Why it matters in the Letby case
The post-conviction review of the Letby twin counts addresses monochorionic risk factors that affect the natural-cause differential.
Medical explainer
Monochorionic twins — shared-placenta risks
Monochorionic twins share a single placenta and are at elevated risk of TTTS, growth discordance and post-delivery instability. Post-delivery management requires close attention to feeding, perfusion and cardiovascular status.
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Prosecution position
The twin counts were presented without shared-placenta pathology being advanced as the explanation for the deteriorations.
Expert challenge / post-conviction reading
Monochorionic twins share a placenta and carry substantially higher rates of growth discordance, TTTS and sudden deterioration than dichorionic twins or singletons. Post-conviction review treats this as a material part of the natural-cause differential in the twin cases.
What remains uncertain
Chorionicity and placental pathology are established antenatally and at delivery. Where the record on those points is thin, the risk profile can be stated in general terms but not applied to an individual case with certainty.
Common questions
What does monochorionic mean?
That both twins share a single placenta, with connecting vessels between their circulations. It is a higher-risk configuration than twins with separate placentas.
What risks does it add?
Higher rates of growth discordance, twin-to-twin transfusion syndrome, and sudden deterioration — including in a surviving twin after the other dies.
Why does it matter to this case?
Because several indicted babies were twins, and the risk profile of the pregnancy bears on the natural-cause differential for their deteriorations.
Was obstetric evidence heard at trial?
The post-conviction commentary argues obstetric expertise was largely absent from the trial, which is why the antenatal picture was not tested.
Related reading
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