Cumulative Blood Pressure Load in Early Pregnancy Predicts Low Birth Weight
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japanese researchers have found that monitoring cumulative blood pressure during the first trimester predicts low birth weight better then simple averages, highlighting how home monitoring could transform prenatal care.
In a recent study published in the journal Hypertension Research, a group of researchers compared cumulative blood pressure at home (RAP) loading with mean arterial pressure to predict low birth weight (LPN).
Background
About one in fifteen newborns has LPN, a warning for future hypertension, diabetes, cardiovascular disease and chronic kidney disease, but many factors are modifiable during early pregnancy. Blood pressure drops during the first trimester and then rises later, so simple averages may not account for risk. RAP monitoring captures readings, while cumulative blood pressure load incorporates the height and duration that values exceed a threshold, which is linked to organ damage in adults. Asian populations often experience lower, but higher, early pregnancy pressure LPN.As pregnancy-specific targets are uncertain, further research should test whether cumulative loading improves stratification.
About the study
This prospective cohort analysis used data from longitudinal observation of babies and their parents at Suzuki Memorial Hospital over the intrauterine period (HEAD) study in Sendai, Japan. Eligible participants were pregnant women with singleton gestations who had recorded at least four RAP measurements between 10 weeks 0 days and 15 weeks 6 days. RAP was measured every morning after urination and a brief rest. Daily systolic blood pressure (SBP) and diastolic blood pressure (PAD) the values were joined linearly to calculate the area; Cumulative blood pressure burden was the percentage above a threshold set at the cohort’s median mean blood pressure (derived after excluding participants with chronic hypertension) (SBP and PAD analyzed separately), while elevation was defined as >20% (selected as the first quartile threshold excluding 0% and 100%).
The main result was LPN (< 2,500 grams).Risk ratios (RR) were estimated using Poisson regression, adjusted for maternal age and body mass index (BMI), smoking, primiparity and history of hypertensive disorders of pregnancy (HDP) as covariates. Sensitivity analyzes varied the elevation threshold (10% and 30%), limited to women without chronic hypertension and those with ≥ 8 measurements, and compared the cumulative burden with the mean arterial pressure models using quasi-likelihood according to the independence model criterion (CIQ).Multiple imputation focused on absences, while analyzes were performed using R and SAS.
Study results
Among