What are the causes of abruptio placenta?

Causes of Abruptio Placentae

Abruptio placentae results from hemorrhage at the decidual-placental interface, with the underlying pathophysiology being multifactorial and not completely understood, but several well-established risk factors dramatically increase the likelihood of this life-threatening complication. 1, 2, 3

Primary Risk Factors

Hypertensive Disorders

• Maternal hypertension is one of the strongest associations with placental abruption, with cases demonstrating mean systolic blood pressure of 155 mmHg versus 120 mmHg in controls (p < 0.01). 4
• Preeclampsia superimposed on chronic hypertension carries the highest risk among all hypertensive disorders for premature placental separation. 5
• Hypertensive diseases consistently appear as major risk factors across multiple studies examining abruption etiology. 1, 2

Prior Placental Abruption

• Previous abruption is one of the most significant predictors of recurrence and represents a critical historical risk factor. 1, 2

Substance Use

• Tobacco smoking is strongly associated with placental abruption in multiple studies, particularly in preterm deliveries. 1, 5
• Cocaine use increases risk through vasoconstrictive effects and hypertensive complications. 1, 6
• Intravenous drug abuse is independently associated with increased abruption risk in preterm gestations. 5
• Moderate-to-heavy smoking (≥20 cigarettes per day) with comorbidities including intrauterine growth restriction further compounds risk. 6

Abdominal Trauma

• Recent abdominal trauma is a well-established precipitating factor for placental separation. 1, 5
• Direct mechanical disruption of the decidual-placental interface can trigger hemorrhage and separation. 2

Multifetal Gestation

• Multiple gestations increase the risk of placental abruption due to increased uterine distension and placental surface area. 1

Membrane and Infection-Related Factors

• Preterm premature rupture of membranes shows a significant dose-response relationship with abruption, with increasing duration of membrane rupture correlating with higher risk (chi-square for trend = 3.93, p = 0.047). 1, 5
• Intrauterine infections are associated with increased abruption risk. 1

Maternal Characteristics

• Advanced maternal age independently increases risk of placental abruption. 1
• Hydramnios (polyhydramnios) is associated with increased abruption risk, likely through overdistension mechanisms. 1

Thrombophilias

• Inherited and acquired thrombophilias predispose to microvascular thrombosis at the decidual-placental interface. 1

Inadequate Prenatal Care

• Low number of antenatal visits is significantly associated with abruption in preterm deliveries, suggesting missed opportunities for risk factor identification and management. 5

Clinical Context

Severity and Outcomes

• Abruption involving more than 50% of the placental surface is frequently associated with fetal death. 1
• Approximately 10% of all preterm births and 10-20% of all perinatal deaths in developed countries are caused by placental abruption. 3
• Maternal complications include obstetric hemorrhage, disseminated intravascular coagulopathy, renal failure, and maternal death (seven times higher than overall maternal mortality rate). 3

Important Distinction from Placenta Accreta

• While the evidence provided discusses placenta accreta spectrum disorder extensively, this is a distinct pathology involving abnormal placental implantation rather than premature separation, though both can cause life-threatening hemorrhage. 6