High Blood Pressure (Hypertension) and Pregnancy Loss: Research Summary

High blood pressure, known clinically as hypertension, is a condition in which the constant force of blood pushing against the walls of the blood vessels is too high. Blood pressure measurements are composed of two numbers:

  • The systolic blood pressure (top number)
  • And diastolic blood pressure (bottom number)

The American College of Cardiology defines normal blood pressure as a reading below 120/80. When the measurement exceeds 120/80, blood pressure is elevated and may cause hypertension if it continues to rise. Hypertension can lead to serious health complications in adults such as heart disease, kidney disease, eye damage, and stroke.

A recent study looking at the impact of high blood pressure in women before becoming pregnant showed a possible link between preconception hypertension and pregnancy loss. The study, by Nobles et al., analyzed a group of 1,228 women who had previously lost a pregnancy, and were attempting to become pregnant again. Of these women, 797 were able to become pregnant again, but about 25% (188) of these women experienced pregnancy loss for a second time.

Nobles et al. looked at blood pressure levels before pregnancy to examine whether this could be a factor behind becoming pregnant or maintaining a pregnancy. The study found that while high blood pressure had no apparent effect of a woman’s ability to become pregnant, it did have an effect on the risk of miscarriage. After controlling for confounding factors such as body mass index (BMI), race, age, and time since last pregnancy loss, the study concluded that for each 10-point increase in diastolic blood pressure (the bottom number) before pregnancy, there was an associated 17% increase in the risk of miscarriage.

While this study is purely observational, and therefore cannot be used to assess the definite cause of pregnancy loss, the relationship between pre-pregnancy hypertension and subsequent pregnancy loss is surely an area for further research. In addition, Nobles et al. stress that regardless of this relationship, maintaining a blood pressure within the healthy range is imperative for an overall healthy lifestyle.


Nobles, C. J. (2018, April 2). Preconception Blood Pressure Levels and Reproductive Outcomes in a Prospective Cohort of Women Attempting Pregnancy. Retrieved April 12, 2018, from http://hyper.ahajournals.org/content/early/2018/03/30/HYPERTENSIONAHA.117.10705.

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