A study of male offspring has found those whose mothers had high blood pressure in pregnancy lost their mental skills quicker throughout their lives than those whose mothers had healthy blood pressure.

The differences were evident at the age of 20, and widened throughout the men’s lives, found Dr Katri Räikkönen and colleagues at Helsinki University in Finland. The biggest gap was in maths ability.

The academics looked at results from 398 men, born between 1934 and 1944, who were tested for maths, language and spatial reasoning at 20 and then again at 69. The study is published in the journal Neurology.

Dr Räikkönen said: “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.

“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.”

By Stephen Adams, Medical Correspondent