine tenderness (70%), abnormal uterine activity (hypertonic or frequent contractions) (35%), preterm labor (25%), intrauterine death ( 15%).
Imminent possible complications: hemorrhagic shock, coagulation disorder, DEP, uterine rupture, renal failure, peripheral ischemic necrosis (hepatic, adrenal, pituitary).
Fetal morbidity includes hypoxia, anemia, growth retardation, CNS disorders, intrauterine death.
RISK FACTORS
Risk factors are pregnancy hypertension, injury-trauma, smoking, substance abuse (cocaine and amphetamines), increased age, pathological uterine vessel flows in the 2nd trimester, premature rupture of membranes, presence of fibroids, history of amniocentesis.
About 70% of cases of placental abruption occur in low-risk pregnancies.
First trimester bleeding increases the risk of detachment later in pregnancy. In the presence of a hematoma documented by ultrasound in the first trimester, the subsequent risk of placental abruption is increased (X 5.6).
Thrombophilic disorders have been associated with an increased risk of placental abruption, but significant associations were only observed in factor V Leiden heterozygosity (OR 4.70, 95% CI 1.13 – 19.59) and prothrombin 20210A heterozygosity (OR 7.71, 95% CI 3.01 – 19.76). More recently, in a systematic review and meta-analysis, a mild association is reported (for placental abruption in women with factor V Leiden it was 1.85 [95% CI 0.92 to 3.70], and for prothrombin 20210A it was 2.02 [95% CI 0,81 – 5,02]).
A history of placental abruption in a previous pregnancy dramatically increases (X10) the risk of abruption in the next.
PREVENTION
Treatment of hypertension in pregnancy.
Injury prevention / family violence.
Prevention of smoking and substance use. Smoking is associated with detachment with a completely dose-dependent association.
Early diagnosis of detachment at an early stage in high-risk pregnant women (with hypertension, injury, history of abuse, smokers, drug users, elderly, with premature rupture of membranes, fibroids, history of amniocentesis).
Pregnant women who come as victims of violence or a traffic accident are placed under observation and cardiotographic control for at least 4 hours.
There are insufficient data to support prophylactic antithrombotic therapy (low dose aspirin +/- low molecular weight heparin) in pregnant women with thrombophilia.
DEALING
In the context of differential diagnosis, a similar clinical picture may have blunt trauma-abdominal injury, acute appendicitis, urinary tract infection, fibroid degeneration, ovarian cyst or torsion, placenta previa, ectopic pregnancy, hemorrhagic or hypothermic shock of another etiology.
The clinical presentation varies from simple preterm labor to tetanic contractions, hemorrhage and PE and intrauterine death, depending on the location and degree of detachment.
Fetal distress is manifested by late or variable decelerations, decreased variability, bradycardia, sinusoidal appearance.
The diagnosis of placental abruption remains clinical.
The laboratory test includes general blood, hemorrhagic test (PT, APTT, fibrinogen, FDP’s (fibrin degradation products), D-dimers), cross-section.
The laboratory test includes general blood, hemorrhagic test (PT, APTT, fibrinogen, FDP’s (fibrin degradation products), D-dimers), cross-section. It has no diagnostic accuracy in ruling out detachment, and any normal findings do not rule it out.
Retroplacental hematoma can be seen in 2-25% of cases. This depends on the extent of the hematoma and the experience of the sonographer.
MRI can accurately visualize placental abruption. It may facilitate management of the third trimester bleeding event with normal ultrasound findings.
The risk of intrauterine death is related to the extent of the detached placental surface and refers to detachments of more than 50% of the surface.
Several patients will not have the typical clinical presentation, especially in posterior placenta, where it initially presents with mild back pain.
It should always be considered as a possible diagnosis in any preterm delivery and requires careful follow-up.
Absence of bleeding does not rule out placental abruption.
The coagulation disorder may be ongoing, even with initially normal coagulation factors. They need to be rechecked.
Placental abruption clearly predisposes to DEP and this in turn to acute tubular necrosis of the placenta.
Intensive monitoring, administration of O2, monitoring of vital signs and diuresis, continuous cardiotocography, adequate administration of intravenous fluids, transfusion of at least 4 units of blood, management of coagulation disorder, immediate cesarean section.
In case of intrauterine death due to ablation, the appropriate route is to induce labor in a hemodynamically stable patient. Usually the uterus makes strong contractions and labor progresses rapidly after amniotomy.
Coagulation disorder complicates 30% of cases of severe detachment and immediate caesarean section is often required to prevent it from worsening, but with care that it is corrected to the maximum extent before surgery.
In healthy fetuses, induction and vaginal delivery may follow, under constant monitoring and awareness that fetal distress can develop rapidly. There is a clear association of neonatal morbidity and delay in decision making on detachment with accompanying pathological cardiotocogram.
In pregnancies of 20-34 weeks, conservative treatment is based on partial detachment and good general condition of the fetus and pregnant woman, with hospitalization, administration of corticosteroids for pulmonary maturation and, on contractions, in selected cases with partial detachment, tocolysis with magnesium sulfate.
BIBLIOGRAPHY
- Antepartum Haemorrhage (Green-top Guideline No. 63)
- Oyelese Y, Ananth CV. Placental abruption. Obstet Gynecol. 2006 Oct. 108(4):1005-16.
- Shad H Deering, MD; Chief Editor: Carl V Smith, MD Abruptio Placentae Treatment & Management
- Hellenic Obstetrics and Gynecology Society. Intrauterine death or stillbirth. Directive No. 21
