A study published in the journal The BMJ has found that early-term and preterm delivery are independent risk factors leading to death in women up to nearly 40 years later. According to researchers, nearly 11 percent of all deliveries across the world are undergone preterm (i.e) before 37 weeks of pregnancy.
Casey Crump, the author of the study, said in a statement, "Women who deliver prematurely need long term clinical follow-up for detection and treatment of chronic disorders associated with early mortality."
Need for Clinical Follow-up
Women who deliver preterm or extremely preterm (22-27 weeks) have been reported to have increased risks of developing conditions such as heart disease or diabetes in later life, but little is known about their long-term risk of death.
For the findings, the research team set out to examine the long term mortality linked to preterm delivery in women and to explore the potential influence of shared genetic or environmental factors within families.
"Women who deliver prematurely need long term clinical follow-up for detection and treatment of chronic disorders associated with early mortality," said study researcher Casey Crump from the Icahn School of Medicine at Mount Sinai in the US.
Using nationwide birth records, they analyzed data on the length of pregnancy for over two million women who gave birth in Sweden from 1973-2015. Deaths were then identified from the Swedish Death Register up to 31 December 2016 (a maximum follow-up time of 44 years). Overall, 76,535 (3.5 percent) of women died, at an average age of 58.
Environmental or Genetic Factors Within Families
The researchers found that women who delivered preterm or extremely preterm had a 1.7-fold and 2.2-fold increased risk of death from any cause, respectively, during the next 10 years compared to those who delivered full term. This equates to around 28 excess deaths per 1,00,000 person-years. Whereas risks were highest in the first 10 years after delivery and then declined, absolute differences in death associated with preterm delivery increased with longer follow-up times.
Overall, an estimated 2,654 excess deaths in this population were associated with preterm delivery (one excess death for every 73 women who delivered preterm). Several specific causes of death associated with preterm 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," the author wrote. However, strengths included the large sample size and long follow-up time, prompting the researchers to say that premature delivery should now be recognized as a risk factor for early mortality in women that can remain raised up to 40 years later.
(With inputs from agencies)