New Delhi , Nov 28 : Women who get pregnant in old age generally suffer changes in the placenta, which in turn, means that baby boy being born to such mothers are more likely to develop heart problems later in life, a new study has found.
Changes occur in the placenta in older pregnant mothers which leads to a greater likelihood of poor health in their male offsprings, pointed out the study published in the journal Scientific Reports.
Both male and female fetuses do not grow as large in older mothers, but there are sex-specific differences in changes to placental development and function. These are likely to play a central role in the increased likelihood of later-life heart problems and high blood pressure in males.
Women over 35 are considered to be of advanced maternal age and in this study, researchers looked at pregnant rats of a comparable age wherein, the placenta of female fetuses showed beneficial changes in structure and function that would maximise the support of fetal growth.
In some instances, the placenta even supported the female fetus better than the placenta of a younger mother. In the case of male fetuses however, the placenta showed changes that would limit fetal growth in the aged pregnant rats.
Pregnancy in older mothers is associated with a heightened risk of complications for both the mother and her baby with conditions like preeclampsia - raised blood pressure in the mother during pregnancy, gestational diabetes, stillbirth and fetal growth restriction.
"With the average age of first pregnancy in women becoming higher and higher, and especially so in developed countries, it is very important to understand how the age of the mother and the sex of the baby interact to determine pregnancy and later-life health of the child," said study's lead author Dr Amanda Sferruzzi-Perri, a Royal Society Fellow in the Centre for Trophoblast Research at the University of Cambridge's Department of Physiology, Development and Neuroscience.
The placenta transports nutrients and oxygen from mother to fetus, secretes signalling factors into the mother so she supports fetal development, and is the main protective barrier for the fetus against toxins, bacteria, and hormones - such as stress hormones - in the mother's blood.
It is highly dynamic in nature, and its function can change to help protect the growing fetus when conditions become less favourable for its development, for example through a lack of nutrients or oxygen or when the mother is stressed.
The study found that advanced maternal age reduced the efficiency of the placenta of both male and female fetuses. It affected the structure and function of the placenta more markedly for male fetuses, reducing its ability to support the growth of the fetus.
"We now know that growth, as well as gene expression in the placenta, is affected in older mothers in a manner that partially depends on sex changes in the placentas of male fetuses are generally detrimental," said first author Dr Tina Napso, post-doctoral fellow at the University of Cambridge.
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