American College of Cardiology and American Heart Association blood pressure categories-a systematic review of the relationship with adverse pregnancy outcomes in the first half of pregnancy

Does the implementation of revised American College of Cardiology and American Heart Association (ACC/AHA) guidelines improve the identification of stillbirths and preterm births in hypertensive pregnancies: a population-based cohort study from South Asia and sub-Saharan Africa

BACKGROUND

Hypertensive disorders of pregnancy (HDP) are a significant cause of maternal mortality worldwide. The classification and treatment of hypertension in pregnancy remain debated. We aim to compare the effectiveness of the revised 2017 ACC/AHA blood pressure threshold in predicting adverse pregnancy outcomes.

METHODS

We conducted a secondary data analysis of the Alliance for Maternal and Newborn Health Improvement (AMANHI) biorepository study, including 10,001 pregnant women from Bangladesh, Pakistan, and Tanzania. Blood pressure was measured using validated devices at different antenatal care visits. The blood pressure readings were categorized as: normal blood pressure (systolic blood pressure (sBP) < 120 mm Hg and diastolic blood pressure (dBP) < 80 mm Hg), elevated blood pressure (sBP 120-129 and dBP < 80), stage 1 hypertension (sBP 130-139 or dBP 80-89, or both), and stage 2 hypertension (sBP ≥ 140 or dBP ≥ 90, or both). We estimated risk ratios for stillbirths and preterm births, as well as diagnostic test properties of both the pre-existing JNC7 (≥ 140/90) and revised ACC/AHA (≥ 130/80) thresholds using normal blood pressure as reference group.

RESULTS

From May 2014 to June 2018, blood pressure readings were available for 9,448 women (2,894 in Bangladesh, 2,303 in Pakistan, and 4,251 in Tanzania). We observed normal blood pressure in 70%, elevated blood pressure in 12.4%, stage 1 hypertension in 15.2%, and stage 2 hypertension in 2.5% of the pregnant women respectively. Out of these, 310 stillbirths and 9,109 live births were recorded, with 887 preterm births. Using the ACC/AHA criteria, the stage 1 hypertension cut-off revealed 15.3% additional hypertension diagnoses as compared to JNC7 criteria. ACC/AHA defined hypertension was significantly associated with stillbirths (RR 1.8, 95% CI 1.4, 2.3). The JNC 7 hypertension cut-off of ≥ 140/90 was significantly associated with a higher risk of preterm births (RR 1.6, 95% CI 1.2, 2.2) and stillbirths (RR 3.6, 95% CI 2.5, 5.3). Both criteria demonstrated low sensitivities (8.4 for JNC-7 and 28.1 for ACC/AHA) and positive predictive values (11.0 for JNC7 and 5.2 for ACC/AHA) in predicting adverse outcomes.

CONCLUSION

The ACC/AHA criteria (≥ 130/80) identified additional cases of hypertension but had limited predictive accuracy for stillbirths and preterm births, highlighting the ongoing need for improved criteria in managing pregnancy-related hypertension.

Blood pressure cutoffs at 11-13 weeks of gestation and risk of preeclampsia

BACKGROUND

A parallel has been drawn between first-trimester placental vascular maturation and maternal cardiovascular adaptations, including blood pressure. Although 140/90 mm Hg is well-accepted as the threshold for chronic hypertension in the general obstetric population in early pregnancy, a different threshold could apply to stratify the risk of adverse outcomes, such as preeclampsia. This could have implications for interventions, such as the threshold for initiation of antihypertensive therapy and the target blood pressure level.

OBJECTIVE

We evaluated the relationship between various blood pressure cutoffs at 11-13 weeks of gestation and the development of preeclampsia, overall and according to key maternal characteristics.

STUDY DESIGN

This secondary analysis was of data from a prospective nonintervention cohort study of singleton pregnancies delivering at ≥24 weeks, without major anomalies, at 2 United Kingdom maternity hospitals, 2006-2020. Blood pressure at 11-13 weeks of gestation was classified according to American College of Cardiology/American Heart Association categories (mm Hg) as (1) normal blood pressure (systolic <120 and diastolic <80), (2) elevated blood pressure (systolic ≥120 and diastolic <80), stage 1 hypertension (systolic ≥130 or diastolic 80-89), and stage 2 hypertension (systolic ≥140 or diastolic ≥90). For blood pressure category thresholds and the outcome of preeclampsia, the following were calculated overall and across maternal age, body mass index, ethnicity, method of conception, and previous pregnancy history: detection rate, screen-positive rate, and positive and negative likelihood ratios, with 95% confidence intervals. A P value of <.05 was considered significant.

RESULTS

There were 137,458 pregnancies screened at 11-13 weeks of gestation. The population was ethnically diverse, with 15.9% of Black ethnicity, 6.7% of South or East Asian ethnicity, and 2.7% of mixed ethnicity, with the remainder of White ethnicity. Compared with normal blood pressure, stage 2 hypertension was associated with both preterm preeclampsia (0.3% to 4.9%) and term preeclampsia (1.0% to 8.3%). A blood pressure threshold of 140/90 mm Hg was good at identifying women at increased risk of preeclampsia overall (positive likelihood ratio, 5.61 [95% confidence interval, 5.14-6.11]) and across maternal characteristics, compared with elevated blood pressure (positive likelihood ratio, 1.70 [95% confidence interval, 1.63-1.77]) and stage 1 hypertension (positive likelihood ratio, 2.68 [95% confidence interval, 2.58-2.77]). There were 2 exceptions: a blood pressure threshold of 130/80 mm Hg was better for the 2.1% of women with body mass index <18.5 kg/m2 (positive likelihood ratio, 5.13 [95% confidence interval, 3.22-8.16]), and a threshold of 135/85 mm Hg better for the 50.4% of parous women without a history of preeclampsia (positive likelihood ratio, 5.24, [95% confidence interval, 4.77-5.77]). There was no blood pressure threshold below which reassurance could be provided against the development of preeclampsia (all-negative likelihood ratios ≥0.20).

CONCLUSION

The traditional blood pressure threshold of 140/90 mm Hg performs well to identify women at increased risk of preeclampsia. Women who are underweight or parous with no prior history of preeclampsia may be better identified by lower thresholds; however, a randomized trial would be necessary to determine any benefits of such an approach if antihypertensive therapy were also administered at this threshold. No blood pressure threshold is reassured against the development of preeclampsia, regardless of maternal characteristics.

Blood Pressure and Heart Rate Variability and the Impact on Pregnancy Outcomes: A Systematic Review

BACKGROUND

Long-term (visit-to-visit) blood pressure variability (BPV) and heart rate variability (HRV) outside pregnancy are associated with adverse cardiovascular outcomes. Given the limitations of relying solely on blood pressure level to identify pregnancies at risk, long-term (visit-to-visit) BPV or HRV may provide additional diagnostic/prognostic counsel. To address this, we conducted a systematic review to examine the association between long-term BPV and HRV in pregnancy and adverse maternal and perinatal outcomes.

METHODS AND RESULTS

Databases were searched from inception to May 2023 for studies including pregnant women, with sufficient blood pressure or heart rate measurements to calculate any chosen measure of BPV or HRV. Studies were excluded that reported short-term, not long-term, variability. Adjusted odds ratios were extracted. Eight studies (138 949 pregnancies) reporting BPV met our inclusion criteria; no study reported HRV and its association with pregnancy outcomes. BPV appeared to be higher in women with hypertension and preeclampsia specifically, compared with unselected pregnancy cohorts. Greater BPV was associated with significantly more adverse pregnancy outcomes, particularly maternal (gestational hypertension [odds ratio range, 1.40-2.15], severe hypertension [1.40-2.20]), and fetal growth (small-for-gestational-age infants [1.12-1.32] or low birth weight [1.18-1.39]). These associations were independent of mean blood pressure level. In women with hypertension, there were stronger associations with maternal outcomes but no consistent pattern for perinatal outcomes.

CONCLUSIONS

Future work should aim to confirm whether BPV could be useful for risk stratification prospectively in pregnancy, and should determine the optimal management path for those women identified at increased risk of adverse outcomes.

Pregnancy outcomes among patients with stage 1 chronic hypertension

In recent years, the American College of Cardiology and the American Heart Association have reduced the thresholds for a hypertension diagnosis among nonpregnant adults. This change has led to more individuals with reproductive potential to be labeled as being chronically hypertensive, and some were started on antihypertensive medications. When these individuals become pregnant, the obstetrical care provider will have to decide whether to manage them as individuals with chronic hypertensive when only a few years ago they would have been managed as normotensive individuals and when the evidence regarding treatment of these patients during pregnancy is limited. If implemented widely, the management of patients with stage 1 hypertension similar to the traditional chronic hypertension will likely lead to additional maternal and fetal testing, to an increase in hospital admissions, and potentially to unnecessary interventions, such as preterm birth. Our goal was to compile the existing evidence regarding the pregnancy outcomes among patients with stage 1 hypertension to assist providers in their diagnosis and management of this patient group.

Blood pressure measurement and adverse pregnancy outcomes: A cohort study testing blood pressure variability and alternatives to 140/90 mmHg

OBJECTIVE

To examine the association with adverse pregnancy outcomes of: (1) American College of Cardiology/American Heart Association blood pressure (BP) thresholds, and (2) visit-to-visit BP variability (BPV), adjusted for BP level.

DESIGN

An observational study.

SETTING

Analysis of data from the population-based UK Southampton Women's Survey (SWS).

POPULATION OR SAMPLE

3003 SWS participants.

METHODS

Generalised estimating equations were used to estimate crude and adjusted relative risks (RRs) of adverse pregnancy outcomes by BP thresholds, and by BPV (as standard deviation [SD], average real variability [ARV] and variability independent of the mean [VIM]). Likelihood ratios (LRs) were calculated to evaluate diagnostic test properties, for BP at or above a threshold, compared with those below.

MAIN OUTCOME MEASURES

Gestational hypertension, severe hypertension, pre-eclampsia, preterm birth (PTB), small-for-gestational-age (SGA) infants, neonatal intensive care unit (NICU) admission.

RESULTS

A median of 11 BP measurements were included per participant. For BP at ≥20 weeks' gestation, higher BP was associated with more adverse pregnancy outcomes; however, only BP <140/90 mmHg was a good rule-out test (negative LR <0.20) for pre-eclampsia and BP ≥140/90 mmHg a good rule-in test (positive LR >8.00) for the condition. BP ≥160/110 mmHg could rule-in PTB, SGA infants and NICU admission (positive LR >5.0). Higher BPV (by SD, ARV, or VIM) was associated with gestational hypertension, severe hypertension, pre-eclampsia, PTB, SGA and NICU admission (adjusted RRs 1.05-1.39).

CONCLUSIONS

While our findings do not support lowering the BP threshold for pregnancy hypertension, they suggest BPV could be useful to identify elevated risk of adverse outcomes.

Perinatal Outcomes Associated With Management of Stage 1 Hypertension

OBJECTIVE

To evaluate the association between maternal blood pressure (BP) below 130/80 mm Hg compared with 130-139/80-89 mm Hg and pregnancy outcomes.

METHODS

We conducted a planned secondary analysis of CHAP (Chronic Hypertension and Pregnancy), an open label, multicenter, randomized controlled trial. Participants with mean BP below 140/90 mm Hg were grouped as below 130/80 mm Hg compared with 130-139/80-89 mm Hg by averaging postrandomization clinic BP throughout pregnancy. The primary composite outcome was preeclampsia with severe features, indicated preterm birth before 35 weeks of gestation, placental abruption, or fetal or neonatal death. The secondary outcome was small for gestational age (SGA).

RESULTS

Of 2,408 patients in CHAP, 2,096 met study criteria; 1,328 had mean BP 130-139/80-89 mm Hg and 768 had mean BP below 130/80 mm Hg. Participants with mean BP below 130/80 mm Hg were more likely to be older, on antihypertensive medication, in the active treatment arm, and to have lower BP at enrollment. Mean clinic BP below 130/80 mm Hg was associated with lower frequency of the primary outcome (16.0% vs 35.8%, adjusted relative risk 0.45; 95% CI 0.38-0.54) as well as lower risk of severe preeclampsia and indicated birth before 35 weeks of gestation. There was no association with SGA.

CONCLUSION

In pregnant patients with mild chronic hypertension, mean BP below 130/80 mm Hg was associated with improved pregnancy outcomes without increased risk of SGA.

CLINICAL TRIAL REGISTRATION

ClinicalTrials.gov , NCT02299414.

Preeclampsia up to date-What's going on?

Preeclampsia is a hypertensive disorder in pregnancy characterized by placental malperfusion and subsequent multi-organ injury. It accounts for approximately 14% of maternal deaths and 10-25% of perinatal deaths globally. In addition, preeclampsia has been attracting attentions for its association with risks for developing chronic diseases in later life for both mother and child. This mini-review discusses on latest knowledge on prediction, prevention, management, and long-term outcomes of preeclampsia and also touches on association between COVID-19 and preeclampsia. HTN hypertension, HDP hypertensive disorders of pregnancy, PE preeclampsia, BP blood pressure, cfDNA cell-free DNA, ST2 human suppression of tumorigenesis 2, sFlt-1 soluble fms-like tyrosine kinase-1, PIGF placental growth factor, VEGF vascular endothelial growth factor, VEGFR VEGF receptor, TGFβ transforming growth factor β, ENG endoglin, sENG soluble ENG, PRES posterior reversible encephalopathy syndrome, AKI acute kidney injury, CVD cardiovascular disease, ESKD end-stage kidney disease, ACE angiotensinogen converting enzyme, Ang angiotensin.

The 2017 American College of Cardiology and American Heart Association blood pressure categories in the second half of pregnancy-a systematic review of their association with adverse pregnancy outcomes

OBJECTIVE

A relationship between the 2017 American College of Cardiology and American Heart Association blood pressure thresholds and adverse pregnancy outcomes has been reported, but few studies have explored the diagnostic test properties of these cutoffs when used within pregnancy.

DATA SOURCES

Electronic databases were searched (2017-2021) for measurements of blood pressure in pregnancy at >20 weeks, classified according to the 2017 American College of Cardiology and American Heart Association criteria, and their relationship with pregnancy outcomes. Blood pressure was categorized as "normal" (systolic blood pressure of <120 mm Hg and diastolic blood pressure of <80 mm Hg), "elevated blood pressure" (systolic blood pressure of 120-129 mm Hg and diastolic blood pressure of <80 mm Hg), "stage 1 hypertension" (systolic blood pressure of 130-139 mm Hg and/or diastolic blood pressure of 80-89 mm Hg), and "stage 2 hypertension" (systolic blood pressure of ≥140 mm Hg and/or diastolic blood pressure of ≥90 mm Hg).

STUDY ELIGIBILITY CRITERIA

Studies recording blood pressure at or above 20 weeks gestation were included.

METHODS

Meta-analyses were used to investigate the strength of the association between blood pressure cutoffs and adverse outcomes, and the diagnostic test properties were calculated accounting for gestation.

RESULTS

There were 12 included studies. The American College of Cardiology or American Heart Association blood pressure categories were determined from peak blood pressures at any point from 20 weeks of gestation and at specific gestational ages (20-27, 28-32, or 33-36 weeks of gestation), as available. A higher (vs normal) blood pressure category was consistently associated with adverse outcomes. The strength of association between blood pressure categories and adverse outcomes was the greatest with "stage 2 hypertension" (blood pressure of ≥140/90 mm Hg). The results were similar when peak blood pressure was reported either at any time from 20 weeks of gestation or within gestational age groups (as above). No blood pressure category was useful as a diagnostic "rule-out test" for adverse outcomes, as all negative likelihood ratios were ≥0.2. Only "stage 2 hypertension" was useful as a "rule in-test," with positive likelihood ratios of ≥5.0, for maximum blood pressure at >20 weeks of gestation for preeclampsia and blood pressure within any gestational age groups for preeclampsia, eclampsia, stroke, maternal death, and stillbirth.

CONCLUSION

From 20 weeks of gestation, blood pressure thresholds of 140 mm Hg (systolic) and 90 mm Hg (diastolic) were useful in identifying women at increased risk of adverse pregnancy outcomes, irrespective of the specific gestational age at blood pressure measurement. Lowering the blood pressure threshold for abnormal blood pressure at >20 weeks of gestation would not assist clinicians in identifying women at heightened maternal or perinatal risk. No American College of Cardiology or American Heart Association blood pressure threshold can provide reassurance that women are unlikely to develop adverse outcomes.

Pregnancy Outcomes in Females with Stage 1 Hypertension and Elevated Blood Pressure Undergoing In Vitro Fertilization and Embryo Transfer

Objective: To determine whether stage 1 hypertension and elevated blood pressure (BP), as defined by the 2017 American College of Cardiology/American Heart Association (ACC/AHA) guidelines, prior to pregnancy contributes to adverse pregnancy outcomes in females who conceived by in vitro fertilization and embryo transfer (IVF-ET). Methods: This retrospective cohort study involved 2239 females who conceived by IVF-ET and delivered live neonates. BPs recorded before IVF-ET were collected. Elevated BP was defined as at least two systolic BPs of 120 to 129 mmHg. Stage 1 hypertension was defined as at least two systolic BPs of 130 to 139 mmHg or diastolic BPs of 80 to 89 mmHg. Results: Among the females included in this study, 18.5% (415/2239) had elevated BP and 10.0% (223/2239) had stage 1 hypertension. Multiple logistic regression analysis showed that females with stage 1 hypertension had higher risks of hypertensive disorders in pregnancy (HDP) [adjusted odds ratio (aOR) 1.65; 95% confidence interval (CI) 1.16-2.35] and preeclampsia (aOR 1.52; 95% CI 1.02-2.26) than normotensive females. However, the risks of HDP (aOR 0.88; 95% CI 0.64-1.21) and preeclampsia (aOR 0.83; 95% CI, 0.57-1.20) in females with elevated BP were not significantly different from those in normotensive females. The females were then categorized into five groups by systolic and diastolic BP; females with systolic BP of 130 to 139 mmHg or diastolic BP of 85 to 89 mmHg had significantly increased risks of HDP and preeclampsia. Conclusion: Stage 1 hypertension before IVF-ET was an independent risk factor for HDP and preeclampsia.