Stage 1 hypertension defined by the 2017 ACC/AHA guidelines and neonatal outcomes: Systematic review and meta-analysis

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.

Clinical Trials That Have Changed Obstetric Practice: The Chronic Hypertension and Pregnancy (CHAP) Trial

We describe the evolution of treatment recommendations for chronic hypertension (CHTN) in pregnancy, the CHTN and pregnancy (CHAP) trial, and its impact on obstetric practice. The US multicenter CHAP trial showed that antihypertensive treatment for mild CHTN in pregnancy [blood pressures (BP)<160/105 mm Hg] to goal<140/90 mm Hg, primarily with labetalol or nifedipine compared with no treatment unless BP were severe reduced the composite risk of superimposed severe preeclampsia, indicated preterm birth <35 weeks, placental abruption, and fetal/neonatal death. As a result of this trial, professional societies in the United States recommended treatment of patients with CHTN in pregnancy to BP goal<140/90 mm Hg.

Perinatal outcomes in women with lower-range elevated blood pressure and stage 1 hypertension: insights from the Kaya health and demographic surveillance system, Burkina Faso

BACKGROUND

The impact of lower thresholds for elevated blood pressure (BP) on adverse perinatal outcomes has been poorly explored in sub-Saharan African populations. We aimed to explore the association between lower BP cutoffs (according to the 2017 American College of Cardiology/American Heart Association [ACC/AHA] criteria) and adverse perinatal outcomes in Kaya, Burkina Faso.

METHODS

This retrospective cohort study included 2,232 women with singleton pregnancies between February and September 2021. BP was categorized according to the ACC/AHA criteria and applied throughout pregnancy. A multivariable Poisson regression model based on Generalized Estimating Equation with robust standard errors was used to evaluate the association between elevated BP, stage 1 hypertension, and adverse perinatal outcomes, controlling for maternal sociodemographic characteristics, parity, and the number of antenatal consultations, and the results were presented as adjusted risk ratios (aRRs) with corresponding 95% confidence intervals (CIs).

RESULTS

Of the 2,232 women, 1000 (44.8%) were normotensive, 334 (14.9%) had elevated BP, 759 (34.0%) had stage 1 hypertension, and 139 (6.2%) had stage 2 hypertension. There was no significant association between elevated BP and adverse pregnancy outcomes. Compared to normotensive women, women with elevated BP had a 2.05-fold increased risk of delivery via caesarean section (aRR;2.05, 95%CI; 1.08-3.92), while those with stage 1 hypertension had a 1.41-fold increased risk of having low birth weight babies (aRR; 1.41, 95%CI; 1.06-1.86), and a 1.32-fold increased risk of having any maternal or neonatal adverse outcome (aRR; 1.32, 95%CI; 1.02-1.69).

CONCLUSIONS

Our results suggest that the risk of adverse pregnancy outcomes is not increased with elevated BP. Proactive identification of pregnant women with stage 1 hypertension in Burkina Faso can improve hypertension management through enhanced clinical surveillance.

Is blood pressure 120-139/80-89 mmHg before 20 weeks a risk factor for hypertensive disorders of pregnancy? A meta-analysis

AIM

Hypertensive disorders of pregnancy affect approximately 10% of pregnant women worldwide with serious fetal and maternal implications. Chronic hypertension is diagnosed prior to 20 weeks of gestation and affects 1.5% of pregnant women. The American College of Obstetricians and Gynecologists defines hypertension in pregnancy as a systolic blood pressure higher than 140 mmHg or a diastolic blood pressure higher than 90 mmHg. In real-world clinical practice, practitioners consider the cut-off of 140/90 mmHg as a marker of true hypertension in pregnancy and consider blood pressures lower than that as normal.

METHODS

To assess the association between a lower range of blood pressures and the development of hypertensive disorders of pregnancy, we performed a meta-analysis of current published studies comparing the occurrence of hypertensive disorders of pregnancy in patients with blood pressures of 120-139/80-89 mmHg before 20 weeks to those with blood pressures<120/80 mmHg.

RESULTS

We included 24 studies: 12362/106870 (11.6 %) patients with blood pressures of 120-139/80-89 mmHg, and 26044/463280 (5.6 %) with blood pressures lower than 120/80 mmHg, developed hypertensive disorders of pregnancy [risk ratio 2.85 (C.I. 2.47-3.3)] - test for overall effect: Z = 14.1 (p < 0.00001).

CONCLUSIONS

We showed evidence of poor pregnancy outcome in patients with blood pressure lower than the routinely accepted cut-off of 140/90 mmHg. Therefore, interventions to mitigate the risk of hypertensive disorders in pregnancy in women with blood pressures 120-139/80-89 mmHg should be planned in new clinical trials.

Change in prevalence of chronic hypertension in pregnancy after the updated ACC/AHA hypertension guidelines

The objective of this population-based retrospective study was to determine the effect of the updated hypertension definition by the American College of Cardiology (ACC) and the American Heart Association (AHA) on the prevalence of chronic hypertension (CHTN) diagnosis in pregnancy. The pre-ACC/AHA group (N = 14,505,399) consisted of births between 2013 and 2016 and the post-ACC/AHA group (N = 7,269,010) consisted of births between 2018 and 2019. After adjusting for differences between groups, CHTN diagnosis was more common in the post-ACC/AHA group (p < 0.001). In conclusion, the prevalence of CHTN diagnosis in pregnancy increased after the new ACC/AHA guidelines publication.

Chronic hypertension and risk of preterm delivery: National Longitudinal Study of Adolescents to Adult Health

BACKGROUND

Chronic hypertension during pregnancy is associated with increased risk of adverse birth outcomes. In 2017, the American College of Cardiology and American Heart Association (ACC/AHA) lowered thresholds to classify hypertension in non-pregnant adults to SBP ≥ 130 mmHg and DBP ≥ 80 mmHg (ie stage I hypertension), resulting in an additional 4.5-million reproductive-aged women meeting criteria for hypertension. Little is known about effects of pre-pregnancy blood pressure (BP) in this range.

OBJECTIVES

To examine the effect of pre-pregnancy maternal BP on preterm delivery.

METHODS

We analysed the data from two waves of the National Longitudinal Study of Adolescent to Adult Health, including participants that had measured BP at Wave IV (2008-09) and a pregnancy that resulted in a singleton live birth between Waves IV and V (2016-18; n = 2038). We categorised BP using ACC/AHA cut-offs: normal (SBP < 120 mmHg and DBP < 80 mmHg), elevated (SBP 120-129 mmHg and DBP < 80 mmHg), hypertension stage I (SBP 130-139 mmHg or DBP 80-89 mmHg) and hypertension stage II (SBP ≥ 140 mmHg or DBP ≥ 90 mmHg). We estimated risk ratios (RR) with log-binomial regression adjusting for maternal demographics, anthropometrics and medication use.

RESULTS

The prevalence of preterm delivery was 12.6%. A standard deviation (SD) increment in SBP (SD = 12.2 mmHg) and DBP (SD = 9.3 mmHg) was associated with a 14% (95% confidence interval [CI] 2, 27) and 20% (95% CI 4, 37) higher risk of preterm delivery. Compared to normotensive controls, stage I (RR 1.33, 95% CI 1.01, 1.74) and stage II (RR 1.34, 95% CI 0.89, 2.00) hypertension were associated with increased risk.

CONCLUSIONS

We observed greater risk of preterm delivery among women with higher pre-pregnancy BP. Women with stage I hypertension during pregnancy may benefit from increased BP monitoring. Additional studies on the utility of foetal surveillance in this group are warranted.