Mom's blood pressure may affect baby's IQ
October 3rd, 2012
05:10 PM ET

Mom's blood pressure may affect baby's IQ

Hypertension isn't just risky for a pregnant woman, it can have lasting consequences for a child's cognitive ability, a new study suggests.

A Finnish study found that men whose mothers' pregnancies had complications from hypertensive disorders scored lower on tests of cognitive ability than those whose mothers did not have high blood pressure during pregnancy. The study appears in the journal Neurology.

About 10% of all pregnancies become complicated by hypertensive disorders, such as preeclampsia, the study said. Such conditions are linked to premature births and small baby body size, factors that are also linked with lower cognitive ability.


Researchers identified 398 men who had taken a basic ability test for the Finnish Defense Forces twice: around age 20 and again around age 69. In this way, study authors were able to look at verbal, arithmetic and visuospatial reasoning scores. Visuospatial means understanding visual representations and their spatial relationships.

Information about the mothers' blood pressure and urinary protein were used to determine which pregnancies were complicated by hypertension.

The study authors had previously shown that men whose mothers had hypertension-complicated pregnancies tended to score lower around the 20-year mark than men whose mothers did not.


Men whose mothers had a hypertensive disorder during pregnancy had worse scores on arithmetic reasoning and total cognitive ability in both young adulthood and old age. This suggests that "a propensity toward lower cognitive ability has its origins in the prenatal period, when the majority of the development of brain structure and function occurs," the study said.

Associations with decline were strongest in math reasoning scores. Men's test scores were on average 4.36 points lower on total thinking ability in old age, and 2.88 points lower at age 20.


The study only looked at men, not women, and only in Finland. Also, only men who survived into older age for the second testing were included, so the findings might be biased toward otherwise healthy men.

Also, there was not enough data to require two high blood pressure measurements in order to establish hypertensive disorders, so the authors found higher-than-average incidence of these conditions among the mothers in the study. Additionally, the sample size is somewhat small.


The results suggest that a person's declines in thinking ability in old age could be tied to his or her mother's high blood pressure disorder in the womb. But this is only an association, not proof. Especially given the limitations of the study, more research is needed to confirm these findings.

In the meantime, separate research is looking at signs for hypertensive disorders in pregnant women.

A recent study in the American Journal of Obstetrics and Gynecology found that women who begin snoring after becoming pregnant may be at increased risk of developing high blood pressure and cardiovascular problems.

Sleeping on the left side is better for pregnant women than sleeping on the back, Louise O'Brien, an associate professor at the University of Michigan's Sleep Disorders Center, told CNN. That's because some of the vessels that return blood to the lungs get pressed down on by the weight of the uterus.

More from CNN Health: Pregnant and didn't know it

CNN's Saundra Young contributed to this report.

soundoff (39 Responses)
  1. john nickum

    helth care is full of fund fund

    October 3, 2012 at 22:06 | Report abuse | Reply
  2. Roll

    Or maybe stupid people tend to get hypertension...

    October 3, 2012 at 23:54 | Report abuse | Reply
    • johndanger

      I think you might have something there, Roll.

      October 4, 2012 at 00:02 | Report abuse |
    • Dee

      Insightful comment. I've been wondering why a young and healthy woman like myself got preecampsia during pregnancy and thanks to you I now know it is because I am stupid.

      If you don't mind my asking, which medical journal is your peer reviewed study linking low IQ's with hypertension published in?

      October 4, 2012 at 07:42 | Report abuse |
    • peter

      Roll's Mom must have had her hypertension during pregnancy off the charts to produce such a dolt.

      October 4, 2012 at 09:46 | Report abuse |
    • LaLa


      October 4, 2012 at 10:58 | Report abuse |
    • Lindalou

      Whatever method you have used to evade hypertension should be sold for a millions of dollars. You obviously have more on the ball than millions of doctors and researchers that have tried to solve this problem thru the ages. Do you even know what hypertension is??? I have a feeling you're confusing it with something else. Best to keep your mouth shut and appear smart that to open it and remove all doubt.

      October 4, 2012 at 11:25 | Report abuse |
    • sanane

      I am contrary proof. My strongest suite is Math and I am working toward a phd in engineering. I got induced at 39 weeks due to preeclampsia. My son is only a toddler, but so far so good. I understand your point though. In research, there is always something not accounted for, so results are taken with a grain of salt. Especially in medicine. There is such diversity among human beings that not one recipe works for all.

      October 4, 2012 at 12:01 | Report abuse |
    • kkdford

      I am also contrary proof. I have a Master's of Public Health in Biostatistics and was induced 3 weeks early due to HELLP syndrome, a sever form of pre-eclampsia. I'm awesome at math and problem solving, as is my 4-year old preschooler, who is on a kindergarten level in math. I would love to see the raw data and the statistical methods used, because it seems like bs to me too.

      October 4, 2012 at 13:51 | Report abuse |
    • kkdford

      Ooops! I meant "severe", not sever. lol

      October 4, 2012 at 13:52 | Report abuse |
  3. Larry

    Well Ill call bs on this. My wife had bp so high that the doctors said it could kill her and the baby they did a c-section and my son was born 6 wks early. Other being unwilling to take that next step in learning how to read hes extremely intelligent. Hes not the only child we knnow that is like this either. The problem is they dont do studies unless they think theres a link and it biases you towards getting the results youre looking for a majority of the time. The reliable results are those they get unexpectedly

    October 4, 2012 at 00:52 | Report abuse | Reply
    • Know What


      Yeah, I know it's anecdotal, buy my mother had terrible high blood pressure (even with uremia) when pregnant with my older brother. He had the highest IQ of all four of us kids, and went on to become a wonderful physician.

      October 4, 2012 at 02:30 | Report abuse |
    • Minesa99

      Same here. My wife has normally high blood pressure and both our kids are gifted. My oldest is in the upper 90s percentile in everything and my youngest skipped a grade.

      October 4, 2012 at 07:25 | Report abuse |
    • Dee

      I have normally low blood pressure, but a few weeks into pregnancy it shot up. I was on strict bedrest and the doctors all told me it wasn't a matter of if my son would be born early, but when he would be born. I spent months in the hospital on and off magnesium sulfate which gave me side effects so bad I actually prayed for death. I'm not going to say my son is gifted (which is a very overused term), but he's only just turned 4 so time will tell where he falls on the intellectual scale.

      My mom had preeclampsia with my brother and he was born so early my parents were told IF he survived he would have lifelong disabilities and he's perfectly normal (member of MENSA actually).

      I don't think one study means anything, and even if it did that doesn't mean any child is doomed to a low IQ because of their mother's high blood pressure, there will always be exceptions. Parent's should focus on the factors they can control such as breastfeeding and a healthy childhood diet, which has the most profound effect on young brain development and lifelong health.

      October 4, 2012 at 07:59 | Report abuse |
    • pensimmon

      Well, they don't say the babies had low IQ, just a little less than it might have been. This probably applies to all health issues. The healthier the parents are the better the outcome is likely to be. It's common sense really. The parents should eat healthily too- organic foods, naturally raised meats and wild caught fish. Maintain a healthy weight too. You can have a perfectly normal, intelligent and beautiful child without doing any of this stuff- but if you want to try to do the best for your baby-

      October 4, 2012 at 11:23 | Report abuse |
    • mane

      My daughter was born 12 weeks early due to eclampsia. Both my wife and daughter were in serious danger of losing their lives. When I left the hospital that April day, I thought that was the last time I will see my daughter alive. She could not talk until she was seven years old. At 15 years of age today, she can't stop talking and. She is in a gifted school and beats all my other kids who were carried full term and went to private schools.

      October 4, 2012 at 11:40 | Report abuse |
    • mane

      My daughter was born 12 weeks early due to eclampsia. Both my wife and daughter were in serious danger of losing their lives and as a result, she had an emergency C-Section. When I left the hospital that April day, I thought that was the last time I will see my daughter alive. She could not talk until she was seven years old. At 15 years of age today, she can't stop talking and. She is in a gifted school and beats all my other kids who were carried full term and went to private schools.

      October 4, 2012 at 11:44 | Report abuse |
    • Er

      Larry, I don't have children, but I do have high blood pressure. I am a raging idiot. Please explain.

      October 4, 2012 at 13:42 | Report abuse |
  4. tom flanigan

    The editor's and author's mother must have had high BP. What is one to make of this sentence: Men's test scores were on average 4.36 points lower on total thinking ability in old age, and 2.88 points lower at age 20.

    On what scale folks? Geez. Talk about cognitive ability.

    October 4, 2012 at 04:31 | Report abuse | Reply
  5. Mike

    Correlation does not imply causation.

    Hats these headlines with word affect. Completely utterly false, which the article even admits in the final paragraph.

    October 4, 2012 at 06:47 | Report abuse | Reply
    • Karl

      Actually it is possible to have correlational studies prove causation if the design is experiemental. However, this is not frequently done.

      October 4, 2012 at 11:10 | Report abuse |
  6. John Vance

    Weak study that will result in a lot of freaked-out mothers with mild pregnancy-induced hypertension. This disorder is hard enough to manage without throwing in information like this to muddy the waters.

    October 4, 2012 at 07:18 | Report abuse | Reply
  7. thedarkelf

    This could explain why women with multiple childrens fathers and abused women have LD children.And why inner city children have a higher rate of under achievement in school then Suburban kids. Definitely worth a look

    October 4, 2012 at 07:27 | Report abuse | Reply
  8. krafty

    I believe studies like these serve two purposes; 1 It makes those that want to prove them wrong try harder, and 2 It gives those that want to give up a reason/explanation of why they should/shouldn't try harder. Otherwise it is all a bunch of non-sense. Humanity has the greatest gift ever, WE can choose our level of achievement!!!

    October 4, 2012 at 09:01 | Report abuse | Reply
  9. Cmarie

    What a load of rubbish! My first pregnancy was fraught with hypertension worries, so much so that my daughter was born early in a high risk situation because of the preeclampsia. She was valedictorian of her high school class, got a full-ride scholarship to our state's 'MIT', and has retired before the age of 30 to write a book. The rest of my pregnancies continued in the same vein. Al the children have above average intelligence.

    October 4, 2012 at 10:11 | Report abuse | Reply
  10. Jewel4352

    Interesting study. I would like to know when BP is in under control via medication, if that has any affect on the fetus/child. Assuming the medication is safe and does not harn the fetus, does controlled BP apply in this study above? Or are they just referring to women who developed preeclampsia and other BP disorders during pregnancy and BP was not in control for a period of time?

    October 4, 2012 at 11:03 | Report abuse | Reply
  11. Gloria

    I can see it now.... 'push...push....push harder but relax...keep your blood pressure down....you're not pushing hard enough...ooops, baby is twisting...watch that cord....got to get it out quick...forceps....relax now...keep your blood prssure down....I know it hurts....dad, get another popsicle...no, not for you......uhhhh....heart rate is falling...let's move here....don't get excited mom...watch your blood pressure....we don;t want to ruin the babies IQ- lower test scores, sat's...poorer colleges....unhappy life....let's not get excited here... no...no..dad, don;t let her hurl that at me..dad...dad...you have to do better than that. NURSE........."

    October 4, 2012 at 11:27 | Report abuse | Reply
  12. dd

    Now anyone with a HS diploma can read the conclusion and realize that this is a non-story. It clearly is a story produced by an ignorant journalist who has an ignorant editor. This is not a scientific result of a study. This is junk science hyped by truth terrorists. CNN should be shutdown!

    October 4, 2012 at 12:02 | Report abuse | Reply
  13. I know someone whose mother. .

    had high blood pressure during his/her pregnancy and he/she grew up to be really smart! Therefore, the results of this study should henceforth be considered invalidated.

    /flawed logic

    October 4, 2012 at 12:46 | Report abuse | Reply
    • JaneWhite

      Well said!

      October 7, 2012 at 09:19 | Report abuse |
  14. su3385

    So basically, Dr.?, you have just gotten your name in the media by discussing a study that is soooo flawed that calling it a study is absurd. The 300+ men were born in approx. 1943 (depending on when they turned 69). Are there really people who find you credible? In my opinion, you are a perfect example of a wasted education.

    October 4, 2012 at 13:07 | Report abuse | Reply
  15. Mike from Seattle

    I think the point being missed is that this is a study from Finland, where they like to study people for 40+ years to make a report that gets 15 minutes of fame.

    October 4, 2012 at 13:15 | Report abuse | Reply
  16. SeeThruIt2

    The hypertension may not be the underlying cause of the cognitive loss. But, conditions associated with hypertension (mother's weight, diet, lack of exercise) could cause the cognitive loss, and the hypertension link is just one of the indicators.

    October 4, 2012 at 13:18 | Report abuse | Reply
    • JaneWhite

      Ah, finally someone points this out! The original article should have mentioned this.

      Sometimes high blood pressure happens to young, healthy pregnant women who are taking care of themselves. However, it is MORE COMMON among women who have health-related risk factors, such as poor diet or limited access to medical care. Those risk factors may also affect their child as he grows up.

      October 7, 2012 at 09:18 | Report abuse |
  17. Donna

    I had very HBP most of pregnancy, hospitalized the last two weeks, had c-section. My son has an IQ of 164, skipped a grade, aced the SAT's and has a BS in Mathematics and MS in Computer Science. Must be other contributing significant factors. They make it sound like HBP is it. Keep looking!

    October 4, 2012 at 13:33 | Report abuse | Reply
  18. Er

    My mother had high blood pressure while I was in the womb. I am most certainly stupid. Let's all jump with exceptions to try and prove a study wrong! This is for the general population. Not just YOU.

    October 4, 2012 at 13:44 | Report abuse | Reply
  19. Aurelia Mustain

    Controlled diet, exercises and herbs are alternative treatments for hypertension or high blood pressure. Hypertension occurs due to excessive pressure exerted on the walls of arteries. Commonly found causes of hypertension are genetic reasons, poor diet, unhealthy lifestyle, lack of exercises, side effects of medicines, bad habits and obesity. These causes either push heart to pump blood with higher pressure, promote blockages in arteries or harden walls of arteries, due to these problems pressure of blood remains higher than healthy limits and cause severe damage to health including life threatening conditions.^

    Newly released article provided by our new internet page

    February 11, 2013 at 03:09 | Report abuse | Reply
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