Temporal trends in perinatal mortality and cerebral palsy: A regional population-based study in southern Japan

Continuing decline in the prevalence of cerebral palsy in Denmark for birth years 2008-2013

AIM

To quantify and analyse the prevalence and clinical features of cerebral palsy (CP) in Denmark for birth years 2008-2013 and compare results with previous periods.

METHOD

A nationwide register-based study covering all children with a confirmed diagnosis of CP born in Denmark. Information about CP subtype, aetiology and severity was collected from the Cerebral Palsy Follow-up Program and supplemented from medical files. Data from the Danish Medical Birth Register was included, and the results were compared to previous data from the Danish National Cerebral Palsy Register. Prevalence per 1000 live births and proportions were analysed using the Cochran-Armitage test for trend.

RESULTS

The period covered 368,618 live births and 636 children with CP, making the overall prevalence for the period 1.73 per 1000 live births. This was significantly lower than the prevalence of 1.99 for the previous period 1999-2007 (p = 0.004). The decline in prevalence between the two periods was mainly due to a decrease in children with bilateral spastic and dyskinetic CP born after 37 gestational weeks. The decline in prevalence was accompanied by a smaller proportion of children with associated impairment.

CONCLUSION

We found a decrease in prevalence and severity in CP among Danish children. The decline was most pronounced in children born after 37 gestational weeks with severe subtypes of CP. National guidelines that recommend induction of labour before the completion of week 42 and therapeutic hypothermia for term neonates with hypoxic-ischaemic encephalopathy, may have contributed to the decline.

Which growth parameters can affect mortality in cerebral palsy?

Background

The objective of this study was to identify growth parameters that can affect mortality of cerebral palsy (CP).

Method

This was a birth cohort study based on the National Health Screening Program for Infants and Children database along with the National Health Insurance Service, which were linked using a personal identifier number. The birth cohort consisted of 2 191 956 subjects, representing 93.5% of live births from 2007–2011, with maximal 10-year follow-up (range, 5–10 years) until October 2016. Subjects with CP were identified. Growth parameters in terms of birth weight, underweight (weight-for-age below the 3rd percentile), rate of body weight gain were collected, along with all-cause mortality after the age of 1 year.

Result

Prevalence of CP was 2.0 per 1000 live births (95% CI, 1.94–2.06). All-cause mortality after the age of 1 year was 0.09 deaths/1000 person-years (95% CI, 0.08–0.09) in the general population (GP) and 2.85 deaths/1000 person-years (95% CI, 2.32–3.50) in subjects with CP during the follow-up. Therefore, the incidence rate ratio for all-cause mortality was 32.15 (95% CI, 25.72–39.76) in subjects with CP compared to GP. Presence of underweight was significantly associated with higher mortality in both subjects with CP and GP, where the adjusted hazard ratio of death was 2.60 (95% CI, 1.93–3.50) at the age of 18–24 months, 3.12 at 30–36 months, 4.37 at 42–48 months, 5.12 at 54–60 months, and 4.17 at 66–71 months. Birth weight did not affect mortality in both subjects with CP and GP after the age of 1 year (p > 0.05).

Conclusion

While subjects with CP shows higher mortality, underweight is an important growth parameter that affects all-cause mortality of both subjects with CP and GP. This study urges increased awareness that subjects with CP who are underweight require special care.

Decline in severe spastic cerebral palsy at term in Denmark 1999-2007

AIM

To analyse trends in prevalence and severity of cerebral palsy (CP) in Denmark in birth years 1999-2007 and compare with previous periods.

METHOD

Data has been collected uniformly in the Danish cerebral palsy national register nationwide since 1995. Rates in the time periods 1999-2001, 2002-2004 and 2005-2007 covering 585,393 births were analysed by gestational age and subtypes.

RESULTS

Total number of CP cases in the period was 1165. The overall prevalence of CP decreased significantly from 2.1 in 1999-2001 to 1.8 in 2005-2007 per 1000 livebirths (p = 0.022). The decline was only significant for children born at term (p = 0.007) but not for the preterm (p = 0.44). The decline in children born at term was based on a decrease in bilateral spastic CP (n = 117 in years 1999-2001 and n = 59 in 2005-2007). Multidisciplinary obstetric skills training with neonatal resuscitation in Denmark was initiated in 2003 and timely associated with the decrease. The prevalence of unilateral spastic CP the prevalence did not change, but in the two last time periods more children had a right-sided than left-sided unilateral spastic CP.

CONCLUSION

The decline in rate of CP seen in 2005-2007 as compared to 1999-2001 was mainly based on fewer cases of severe spastic CP in term infants. We hypothesize that improved neonatal resuscitation in the delivery room may be partly responsible for the decrease. In premature children the decline was not significant in this time period, but has been dramatically decreasing in the years before the time period here analysed.

Pretreatment with magnesium sulfate attenuates white matter damage by preventing cell death of developing oligodendrocytes

AIM

Antenatal maternal administration of magnesium sulfate (MgSO₄ ) reduces cerebral palsy in preterm infants. However, it remains controversial as to whether it also reduces occurrence of white matter damage, or periventricular leukomalacia. We assessed the effect of MgSO₄ against white matter damage induced by hypoxic-ischemic insult using a neonatal rat model and culture of premyelinating oligodendrocytes (pre-OL).

METHODS

Rat pups at postnatal day (P) 6 were administered either MgSO₄ or vehicle intraperitoneally before hypoxic-ischemic insult (unilateral ligation of the carotid artery followed by 6% oxygen for 1 h). The population of oligodendrocyte (OL) markers and CD-68-positive microglia at P11, and TdT-mediated biotin-16-dUTP nick-end labeling (TUNEL)-positive cells at P8 were evaluated in pericallosal white matter. Primary cultures of mouse pre-OL were subjected to oxygen glucose deprivation condition, and the lactate dehydrogenase release from culture cells was evaluated to assess cell viability.

RESULTS

Pretreatment with MgSO₄ attenuated the loss of OL markers, such as myelin basic protein and Olig2, in ipsilateral pericallosal white matter and decreased the number of CD-68-positive microglia and TUNEL-positive cells in vivo. Pretreatment with MgSO₄ also inhibited lactate dehydrogenase release from pre-OL induced by oxygen glucose deprivation in vitro.

CONCLUSION

Pretreatment with MgSO₄ attenuates white matter damage by preventing cell death of pre-OL.