Children of women who had high blood pressure or "hypertension" during pregnancy may lose their mental skills quicker throughout their lives compared to those whose mother had healthy blood pressure, according to new research.

A new study, published in the journal Neurology, examined the blood pressure levels of the mothers of nearly 400 men who were born between 1934 and 1944 in Finland. Researchers tested the men's language, math and visual spatial reasoning skills at age 20 and then again at age 69.

They found that those with mothers who had high blood pressure, defined as a systolic blood pressure of 140 mmHg or higher, or a diastolic blood pressure of 90 mmHg or higher, scored an average of 4.36 points lower on IQ tests at age 69 compared to men whose mothers did not suffer from hypertension.

Researchers added that these men also had the sharpest decline in overall cognitive ability after the age of 20. Researchers noted that at age 20, those whose mothers had higher blood pressure also had lower scores. The researchers said that the difference in cognitive test scores of the 398 men between those whose mothers had hypertension and those who did not was most pronounced in tests requiring math-related reasoning.

"High blood pressure and related conditions such as preeclampsia complicate about 10 percent of all pregnancies and can affect a baby's environment in the womb," study author Katri Räikönen of the University of Helsinki in Finland said in a statement. "Our study suggests that even declines in thinking abilities in old age could have originated during the prenatal period when the majority of the development of brain structure and function occurs," Räikönen said.

Researchers said that premature birth or occupation of the father did not affect the findings.  "We found that men who were born after pregnancies complicated by a hypertensive disorder, compared with men born after normotensive pregnancies, scored lower on tests measuring arithmetic reasoning and total cognitive ability in old age," researchers wrote.

"Maternal hypertensive disorders in pregnancy predict lower cognitive ability and greater cognitive decline up to old age," they concluded.  "A propensity to lower cognitive ability and decline up to old age may have prenatal origins."