Impact of ethnicity on adverse perinatal outcome in women with chronic hypertension: a cohort study

The Contribution of Hypertensive Disorders of Pregnancy to Neonatal Unit Admissions and Iatrogenic Preterm Delivery at < 34+0 Weeks' Gestation in the UK: A Population-Based Study Using the National Neonatal Research Database

OBJECTIVES

The objectives of this study were to (i) quantify the contribution of maternal hypertensive disorders of pregnancy (HDP) to iatrogenic preterm birth (PTB) and neonatal unit (NNU) admissions < 34+0 weeks and (ii) describe short-term population-level outcomes for HDP infants, exploring ethnic disparities and comparing outcomes by HDP exposure.

DESIGN

Retrospective population-based study using the National Neonatal Research Database.

SETTING

England and Wales.

POPULATION

Infants born < 34+0 weeks and admitted to NNU 2012-2020.

METHODS

Descriptive statistics, linear and logistic regression models to compare outcomes between groups.

MAIN OUTCOME MEASURES

Survival to discharge with/without comorbidity.

RESULTS

122 228 infants met inclusion criteria. Where collected, 49 839/114 164 (43.7%, 95% CI 43.4%-43.9%) of infants had an iatrogenic PTB. HDP was recorded in 16 510/122 228 (13.5%) of all infants and 13 560/49 839 (27.2%) of iatrogenic PTBs. HDP and/or foetal growth restriction (FGR) were recorded in 24 124/49 839 (48.4%) of iatrogenic PTBs. Singleton HDP infants < 10th BWC had ≥ 90% survival to discharge from 28 weeks' gestation, versus from 26 weeks' gestation for those born ≥ 10th BWC. In extreme preterm HDP infants (< 27 weeks), 27.3% of infants < 10th BWC died compared to 15.2% of those ≥ 10th BWC. Survival without comorbidity was ≥ 90% from 32 weeks' gestation in HDP infants across BWC.

CONCLUSIONS

These contemporaneous population-level data show that almost one in two PTB < 34+0 weeks' gestation are iatrogenic, with HDP and/or FGR being the major contributors to iatrogenic prematurity. This has substantial implications for strategies to reduce preterm birth in the UK and internationally. The data further inform antenatal and at-birth counselling of HDP-exposed infants.

Prediction of adverse maternal and perinatal outcomes associated with pre-eclampsia and hypertensive disorders of pregnancy: a systematic review and meta-analysis

Background

Hypertensive disorders of pregnancy are a leading cause of maternal and perinatal morbidity and mortality. If women at high risk for developing complications could be identified early, level of care could be triaged, limited resources could be correctly allocated and targeted interventions to prevent complications could be implemented.

Methods

We updated a systematic review and meta-analysis and added single outcomes. Women with hypertensive disorders of pregnancy were included. Exposures were tests predicting adverse maternal and/or perinatal outcomes. We searched Medline, Embase, CINAHL, and Cochrane library from January 2016-February 2024. We included studies identified from the previous review. We calculated effect measures. For similar predictive tests and outcomes, area under the receiver-operating-characteristic curve (AUROC) were pooled. This study was registered by PROSPERO: CRD42022336368.

Findings

Of the 2898 studies identified, 80 were included. Thirty were added from the previous review resulting in 110 included studies with 506,178 women. Despite more than 1500 tests being performed, most outcomes could not be pooled due to heterogeneity in populations, tests, and outcome definitions. For maternal outcomes, only studies reporting on the Pre-eclampsia Integrated Estimate of RiSk (fullPIERS) model could be pooled. For the composite outcome within 48-h the AUROC was 0.78 (95% CI 0.71-0.86, N = 8). There was significant heterogeneity (I 2  = 95.7%). For perinatal outcomes, data were pooled for pulsatility index in the umbilical artery and soluble FMS-like tyrosine kinase-1 (sFlt-1)/placental growth factor (PlGF) ratio. Biomarkers like the sFlt-1/PlGF ratio showed promising predictive performance for some outcomes but were not externally validated.

Interpretation

Despite including over 100 studies with more than 1500 predictors, we were unable to pool any single maternal outcomes and only a few individual perinatal outcomes. The fullPIERS model was externally validated, showing moderate accuracy which varied across studies and should be validated in each new population. Angiogenic biomarkers showed promise but need validation. Future studies should use standardized outcome measures and validate promising tests.

Funding

VB is supported by the Swedish Research Council, Grant number 2020-01481. University of Gothenburg.

The contribution of hypertensive disorders of pregnancy to late preterm and term admissions to neonatal units in the UK 2012-2020 and opportunities to avoid admission: A population-based study using the National Neonatal Research Database

OBJECTIVE

To quantify maternal hypertensive disorder of pregnancy (HDP) prevalence in late preterm and term infants admitted to neonatal units (NNU) and assess opportunities to avoid admissions.

DESIGN

A retrospective population-based study using the National Neonatal Research Database.

SETTING

England and Wales.

POPULATION

Infants born ≥34 weeks' gestation admitted to NNU between 2012 and 2020.

METHODS

Outcomes in HDP infants are compared with non-HDP infants using regression models.

MAIN OUTCOME MEASURES

Hypertensive disorder of pregnancy, primary reason for admission, clinical diagnoses and resource use.

RESULTS

16 059/136 220 (11.8%) of late preterm (34+0 to 36+6 weeks' gestation) and 14 885/284 646 (5.2%) of term (≥37 weeks' gestation) admitted infants were exposed to maternal HDP. The most common primary reasons for HDP infant admission were respiratory disease (28.3%), prematurity (22.7%) and hypoglycaemia (16.4%). HDP infants were more likely to be admitted with primary hypoglycaemia than were non-HDP infants (odds ratio [OR] 2.1, 95% confidence interval [CI] 2.0-2.2, P < 0.0001). 64.5% of HDP infants received i.v. dextrose. 35.7% received mechanical or non-invasive ventilation. 8260/30 944 (26.7%) of HDP infants received intervention for hypoglycaemia alone (i.v. dextrose) with no other major intervention (respiratory support, parenteral nutrition, central line, arterial line or blood transfusion).

CONCLUSIONS

The burden of maternal HDP on late preterm and term admissions to NNU is high, with hypoglycaemia and respiratory disease being the main drivers for admission. Over one in four were admitted solely for management of hypoglycaemia. Further research should determine whether maternal antihypertensive agent choice or postnatal pathways may reduce NNU admission.

Stillbirth risk and smallness for gestational age according to Hadlock, INTERGROWTH-21st, WHO, and GROW fetal weight standards: analysis by maternal ethnicity and body mass index

BACKGROUND

Appropriate growth charts are essential for fetal surveillance, to confirm that growth is proceeding normally and to identify pregnancies that are at risk. Many stillbirths are avoidable through antenatal detection of the small-for-gestational-age fetus. In the absence of an international consensus on which growth chart to use, it is essential that clinical practice reflects outcome-based evidence.

OBJECTIVE

This study investigated the performance of 4 internationally used fetal weight standards and their ability to identify stillbirth risk in different ethnic and maternal size groups of a heterogeneous population.

STUDY DESIGN

We analyzed routinely collected maternity data from more than 2.2 million pregnancies. Three population-based fetal weight standards (Hadlock, Intergrowth-21st, and World Health Organization) were compared with the customized GROW standard that was adjusted for maternal height, weight, parity, and ethnic origin. Small-for-gestational-age birthweight and stillbirth risk were determined for the 2 largest ethnic groups in our population (British European and South Asian), in 5 body mass index categories, and in 4 maternal size groups with normal body mass index (18.5-25.0 kg/m2). The differences in trend between stillbirth and small-for-gestational-age rates were assessed using the Clogg z test, and differences between stillbirths and body mass index groups were assessed using the chi-square trend test.

RESULTS

Stillbirth rates (per 1000) were higher in South Asian pregnancies (5.51) than British-European pregnancies (3.89) (P<.01) and increased in both groups with increasing body mass index (P<.01). Small-for-gestational-age rates were 2 to 3-fold higher for South Asian babies than British European babies according to the population-average standards (Hadlock: 26.2% vs 12.2%; Intergrowth-21st: 12.1% vs 4.9%; World Health Organization: 32.2% vs 16.0%) but were similar by the customized GROW standard (14.0% vs 13.6%). Despite the wide variation, each standard's small-for-gestation-age cases had increased stillbirth risk compared with non-small-for-gestation-age cases, with the magnitude of risk inversely proportional to the rate of cases defined as small for gestational age. All standards had similar stillbirth risk when the small-for-gestation-age rate was fixed at 10% by varying their respective thresholds for defining small for gestational age. When analyzed across body mass index subgroups, the small-for-gestation-age rate according to the GROW standard increased with increasing stillbirth rate, whereas small-for-gestation-age rates according to Hadlock, Intergrowth-21st, and World Health Organization fetal weight standards declined with increasing body mass index, showing a difference in trend (P<.01) to stillbirth rates across body mass index groups. In the normal body mass index subgroup, stillbirth rates showed little variation across maternal size groups; this trend was followed by GROW-based small-for-gestation-age rates, whereas small-for-gestation-age rates defined by each population-average standard declined with increasing maternal size.

CONCLUSION

Comparisons between population-average and customized fetal growth charts require examination of how well each standard identifies pregnancies at risk of adverse outcomes within subgroups of any heterogeneous population. In both ethnic groups studied, increasing maternal body mass index was accompanied by increasing stillbirth risk, and this trend was reflected in more pregnancies being identified as small for gestational age only by the customized standard. In contrast, small-for-gestation-age rates fell according to each population-average standard, thereby hiding the increased stillbirth risk associated with high maternal body mass index.

Encouraging brisk walking with the free Active10 app in postnatal women who had a hypertensive pregnancy: "Just Walk It" feasibility study

OBJECTIVE

To explore the feasibility of a future trial to investigate whether encouraging use of the free NHS smartphone app Active10 increases brisk walking and reduces blood pressure (BP) in postnatal mothers who had hypertensive disorders of pregnancy (HDP).

DESIGN

3-month feasibility study.

SETTING

London maternity unit.

POPULATION

21 women with HDP.

METHODS

At recruitment we recorded initial (booking) clinic BP and asked participants to complete a questionnaire. Two months after delivery all participants were sent (by post/email/WhatsApp) a "Just Walk It" leaflet encouraging them to download the Active10 app and walk briskly for at least 10 minutes/day. This was backed by a telephone call after 2-weeks. Assessments were repeated 3-months later, and included telephone interviews about the acceptability and use of Active10.

MAIN OUTCOME MEASURES

Were recruitment rate, follow-up rate and acceptability/use of Active10.

RESULTS

Of 28 women approached, 21 (75%, 95% CI 55.1-89.3%) agreed to participate. Age range was 21-46 years and five (24%) self-identified as black ethnicity. One woman dropped out of the study, and one became ill. The remaining participants (90%, 19/21, 95% CI 69.6-98.8%) were followed up after 3-months. Ninety-five percent (18/19) downloaded the Active10 app and 74% (14/19) continued using it at 3-months, averaging 27-minutes brisk walking/day according to Active10 weekly screenshots. Comments included: "Brilliant app", "Really motivates me". Mean BP was 130/81mmHg at booking and 124/80mmHg at 3-months follow-up.

CONCLUSIONS

The Active10 app was acceptable to postnatal women after HDP and may have increased minutes of brisk walking. A future trial could explore whether this simple, low-cost intervention could reduce long-term BP in this vulnerable group.

Cross-sectional diagnostic accuracy study of self-testing for proteinuria during hypertensive pregnancies: The UDIP study

OBJECTIVE

To determine the accuracy of self-testing for proteinuria during pregnancy.

DESIGN

Diagnostic accuracy study.

SETTING

Antenatal clinics, maternity assessment units and inpatient wards at three hospital sites.

POPULATION OR SAMPLE

345 pregnant women.

METHODS

Pregnant women self-tested in-clinic for urinary protein using visually read dipsticks with samples then sent for laboratory estimation of the spot protein-creatinine ratio (PCR) (primary reference test). Secondary index tests included testing by antenatal healthcare professionals and an automated colorimetric reader.

MAIN OUTCOME MEASURES

Sensitivity, specificity, negative predictive value, positive predictive value and likelihood ratios were calculated for self-testing (primary index test) along with healthcare professional and colorimetric testing compared to the primary reference test (PCR).

RESULTS

335/345 (97%) had sufficient data to be included in the analysis. Self-testing had a sensitivity of 0.71 (95% confidence interval [CI] 0.62-0.79) and a specificity of 0.89 (95% CI 0.84-0.92) compared to PCR. Sensitivity and specificity of testing by healthcare professionals and the colorimetric reader were similar: sensitivity 0.73 (95% CI 0.64-0.80) and 0.78 (95% CI 0.69-0.85), respectively; specificity 0.88 (95% CI 0.82-0.92) and 0.83 (95% CI 0.78-0.88), respectively.

CONCLUSION

Pregnant women can visually read a dipstick for urinary protein with similar accuracy to antenatal healthcare professionals. Automated colorimetric testing was not significantly different, in contrast to some previous studies. Self-testing has the potential to form part of a self-monitoring regime in pregnancy.

Detecting fetal growth restriction with customised assessment: Is the jury still out?

In this Perspective, Kate Duhig and Jenny Myers discuss strategies to improve the detection of abnormal fetal growth trajectories in the antenatal period.

Racial Disparities in Diagnosis, Management, and Outcomes in Preeclampsia

PURPOSE OF THE REVIEW

Racial disparities are prevalent in many aspects of obstetric care in the USA. Non-Hispanic black women have a higher prevalence of the diagnosis of hypertensive disorders of pregnancy in addition to associated morbidity and mortality. The purpose of this review is to review current data regarding racial disparities in the diagnosis and management of hypertensive disorders of pregnancy.

RECENT FINDINGS

Diagnosis of hypertensive disorders of pregnancy is more common among non-Hispanic black women even after adjustment for comorbidities. Furthermore, prevalence of severe morbidity among those with hypertensive disorders of pregnancy is increased in non-Hispanic black women, including cardiovascular events related. Proposed management solutions include quality improvement initiatives, telehealth, and strategies to reduce both structural racism and implicit bias. Racial disparities exist in both diagnosis and management of hypertensive disorders of pregnancy; further innovative work is needed to reduce these disparities.

Customized GROW vs INTERGROWTH-21st birthweight standards to identify small for gestational age associated perinatal outcomes at term

BACKGROUND

Fetal growth restriction is associated with stillbirth and other adverse pregnancy outcomes, and use of the correct weight standard is an essential proxy indicator of growth status and perinatal risk.

OBJECTIVE

We sought to assess the performance of two international birthweight standards for their ability to identify perinatal morbidity and mortality indicators associated with small for gestational age (SGA) infants at term.

STUDY DESIGN

This retrospective cohort study used data from a multi-center perinatal quality initiative including a multi-ethnic dataset of 125,826 births from 2012-2017. Of the singleton term births, 92,622 had complete outcome data including stillbirth, neonatal death, 5-minute Apgar <7, neonatal glucose instability and need for newborn transfer to a higher level of care or NICU admission. The customized (GROW) and INTERGROWTH-21^st (IG21) birthweight standards were applied to determine SGA (<10^th centile) according to their respective methods and formulae. Associations with adverse outcomes were expressed as relative risk (RR) with 95% confidence interval (CI) and population attributable fraction (PAF).

RESULTS

GROW classified 9,578 (10.3%) and IG21 classified 4,079 (4.4%) pregnancies as SGA, respectively. For all of the outcomes assessed, GROW identified more SGA infants with adverse outcomes than IG21, including more stillbirths, perinatal deaths, low Apgar scores, glucose instability, newborn seizure and transfers to a higher level of care. Thirteen of the 27 stillbirths (48%) that were SGA by either method were identified as SGA by GROW but not by IG21. Similarly, additional cases of all other adverse outcome indicators were identified by GROW as SGA, while only in one category (glucose instability) did IG21 identify 9 of 295 cases (3.1%) which were not identified as SGA by GROW.

CONCLUSION

Customized assessment using GROW results in increased identification of small for gestational age term babies that are at significantly increased risk of an array of adverse pregnancy outcomes.

Does the Oral Microbiome Play a Role in Hypertensive Pregnancies?

Chronic hypertension during gestation is associated with an increased risk of adverse pregnancy outcomes including pre-eclampsia, fetal growth restriction and preterm birth. Research into new chemotherapeutic regimes for the treatment of hypertension in pregnancy is limited due to concerns about fetal toxicity and teratogenicity, and new therapeutic avenues are being sought in alternative physiological pathways. Historically, generation of the vasodilator nitric oxide was believed to be solely from L-arginine by means of nitric oxide synthase enzymes. Recently, a novel pathway for the reduction of dietary inorganic nitrate to nitrite by the bacteria in the oral cavity and subsequently to vasodilatory nitric oxide within the body has been uncovered. Dietary nitrate is abundant in green leafy vegetables, including beetroot and spinach, and reduction of exogenous nitrate to nitrite by oral bacteria can increase nitric oxide in the vasculature, lessening hypertension. Supplements rich in nitrate may be an attractive choice for treatment due to fewer side effects than drugs that are currently used to treat hypertensive pregnancy disorders. Additionally, manipulation of the composition of the oral microbiota using pro- and prebiotics in tandem with additional dietary interventions to promote cardiovascular health during gestation may offer a safe and effective means of treating hypertensive pregnancy disorders including gestational hypertension and pre-eclampsia. The use of dietary inorganic nitrate as a supplement during pregnancy requires further exploration and large scale studies before it may be considered as part of a treatment regime. The aim of this article is to review the current evidence that oral microbiota plays a role in hypertensive pregnancies and whether it could be manipulated to improve patient outcomes.

Effect of blood pressure control in early pregnancy and clinical outcomes in African American women with chronic hypertension

OBJECTIVE

Chronic hypertension (cHTN) affects 3-5% of all pregnancies and is twice as prevalent in African American (AA) women. AA women develop more severe HTN at an earlier onset and have higher rates of adverse pregnancy outcomes. Blood pressure control during pregnancy is controversial.

STUDY DESIGN

This retrospective cohort included AA women with cHTN and singleton pregnancies delivering between January 2013 and December 2016. Patients were classified as not receiving antihypertensives in the first 20 weeks (Group A), on antihypertensives in the first 20 weeks but with an average BP <140/90 during pregnancy (Group B) and on antihypertensives in the first 20 weeks but with average BP during pregnancy ≥140/90 (Group C). Adverse outcomes including severe HTN and preterm delivery <35 weeks was compared between groups.

RESULTS

Of the 198 patients included, 68 received at least one AHT before 20 weeks including 45 patients with average BP <140/90 and 23 with average BP ≥140/90 during pregnancy. The incidence of superimposed PE and preterm birth was significantly higher among women with elevated BPs on AHT (39.1% vs 8.9% vs 17.7%, p = 0.01; preterm birth 52.2%, 8.9% and 9.2%, p < 0.001 for Groups C, B and A, respectively). A significantly higher proportion of adverse neonatal outcomes were observed in Group C (78.3%) as opposed to those in Group B (53.3%) or Group A (50.0%; p = 0.04).

CONCLUSIONS

Among AA women with cHTN, use of antihypertensives prior to 20 weeks and lower antenatal BP was associated with a decreased risk of adverse maternal and neonatal outcomes.

Postnatal care following hypertensive disorders of pregnancy: a qualitative study of views and experiences of primary and secondary care clinicians

OBJECTIVES

To explore clinicians' views and experiences of caring for postnatal women who had hypertensive disorders of pregnancy (HDP), awareness of relevant National Institute for Health and Care Excellence (NICE) guidance to inform their postnatal management, the extent to which NICE guidance was implemented, barriers and facilitators to implementation and how care could be enhanced to support women's future health.

DESIGN

A qualitative study using semistructured interviews. Thematic analysis was used for coding and theme generation.

SETTING

Four National Health Service maternity units and three general practice clinics in South-East and South-West London.

PARTICIPANTS

A maximum variation, purposive sample of 20 clinicians with experience of providing postnatal care to women following HDP.

RESULTS

Four main themes were generated: variation in knowledge and clinical practice; communication and education; provision of care; locus of responsibility for care. Perceived barriers to implementation of NICE guidance included lack of postnatal care plans and pathways, poor continuity of care, poor antihypertensive medication management, uncertainty around responsibility for postnatal care and women's lack of awareness of the importance of postnatal follow-up for their future health. Some clinicians considered that women were discharged from inpatient care too soon, as primary care clinicians did not have specialist knowledge of HDP management. Most clinicians acknowledged the need for better planning, communication and coordination of care across health settings.

CONCLUSIONS

Evidence of longer term consequences for women's health following HDP is accumulating, with potential for NICE guidance to support better outcomes for women if implemented. Clinicians responsible for postnatal care following HDP should ensure that they are familiar with relevant NICE guidance, able to implement recommendations and involve women in decisions about ongoing care and why this is important. The continued low priority and resources allocated to postnatal services will continue to promote missed opportunities to improve outcomes for women, their infants and families.

Hypertension during pregnancy and risk of stillbirth: challenges in a developing country

Objective: To explore the factors associated with hypertensive disorders of pregnancy (HDP) in women experiencing stillbirth (SB).Material and methods: It was an observational, analytical case-control study, done as part of the World Health Organization South-East Asian Region Office SB project. The epidemiological profile, history, clinical features, and investigations of stillborn cases having HDP were noted, an equal number of age and parity matched subjects with HDP having livebirth were taken as controls.Results: Out of 46,816 deliveries, 1239 (26.2/1000) were stillborn. The maternal causes contributed 374/1239 (30.2%) stillbirths according to the CODAC classification, HDP was the most common maternal cause (304/1239, 24.9%). Subjects with HDP were included as cases. On comparing the cases with controls it was found that significantly more number of cases had inadequate antenatal visits (p < .001, OR -4.8), two or more abortions (p < .001, OR -1.9), early onset of hypertension (p < .0001, OR -5.6) and complications such as fetal growth restriction (FGR) (p < .001, OR -2.3) and abruption (p < .001, OR -4.0). Women with preeclampsia were less likely to have SB compared to those with gestational or chronic hypertension (p = .0001, OR -2.3). The birth weight/placental weight ratio of more than eight had the highest odds ratio regarding contribution to SB among hypertensive women (p = .0001 OR -6.7).Conclusion: In women with HDP, adequate antenatal care would lead to the prevention of complications such as anemia, abruption, and FGR, and thus prevent SB. The high BW/PW ratio is a potential marker of risk of SB.