Gestational Age of Delivery in Pregnancies Complicated by Chronic Hypertension

Optimal Timing of Delivery for Pregnant Individuals With Mild Chronic Hypertension

OBJECTIVE

To investigate the optimal gestational age to deliver pregnant people with chronic hypertension to improve perinatal outcomes.

METHODS

We conducted a planned secondary analysis of a randomized controlled trial of chronic hypertension treatment to different blood pressure goals. Participants with term, singleton gestations were included. Those with fetal anomalies and those with a diagnosis of preeclampsia before 37 weeks of gestation were excluded. The primary maternal composite outcome included death, serious morbidity (heart failure, stroke, encephalopathy, myocardial infarction, pulmonary edema, intensive care unit admission, intubation, renal failure), preeclampsia with severe features, hemorrhage requiring blood transfusion, or abruption. The primary neonatal outcome included fetal or neonatal death, respiratory support beyond oxygen mask, Apgar score less than 3 at 5 minutes, neonatal seizures, or suspected sepsis. Secondary outcomes included intrapartum cesarean birth, length of stay, neonatal intensive care unit admission, respiratory distress syndrome (RDS), transient tachypnea of the newborn, and hypoglycemia. Those with a planned delivery were compared with those expectantly managed at each gestational week. Adjusted odds ratios (aORs) with 95% CIs are reported.

RESULTS

We included 1,417 participants with mild chronic hypertension; 305 (21.5%) with a new diagnosis in pregnancy and 1,112 (78.5%) with known preexisting hypertension. Groups differed by body mass index (BMI) and preexisting diabetes. In adjusted models, there was no association between planned delivery and the primary maternal or neonatal composite outcome in any gestational age week compared with expectant management. Planned delivery at 37 weeks of gestation was associated with RDS (7.9% vs 3.0%, aOR 2.70, 95% CI, 1.40-5.22), and planned delivery at 37 and 38 weeks was associated with neonatal hypoglycemia (19.4% vs 10.7%, aOR 1.97, 95% CI, 1.27-3.08 in week 37; 14.4% vs 7.7%, aOR 1.82, 95% CI, 1.06-3.10 in week 38).

CONCLUSION

Planned delivery in the early-term period compared with expectant management was not associated with a reduction in adverse maternal outcomes. However, it was associated with increased odds of some neonatal complications. Delivery timing for individuals with mild chronic hypertension should weigh maternal and neonatal outcomes in each gestational week but may be optimized by delivery at 39 weeks.

Comparison of Adverse Maternal Outcomes between Early- and Late-Onset Superimposed Preeclampsia

OBJECTIVE

Superimposed preeclampsia (SIPE), defined as preeclampsia in individuals with chronic hypertension, is one of the most common complications, accounting for 13 to 40% of pregnancies with chronic hypertension. However, there are limited data regarding maternal outcomes of early- and late-onset SIPE in individuals with chronic hypertension. We hypothesized that early-onset SIPE was associated with increased odds of adverse maternal outcomes compared with late-onset SIPE. Therefore, we aimed to compare adverse maternal outcomes between individuals with early-onset SIPE and those with late-onset SIPE.

STUDY DESIGN

This was a retrospective cohort study of pregnant individuals with SIPE who delivered at 22 weeks' gestation or greater at an academic institution. Early-onset SIPE was defined as the onset of SIPE before 34 weeks' gestation. Late-onset SIPE was defined as the onset of SIPE at or after 34 weeks' gestation. Our primary outcome was a composite of eclampsia, hemolysis, elevated liver enzymes, low platelet count (HELLP) syndrome, maternal death, placental abruption, pulmonary edema, SIPE with severe features, and thromboembolic disease. Maternal outcomes were compared between early- and late-onset SIPE. We used simple and multivariate logistic regression models to calculate crude and adjusted odds ratios (aOR) with 95% confidence intervals (95% CI).

RESULTS

Of 311 individuals, 157 (50.5%) had early-onset SIPE, 154 (49.5%) had late-onset SIPE. There were significant differences in the proportions of obstetric complications, including the primary outcome, HELLP syndrome, SIPE with severe features, fetal growth restriction (FGR), and cesarean delivery between early- and late-onset SIPE. Compared with individuals with late-onset SIPE, those with early-onset SIPE had increased odds of the primary outcome (aOR: 3.28; 95% CI: 1.42-7.59), SIPE with severe features (aOR: 2.72; 95% CI: 1.25-5.90), FGR (aOR: 6.07; 95% CI: 3.25-11.36), and cesarean delivery (aOR 3.42; 95% CI: 2.03-5.75).

CONCLUSION

Individuals with early-onset SIPE had higher odds of adverse maternal outcomes compared with those with late-onset SIPE.

KEY POINTS

· We revealed the incidence of maternal outcomes in early- and late-onset SIPE.. · Severe features were common in individuals with SIPE.. · Early-onset SIPE was associated with increased adverse maternal outcomes compared with late-onset SIPE..

Immediate delivery versus expectant management in women with chronic hypertension: a meta-analysis of randomized controlled trials

INTRODUCTION

The current guidelines regarding chronic hypertension during pregnancy recommend induction of labor at term. The only previous meta-analysis on this topic found two randomized controlled trials but failed to pool together their results. We aimed to find the best literature-based evidence regarding delivery timing in chronic hypertension during pregnancy.

EVIDENCE ACQUISITION

We searched the following electronic databases: MEDLINE, EMBASE, Scopus, ClinicalTrials.gov, the PROSPERO International Prospective Register of Systematic Reviews, and the Cochrane Central Register of Controlled Trials, Google Scholar. We selected randomized controlled trials comparing expectant management versus immediate delivery. The search was performed by two authors and the conflicts resolved in meetings. Data collection and analysis: we collected maternal and neonatal outcomes in a metanalysis following the random-effects model.

EVIDENCE SYNTHESIS

Two studies were found. The summary effect measure was 1.1 (C.I. 0.51-2.1) regarding the maternal outcomes, 2.6 (C.I. 0.91-7.44) regarding the neonatal outcomes, and 1.5 (C.I. 0.8-2.79) combined. There was no statistically significant difference between maternal and neonatal outcomes (P=0.2).

CONCLUSIONS

The results of our meta-analysis pointed towards a non-difference between immediate delivery and expectant management, in women with chronic hypertension.

The optimal gestational age to deliver patients with chronic hypertension on antihypertensive therapy

OBJECTIVE

To identify the optimal gestational age of planned delivery in pregnancies complicated by chronic hypertension requiring antihypertensive medications that minimizes the risk of adverse perinatal events and maternal morbidity.

METHODS

Retrospective cohort study of singleton pregnancies after 37 weeks of gestation complicated by chronic hypertension on antihypertensive medication, delivered at 7 hospitals within an academic health system in New York from 12/1/2015 to 9/3/2020. Two comparisons were made (1) planned deliveries at 37-37^6/7weeks versus expectant management, (2) planned deliveries at 38-38^6/7weeks versus expectant management. Patients with other maternal or fetal conditions were excluded. The primary outcome was a composite of adverse perinatal outcomes including stillbirth, neonatal death, assisted ventilation, cord pH < 7.0, 5-minute Apgar ≤5, diagnosis of respiratory disorder, and neonatal seizures. The secondary outcomes included preeclampsia, eclampsia, primary cesarean delivery, postpartum readmission, and infant stay greater than 5 days. Odds ratios were estimated with multiple logistic regression and adjusted for confounding effects.

RESULTS

A total of 555 patients met inclusion criteria. Patients who underwent planned delivery at 37 weeks compared to expectant management did not appear to be at higher risk of adverse perinatal outcomes (14.9% vs 10.4%, aOR 1.49, 95% CI: 0.77-2.88). Similarly, we did not find a difference in the primary outcome in patients who underwent planned delivery at 38 weeks versus those expectantly managed (9.7% vs 10.1%, (aOR 0.84, 95% CI: 0.39-1.76). There were no differences in the rates of primary cesarean or preeclampsia at 37 and 38 weeks.

CONCLUSION

Our findings suggest that there is no difference in neonatal or maternal outcomes for chronic hypertensive patients on medication if delivery is planned or expectantly managed at 37 or 38 weeks' gestation.

Hypertensive disorders of pregnancy

Hypertensive disorders of pregnancy (HDP) are one of the most commonly occurring complications of pregnancy and include chronic hypertension, gestational hypertension, and pre-eclampsia. New developments in early pregnancy screening to identify women at high risk for pre-eclampsia combined with targeted aspirin prophylaxis could greatly reduce the number of affected pregnancies. Furthermore, recent advances in the diagnosis of pre-eclampsia, such as placental growth factor based testing, have been shown to improve the identification of those pregnancies at highest risk of severe complications. Evidence from trials has refined the target blood pressure and timing of delivery to manage chronic hypertension and pre-eclampsia with non-severe features, respectively. Importantly, a wealth of epidemiological data now links HDP to future cardiovascular disease and diabetes decades after an affected pregnancy. This review discusses the current guidelines and research data on the prevention, diagnosis, management, and postnatal follow-up of HDP. It also discusses the gap in knowledge regarding the long term risks for cardiovascular disease following HDP and illustrates the importance of improving adherence to postnatal guidelines to monitor hypertension and the need for more research focused on primary prevention of future cardiovascular disease in women identified as being at high risk because of HDP.

Chronic hypertension, perinatal mortality and the impact of preterm delivery: a population-based study

OBJECTIVES

To estimate the association between chronic hypertension and perinatal mortality and to evaluate the extent to which risks are impacted by preterm delivery.

DESIGN

Cross-sectional analysis.

SETTING

United States, 2015-18.

POPULATION

Singleton births (20-44 weeks of gestation).

EXPOSURE

Chronic hypertension, defined as elevated blood pressure diagnosed before pregnancy or recognised before 20 weeks of gestation.

MAIN OUTCOMES AND MEASURES

We derived the risk of perinatal mortality in relation to chronic hypertension from Poisson models, adjusted for confounders. The impacts of misclassification and unmeasured confounding were assessed. Causal mediation analysis was performed to quantify the impact of preterm delivery on the association.

RESULTS

Of the 15 090 678 singleton births, perinatal mortality rates were 22.5 and 8.2 per 1000 births in chronic hypertensive and normotensive pregnancies, respectively (adjusted risk ratio 2.05, 95% CI 2.00-2.10). Corrections for exposure misclassification and unmeasured confounding biases substantially increased the risk estimate. Although causal mediation analysis revealed that most of the association of chronic hypertension on perinatal mortality was mediated through preterm delivery, the perinatal mortality rates were highest at early term, term and late term gestations, suggesting that a planned early term delivery at 37-38^6/7  weeks may optimally balance risk in these pregnancies. Additionally, 87% (95% CI 84-90%) of perinatal deaths could be eliminated if preterm deliveries, as a result of chronic hypertension, were preventable.

CONCLUSIONS

Chronic hypertension is associated with increased risk for perinatal mortality. Planned early term delivery and targeting modifiable risk factors for chronic hypertension may reduce perinatal mortality rates.

TWEETABLE ABSTRACT

Maternal chronic hypertension is associated with increased risk for perinatal mortality, largely driven by preterm birth.

Optimal timing of labour induction in contemporary clinical practice

Induction of labour (IoL) is generally conducted when maternal and foetal risks of remaining pregnant outweigh the risks of delivery. With emerging literature around non-medically indicated IoL, contemporary clinical practice has seen an increase in IoL at 39 weeks' gestation. This review highlights recent evidence on the most common indications for IoL including gestational diabetes, hypertensive disorders of pregnancy, intrahepatic cholestasis of pregnancy, and post-term pregnancies. It also summarizes the evidence related to the timing of IoL for other common conditions based on recent literature reviews.

Chronic hypertension in pregnancy: synthesis of influential guidelines

Chronic hypertension in pregnancy accounts for a substantial proportion of maternal morbidity and mortality and is associated with adverse perinatal outcomes, most of which can be mitigated by appropriate surveillance and management protocols. The aim of this study was to review and compare recommendations of published guidelines on this condition. Thus, a descriptive review of influential guidelines from the National Institute for Health and Care Excellence, the Society of Obstetric Medicine of Australia and New Zealand, the International Society of Hypertension, the International Society for the Study of Hypertension in Pregnancy, the European Society of Cardiology, the International Federation of Gynecology and Obstetrics, the Society of Obstetricians and Gynaecologists of Canada and the American College of Obstetricians and Gynecologists on chronic hypertension in pregnancy was conducted. All guidelines agree on the definition and medical management, the need for more frequent antenatal care and fetal surveillance and the re-evaluation at 6-8 weeks postpartum. There is also a consensus that the administration of low-dose aspirin is required to prevent preeclampsia, although the optimal dosage remains controversial. No universal agreement has been spotted regarding optimal treatment blood pressure (BP) targets, need for treating mild-to-moderate hypertension and postnatal BP measurements. Additionally, while the necessity of antenatal corticosteroids and magnesium sulfate for preterm delivery is universally recommended, the appropriate timing of delivery is not clearly outlined. Hence, there is a need to adopt consistent practice protocols to optimally manage these pregnancies; i.e. timely detect and treat any potential complications and subsequently reduce the associated morbidity and mortality.

Chronic hypertension in pregnancy

Chronic hypertension and associated cardiovascular disease are among the leading causes of maternal and perinatal morbidity and death in the United States. Chronic hypertension in pregnancy is associated with a host of adverse outcomes that include preeclampsia, cesarean delivery, cerebrovascular accidents, fetal growth restriction, preterm birth, and maternal and perinatal death. There are several key issues related to the diagnosis and management of chronic hypertension in pregnancy where data are limited and further research is needed. These challenges and recent guidelines for the management of chronic hypertension are reviewed. Well-timed pregnancies are of utmost importance to reduce the risks of chronic hypertension; long-acting reversible contraceptive options are preferred. Research to determine optimal blood pressure thresholds for diagnosis and treatment to optimize short- and long-term maternal and perinatal outcomes should be prioritized along with interventions to reduce extant racial and ethnic disparities.

Timing of Delivery in Women With Chronic Hypertension

OBJECTIVE

To assess whether routine induction of labor at 38 or 39 weeks in women with chronic hypertension is associated with the risk of superimposed preeclampsia or cesarean delivery.

METHODS

We conducted a retrospective population-based study of women with chronic hypertension who had a singleton hospital birth at 38 0/7 weeks of gestation of gestation in Ontario, Canada, between 2012 and 2016. Women who underwent induction of labor at 38 0/7 to 38 6/7 weeks of gestation for chronic hypertension (n=281) were compared with those who were managed expectantly during that week and remained undelivered at 39 0/7 weeks of gestation (n=1,606). Separately, women who underwent induction of labor at 39 0/7 to 39 6/7 weeks of gestation for chronic hypertension (n=259) were compared with women who remained undelivered at 40 0/7 weeks of gestation (n=801).

RESULTS

Of 534,529 women gave birth during the study period, 6,054 (1.1%) had chronic hypertension and 2,420 met the inclusion criteria. Women managed expectantly at 38 or 39 weeks of gestation were at risk of new-onset superimposed preeclampsia (19.2% [308/1,606] and 19.0% [152/801], respectively) and eclampsia (0.6% [10/1,606] and 0.7% [6/801], respectively), and more than half underwent induction of labor later in gestation (56.8% and 57.8%, respectively). The risk of cesarean delivery in the induction groups was lower (38 weeks of gestation) or similar (39 weeks of gestation) to that observed in women managed expectantly at the corresponding weeks (38 weeks of gestation: 17.1% vs 24.0%, adjusted relative risk 0.74 [95% CI 0.57-0.95]; 39 weeks of gestation: 20.1% vs 26.0%, adjusted relative risk 0.90 [95% CI 0.69-1.17]).

CONCLUSION

Our findings suggest that in women with isolated chronic hypertension, induction of labor at 38 or 39 weeks of gestation may prevent severe hypertensive complications without increasing the risk of cesarean delivery.

Out of Office Blood Pressure Measurement in Pregnancy and the Postpartum Period

PURPOSE

Hypertensive disorders of pregnancy are increasing in prevalence and associated with significant maternal and perinatal morbidity and mortality.

RECENT FINDINGS

Increased emphasis has been placed recently on the use of out-of-office (i.e., home and ambulatory) blood pressure (BP) monitoring to diagnose and manage hypertension in the general population. Current guidelines offer limited recommendations on the use of out-of-office BP monitoring during pregnancy and postpartum. This review will discuss the recent literature on BP measurement outside of the office and its use for screening, diagnosis, and treatment in pregnancy and postpartum, and will illuminate areas for future research.

Perinatal Outcomes in Women With a History of Chronic Hypertension but Normal Blood Pressures Before 20 Weeks of Gestation

OBJECTIVE

To compare the perinatal outcomes of normotensive women with those of women with a history of chronic hypertension with normal blood pressures before 20 weeks of gestation, stratifying the latter by whether they were receiving antihypertensive medication.

METHODS

We conducted a retrospective cohort study of all singletons with a history of chronic hypertension from 2000 to 2014. Exclusions were blood pressure greater than 140/90 mm Hg before 20 weeks of gestation, fetal anomalies, major medical problems other than hypertension, and diabetes. For the same time period, a randomly selected group without a diagnosis of chronic hypertension was chosen using the same exclusion criteria. Outcomes were compared among women without chronic hypertension, women with chronic hypertension on no antihypertensive medication but with blood pressures less than 140/90 mm Hg before 20 weeks of gestation, and women with chronic hypertension on antihypertensive medication with blood pressures less than 140/90 mm Hg before 20 weeks of gestation. The primary outcome was a perinatal composite of stillbirth, neonatal death, respiratory support at birth, arterial cord pH less than 7, 5-minute Apgar score 3 or less, and seizures. Secondary outcomes assessed were preterm birth before 37 and 34 weeks of gestation, small for gestational age, and preeclampsia.

RESULTS

Of 830 women with chronic hypertension and blood pressures less than 140/90 mm Hg before 20 weeks of gestation, 212 (26%) were not taking antihypertensive medication and 618 (74%) were. These groups were compared with 476 women without chronic hypertension. Women with hypertension were more likely to be older and have baseline renal disease and diabetes compared with women in the no hypertension group. The perinatal composite was more common in both hypertensive groups: no antihypertensive medication (9.9%) and antihypertensive medication (14.6%) compared with women in the control group (2.9%) (adjusted odds ratio [OR] 2.9, 95% CI 1.21-6.85 no antihypertensive medications compared with no chronic hypertension; adjusted OR 5.0, 95% CI 2.38-10.54 antihypertensive medications vs no chronic hypertension). The risk of early preterm birth, small for gestational age, and preeclampsia was not significantly increased in women with chronic hypertension and no antihypertensive medications compared with women without chronic hypertension.

CONCLUSION

Despite normal baseline blood pressures without medications before 20 weeks of gestation, women with chronic hypertension are at an increased risk of adverse perinatal outcomes compared with women without.

Accuracy of Blood Pressure Measurement Devices in Pregnancy: A Systematic Review of Validation Studies

The accurate measurement of blood pressure (BP) in pregnancy is essential to guide medical decision making that affects both mother and fetus. The aim of this systematic review was to determine the accuracy of ambulatory, home, and clinic BP measurement devices in pregnant women. We searched Ovid MEDLINE, The Cochrane Library, EMBASE, CINAHL EBSCO, ClinicalTrials.gov, International Clinical Trials Registry Platform, and dabl from inception through August 3, 2017 for articles that assessed the validity of an upper arm BP measurement device against a mercury sphygmomanometer in pregnant women. Two independent investigators determined eligibility, extracted data, and adjudicated protocol violations. From 1798 potential articles identified, 41, that assessed 28 devices, met the inclusion criteria. Most articles (n=32) followed a standard or modified American National Standards Institute/Association for the Advancement of Medical Instrumentation/International Organization for Standardization, British Hypertension Society, or European Society of Hypertension validation protocol. Several articles described the results of validation studies performed on >1 device (n=7) or in >1 population of pregnant women (n=12), comprising 64 pairwise validity assessments. The device was validated in 61% (32 of 52) of studies which used a standard or modified protocol. Only 34% (11 of 32) of the studies wherein the device was successfully validated were performed without a protocol violation. Given the implications of inaccurate BP measurement in pregnant women, healthcare providers should be aware of and try to use the BP measurement devices which have been properly validated in this population.