High blood pressure during pregnancy linked to infant mortality

A condition that can produce extremely high blood pressure during pregnancy has been associated with an increased risk of death in offspring from birth to young adulthood, according to a study.

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The findings of the study were published in the BMJ. The research, which was based on information from more than two million people in Denmark, found that children born to mothers who had hypertensive disorders of pregnancy (HDP), a group of illnesses that include pre-eclampsia, eclampsia, and hypertension and can cause abnormally high blood pressure and other complications in pregnancy, had an increased risk of dying.

Up to 10% of pregnancies worldwide are affected by HDP, which is also one of the main reasons mothers and their babies get sick and die. Additionally, HDP has been linked to several illnesses in offspring later in life, including immunological diseases, metabolic syndrome (a condition characterised by diabetes, high blood pressure, and obesity), and neurodevelopmental and psychiatric issues. 

However, there is little proof that HDP causes long-term mortality in offspring from infancy through adolescence and beyond.Researchers set out to investigate the relationship between HDP among mothers and total and cause-specific mortality in kids from birth to young adulthood to fill this information gap.

They followed 2.4 million people born in Denmark between 1978 and 2018 from birth to the date of death, emigration, or December 31, 2018, whichever occurred first, using information from Danish national health registers.

Their primary outcome of interest was all-cause mortality (all-cause mortality), which was followed by 13 specific causes of death in kids from birth to young adulthood, up to age 41. These included birth defects, diseases of the nervous and musculoskeletal systems, cancer, mental and behavioural disorders, cardiovascular diseases, and others.

The sex of the kids, the mother's age at childbirth, her education, her income, her living situation, her smoking throughout pregnancy, and her medical history were all considered to be potentially significant variables.

A total of 102,095 (4.2%) of the 2,437,718 offspring included in the analysis were exposed to HDP before birth, including 33,733 (1.4%) who were subjected to hypertension and 68,362 (2.8%) who were exposed to pre-eclampsia or eclampsia or both.

Deaths occurred in 781 (59 per 100,000 person-years) offspring born to pre-eclamptic mothers, 17 (134 per 100,000 person-years) born to eclamptic mothers, 223 (44 per 100,000 person-years) born to mothers with hypertension, and 19,119 (42 per 100,000 person-years) born to mothers without HDP over the course of an average 19-year follow-up period.

The findings indicate that compared to the non-exposed group, all-cause mortality was more significant in children exposed to HDP through their mothers.Compared to non-exposed kids, offspring exposed to HDP had a 26% greater risk (55 per 100,000 person-years) of all-cause death. Pre-eclampsia risk increased by 29% (59 per 100,000 person-years), eclampsia risk increased by 188% (134 per 100,000 person-years), and hypertension risk increased by 12% (44 per 100,000 person-years), correspondingly.

The mortality risk for the offspring of moms with severe and early onset pre-eclampsia was more than six times higher than that for offspring of mothers without HDP. 

Offspring of moms with HDP and a history of diabetes or low education were also found to have a substantial correlation.Increased risks were also observed for a number of cause-specific fatalities. For instance, among offspring exposed to maternal HDP, deaths from endocrine, nutritional, metabolic, and diseases">cardiovascular diseases increased by more than 50%, while deaths from digestive diseases and conditions originating in the perinatal period (during pregnancy or in the first year after birth) more than doubled.

However, the researchers did not discover a significant link between maternal HDP and child cancer fatalities.The researchers recognise that because this is an observational study, they were unable to rule out the influence of several unmeasured characteristics, such as smoking, alcohol use, a poor diet, obesity, and a sedentary lifestyle in the offspring.

They also point out that Denmark has high-quality universal health care, which may limit how far the results may be applied. However, this was a sizable, prolonged study based on excellent national health data. 

After additional sibling analysis to account for the impact of genetic factors and other unmeasured family characteristics, the results were likewise consistent, indicating that they are robust. In light of this, the researchers claim that this study offers compelling evidence that maternal HDP, particularly eclampsia and severe pre-eclampsia, is linked to higher chances of overall mortality and a variety of cause-specific mortalities in kids from birth through young adulthood.

They go on to say that more study is required to look into the physiological mechanisms that link maternal HDP to offspring mortality.