A new study has appeared in orgyn.com, a website dedicated to the research in the field of women’s health.  This study details the effects of exercise during pregnancy and the preventative factors with respect to preeclampsia (a condition diagnosed by high blood pressure and protein in the urine during pregnancy which, if left untreated, can lead to maternal seizure and death mother and/or baby).

Previously it had been thought that exercise could prevent preeclampsia since exercise lowers blood pressure.  This study showed that among the low to moderate exercise groups the rate of preeclampsia wasn’t affected at all.  However, in the high exercise group (over 420 minutes of exercise per week) the rate of preeclampsia actually increased.  While it’s good to be in general good health during pregnancy and exercise is a part of that, this seems to show that it’s not a good idea to exercise to the brink of body-builder status 🙂

Here is the full article:

Exercise and pre-eclampsia risks

Issue 25: 5 Jan 2009
Source: BJOG: An International Journal of Obstetrics and Gynaecology 2008;in press
Researchers have found that physical activity in early pregnancy may not have a protective effect against pre-eclampsia, and that high levels of exercise may actually increase the risk of developing the condition.

In a new paper published in the BJOG: An International Journal of Obstetrics and Gynaecology, the researchers from centers in Copenhagen and Odense, Denmark, in Oslo, Norway, and in Boston, Massachusetts, USA, write that it has been thought that physical activity in pregnancy protects against pre-eclampsia. This is based at least in part on physiological principles (such as exercise being understood to lower blood pressure) and has been supported by the findings of some case-control studies.

However, the researchers write, high quality empirical evidence on the association between physical activity and pre-eclampsia is limited. For the new study they analyzed data in the Danish National Birth Cohort, the largest prospective database of its kind, which enrolled 101,045 pregnant women between 1996 and 2002.

The study population consisted of 93,315 women with singleton pregnancies, of which 92,676 resulted in a liveborn child.

The women in the cohort were categorized into seven groups according to the amount of leisure-time physical activity they performed in the first trimester, as documented by telephone interviews. The groups were: 0, 1-44, 45-74, 75-149, 150-269, 270-419, and 420 or more minutes per week.

The researchers assessed the risks of pre-eclampsia and of severe subtypes of pre-eclampsia (including HELLP and eclampsia), according to the level of activity. They found no statistically significant relationships, including no protective effects, except for in the two groups with the highest levels of physical activity – where the risk of severe subtypes of pre-eclampsia was significantly raised.

The odds ratios for severe subtypes of pre-eclampsia, compared with the reference group who took no exercise, were 1.65 (95 percent confidence interval 1.11-2.43) for the women who took 270-419 minutes of physical activity per week, and 1.78 (95 percent confidence interval 1.07-2.95) for the women who took 420 minutes or more of physical activity per week.

Lead author of the paper Dr Sjurdur Ollsen said: “In our study we were unable to substantiate that physical activity in early pregnancy has a protective effect against pre-eclampsia. Another unexpected finding was that leisure-time exercise, in amounts that were only slightly higher than the recommended amount, seemed even to be associated with an increased risk of severe types of pre-eclampsia.” He suggested that further research is need to investigate this association, ideally utilizing large prospective cohort databases, but that in the meantime current recommendations on exercise in pregnancy should remain unchanged.

The journal’s editor-in-chief, Professor Philip Steer, commented that clinical guidelines in the UK stress that selective and moderate exercise during pregnancy, including aerobic and strength-conditioning exercises, can be beneficial, but he added: “While general fitness is a good thing in many respects, these data suggest that it may be unwise to exercise to peak fitness levels.

“This new research is useful as it provides us with an indication of how much exercise pregnant women should take. As with everything in life, too much of a good thing can be bad for you, and moderation in all things remains a good policy.”