Ethnic differences in blood pressure from early pregnancy to postpartum: a Norwegian cohort study

Prospective validation of a mobile health application for blood pressure management in patients with hypertensive disorders of pregnancy: study protocol for a randomized controlled trial

BACKGROUND

Hypertensive disorders of pregnancy (HDP) pose significant risks to both maternal and fetal health, contributing to global morbidity and mortality. Management of HDP is complex, particularly because of concerns regarding potential negative effects on utero-placental circulation and limited therapeutic options due to fetal safety. Our study investigates whether blood pressure monitoring through a mobile health (mHealth) application can aid in addressing the challenges of blood pressure management in pregnant individuals with HDP. Additionally, we aim to assess whether this intervention can improve short-term maternal and fetal outcomes and potentially mitigate long-term cardiovascular consequences.

METHODS

This prospective, randomized, single-center trial will include 580 pregnant participants who meet the HDP criteria or who have a heightened risk of pregnancy-related hypertension due to factors such as multiple pregnancies, obesity, diabetes, or a history of HDP in prior pregnancies leading to preterm birth. Participants will be randomized to either the mHealth intervention group or the standard care group. The primary endpoint is the difference in systolic blood pressure from enrollment to 1 month after childbirth. The secondary endpoints include various blood pressure parameters, obstetric outcomes, body mass index trajectory, step counts, mood assessment, and drug adherence.

CONCLUSIONS

This study emphasizes the potential of mHealth interventions, such as the Heart4U application, to improve blood pressure management in pregnant individuals with HDP. By leveraging technology to enhance engagement, communication, and monitoring, this study aims to positively impact maternal, fetal, and postpartum outcomes associated with HDP. This innovative approach demonstrates the potential of personalized technology-driven solutions for managing complex health conditions.

TRIAL REGISTRATION

ClinicalTrials.gov NCT05995106. Registered on 16 August 2023.

Epigenome-wide association study of DNA methylation in maternal blood leukocytes with BMI in pregnancy and gestational weight gain

OBJECTIVES

We aimed to discover CpG sites with differential DNA methylation in peripheral blood leukocytes associated with body mass index (BMI) in pregnancy and gestational weight gain (GWG) in women of European and South Asian ancestry. Furthermore, we aimed to investigate how the identified sites were associated with methylation quantitative trait loci, gene ontology, and cardiometabolic parameters.

METHODS

In the Epigenetics in pregnancy (EPIPREG) sample we quantified maternal DNA methylation in peripheral blood leukocytes in gestational week 28 with Illumina's MethylationEPIC BeadChip. In women with European (n = 303) and South Asian (n = 164) ancestry, we performed an epigenome-wide association study of BMI in gestational week 28 and GWG between gestational weeks 15 and 28 using a meta-analysis approach. Replication was performed in the Norwegian Mother, Father, and Child Cohort Study, the Study of Assisted Reproductive Technologies (MoBa-START) (n = 877, mainly European/Norwegian).

RESULTS

We identified one CpG site significantly associated with GWG (p 5.8 × 10-8) and five CpG sites associated with BMI at gestational week 28 (p from 4.0 × 10-8 to 2.1 × 10-10). Of these, we were able to replicate three in MoBa-START; cg02786370, cg19758958 and cg10472537. Two sites are located in genes previously associated with blood pressure and BMI. DNA methylation at the three replicated CpG sites were associated with levels of blood pressure, lipids and glucose in EPIPREG (p from 1.2 × 10-8 to 0.04).

CONCLUSIONS

We identified five CpG sites associated with BMI at gestational week 28, and one with GWG. Three of the sites were replicated in an independent cohort. Several genetic variants were associated with DNA methylation at cg02786379 and cg16733643 suggesting a genetic component influencing differential methylation. The identified CpG sites were associated with cardiometabolic traits.

CLINICALTRIALS

GOV REGISTRATION NO

Not applicable.

Placental weight, surface area, shape and thickness - Relations with maternal ethnicity and cardio-metabolic factors during pregnancy

INTRODUCTION

A better understanding of the determinants of placental growth is needed. Our primary aim was to explore associations between maternal ethnic origin and cardio-metabolic factors during pregnancy, and placental weight, surface area, shape and thickness.

METHODS

A multi-ethnic population-based cohort study of 474 pregnant women examined at mean 15 and 28 weeks' gestation. Placentas were inspected after birth by a placental pathologist. Outcome measures were trimmed placental weight and three uncorrelated placental components; surface area, shape (oval vs round) and thickness, created through a principal components analysis. Multivariate linear regression models were used to explore the associations with maternal factors.

RESULTS

Compared with ethnic European women, mothers with South- and East Asian ethnicity had placentas with lower weight (-51 g (95% CI: 75, -27) and -55 g (-95, -14) respectively), primarily due to a smaller surface area. The association between South Asian ethnicity and placental surface area was still significant after adjusting for maternal characteristics and cardio-metabolic factors. Fat mass index in early pregnancy was associated with higher placental weight and thickness. Placental surface area was positively associated with mid-gestational increases in fat mass, fasting glucose and triglycerides and with the 2-h glucose value at the 28 week oral glucose tolerance test, and inversely with a mid-gestational increase in HDL-cholesterol.

DISCUSSION

Mid-gestational changes in fat mass, glucose, triglycerides and cholesterol were associated with, but only partly explained ethnic differences in placental surface area, while maternal fat mass in early pregnancy was associated with placental thickness.

Lipid and lipoprotein concentrations during pregnancy and associations with ethnicity

Background

To describe ethnic differences in concentrations of lipids and lipoproteins, and their changes, during pregnancy to postpartum.

Methods

This was a population-based cohort study conducted in primary antenatal care in Norway. The participants (n = 806) were healthy, pregnant women, 59% were ethnic minorities. Outcomes were triglycerides, total cholesterol, HDL- and LDL-cholesterol, analysed from fasting blood samples drawn at gestational age (weeks) 15, 28 and 14 weeks postpartum. We performed linear regression models and linear mixed models to explore the total effect of ethnicity on the outcomes, adjusting for gestational age /week postpartum, maternal age and education. The analyses are corrected for multiple testing using the Bonferroni correction.

Results

At gestational age 15, triglyceride concentrations were lower in women of African origin (1.03 mmol/mol (95% CI: 0.90, 1.16)) and higher in women of South Asian (primarily Pakistan and Sri Lanka) origin (1.42 mmol/mol (1.35, 1.49)) and East Asian (primarily Vietnam, Philippines and Thailand) origin (1.58 mmol/mol (1.43, 1.73)) compared with Western Europeans (1.26 mmol/mol (1.20, 1.32)). Women of Asian and African origin had a smaller increase in triglycerides, LDL- and total cholesterol from gestational age 15 to 28. At gestational age 28, LDL-cholesterol levels were lowest among East Asians (3.03 mmol/mol (2.72, 3.34)) compared with Western Europeans (3.62 mmol/mol (3.50, 3.74)). Triglycerides and HDL-cholesterol were lower postpartum than at gestational age 15 in all groups, but the concentration of LDL-cholesterol was higher, except in Africans. South and East Asian women had lower HDL-cholesterol and higher triglycerides postpartum, while African women had lower triglycerides than Western Europeans.

Conclusion

We found significant differences in the concentrations of lipids and lipoproteins and their changes during pregnancy and the early postpartum period related to ethnic origin.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12884-022-04524-2.

Cohort profile: Epigenetics in Pregnancy (EPIPREG) - population-based sample of European and South Asian pregnant women with epigenome-wide DNA methylation (850k) in peripheral blood leukocytes

Pregnancy is a valuable model to study the association between DNA methylation and several cardiometabolic traits, due to its direct potential to influence mother's and child's health. Epigenetics in Pregnancy (EPIPREG) is a population-based sample with the aim to study associations between DNA-methylation in pregnancy and cardiometabolic traits in South Asian and European pregnant women and their offspring. This cohort profile paper aims to present our sample with genetic and epigenetic data and invite researchers with similar cohorts to collaborative projects, such as replication of ours or their results and meta-analysis. In EPIPREG we have quantified epigenome-wide DNA methylation in maternal peripheral blood leukocytes in gestational week 28±1 in Europeans (n = 312) and South Asians (n = 168) that participated in the population-based cohort STORK Groruddalen, in Norway. DNA methylation was measured with Infinium MethylationEPIC BeadChip (850k sites), with technical validation of four CpG sites using bisulphite pyrosequencing in a subset (n = 30). The sample is well characterized with few missing data on e.g. genotype, universal screening for gestational diabetes, objectively measured physical activity, bioelectrical impedance, anthropometrics, biochemical measurements, and a biobank with maternal serum and plasma, urine, placenta tissue. In the offspring, we have repeated ultrasounds during pregnancy, cord blood, and anthropometrics up to 4 years of age. We have quantified DNA methylation in peripheral blood leukocytes in nearly all eligible women from the STORK Groruddalen study, to minimize the risk of selection bias. Genetic principal components distinctly separated Europeans and South Asian women, which fully corresponded with the self-reported ethnicity. Technical validation of 4 CpG sites from the methylation bead chip showed good agreement with bisulfite pyrosequencing. We plan to study associations between DNA methylation and cardiometabolic traits and outcomes.

A cohort study of antihypertensive use during pregnancy in South Korea, 2013-2017

OBJECTIVES

Hypertensive disorder is a common medical condition in pregnancy. However, the recommendations for antihypertensive use during pregnancy are based on limited evidence and various factors affect their selection in clinical practice. We aim to assess the prevalence of antihypertensive use and describe which medications are being used in pregnancy.

STUDY DESIGN

We conducted a cohort study of all pregnancies resulted in a live birth between 2013 and 2017, by using the Health Insurance Review and Assessment (HIRA) database of South Korea. Based on duration of drug supplied, we examined antihypertensive use during the pre-pregnancy, pregnancy, and postpartum periods. We described the patterns of discontinuing, continuing, switching, and initiating antihypertensive medications during pregnancy.

RESULTS

We included 2,030,821 pregnancies, of whom 0.9%, 3.1%, and 1.8% were dispensed antihypertensives in the pre-pregnancy, pregnancy, and postpartum periods, respectively. The most frequent medications used were dihydropyridines (40.7%), beta-blockers (38.4%) and Angiotensin II Receptor Blockers (16.8%) in the first trimester, and dihydropyridines (89.7%) and vasodilators (11.5%) in the third trimester. Among women exposed to antihypertensives during pregnancy, this was the first use in 86.3% of women. Among women receiving antihypertensives before pregnancy, 77.9% discontinued treatment during pregnancy, whereas 13.2% continued to take their pre-pregnancy medications.

CONCLUSION

The prevalence of antihypertensive use during pregnancy was 3.1% in South Korea. Overall, while dihydropyridines were predominant, other types of antihypertensives were also commonly dispensed during pregnancy. It suggests a need to investigate the effect of exposure to various types of antihypertensives of which safety remains unclear during pregnancy.

Population reference and healthy standard blood pressure range charts in pregnancy: findings from the Born in Bradford cohort study

Women who develop gestational hypertension are at increased risk of adverse perinatal and longer-term outcomes. Reference charts may aid early detection of raised blood pressure (BP) and in doing so reduce adverse outcome risk. We used repeated BP measurements to produce ‘reference’ (whole population) and ‘standard’ (healthy pregnancies only) gestational-age-specific BP charts for all pregnant women (irrespective of ethnicity) and for White British (WB) and Pakistani (P) women. We included 9218 women recruited to the Born in Bradford study with 74,770 BPs. 19% of the whole population, 11% and 25% of WB and P women respectively were defined as healthy pregnancies. For reference and standard charts, for all women and each ethnic group, SBP/DBP at 12 and 20 weeks gestation was similar before rising at 37 weeks. DBP/SBP of reference charts for all women and for each ethnic group were higher than those of the corresponding standard charts. Compared to WB, P women had lower SBP/DBP at 12, 20 and 37 weeks gestation. To conclude; maternal population BP reference charts are higher compared to standard charts (healthy pregnancies) and are influenced by ethnicity.

Blood pressure change across pregnancy in white British and Pakistani women: analysis of data from the Born in Bradford cohort

The incidence of gestational hypertension (GH) and pre-eclampsia (PE) is increasing. Use of blood pressure (BP) change patterns may improve early detection of BP abnormalities. We used Linear spline random-effects models to estimate BP patterns across pregnancy for white British and Pakistani women. Pakistani women compared to white British women had lower BP during the first two trimesters of pregnancy, irrespective of the development of GH or PE or presence of a risk factor. Pakistani compared to white British women with GH and PE showed steeper BP increases towards the end of pregnancy. Pakistani women were half as likely to develop GH, but as likely to develop PE than white British women. To conclude; BP trajectories differ by ethnicity. Because GH developed evenly from 20 weeks gestation, and PE occurred more commonly after 36 weeks in both ethnic groups, the lower BP up to the third trimester in Pakistani women resulted in a lower GH rate, whereas PE rates, influenced by the steep third trimester BP increase were similar. Criteria for diagnosing GH and PE may benefit from considering ethnic differences in BP change across pregnancy.

Associations of social and economic and pregnancy exposures with blood pressure in UK White British and Pakistani children age 4/5

South Asians have higher rates of coronary heart disease (CHD) than White European individuals. Blood pressure (BP) is one of the most important risk factors for CHD and ethnic differences in BP have been identified in childhood. Early life exposures could explain some of these differences. We examined associations of family social and economic and maternal pregnancy exposures and BP at age 4/5 in 1644 White British and 1824 Pakistani mother-offspring pairs from the Born in Bradford study. We found that systolic BP was similar but diastolic BP was higher, in Pakistani compared to White British children (adjusted mean differences were −0.170 mmHg 95% CI −0.884, 0.543 for systolic BP; 1.328 mmHg 95% CI 0.592, 2.064 for diastolic BP). Social and economic exposures were not associated with BP in either ethnic group. Maternal BMI was positively associated with BP in both groups but this association was mediated by child BMI. Only gestational hypertension was associated with child systolic and diastolic BP and this was only identified in Pakistani mother-offspring pairs. These findings suggest that Pakistani populations may have a different BP trajectory compared to White British groups and that this is already evident at age 4/5 years.

Associations between gestational diabetes mellitus and elevated HbA1c early postpartum in a multi-ethnic population

AIMS

To investigate the prevalence of elevated HbA_1c 14 weeks postpartum in different ethnic groups and in women with and without gestational diabetes mellitus (GDM) in the index pregnancy and to explore demographic and biological factors from early pregnancy associated with elevated HbA_1c (HbA_1c ≥5.7% (≥39mmol/mol)) postpartum.

METHODS

From a cohort study in Oslo, Norway, we included 570 pregnant women, examined in gestational week 15, 28, and 14 weeks postpartum. The association between elevated HbA_1c and demographic and biological factors were assessed by logistic regression analyses.

RESULTS

The prevalence of elevated HbA_1c postpartum was 23% in the total population, 15% among Western Europeans and 28% among women with ethnic minority background (p<0.01). In ethnic minorities elevated HbA_1c was found in 39% of women with recent GDM diagnosed by the World Health Organization 2013 criteria and in 21% of women without GDM (p<0.01), compared to 22% and 13% in Western Europeans (p=0.11). We found independent associations between elevated HbA_1c and ethnic minority background (OR 2.0, 95% CI 1.27, 3.18), and GDM (OR 2.04, 95% CI 1.35, 3.10) (p<0.01).

CONCLUSIONS

The prevalence of elevated HbA_1c postpartum was 23%, and significantly higher among women with ethnic minority background irrespective of GDM.