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Research explores placenta's story of blood pressure in early pregnancy

Research Roundup: Preeclampsia studies you don't want to miss


Pre-conception blood pressure and evidence of placental malperfusion

BMC Pregnancy & Childbirth

Researchers are beginning to study if there is a link between the health of a mother’s placenta and her risk of certain pregnancy outcomes, like hypertensive disorders of pregnancy. In this study, researchers studied a placenta issue called “malperfusion lesions”. These lesions can be seen in tiny sample pieces of a placenta under a microscope (when/if a placenta is sent to a pathologist for examination), and they suggest that the blood vessels of the mother’s uterus did not grow or change how they should to help the placenta deliver mom’s blood, oxygen and nutrients to her baby. We know that malperfusion lesions in the placenta are linked to preeclampsia. We also know that early rises in blood pressure during pregnancy are linked to preeclampsia. So, researchers in this study asked if malperfusion lesions in the placenta may be linked to early rises in blood pressure during pregnancy. Studying 100 women whose placentas had malperfusion lesions and 102 women whose placentas did not, researchers looked at how these patients’ blood pressure changed in early pregnancy. It is expected in a typical pregnancy that a woman’s blood pressure drops, and in the “control group”, women with the healthy placentas saw an average 6 mmHg drop in their diastolic blood pressure. Interestingly, in the women who had placentas with malperfusion lesions, their diastolic blood pressure dropped only by 1 mmHg in early pregnancy. These results may mean that a lack of drop in blood pressure early in pregnancy could be a risk factor for a sick placenta, meaning a placenta with malperfusion. Read the original article here.



Are blood pressure level and variability related to pregnancy outcome? Analysis of control of hypertension in pregnancy study data

Pregnancy Hypertension

In the general population (meaning not in pregnant patients specifically), how much your blood pressure changes is a known risk factor for heart disease. This rise and fall of blood pressure is called blood pressure variability. In this study, researchers asked if a pregnant patient’s rapid rises and falls of blood pressures were linked to poor outcomes in pregnant women with hypertension (meaning they either had preexisting high blood pressure before pregnancy or were diagnosed with high blood pressure for the first time during pregnancy but did not have preeclampsia). Data from 913 women enrolled in the CHIPS study (Control of Hypertension In Pregnancy Study) were used to answer this research question. Results showed that higher blood pressure variability during pregnancy was linked with a higher chance of preeclampsia, but not poorer outcomes (like pregnancy loss, baby NICU admission for more than 2 days, preterm birth, or small for gestational age baby). However, an additional analysis showed that if researchers looked at blood pressure variability only 4 weeks or more before the outcomes- the more variable a patient’s diastolic blood pressure was (the bottom number of your blood pressure), the less likely she was to have a poor outcome. Read the original article here.



Family history of preeclampsia and cardiovascular disease as risk factors for preeclampsia: The GenPE case-control study

Hypertension in Pregnancy

Researchers conducting this study wanted to measure the effect family history of preeclampsia has on a pregnant woman’s risk for preeclampsia. This study used data from 8,022 women with and without preeclampsia from 8 cities in Colombia, South America between 2000 and 2012. Risk of preeclampsia for Hispanic women with a mother who had preeclampsia was a 3.4 times as high as the risk of preeclampsia for Hispanic women whose mothers did not have preeclampsia. Similarly, for Hispanic women whose sister had preeclampsia, their own preeclampsia risk was 2.4 as times as high. These findings show that a family history of preeclampsia is linked to a risk for preeclampsia in a Hispanic population. Read the original article here.

Editor's Note: A consideration a reader should always make when reading the findings of research studies is the population being studied. Asking how diverse (or not diverse) the patients or participants from the research study are, can help you understand how the study’s findings might relate specifically to you, or to a group of people. The ability for a study’s findings to relate to a broad range of individuals is called “generalizability”.

For example, this study was conducted in Colombia, South America. While there is strength in the study that the patients are from 8 different cities, the study participants are predominately Hispanic. Because we know general health, pregnancy outcomes, etc. are different among different races and ethnicities, this should be something the reader takes into consideration when trying to apply the findings to a non-Hispanic demographic.

Here are some example questions you can ask when looking at the generalizability of research findings: Are there multiple races included? multiple ethnicities included? patients with all levels of education included? Is the study done in one location or multiple locations? If multiple locations, is the study national or international?



Expectant management of hypertensive disorders of pregnancy and future cardiovascular morbidity

Obstetrics & Gynecology

Women with a history of a hypertensive disorder of pregnancy (such as preeclampsia) have a higher chance of heart disease later in their lives. In this study, researchers wanted to investigate if there was a relationship between how long a mother had a hypertensive disorder of pregnancy (meaning, how many days from her diagnosis to when she delivered her baby) and her chance of heart disease as she aged. Researchers hypothesized that the longer length of time between diagnosis and delivery, the higher her change of cardiovascular disease would be. Over 22,000 patients with a hypertensive disorder of pregnancy were studied for about 5 years after delivery in the New York State Inpatient Database (deliveries between 2005 and 2014). 87% of these women delivered their baby within 1 week of being diagnosed with a hypertensive disorder of pregnancy, and the other 13% delivered their babies more than 1 week after diagnosis. Compared to mothers who delivered their babies within 1 week of diagnosis, mothers who delivered more than 1 week after diagnosis had a 45% increase risk of heart disease. This study raises the question about how doctors can and should balance early delivery of a mother with a hypertensive disorder of pregnancy while also protecting her baby’s health. Read the original article here.



Maternal Race/Ethnicity, Hypertension, and Risk for Stroke During Delivery Admission

Journal of the American Heart Association

It is well established that race and ethnicity are linked to health outcomes of mothers in the United States. In this study, researchers asked if there was a link between a risk of stroke at hospital admission for delivery and the race/ethnicity of the pregnant patients. Investigators used data for over 65 million women in the Healthcare Cost and Utilization Project’s National Inpatient Sample database- 7,764 of whom had a stroke. The results showed that women from minority groups (black, Hispanic, and Asian/Pacific Islander) had increased risk of stroke compared to white, non-Hispanic women. Among all women who had chronic hypertension or pregnancy-induced hypertension (meaning high blood pressure before they became pregnant; or gestational hypertension, preeclampsia, eclampsia, or HELLP syndrome), black and Hispanic women both had 2 times as high as a risk for stroke as non-Hispanic white women. Researchers of this article suggest that their findings support having a personalized approach to managing blood pressure in pregnancy for women of particular minorities, reviewing blood pressure goals for pregnant women in minority groups, as well as paying close attention to a patient’s response to an antihypertensive medications (which might be different in different minority groups). Read the original article here.



Article selections for the Research Roundup are guided by Dr. Elizabeth Sutton and a team of preeclampsia experts: Dr. Jenny Sones, Dr. Alisse Hauspurg, Dr. Felicia LeMoine, and Dr. Michelle Ogunwole.

About Dr. Elizabeth Sutton

Research Roundup Editor

Dr. Elizabeth Sutton is the Research Roundup Editor for the Preeclampsia Foundation, while serving full-time as the Scientific Research Director at Woman's Hospital in Baton Rouge, Louisiana. Dr. Sutton is a preeclampsia survivor and researcher with a PhD in Molecular and Developmental Biology from Louisiana State University. Her research efforts are focused on the short and long-term cardiovascular and metabolic consequences of preeclampsia in mothers and their children. Her work has been published in numerous scientific journals including Cell Metabolism, Obstetrics & Gynecology, Diabetes, and the American Journal of Physiology. Dr. Sutton is dedicating her life's work to the study of preeclampsia and the dissemination of health education to preeclampsia survivors to honor her resilient daughter, Willow (born at 35 weeks from preeclampsia with severe features in 2017). Her second child, Gregory, was born in 2019 at 40 weeks after a normotensive pregnancy.

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