Results from a large Danish study suggest that children of mothers who experience disorders that include high blood pressure during pregnancy are at increased risk of dying in childhood or early adulthood.
Hypertensive disorders of pregnancy (HDP) impact around 10% of pregnancies around the world. HDP refers to several conditions such as pre-eclampsia, eclampsia, and others that can lead to abnormally high blood pressure and other pregnancy complications.
Research suggests babies born to mothers who experienced HDP are more susceptible to a number of different metabolic, immune, and neurological disorders compared with other children. However, limited findings about possible links with mortality have been published in the past.
To investigate this further, Yongfu Yu, a professor at Fudan University in Shanghai, and colleagues in China and Denmark carried out a large population-based cohort study using information collected from Danish national health registers.
The study population included, 2.4M individuals born in Denmark between 1978 and 2018, with follow-up data from date of birth until death, emigration, or the end of 2018.
As reported in the BMJ, the study included 102,095 mothers who experienced HDP (67,683 pre-eclampsia, 679 eclampsia, and 33,733 hypertension). There were 1021 deaths of offspring in the HDP group over 41 years of follow-up versus 19,119 in the 2.3M births not impacted by HDP.
The results show that exposure to maternal HDP resulted in a 26% higher risk for all-cause mortality in offspring, compared with those whose mothers did not experience HDP. Of the three conditions encompassed by HDP, eclampsia was linked to the highest risk for offspring death and hypertension the lowest.
Exposure to HDP was also linked to increased risk for death from several specific causes including: conditions originating in the perinatal period, cardiovascular diseases, digestive system diseases, and endocrine, nutritional, and metabolic diseases.
“Previous studies of maternal HDP and mortality in offspring mainly focused on the negative impacts of maternal HDP in the fetal and neonatal periods, with one exception in mid-adulthood, whereas no evidence has been presented for mortality in childhood, adolescence, and young adulthood,” write the authors.
They explain that while the underlying mechanisms linking exposure to HDP with early death are not completely clear, there are several possible reasons for the association.
“Maternal HDP, a disease related to placental disorder, might result in placental lesions, DNA methylation in the placenta, and changes in gene expression. HDP related placental dysfunction is associated with impaired fetal development and could have a negative long-term effect on health outcomes in offspring,” they suggest.
“Furthermore, the epigenetic changes resulting from exposure to maternal HDP in utero, or shared environment or lifestyle behavioural factors of offspring after delivery, may also play an important role.”