Researchers investigated the association between blood pressure in women before getting pregnant and early pregnancy, and the risk of miscarriage.
Knowledge is power. For women who have lost pregnancies before, as many as 20-30% of women will do so again. Knowing as much as possible about the risk of another miscarriage is important.
Previous studies have looked into the factors leading to the risk of miscarriage, but for the first time, researchers in the United States looked at increased blood pressure as a potential risk. They theorized that some of the key biological processes that occur as a result of high blood pressure are the same ones that affect key reproductive processes.
A large dataset was available to the researchers as a result of a previous study on miscarriage and folic acid. A total of 1228 women were included in the study and they had all experienced one to two previous miscarriages and up to two live births. Blood pressure measurements had been recorded from the women in the months leading up to being pregnant and during pregnancy.
Through statistical analysis, the researchers compared the blood pressure of women who had a miscarriage with those who did not, and published their findings in Hypertension.
They found that there was an association between high blood pressure in the months prior to getting pregnant and miscarriage. The risk of miscarriage increased by 18% with every 10mmHg increase in mean arterial blood pressure. The findings were similar for increased blood pressure in early pregnancy also.
The researchers discuss that lifestyle changes that allow a decrease in blood pressure, such as healthy eating and exercise may help women who are at risk of miscarriage. They point out, however, that their research does not indicate that increased blood pressure is a cause of miscarriage, merely that there is an association. Further research is therefore necessary to unravel the meaning of the association.
Written by Nicola Cribb, VetMB DVSc Dip.ACVS
Reference: Nobles CJ, Mendola P, Mumford SL, Naimi AI, Yeung EH, Kim K, Park H, Wilcox B, Silver RM, Perkins NJ, Sjaarda L, Schisterman EF. Preconception Blood Pressure Levels and Reproductive Outcomes in a Prospective Cohort of Women Attempting Pregnancy.Hypertension. 2018 May;71(5):904-910. doi: 10.1161/HYPERTENSIONAHA.117.10705. Epub 2018 Apr 2.