What Placental Pathology Can Show After a Birth Injury in Illinois

Modern obstetrics has given families remarkable tools: continuous fetal monitoring, rapid surgical delivery, and neonatal intensive care that saves children who once could not have survived. Even so, when a baby is hurt during birth, one of the most informative pieces of evidence is often an organ that left the delivery room in a specimen container.

The placenta sustained the baby through every hour of pregnancy and labor, and it carries a physical record of what it went through. A placental pathology report turns that record into findings that physicians, attorneys and courts can read.

We understand that many families first hear about this report months after delivery, if they hear about it at all. This guide covers what the report documents, why the placenta has to be preserved and examined promptly, and how experts use it when they reconstruct a labor. It builds on our broader coverage of what happens in the delivery room.

A placental pathology report is a surgical pathology document prepared after the placenta, fetal membranes and umbilical cord are sent to the hospital's pathology department. It has two parts: a gross description of what the pathologist saw and measured, and a microscopic diagnosis based on tissue slides.

The gross examination records the physical features of the specimen. A typical report includes but is not limited to:

• Weight and dimensions. The pathologist weighs the trimmed placenta and compares the result with reference ranges for gestational age. A placenta that is unusually small or large can point to longstanding problems with blood flow or growth.
• Membranes. The report notes the color, clarity and completeness of the membranes. Green or brown staining may suggest meconium exposure, and cloudy membranes may suggest infection.
• Umbilical cord. The pathologist records cord length, diameter, coiling, the number of vessels, and where the cord inserts into the placenta. Knots, thrombi and abnormal insertions are noted here.
• Maternal and fetal surfaces. Any clot attached to the maternal surface, areas of firm discolored tissue, or visible lesions are described and sampled.

The microscopic section is where most diagnostic weight sits. Pathologists sample the cord, the membranes and several areas of placental tissue, and many now organize their findings using the terminology of the Amsterdam Placental Workshop Group consensus statement, an internationally used framework for placental lesions.

All of this adds up to a record that is unusually objective. Placental tissue cannot be revised after the fact, which is why experts on both sides of a case tend to treat it as an anchor for every other record.

The findings that matter most in birth injury cases usually fall into a few categories. Each one says something different about when and how a baby may have been compromised.

Infection and inflammation. Acute chorioamnionitis is inflammation of the membranes, usually caused by bacteria ascending from the birth canal. Pathologists separate the maternal inflammatory response from the fetal inflammatory response. Inflammation of the umbilical cord vessels, called funisitis, indicates that the baby's own immune system was reacting.

That distinction matters. A fetal inflammatory response has been associated in the medical literature with neonatal brain injury, so a case involving infection may ask whether maternal fever, rupture of membranes or abnormal lab values were recognized and treated when the standard of care required it.

Placental abruption. An abruption occurs when the placenta separates from the uterine wall before delivery, which cuts off oxygen exchange. The pathologist looks for a retroplacental blood clot, compressed tissue beneath it, and bleeding into the placental tissue.

Keep in mind that an acute abruption, one that happens shortly before delivery, may leave only subtle findings. Accordingly, experts read the pathology together with the clinical picture, such as bleeding, uterine tenderness and changes on the fetal heart tracing.

Infarction and malperfusion. An infarct is an area of placental tissue that died because its blood supply failed. Pathologists group these lesions into maternal vascular malperfusion, meaning problems on the mother's side of the circulation, and fetal vascular malperfusion, meaning clots or obstruction in the baby's vessels.

Many of these lesions develop over days or weeks rather than minutes. As a result, they often become central to the timing debate described below.

Cord abnormalities. The umbilical cord is the baby's lifeline, and several findings can bear on a labor:

• True knots. A knot that tightens during descent can restrict blood flow. The pathologist looks for vessel congestion or clotting on one side of the knot.
• Velamentous insertion. When the cord inserts into the membranes rather than the placental disc, its vessels run unprotected. Those vessels can be compressed or torn during labor.
• Abnormal coiling or length. A cord that is unusually long, short or tightly coiled has been associated with impaired blood flow. Length also bears on entanglement and on traction during delivery.
• Thrombosis. A clot within a cord vessel can obstruct circulation and may send clots into the baby's circulation.

Other findings round out the picture. Pathologists may note meconium-laden macrophages, elevated nucleated red blood cells in fetal vessels, chronic villitis, and chorangiosis, each of which experts weigh for what it may suggest about the duration of fetal stress.

Overall, no single finding tells the whole story. The value of the report lies in how its findings line up with the fetal monitoring strip, the umbilical cord blood gases, and the newborn's condition at birth.

The placenta is not automatically sent to pathology after every delivery. Hospitals generally follow written criteria, and the College of American Pathologists has published practice guidance listing the clinical situations in which examination is recommended, including signs of fetal distress, a depressed newborn and admission to neonatal intensive care.

When the delivery does not trigger those criteria, or when the criteria are missed, the placenta may be held briefly in refrigeration and then discarded. Once it is gone, that evidence cannot be recreated.

Timing matters for several practical reasons:

• Fresh tissue is needed for some tests. Bacterial cultures and certain specialized studies require unfixed tissue. Once the placenta is placed in formalin, those options narrow.
• Tissue changes after delivery. Autolysis begins quickly and can blur microscopic findings. Prompt fixation preserves the cellular detail that timing opinions depend on.
• Sampling decisions are permanent. The pathologist chooses which areas to sample. Tissue that was never sampled cannot be examined later once the rest of the placenta is discarded.
• The chain of custody begins at delivery. Labeling, handling and transfer records show that the specimen examined is the specimen delivered.

In many cases, the most important material that survives is the set of glass slides and paraffin tissue blocks. Hospitals typically keep these much longer than the placenta itself, and an independent perinatal pathologist can review them or request new sections for special stains.

This is why the urgency in these cases attaches to the evidence. A written request to preserve the slides, blocks and any remaining tissue, sent early, can protect material that might otherwise be lost under routine retention schedules. Illinois courts have addressed lost evidence through negligent spoliation principles, as in Boyd v. Travelers Insurance Co., and how those principles apply to a given case is something to confirm with counsel.

When a child is diagnosed with hypoxic-ischemic encephalopathy or later with cerebral palsy, the central medical-legal question is usually one of timing. Did the injury happen during labor, when timely intervention might have changed the outcome, or did it begin earlier?

Placental pathology is one of the main tools experts use to answer that question. Of course, it is never read in isolation.

Experts typically line up the placental findings against several other records:

• The fetal heart rate tracing. A tracing that was reassuring on admission and then deteriorated tends to support a labor-related event. Our guide to fetal monitoring failures covers how those strips are interpreted.
• Cord blood gases. Severe acidosis at birth points to significant oxygen deprivation close to delivery. Mild values alongside chronic placental lesions may support a different timeline.
• Newborn assessment and imaging. Apgar scores, the need for resuscitation, seizure onset and the pattern of injury on brain MRI each carry timing information. Certain injury patterns on imaging are associated with acute, near-total oxygen deprivation.
• The nursing and physician notes. These show what the care team saw, when they saw it, and how they responded.

Defense experts often point to chronic placental lesions to argue that the injury began before labor and could not have been prevented. That said, plaintiff experts may respond that a compromised placenta reduces a baby's reserve, leaving less tolerance for the stress of contractions.

On that view, a vulnerable fetus may call for closer monitoring and a faster response to warning signs, such as a delayed emergency C-section decision. Whether that argument holds depends on the specific findings, the tracing and expert testimony, which is what a case must prove rather than something to assume.

The absence of findings can matter as well. A placenta with no chronic lesions, no significant infection and no evidence of longstanding malperfusion can support the conclusion that the baby entered labor healthy.

In Illinois, a medical negligence claim must establish the applicable standard of care, a deviation from it, and that the deviation was a cause of the harm. Placental pathology bears most directly on causation, though it can also inform what clinicians should have recognized during labor.

Before a claim is filed, 735 ILCS 5/2-622 requires an affidavit along with a written report from a qualified health professional stating that there is a reasonable and meritorious cause for filing. Placental findings are often among the records that reviewer considers, together with the fetal monitoring strip and neonatal records.

The time limits are a separate question, and they do not reduce to a single date. The Illinois provision governing medical negligence claims, 735 ILCS 5/13-212, treats a child's claim differently from a parent's own claim and also contains a repose period. How those rules apply depends on the facts, so confirm with counsel and review our overview of bringing a claim in Illinois.

Placental evidence can come up in several ways during a case. These include but are not limited to:

• Disputed timing. Both sides retain perinatal pathologists who may read the same slides differently. Their disagreements often focus on how long a lesion had been developing.
• Missing examinations. If the hospital's own criteria called for pathology and none was performed, that gap may become a subject of discovery.
• Infection-related claims. Inflammatory findings may connect to questions about how maternal fever or prolonged rupture of membranes was managed.
• Cord-related claims. Cord findings may bear on how decelerations on the tracing were interpreted and acted upon.

All of these point back to the same principle. The report is evidence to be tested by qualified experts, and its meaning in any one case is never settled in advance.

One practical problem catches many families off guard: the placental pathology report is usually filed in the mother's medical record, not the baby's. Because the placenta is technically a specimen removed from the mother, a request for only the newborn's chart may come back without it.

A complete records request generally covers the mother's full delivery admission, including the surgical pathology section, along with the baby's birth and NICU records. It can also ask the pathology department directly to confirm whether slides and blocks exist and to preserve them.

If the report shows that no examination was performed, that answer is itself useful information. It tells the reviewing experts which evidence they will need to rely on instead and may raise questions about the hospital's own handling criteria.

We know that sorting through these records while caring for a child with new medical needs can feel overwhelming. While no report can change what happened, a careful review can help a family understand what the evidence shows and whether a claim may be worth pursuing.

If your family is trying to make sense of a placental pathology report or the absence of one, our team can review the records with you in a free consultation, and there is no fee unless we recover compensation. More background on related delivery-room issues is available in our birth injury library.

This article is for informational purposes and does not constitute legal or medical advice. Consult a qualified attorney licensed in Illinois about your specific situation.