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In Depth

Maceration and the Timing of Intrauterine Death

Richard M. Pauli, M.D., Ph.D.

Maceration is the process of tissue degeneration which begins to occur as soon

as an undelivered infant dies. It arises secondary to the effects of autolytic

enzymes. Since this process occurs in what is usually a sterile environment, the

changes which arise are unlike those which occur following other deaths.

There are multiple reasons for trying to estimate the time of fetal death. Such

information is of some importance to a babys parents; in fact, nearly all parents

desire to know when their baby died. Certainly differentiation of intrapartum

andprepartum deaths is relevant to the assessment of any methods of

intervention or prevention; intrapartum deaths are less often of fetal origin and

may include instances more amenable to medical intervention. Estimation of

timing of death also may help in assessing whether a proposed cause of death isreasonable.

Only occasionally, however, is independent documentation of the time of fetal

death obtained. For example, it is uncommon to have ultrasonographic

evaluations close enough together to bracket the time of death accurately. Most

often, then, assessing severity of maceration is the only method available for

confirming when death occurred.

The sequence of macerative changes has been well described. Within hours

after death changes occur in the epidermal-dermal junction resulting in what

usually is termed skin slippage. If the skin is rubbed the epidermis will detach

from the underlying tissues. Shortly thereafter, fluid begins to accumulate under

the skin. Bullae (blisters) may develop (which should not be misinterpreted as

being secondary to an abnormality of development such as epidermolysis

bullosa). These bullae rupture spontaneously or from delivery resulting in

patchy denudation of the skin. Sloughing of skin from larger and greater

number of surfaces indicates that the interval between death and delivery is

longer. With antenatal death more than a few days prior to delivery other

changes begin to occur including generalized hypermobility of joints, change inthe color of the fetal skin surfaces to a pale grey-yellow and liquefaction of

internal organs.

Qualitative scales can be generated based upon this sequence of events. We

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chose to use a five-grade scale based primarily on the external characteristics

of the stillborn, since virtually all infants with studies submitted to WiSSP are

clinically assessed and since we usually could double check the estimates of

maceration using submitted photographs. That scale of severity of maceration is

as follows:

None

Slight -- skin slippage, rare bullae, little (e.g. scrotum only or single spots of

skin loss elsewhere) or no denudation

Mild -- focal denudation of multiple regions without other changes

Moderate-- generalized skin maceration/ denudation but without significant

compressive changes Advanced -- compression and/or mummification and/or

internal liquefaction

Examples of each of these are shown in the figures.

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In the WiSSP series, the distribution of degree of maceration in the first 1040stillborns is:

None 16.0%

Slight 11.6%

Mild 17.7%

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Moderate 29.4%

Advanced 22.5%

(with the rest "indeterminate").

Note that intrapartum deaths (babies with no macerative changes) are quite

infrequent, accounting for only about a sixth of all stillborns.

Given the relevance of severity of maceration to timing of fetal death, it is a little

surprising that no careful assessment of the absolute relationship (rather than

just the sequence) between macerative changes and interval since death was

attempted until recently. Prior to then we could only vaguely correlate severity

of maceration and interval since death. A series of articles (References 1-3)

appeared in 1992 which made such estimation much more precise. David

Genest and his colleagues conducted careful assessments of fetuses in whom

timing of death was well documented. From those assessments they were able

to provide far more specific information about the absolute timing of externalmacerative changes, internal histologic changes and placental changes. Related

to external characteristics they found that changes occurred somewhat more

rapidly than previously assumed. Six of their measures seem applicable to the

scale used by WiSSP:

FeatureInterval between death and

delivery

Skin desquamation of > or =1 cm > or = 6 hours

Skin desquamation involving the face, back

and/or abdomen> or =12 hours

Skin desquamation involving at least 5% of

body surface> or = 18 hours

Change of skin coloration to tan or brown > or = 24 hours

Generalized skin desquamation > or = 24 hours

Mummification > or = 14 days

Note that Genest failed to find any good measures for intervals between 24

hours and 2 weeks. Nonetheless, based on these findings we can better

estimate the relationship between our maceration scale and time interval

between death and delivery:

None = intrapartum death

Slight = less than 12 hours between death and delivery

Mild = about 12-24 hours between death and delivery

Moderate = one to a few days between death and delivery

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Advanced = more than a few days between death and delivery.

The gap between 24 hours and 2 weeks can be filled using histologic features if

they are adequately searched for. Genest et al. found that the distribution of a

single feature on routine histologic slides allowed for interval estimates. That

feature was loss of nuclear basophilia (loss of hematoxylin staining of

nucleoproteins of cells) of a particular organ:

Loss of at least 1% of nuclear staining -

Kidney tubules > or = 4 hours

Hepatocytes > or = 24 hours

Inner half of Myocardium > or = 24 hours

Outer half of Myocardium > or = 48 hours

Bronchial epithelium > or = 96 hours

Loss of all or virtually all nuclear staining -

Liver > or = 96 hours

GI tract > or = 1 week

Adrenal > or = 1 week

Tracheal chondrocytes > or = 1 week

Kidney > or = 4 weeks

We have not routinely included estimates of time interval between death and

delivery in our summaries. We would be interested in knowing whether

inclusion of such an estimate would be helpful to referring health care providers.

Further Reading*

1. Genest DR, Williams MA, Greene MF: Estimating the time of death in

stillborn fetuses: I. Histologic evaluation of fetal organs; and autopsy study of150 stillborns. Obstet Gynecol 80:575-584, 1992.

2. Genest DR: Estimating the time of death in stillborn fetuses: II. Histologic

evaluation of the placenta; a study of 71 stillborns. Obstet Gynecol 80:585-

592, 1992.

3. Genest DR, Singer DB: Estimating the time of death in stillborn fetuses: III.

External fetal examination; a study of 86 stillborns. Obstet Gynecol 80:593-

600, 1992.

4. Wigglesworth JS: The macerated stillborn fetus, in Perinatal Pathology,

Philadelphia: Saunders, 1984, pp. 84-92.

*Copies of these and other relevant articles are available for personal use by

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request from WiSSP.

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