In recent years, there have been considerable research advances regarding perinatal management. This includes the use of placental pathology examination to explain prenatal as well as short- and long-term postnatal adverse outcomes. However, this resource remains undervalued and underutilized. Here, I’ll discuss the ways attorneys should be leveraging placental evaluation by qualified pathology experts in their next perinatal malpractice case.
A Record of Abnormal Events
Any significant abnormal event during pregnancy will most likely leave behind a discoverable “fingerprint.” An expert pathology examination can identify such morphologic changes. These are important indicators of any abnormal, acute, or chronic intrauterine conditions. This is what could have caused, or in combination contributed to, an adverse pregnancy outcome. Many of these adverse events are the result of missed/delayed diagnosis or otherwise treatable antenatal maternal or fetal conditions.
The placenta is mostly of fetal origin. However, there are also important maternal elements in the so-called basal plate and maternal decidua of the extraplacental membranes. The maternal elements contain maternal decidual vessels. They bring maternal blood to the placenta for the exchange of oxygen and nutrients with the fetus. These vessels hold evidence of maternal conditions such as preeclampsia, hypertensive disorders, and diabetes. All of which can result in decreased uteroplacental perfusion. Consequences of decreased uteroplacental perfusion range from slow growth (intrauterine growth restriction) to fetal death (stillbirth) in severe cases.
Case Study
For instance, a mother may have had a high-risk obstetrical condition such as pre-eclampsia or abruption. Adverse outcomes could result if this condition was not appropriately evaluated, diagnosed, and treated. Placental evaluation can prove the presence of such conditions by showing evidence of maternal vascular malperfusion. This is demonstrated through a combination of morphologic alterations within both the fetal and maternal compartment of the placenta.
Unexpected Peripartum Events
One of the most common reasons for litigation is an uneventful full-term pregnancy followed by an unexpected peripartum adverse outcome. One example of this is an infant unresponsive at birth with low Apgar scores who requires resuscitation. This scenario is common in children who later develop cerebral palsy or other types of neurologic injury, neurologic impairment, or developmental delays.
In these types of cases, a pathology expert will examine for placental lesions. Placental lesions associated with adverse neurologic outcomes can be divided into a few categories:
- those with abnormal blood flow in the maternal circulation (maternal vascular malperfusion)
- abnormal blood flow in the fetal circulation (primarily fetal thrombotic vasculopathy)
- inflammatory processes (acute chorioamnionitis, chronic villitis/villitis of unknown etiology)
- primary placental lesions
Each category is associated with well-defined identifiable pathologic alterations. On the other hand, the absence of such placental lesions on pathology examination speaks against significant prenatal intrauterine adverse conditions. Thus, negative findings on placental examination can also be used to support a case.
Intrauterine Growth Restriction
Intrauterine growth restriction is a common prenatal complication. It’s associated with serious adverse pregnancy outcomes, including stillbirth and long-term disability. Growth restriction is a significant risk factor for cerebral palsy as well.
Severe growth restriction is associated with placental abnormalities. These include maternal vascular malperfusion or diffuse chronic villitis. In addition, severe growth restriction has been linked to massive perivillous fibrin deposition and chronic histiocytic perivillositis, among others. However, undiagnosed and improperly managed intrauterine growth restriction is difficult to substantiate based on clinical evaluation alone.
Under normal conditions, one-quarter to a third of the placenta may be rendered nonfunctional by such pathologic processes without impacting oxygen exchange. However, when chronic processes have resulted in a placenta with little or no reserves, the infant is particularly susceptible to additional insults that may occur during labor and delivery.
Multiple Factors Acting Simultaneously
Many times, the adverse pregnancy outcome is a result of several unfavorable factors acting simultaneously Intrauterine infection and its histologic counterpart in the placenta—acute chorioamnionitis—is common. However, most healthy fetuses will be able to fight the infection successfully without significant long-term sequelae.
On the other hand, a fetus already compromised by intrauterine growth restriction due to maternal vascular malperfusion is far more likely to suffer serious consequences from a similar infection. This is true even in the event of antibiotic therapy.
Duration and Timing of Pathologic Processes
Expert placental evaluation can furthermore estimate duration and approximate timing of pathologic processes in utero. When under stress of any kind in utero, the fetus is likely to release meconium in the amniotic fluid. This is next deposited within the placental membranes. It is possible to estimate the duration of meconium exposure, and therefore approximate timing of noxious stimuli, by identifying the location of meconium-laden macrophages. A pathologist performs this through histologic examination of the fetal membranes.
The placentas of neurologically impaired infants often show multiple lesions. The timing of these lesions can provide a storyline of events in the creation of an adverse intrauterine environment. Multiple lesions of different etiologies, and involving different aspects of placental function (eg. fetal versus maternal blood circulation), can act synergistically to decrease placental reserves and function. The same is true when acute events occur in combination with chronic processes. The presence of multiple placental lesions greatly increases the susceptibility of the fetus to neurologic injury.
The extent to which placental pathology can be helpful in understanding adverse antenatal and perinatal events varies with the type and significance of placental lesions. Interpretation of these lesions is complex and requires experience and insight into clinicopathologic correlation with outcome. However, performing the placental examination is the most important part. Collaboration with a pathology expert is an invaluable tool for building your strongest perinatal malpractice case.
