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Who's at risk and why?

Adults :: Maternity and pregnancy :: Who's at risk and why?

While most births occur following an uneventful pregnancy, occasionally there are complications and rare tragedies which good antenatal care seeks to minimise. A maternal death is defined as 'the death of a woman while pregnant or within 42 days of termination of pregnancy, from any cause related to or aggravated by the pregnancy or its management, but not from accidental or incidental causes'. There have been five maternal deaths in the last 10 years (that is with an underlying cause of death in chapter 'O' of the ICD 10 codes).[1]

Babies may also die – in utero, during labour or in the early days, weeks and months of life.


• Still births are deaths after 24 or more weeks of completed gestation — death may occur in utero or during labour.
• Perinatal deaths are deaths from the 24th week of gestation up to 6 completed days of life (i.e. include still births)
• Early neonatal deaths are deaths between birth and 6 completed days of life.
• Late neonatal deaths are deaths from 7–27 completed days of life.
• Neonatal deaths are deaths in the first 27 completed days of life.
• Post neonatal deaths are deaths at 28 days but under one year of life.
• Infant deaths are deaths between birth and under one year of life.

Still births and deaths in infancy are fortunately relatively rare events. Confidential enquires into still births and neonatal deaths have been undertaken in the UK for many years and risk factors for these events have been identified.[2] They are:


• Maternal age – greater risk if less than 20 or 40 years and over
• Maternal Body Mass Index (BMI) – greater risk if underweight, overweight, obese or very obese.
• Maternal smoking
• BME ethnicity
• Maternal country of birth is outside the UK
• Maternal social deprivation – greater risk if living in more deprived area
• Booking for antenatal care after 12 weeks gestation
• Prematurity – greater risk if born before 37 weeks
• Low birthweight – greater risk if less than 2,500g and even higher risk if less than 1,500g
• Parity

Smoking in pregnancy has significant health consequences. Babies of women who smoke during pregnancy are more likely to be born prematurely, have twice the risk of being low birthweight and are up to three times more likely to die from sudden unexpected death in infancy (SUDI).[2]

Multiple births

Twins are at a higher risk of stillbirth (2.5 times higher) and neonatal deaths (6.4 times higher) than singletons but more research is needed to determine whether this is due to prematurity and growth restriction rather than specific twin factors.[2]

Causes of prematurity

The causes of prematurity are complex and in many premature births are unidentifiable. However risk factors in addition to smoking are maternal pre-eclampsia (a condition causing hypertension, severe headaches, vision problems etc, the risk of which itself is increased by obesity), cervical incompetence (where the cervix begins to thin and dilate before the pregnancy has reached term), multiple births, infections, a previous preterm delivery, low BMI and domestic violence. Preterm babies often have low birth weights which is associated with inhibited growth and cognitive development, and chronic diseases later in life.


References

[1]   Office for National Statistics. Primary Care Mortality Database
[2]   Centre of Maternal and Child Enquiries, CMACE. Perinatal Mortality 2009 2011; Centre of Maternal and Child Enquiries, CMACE. http://www.hqip.org.uk/assets/NCAPOP-Library/CMACE-Reports/35.-March-2011-Perinatal-Mortality-2009.pdf .