An infant’s scores on the so-called Apgar scale can predict
the risk of a later diagnosis of cerebral palsy or epilepsy. The risk rises
with decreasing  Apgar score, but even slightly lowered scores can be
linked to a higher risk of these diagnoses, according to an extensive
observational study by researchers at Karolinska Institutet published in The BMJ.

“However, it’s important to remember that even if the
relative risks are high, the absolute risks of CP and epilepsy are still
small,” says researcher Martina Persson, paediatrician and associate
professor at Karolinska Institutet’s Department of Medicine, Solna. “This
means that most babies with very low Apgar scores do not develop CP or

It is well  known that a low Apgar score of between 0
and 6 points at one or five minutes after birth is linked to a higher risk of
cerebral palsy (CP) and epilepsy, and that a very low score of between 0 and 3
points at ten minutes indicates a significantly higher risk of CP. However, no
linear correlation has yet been confirmed and it is unclear whether even small
changes on the scale at the different times affect the risk of neurological

Various national registers

To interrogate this relationship, researchers at Karolinska
Institutet analysed data from the national Medical Birth Registry for over 1.2
million babies without malformations born at full term between the years 1999
and 2012. The researchers identified children diagnosed with CP or
epilepsy before the age of 16 in various national registers using diagnostic
codes and then calculated the risk of CP and epilepsy for every Apgar level at
five and ten minutes after birth and in relation to changes in Apgar score
between ten and five minutes.

A total of 1221 babies (0.1%) developed CP and the risk
successively increased with decreasing scores at five minutes. Compared with
infants with a top Apgar score (10) at five minutes, babies with a score of 9
had almost twice the risk of developing CP, while a score of 0 at five minutes was
associated with a 280-fold risk. An even higher risk was noted for babies with
similar Apgar scores at 10 minutes. A total of 3975 babies (0.3%) were
diagnosed with epilepsy, and the risks of epilepsy increased with decreasing
scores at five and ten minutes, although not as markedly as for CP.

Small changes in score

Even small changes in score between five and ten minutes
after birth were shown to affect the risks. For example, babies with a score of
7/8 at five minutes and 9/10 at ten minutes had a higher risk of CP or epilepsy
than babies with a score of 9/10 at both times. A higher risk of epilepsy was
also observed in babies who scored a full 10 points at five minutes and then 9
at ten minutes compared to babies that had top scores at both times.

“The results show that it’s important to evaluate neonate
vitality at both five and ten minutes, even if the score is normal at five,”
says Dr Persson. “We also need to work actively with the babies who do not
score full Apgar points since it is likely to improve their prospects.”

Some of the strengths of the study are that it was based on
a large number of individuals and that the researchers were able to control for
the many so-called confounders in their analyses. The researchers point out,
however, that it was an observational study and that no definite conclusions
about causality between Apgar score and the risk of neurological morbidity in
babies can be drawn.


Reference: Persson
M, et al. Five and 10 minute Apgar scores and risks of cerebral palsy and
epilepsy: population based cohort study in Sweden. The BMJ. Published online 8 February 2018.