Women who give birth to a premature baby are much more likely to die young than other mums, warns a new study.
And the risk of an early death persists for up to 40 years after delivery, say researchers.
The study, published by The BMJ, shows that pre-term and early term delivery are independent risk factors for premature death in women.
Researchers say that their findings were not explained by shared genetic or early life environmental factors in families, suggesting that women who deliver prematurely ‘need long term clinical follow-up for detection and treatment of chronic disorders associated with early mortality.’
Women who delivered their babies before 27 weeks were 2.2 times more likely than average women to die early, and those who delivered before 37 weeks were at 1.7 times greater risk, an Icahn School of Medicine study found (file)
Around one in nine of all births worldwide occur pre-term, defined as before 37 weeks of pregnancy.
Women who deliver pre-term or extremely pre-term, defined as after 22 to 27 weeks of pregnancy, have been reported to have increased risks of developing conditions including heart disease or diabetes in later life.
But, until now, little was known about their long term risk of death.
The research team led by Dr Casey Crump, at Icahn School of Medicine at Mount Sinai in New York, set out to examine the long term effect on life expectancy of pre-term delivery.
They analysed figures on length of pregnancy for more than two million women who gave birth in Sweden during the period from 1973 to 2015.
Deaths were then identified from the Swedish Death Register up to December 31, 2016, giving maximum follow-up time of 44 years.
Overall, 76,535 women died (3.5 percent), at an average age of 58.
After taking account of several other risk factors, the researchers found that women who delivered pre-term or extremely pre-term had 1.7-fold and 2.2-fold increased risk of death from any cause, respectively, during the next 10 years compared with those who delivered full term, equating to around 28 excess deaths per 100,000 person years.
The findings showed that whereas risks were highest in the first 10 years after delivery and then declined, absolute differences in death associated with pre-term delivery increased with longer follow-up times.
For example, there was a 1.5-fold increased risk / equivalent to 48 excess deaths per 100,000 person years – 10 to 19 years after delivery, and a 1.4-fold increased risk – equivalent to 143 excess deaths per 100,000 person years – 20 to 44 years after delivery.
Overall, an estimated 2,654 excess deaths in this population were associated with pre-term delivery, or one excess death for every 73 women who delivered pre-term.
Dr Crump said: ‘Several specific causes of death associated with pre-term delivery were identified, including cardiovascular and respiratory disorders, diabetes, and cancer.
‘What’s more, these findings did not seem to be attributable to shared genetic or environmental factors within families.’
He said that premature delivery should now be recognised as a risk factor for early mortality in women that can remain raised up to 40 years later.
Dr Crump added: ‘Women who deliver prematurely need long term clinical follow-up for detection and treatment of chronic disorders associated with early mortality.’
WHAT IS A PREMATURE BIRTH, AND WHAT ARE THE RISKS TO BABIES?
Around 10 per cent of all pregnancies worldwide result in premature labour – defined as a delivery before 37 weeks.
When this happens, not all of the baby’s organs, including the heart and lungs, will have developed. They can also be underweight and smaller.
Tommy’s, a charity in the UK, says this can mean preemies ‘are not ready for life outside the womb’.
Premature birth is the largest cause of neonatal mortality in the US and the UK, according to figures.
Babies born early account for around 1,500 deaths each year in the UK. In the US, premature birth and its complications account for 17 per cent of infant deaths.
Babies born prematurely are often whisked away to neonatal intensive care units, where they are looked after around-the-clock.
What are the chances of survival?
- Less than 22 weeks is close to zero chance of survival
- 22 weeks is around 10%
- 24 weeks is around 60%
- 27 weeks is around 89%
- 31 weeks is around 95%
- 34 weeks is equivalent to a baby born at full term
Source: Health & wellbeing | The Guardian