The phenomenon commonly referred to as “coffin birth” is a rare, natural process that occurs after the death of a pregnant person. This terminology is a colloquial descriptor for what scientists and medical professionals accurately call Postmortem Fetal Extrusion, or PFE. The event is not a form of labor or childbirth but rather a mechanical consequence of decomposition. Understanding PFE requires focusing on the biological mechanisms of putrefaction and pressure dynamics within the deceased body. The process is an illustration of biology continuing its course long after life has ceased, leading to a startling postmortem event that has been documented across centuries.
Defining Postmortem Fetal Extrusion
Postmortem Fetal Extrusion (PFE) is defined as the expulsion of a nonviable fetus from the vaginal canal of a deceased pregnant individual due to increasing pressure from internal decomposition gases. This event is fundamentally distinct from live birth, as it lacks the physiological processes of labor, such as uterine contractions and active cervical dilation. The fetus is deceased at the time of expulsion, having died shortly after the pregnant person’s death due to the cessation of maternal circulation.
The term “birth” is misleading because it implies a biological function of the living body, which PFE is not. Instead, it is a passive, mechanical expulsion driven by the forces of decay. The process is a predictable, though uncommon, outcome of advanced decomposition when specific conditions of pregnancy and environment are present. The clinical term is preferred over “coffin birth” because PFE can occur regardless of where the body is located.
The Physiological Mechanism
The scientific basis for PFE lies entirely in the process of putrefaction, which begins shortly after death. Once oxygen is depleted, anaerobic bacteria naturally residing in the gastrointestinal tract, particularly species like Clostridium, begin to proliferate unchecked. These microbes break down organic matter, including proteins and carbohydrates, through anaerobic metabolism. This breakdown process generates a significant volume of putrefaction gases, including methane, carbon dioxide, and hydrogen sulfide.
As these gases accumulate within the abdominal and intestinal cavities, the deceased’s torso begins to bloat noticeably. The internal volume of gas creates tremendous intra-abdominal pressure, which can force fluids and other contents out of the body’s natural orifices. This mounting pressure acts upon the uterus, which, along with the surrounding pelvic structures, is no longer held firm by muscle tone.
The pressure squeezes the uterus, forcing it downward and sometimes causing it to prolapse or evert out of the body through the vaginal opening. If a fetus is contained within the uterus, this mechanical force pushes the fetus out along with it. This expulsion is facilitated by the relaxation of the pelvic ligaments and the cervical opening, which naturally loosen after death. The entire process is a purely mechanical, pressure-driven displacement.
Historical Context and Forensic Significance
Accounts of postmortem fetal extrusion have been documented in medical and legal texts dating back centuries, with one of the earliest recorded cases occurring in 1551. Archaeological evidence from sites in medieval Europe also supports the historical occurrence of PFE, with fetal remains found positioned outside the pelvic cavity of the deceased. The phenomenon was more frequently observed in the past because bodies were often interred or left undisturbed for longer periods without preservation.
The widespread use of modern embalming techniques, which introduce preservative chemicals and replace bodily fluids, has made PFE significantly rarer today. Embalming inhibits the bacterial growth that is necessary to produce the high volume of gas required for the expulsion. However, PFE can still occur in forensic contexts where a body is undiscovered for an extended period, allowing natural decomposition to progress.
In modern forensic investigations, PFE is a finding that requires careful distinction from cases of live birth followed by infanticide. A medical examiner must identify the signs of advanced decomposition and confirm that the expulsion was a postmortem event, often by examining the state of the fetus and the presence of putrefactive changes. The timing of PFE, which typically occurs between two and five days after death depending on environmental factors, provides investigators with an estimation of the postmortem interval.