Trends and outcomes for deliveries with hypertensive disorders of pregnancy from 2000 to 2018: A repeated cross-sectional study

Using machine learning to predict the risk of developing hypertensive disorders of pregnancy using a contemporary nulliparous cohort

Background

Hypertensive disorders of pregnancy (HDP) are significant drivers of maternal and neonatal morbidity and mortality. Current management strategies include early identification and initiation of risk mitigating interventions facilitated by a rules-based checklist. Advanced analytic techniques, such as machine learning, can potentially offer improved and refined predictive capabilities.

Objective

To develop and internally validate a machine learning prediction model for hypertensive disorders of pregnancy (HDP) when initiating prenatal care.

Study Design

We developed a prediction model using data from the prospective multisite cohort Nulliparous Pregnancy Outcomes Study: Monitoring Mothers-to-Be (nuMoM2b) among low-risk individuals without a prior history of aspirin utilization for preeclampsia prevention. The primary outcome was the development of HDP. Random forest modeling was utilized to develop predictive models. Recursive feature elimination (RFE) was employed to create a reduced model for each outcome. Area under the curve (AUC), 95% confidence intervals (CI), and calibration curves were utilized to assess discrimination and accuracy. Sensitivity analyses were conducted to compare the sensitivity and specificity of the reduced model compared to existing risk factor-based algorithms.

Results

Of 9,124 assessed low risk nulliparous individuals, 21% (n=1,927) developed HDP. The prediction model for HDP had satisfactory discrimination with an AUC of 0.73 (95% CI: 0.70, 0.75). After RFE, a parsimonious reduced model with 30 features was created with an AUC of 0.71 (95% CI: 0.68, 0.74). Variables included in the model after RFE included body mass index at the first study visit, pre-pregnancy weight, first trimester complete blood count results, and maximum systolic blood pressure at the first visit. Calibration curves for all models revealed relatively stable agreement between predicted and observed probabilities. Sensitivity analysis noted superior sensitivity (AUC 0.80 vs 0.65) and specificity (0.65 vs 0.53) of the model compared to traditional risk factor-based algorithms.

Conclusion

In cohort of low-risk nulliparous pregnant individuals, a prediction model may accurately predict HDP diagnosis at the time of initiating prenatal care and aid employment of close interval monitoring and prophylactic measures earlier in pregnancy.

Ambient air pollutants exposure during gestation and incidence risk of hypertensive disorders of pregnancy or preeclampsia in China

The relationships between the exposure to ambient air pollutants during gestation and the incidence of hypertensive disorders in pregnancy (HDPs) or preeclampsia are contradictory. This prospective cohort study enrolled the participants between January 2020 and December 2021 from the Maternal and Child Health Hospital of Hubei Province, Tongji Medical College, Huazhong University of Science and Technology. The exposure to ambient air pollutants and daily temperatures were obtained from the ChinaHighAirPollutants dataset and the Big Earth Data Platform for Three Poles, respectively. Logistic regression models were used as single- and two-pollutant models. Restricted cubic splines were applied to each ambient air pollutant exposure to further evaluate the exposure-response relationships. Quantile G-computation approaches were employed to evaluate the cumulative impact of mixed ambient air pollutants on the incidence risk HDPs and preeclampsia. Among 19,325 participants (median age: 30.2 years), 1669 (8.64%) were diagnosed with HDPs and 180 (0.94%) with preeclampsia. While mostly null risk estimates were observed, exposure to PM1, PM2.5, PM10, and NO2 correlated with a decreased incidence risk for HDPs and preeclampsia during most gestational periods. Additionally, our multi-pollutant model presented that an increase by one quartile in the cumulative effect of ambient air pollutants was associated with a significantly decreased incidence risk for HDPs in the trimester before gestation and in the third trimester during gestation, as well as for preeclampsia in the third trimester during gestation. These findings warrant further investigation into the mechanisms underlying these associations.

Hypertension phenotypes and adverse pregnancy outcome-related office and ambulatory blood pressure thresholds during pregnancy: a retrospective cohort study

Blood pressure (BP) phenotypes, as determined by the consistency between office BP (OBP) and ambulatory BP (ABP) measurements, enhance risk assessment during pregnancy. However, diagnostic criteria for hypertension in pregnancy are based on data from non-pregnant populations regarding long-term cardiovascular risks. This study aimed to identify adverse pregnancy outcomes (APOs; including maternal/fetal outcomes)-related BP thresholds to refine risk assessment in pregnant women. We analyzed 967 high-risk pregnant women who underwent simultaneous OBP and ABP measurements at an average gestational age of 29.6 ± 8.0 weeks. All hypertension phenotypes were associated with an increased risk of maternal and fetal outcomes, except white coat hypertension, which showed no association with fetal outcomes. Using an XGBoost algorithm, the receiver operating characteristic (ROC) curve-derived daytime diastolic BP (DBP) thresholds of 81.5 mmHg for maternal and 82.5 mmHg for fetal outcomes were identified as the BP parameters most strongly linked to APOs. Incorporating these thresholds into the BP phenotype-based model improved the area under the curve for APOs and the net reclassification index for maternal and fetal outcomes. Decision curve analysis demonstrated a consistent positive net benefit after incorporating BP thresholds into the phenotype-based model for maternal and composite outcomes. In conclusion, in a Chinese pregnancy cohort, we identified daytime DBP as the most influential parameter for APOs, significantly enhancing the predictive performance of BP phenotype-based models. This study underscores the importance of ABP monitoring in high-risk pregnancies and the need for further research to establish optimal BP monitoring criteria for pregnancy.

Peripartum cardiomyopathy delivery hospitalization and postpartum readmission trends, risk factors, and outcomes

OBJECTIVE

To evaluate risk for peripartum cardiomyopathy during delivery and postpartum hospitalizations, and analyze associated trends, risk factors, and clinical outcomes.

METHODS

The 2010-2020 Nationwide Readmissions Database was used for this retrospective cohort study. Delivery hospitalizations along with postpartum readmissions occurring within five months of delivery discharge were analyzed. Risk factors associated with peripartum cardiomyopathy were analyzed with unadjusted and adjusted logistic regression models with odds ratios as measures of effect. Risk for severe adverse outcomes associated with peripartum cardiomyopathy was analyzed. Trends were analyzed with joinpoint regression.

RESULTS

Of 39,790,772 delivery hospitalizations identified, 9,210 were complicated by a diagnosis of peripartum cardiomyopathy (2.3 per 10,000). Risk for a 5-month readmission with a peripartum cardiomyopathy diagnosis was 4.8 per 10,000. Factors associated with peripartum cardiomyopathy during deliveries included preeclampsia with severe features (OR 18.9, 95 % CI 17.2, 20.7), preeclampsia without severe features (OR 6.9, 95 % CI 6.1, 7.8), multiple gestation (OR 4.7, 95 % CI 4.1, 5.3), chronic hypertension (OR 10.1, 95 % CI 8.9, 11.3), and older maternal age. Associations were attenuated but retained significance in adjusted models. Similar estimates were found when evaluating associations with postpartum readmissions. Peripartum cardiomyopathy readmissions were associated with 10 % of overall postpartum deaths, 21 % of cardiac arrest/ventricular fibrillation diagnoses, 18 % of extracorporeal membrane oxygenation cases, and 40 % of cardiogenic shock. In joinpoint analysis, peripartum cardiomyopathy increased significantly during delivery hospitalizations (average annual percent change [AAPC] 2.2 %, 95 % CI 1.0 %, 3.4 %) but not postpartum readmissions (AAPC 0.0 %, 95 % CI -1.6 %, 1.6 %).

CONCLUSION

Risk for peripartum cardiomyopathy increased during delivery hospitalizations over the study period. Obstetric conditions such as preeclampsia and chronic medical conditions that are increasing in prevalence in the obstetric population were associated with the highest odds of peripartum cardiomyopathy.

Association of Elevated Serum Aldosterone Concentrations in Pregnancy with Hypertension

Emerging evidence indicates a previously unrecognized, clinically relevant spectrum of abnormal aldosterone secretion associated with hypertension severity. It is not known whether excess aldosterone secretion contributes to hypertension during pregnancy. We quantified aldosterone concentrations and angiotensin peptides in serum (using liquid chromatography with tandem mass spectrometry) in a cohort of 128 pregnant women recruited from a high-risk obstetrics clinic and followed prospectively for the development of gestational hypertension, pre-eclampsia, superimposed pre-eclampsia, chronic hypertension, or remaining normotensive. The cohort was grouped by quartile of aldosterone concentration in serum measured in the first trimester, and blood pressure, angiotensin peptides, and hypertension outcomes compared across the four quartiles. Blood pressures and body mass index were greatest in the top and bottom quartiles, with the top quartile having the highest blood pressure throughout pregnancy. Further stratification of the top quartile based on increasing (13 patients) or decreasing (19 patients) renin activity over gestation revealed that the latter group was characterized by the highest prevalence of chronic hypertension, use of anti-hypertensive agents, pre-term birth, and intrauterine growth restriction. Serum aldosterone concentrations greater than 704 pmol/L, the 75th percentile defined within the cohort, were evident across all categories of hypertension in pregnancy, including normotensive. These findings suggest that aldosterone excess may underlie the development of hypertension in pregnancy in a significant subpopulation of individuals.

Young women were associated with higher risk of hypertensive disorders of pregnancy and cesarean section from hormone replaced cycles in frozen-thawed embryo transfer: a retrospective study of 5316 singleton deliveries

Background

The utilization of frozen-thawed embryo transfer (FET) cycles has been linked to heightened risks of adverse perinatal outcomes. However, the potential association between adverse perinatal outcomes and distinct endometrial preparation regimens remains unclear. Therefore, we aim to investigate the maternal and neonatal outcomes after hormone replacement treatment (HRT) cycles, natural cycles (NC) and HRT cycles with pretreatment using GnRHa (HRT + GnRHa) for ovulatory women undergoing FET cycles.

Methods

A large sample retrospective cohort study was carried out from 2016 to 2020. The data included a total of 5316 women who had singleton deliveries undergoing FET cycles and which were divided into three groups based on different endometrial preparation protocols: 4399 patients in HRT groups, 621 in GnRHa+HRT groups, 296 in NC groups. The outcomes consisted of maternal outcomes (cesarean section, hypertensive disorders of pregnancy (HDP), placenta previa, gestational diabetes mellitus (GDM));and neonatal outcomes (preterm birth, newborn birthweight, low birthweight, small for gestational age (SGA), macrosomia, large for gestational age (LGA), fetal malformation).

Results

After adjusting for a series of confounding variables, we found an increased risk of HDP (aOR=3.362; 95%CI, 1.059-10.675) and cesarean section (aOR=1.838; 95%CI, 1.333-2.535) in HRT cycles compared with NC, especially for ovulatory women under 35 years old. However, in all three groups, newborn birth weight was not significantly different. Meanwhile, perinatal outcomes did not differ significantly in terms of perinatal outcomes in HRT +GnRHa cycles compared with HRT cycles solely.

Conclusion

During FET cycles, singletons from HRT were related to higher risks of HDP and cesarean section, particularly for young women. GnRHa pretreatment didn't bring any benefit to perinatal outcomes compared with HRT cycles alone. Therefore, the natural cycle may be a more appropriate and safer option for young ovulatory women.

Activation of the Renin-Angiotensin-Aldosterone System Is Attenuated in Hypertensive Compared with Normotensive Pregnancy

Hypertension during pregnancy increases the risk of adverse maternal and fetal outcomes, but the mechanisms of pregnancy hypertension are not precisely understood. Elevated plasma renin activity and aldosterone concentrations play an important role in the normal physiologic adaptation to pregnancy. These effectors are reduced in patients with pregnancy hypertension, creating an opportunity to define the features of the renin-angiotensin-aldosterone system (RAAS) that are characteristic of this disorder. In the current study, we used a novel LC-MS/MS-based methodology to develop comprehensive profiles of RAAS peptides and effectors over gestation in a cohort of 74 pregnant women followed prospectively for the development of gestational hypertension and pre-eclampsia (HYP, 27 patients) versus those remaining normotensive (NT, 47 patients). In NT pregnancy, the plasma renin activity surrogate, (PRA-S, calculated from the sum of Angiotensin I + Angiotensin II) and aldosterone concentrations significantly increased from the first to the third trimester, accompanied by a modest increase in the concentrations of angiotensin peptide metabolites. In contrast, in HYP pregnancies, PRA-S and angiotensin peptides were largely unchanged over gestation, and third-trimester aldosterone concentrations were significantly lower compared with those in NT pregnancies. The results indicated that the predominant features of pregnancies that develop HYP are stalled or waning activation of the RAAS in the second half of pregnancy (accompanied by unchanging levels of angiotensin peptides) and the attenuated secretion of aldosterone.

Novel therapeutic and diagnostic approaches for preeclampsia

PURPOSE OF REVIEW

This review will summarize recent findings relating to the diagnostic approach to preeclampsia and current avenues of research aimed at modifying the underlying disease process.

RECENT FINDINGS

Growing international consensus supports a broad preeclampsia definition that incorporates maternal end-organ and uteroplacental dysfunction. Recent evidence demonstrates that this definition better identifies women and babies at risk of adverse outcomes compared to the traditional definition of hypertension and proteinuria. Multiple studies have demonstrated the usefulness and cost-effectiveness of angiogenic biomarkers such as soluble fms-like tyrosine kinase-1 and placental growth factor as a clinical adjunct to diagnose and predict severity of preeclampsia associated outcomes. Current novel therapeutic approaches to preeclampsia target pathogenic pathways (e.g. antiangiogenesis) or downstream effects such as oxidative stress and nitric oxide. Recent findings relating to these promising candidates are discussed. Multicenter clinical trials are needed to evaluate their effectiveness and ability to improve fetal and maternal outcomes.

SUMMARY

We provide an updated framework of the current approaches to define and diagnose preeclampsia. Disease modifying therapies (in particular, targeting the angiogenic pathway) are being developed for the first time and promise to revolutionize the way we manage preeclampsia.

Postpartum stroke trends, risk factors, and associated adverse outcomes

BACKGROUND

Management of postpartum stroke has been the focus of several quality improvement efforts in the past decade. However, there is little recent national trends data for postpartum stroke readmissions.

OBJECTIVE

This study aimed to determine trends, risk factors, and complications associated with postpartum stroke readmission.

STUDY DESIGN

The 2013 to 2019 Nationwide Readmissions Database was used to perform a retrospective cohort study that evaluated the risk for readmission for stroke within 60 days of delivery hospitalization discharge. Temporal trends in readmissions were analyzed using the National Cancer Institute's Joinpoint Regression Program to estimate the average annual percent change with 95% confidence intervals. Stratified trends were analyzed for hemorrhage stroke, ischemic stroke, and stroke readmissions at 1 to 10, 11 to 30, and 31 to 60 days after delivery discharge. Risk factors for stroke were analyzed using unadjusted and adjusted logistic regression models with odds ratios and 95% confidence intervals as measures of association. The risk for stroke complications, including mechanical ventilation, seizures, death, and a prolonged stay ≥14 days, was analyzed.

RESULTS

Of an estimated 21,754,603 delivery hospitalizations, 5006 were complicated by a 60-day postpartum readmission with a diagnosis of stroke. The average annual percent change for all stroke readmissions over the study period was not significant (average annual percent change, 0.1%; 95% confidence interval, -2.2% to 2.4%). When the trends in readmission for ischemic and hemorrhagic stroke were analyzed, the results were similar, as were the stratified analyses by readmission timing. Risk factors associated with increased odds included superimposed preeclampsia (odds ratio, 4.8; 95% confidence interval, 3.9-5.9), preeclampsia with severe features (odds ratio, 3.7; 95% confidence interval, 3.0-4.4), maternal cardiac disease (odds ratio, 3.0; 95% confidence interval, 2.5-3.7), chronic kidney disease (odds ratio, 5.0; 95% confidence interval, 3.4-7.5), and lupus (odds ratio, 7.0; 95% confidence interval, 4.9-10.2). Risk was retained in adjusted analyses. Common stroke-related complications included a prolonged hospital stay ≥14 days (12.1 per 1000 stroke-related readmissions), seizures (9.9 per 1000 stroke-related readmissions), and mechanical ventilation (6.6 per 1000 stroke-related readmissions).

CONCLUSION

This analysis of nationally representative data demonstrated no change in the rate of 60-day postpartum hospitalizations for stroke from 2013 to 2019. Further clinical research is indicated to optimize risk reduction for stroke after delivery hospitalization discharge.

Association between programmed frozen embryo transfer and hypertensive disorders of pregnancy

Dissociation of embryo transfer from the ovarian stimulation cycle has afforded patients increased flexibility for genetic testing and fertility preservation. Although frozen embryo transfer (FET) has largely been demonstrated to be safe and effective compared with fresh transfer, programmed FET cycles, where a corpus luteum is absent, have come under increasing scrutiny. In observational trials, programmed FET protocols appear to be associated with an increased risk of ineffective decidualization and impaired placental function. Together with the appropriate preexisting risk factors, this additive risk may potentiate hypertensive disorders of pregnancy later in gestation. Efforts to understand the reasons for this apparent risk may afford us opportunities to better individualize the FET cycle type offered to patients with cryopreserved embryos. Randomized controlled trials will help us to understand whether the apparent risk is due to patient factors, which influence protocol choice, or a characteristic of the protocol itself, such as the absence of the corpus luteum or suboptimal replacement of estradiol and progesterone.