Mid-trimester blood pressure drop in normal pregnancy: myth or reality?

Adverse cardiovascular, obstetric and perinatal events during pregnancy and puerperium in patients with heart disease

BACKGROUND AND OBJECTIVES

cardiovascular changes during pregnancy carry greater risk in heart disease. We analyze cardiovascular, obstetric and perinatal adverse effects associated with congenital and acquired heart disease during pregnancy and postpartum.

MATERIALS AND METHODS

Cross-sectional and retrospective study, which included the 2017-2023 registry of pregnant or postpartum patients hospitalised with diagnosis of congenital or acquired heart disease. Adverse events (heart failure, stroke, acute pulmonary edema, maternal death, obstetric haemorrhage, prematurity and perinatal death) were compared with the clinical variables and the implemented treatment.

RESULTS

112 patients with a median age of 28 years (range 15-44) were included. Short circuits predominated 28 (25%). Thirty-six patients (32%) were classified in class IV of the modified WHO scale for maternal cardiovascular risk. Heart failure occurred in 39 (34.8%), acute lung edema 12 (10.7%), stroke 2 (1.8%), maternal death 5 (4.5%), obstetric haemorrhage 4 (3.6%), prematurity 50 (44.5%) and perinatal death 6 (5.4%). Shunts were associated with prematurity (adjusted odds ratio 4; 95% CI: 1.5-10, p = 0.006). Peripartum cardiomyopathy represented higher risk of pulmonary edema (adjusted OR 34; 95% CI: 6-194, p = 0.001) and heart failure (adjusted OR 16; 95% CI: 3-84, p = 0.001). An increased risk of obstetric haemorrhage was observed in patients with prosthetic valves (adjusted OR 30; 95% CI: 1.5-616, p = 0.025) and with the use of acetylsalicylic acid (adjusted OR 14; 95% CI: 1.2-16, p = 0.030). Furthermore, the latter was associated with perinatal death (adjusted OR 9; 95% CI: 1.4-68, p = 0.021).

CONCLUSIONS

severe complications were found during pregnancy and postpartum in patients with heart disease, which is why preconception evaluation and close surveillance are vital.

Antimicrobial stewardship and targeted therapies in the changing landscape of maternal sepsis

Pregnant and postnatal women are a high-risk population particularly prone to rapid progression to sepsis with significant morbidity and mortality worldwide. Moreover, severe maternal infections can have a serious detrimental impact on neonates with almost 1 million neonatal deaths annually attributed to maternal infection or sepsis. In this review we discuss the susceptibility of pregnant women and their specific physiological and immunological adaptations that contribute to their vulnerability to sepsis, the implications for the neonate, as well as the issues with antimicrobial stewardship and the challenges this poses when attempting to reach a balance between clinical care and urgent treatment. Finally, we review advancements in the development of pregnancy-specific diagnostic and therapeutic approaches and how these can be used to optimize the care of pregnant women and neonates.

Association of a Lifestyle Intervention with Blood Pressure Trajectories During Pregnancy and Postpartum in Women with Pre-pregnancy Overweight and Obesity

OBJECTIVES

Healthy lifestyle, including healthy diet and physical activity, has been associated with lower blood pressure (BP). We hypothesized that overweight/obese women randomized to a lifestyle intervention beginning in early pregnancy would be less likely to have a higher BP trajectory.

METHODS

The Health in Pregnancy and Postpartum study promoted a healthy lifestyle in pregnant and postpartum women with pre-pregnancy overweight or obesity. BP was measured at study visits at ≤ 16 and 32 weeks of pregnancy and 6 and 12 months postpartum. Latent class trajectories were constructed to identify groups of participants with similar BP patterns throughout the study period. Odds of being assigned to the higher BP trajectories between the intervention and control group were determined with logistic regression, adjusted for age, race, pre-pregnancy BMI, gestational weight gain, smoking during the study period, and household income.

RESULTS

Of the 219 participants enrolled (44.3% Black participants, 55.7% White participants, mean age = 29.7 ± 0.3 years), 112 (51.1%) were randomized to the intervention. Two systolic and diastolic BP trajectory groups were identified (Low-Stable, Moderate-Increasing). Randomization to the lifestyle intervention was not associated with odds of Moderate-Increasing systolic (OR 0.83, 95%CI 0.4, 1.6) or diastolic (OR 0.67, 95%CI 0.3, 1.3) BP trajectory assignment. Those in the Moderate-Increasing BP groups had higher BMI and were more likely to have an adverse pregnancy outcome.

CONCLUSIONS

A lifestyle intervention initiated in early pregnancy to help prevent excessive gestational weight gain was not associated with odds of specific BP patterns through pregnancy and postpartum.

Remote multimodality monitoring of maternal physiology from the first trimester to postpartum period: study results

OBJECTIVES

Current antenatal care largely relies on widely spaced appointments, hence only a fraction of the pregnancy period is subject to monitoring. Continuous monitoring of physiological parameters could represent a paradigm shift in obstetric care. Here, we analyse the data from daily home monitoring in pregnancy and consider the implications of this approach for tracking pregnancy health.

METHODS

Prospective feasibility study of continuous home monitoring of blood pressure, weight, heart rate, sleep and activity patterns from the first trimester to 6 weeks postpartum.

RESULTS

Fourteen out of 24 women completed the study (58%). Compared to early pregnancy [week 13, median heart rate (HR) 72/min, interquartile range (IQR) 12.8], heart rate increased by week 35 (HR 78/min, IQR 16.6; P  = 0.041) and fell postpartum (HR 66/min, IQR 11.5, P  = 0.021). Both systolic and diastolic blood pressure were lower at mid-gestation (week 20: SBP 103 mmHg, IQR 6.6; DPB 63 mmHg, IQR 5.3 P  = 0.005 and P  = 0.045, respectively) compared to early pregnancy (week 13, SBP 107 mmHg, IQR 12.4; DPB 67 mmHg, IQR 7.1). Weight increased during pregnancy between each time period analyzed, starting from week 15. Smartwatch recordings indicated that activity increased in the prepartum period, while deep sleep declined as pregnancy progressed.

CONCLUSION

Home monitoring tracks individual physiological responses to pregnancy in high resolution that routine clinic visits cannot. Changes in the study protocol suggested by the study participants may improve compliance for future studies, which was particularly low in the postpartum period. Future work will investigate whether distinct adaptative patterns predate obstetric complications, or can predict long-term maternal cardiovascular health.

Diagnosing Arterial Stiffness in Pregnancy and Its Implications in the Cardio-Renal-Metabolic Chain

Cardio-renal and metabolic modifications during gestation are crucial determinants of foetal and maternal health in the short and long term. The cardio-renal metabolic syndrome is a vicious circle that starts in the presence of risk factors such as obesity, hypertension, diabetes, kidney disease and ageing, all predisposing to a status dominated by increased arterial stiffness and alteration of the vascular wall, which eventually damages the target organs, such as the heart and kidneys. The literature is scarce regarding cardio-renal metabolic syndrome in pregnancy cohorts. The present paper exposes the current state of the art and emphasises the most important findings of this entity, particularly in pregnant women. The early assessment of arterial function can lead to proper and individualised measures for women predisposed to hypertension, pre-eclampsia, eclampsia, and diabetes mellitus. This review focuses on available information regarding the assessment of arterial function during gestation, possible cut-off values, the possible predictive role for future events and modalities to reverse or control its dysfunction, a fact of crucial importance with excellent outcomes at meagre costs.

Maternal blood pressure trajectories and associations with gestational age at birth: a functional data analytic approach

BACKGROUND

Research has revealed group-level differences in maternal blood pressure trajectories across pregnancy. These trajectories are typically constructed using clinical blood pressure data and multivariate statistical methods that are prone to bias and ignore the functional, dynamic process underlying a single blood pressure observation. The aim of this study was to use functional data analysis to explore blood pressure variation across pregnancy, and multivariate methods to examine whether trajectories are related to gestational age at birth.

METHODS

Clinical blood pressure observations were available from 370 women who participated in a longitudinal pregnancy cohort study conducted in Montreal, Quebec, Canada. Functional data analysis was used to smooth blood pressure data and then to conduct a functional principal component analysis to examine predominant modes of variation.

RESULTS

Three eigenfunctions explained greater than 95% of the total variance in blood pressure. The first accounted for approximately 80% of the variance and was characterized by a prolonged-decrease trajectory in blood pressure; the second explained 10% of the variance and captured a late-increase trajectory; and the third accounted for approximately 7% of the variance and captured a mid-decrease trajectory. The prolonged-decrease trajectory of blood pressure was associated with older, and late-increase with younger gestational age at birth.

CONCLUSION

Functional data analysis is a useful method to model repeated maternal blood pressure observations and many other time-related cardiovascular processes. Results add to previous research investigating blood pressure trajectories across pregnancy through identification of additional, potentially clinically important modes of variation that are associated with gestational age at birth.

Blood pressure adjustments throughout healthy and hypertensive pregnancy: A systematic review and meta-analysis

Gestational hypertensive complications are preceded by deviant hemodynamic adjustments affecting blood pressure. Our objective was to determine the timing and magnitude of changes in blood pressure during singleton normotensive and hypertensive pregnancies. PubMed (NCBI) and Embase (Ovid) databases were searched for relevant studies up to November 2019. Studies reporting original blood pressure measurements during pregnancy together with a non-pregnant reference measurement were included. Studies including women with a history of cardiovascular or metabolic disease, or women using antihypertensive drugs were excluded. Pooled mean differences between pregnant and non-pregnant women, and absolute blood pressure values were calculated for predefined gestational intervals in normotensive and hypertensive pregnancy, using a random-effects model. Meta-regression analysis was used to analyze group differences in adjustments. In early normotensive pregnancy, both systolic and diastolic blood pressure decreased, reaching their maximum reduction of -4 mmHg (95%CI -6 to -1 mmHg) and -4 mmHg (95%CI, -5 to -3 mmHg), respectively in the second trimester. Thereafter, blood pressure gradually increased towards non-pregnant values. All absolute blood pressure measurements throughout normotensive pregnancy were below 130/80 mmHg. In hypertensive pregnancies, only diastolic blood pressure decreased early in pregnancy. In conclusion, this meta-analysis showed a clinically moderate, but significant mid-pregnancy drop in blood pressure during normotensive pregnancy. Reference curves with absolute values underscore the current liberal cut-off limit for gestational hypertension. A lack of a mid-pregnancy systolic blood pressure drop might reflect increased vascular resistance in women destined to develop hypertensive pregnancy complications.

Parameterization of the mid-trimester drop in blood pressure trajectory during pregnancy and its utility for predicting preeclampsia

OBJECTIVES

The purpose of this study was to parameterize mid-trimester drop in blood pressure (BP) trajectory during pregnancy and to evaluate its utility for predicting preeclampsia.

METHODS

To develop parametric models for BP trajectory during pregnancy, we used data from 7923 Chinese pregnant women with 24 810 routine antenatal care visits. Then, we evaluated the utility of BP trajectory parameters for predicting clinician-diagnosed preeclampsia in a separate sample of 3524 pregnant women from a randomized controlled trial of prenatal vitamin supplementation conducted in the same area. We focused on parameters related to the mid-trimester BP drop, including the gestational age and BP value at the nadir (lowest point), change in BP, velocity, and area under curve during two periods (from 12 weeks of gestation to the nadir and from the nadir to 33 weeks of gestation).

RESULTS

All participants in our analysis had a mid-pregnancy drop in their SBP, DBP, and mean arterial pressure (MAP) trajectories. There were high correlations (|r| > 0.90) among trajectory parameters of the same BP measure. The final prediction model included selective parameters of SBP, DBP, and MAP trajectories, prepregnancy BMI and gestational age at the first antenatal care visit. The area under the receiver-operating curve for predicting preeclampsia was 0.886 (95% confidence interval 0.846--0.926) in the training dataset and 0.802 (0.708--0.895) in the validation dataset.

CONCLUSION

Our novel BP trajectory parameters are informative and can predict preeclampsia at a clinically acceptable level.

International gestational age-specific centiles for blood pressure in pregnancy from the INTERGROWTH-21st Project in 8 countries: A longitudinal cohort study

BACKGROUND

Gestational hypertensive and acute hypotensive disorders are associated with maternal morbidity and mortality worldwide. However, physiological blood pressure changes in pregnancy are insufficiently defined. We describe blood pressure changes across healthy pregnancies from the International Fetal and Newborn Growth Consortium for the 21st Century (INTERGROWTH-21st) Fetal Growth Longitudinal Study (FGLS) to produce international, gestational age-specific, smoothed centiles (third, 10th, 50th, 90th, and 97th) for blood pressure.

METHODS AND FINDINGS

Secondary analysis of a prospective, longitudinal, observational cohort study (2009 to 2016) was conducted across 8 diverse urban areas in Brazil, China, India, Italy, Kenya, Oman, the United Kingdom, and the United States of America. We enrolled healthy women at low risk of pregnancy complications. We measured blood pressure using standardised methodology and validated equipment at enrolment at <14 weeks, then every 5 ± 1 weeks until delivery. We enrolled 4,607 (35%) women of 13,108 screened. The mean maternal age was 28·4 (standard deviation [SD] 3.9) years; 97% (4,204/4,321) of women were married or living with a partner, and 68% (2,955/4,321) were nulliparous. Their mean body mass index (BMI) was 23.3 (SD 3.0) kg/m2. Systolic blood pressure was lowest at 12 weeks: Median was 111.5 (95% CI 111.3 to 111.8) mmHg, rising to a median maximum of 119.6 (95% CI 118.9 to 120.3) mmHg at 40 weeks' gestation, a difference of 8.1 (95% CI 7.4 to 8.8) mmHg. Median diastolic blood pressure decreased from 12 weeks: 69.1 (95% CI 68.9 to 69.3) mmHg to a minimum of 68.5 (95% CI 68.3 to 68.7) mmHg at 19+5 weeks' gestation, a change of -0·6 (95% CI -0.8 to -0.4) mmHg. Diastolic blood pressure subsequently increased to a maximum of 76.3 (95% CI 75.9 to 76.8) mmHg at 40 weeks' gestation. Systolic blood pressure fell by >14 mmHg or diastolic blood pressure by >11 mmHg in fewer than 10% of women at any gestational age. Fewer than 10% of women increased their systolic blood pressure by >24 mmHg or diastolic blood pressure by >18 mmHg at any gestational age. The study's main limitations were the unavailability of prepregnancy blood pressure values and inability to explore circadian effects because time of day was not recorded for the blood pressure measurements.

CONCLUSIONS

Our findings provide international, gestational age-specific centiles and limits of acceptable change to facilitate earlier recognition of deteriorating health in pregnant women. These centiles challenge the idea of a clinically significant midpregnancy drop in blood pressure.

Gestational systolic blood pressure trajectories and risk of adverse maternal and perinatal outcomes in Chinese women

Background

Associations between trajectories of systolic blood pressure (SBP) during pregnancy and pregnant outcomes remain unclear and disparate.

Methods

Data of 20,353 mothers without chronic hypertension and who delivered live singletons between January, 2014 and November, 2019, was extracted from Taicang register-based cohort. Based on SBP measured during 10 to 40 weeks of gestation, SBP trajectories were explored using latent class growth mixture model, and their associations with maternal and neonatal outcomes were assessed by logistic regression analyses.

Results

Six heterogeneous SBP trajectories were identified: low delayed-increasing (7.47%), low reverse-increasing (21.88%), low-stable (19.13%), medium-stable (21.64%), medium reverse-increasing (16.47%), and high stable (13.41%) trajectories. The high-stable trajectory had SBP around 125 mmHg in the 10th gestational week, and increased slightly onwards. When compared with the low-stable trajectory, the high-stable trajectory had maximally adjusted odds ratio (95% confidence interval) of 5.28 (2.76–10.10), 1.30 (1.13–1.50), 1.53 (1.12–2.08), 1.32 (1.06–1.65) and 1.64 (1.08–2.48) for gestational hypertension (GH), early-term delivery (ETD), preterm delivery (PTD), small for gestational age and low birth weight (LBW), respectively. Besides, the medium reverse-increasing trajectory showed significantly increased risk of GH and ETD, while the medium-stable trajectory had significantly elevated risk of ETD and PTD. Notably, SBP trajectories slightly but significantly improved risk discrimination of GH, ETD and LBW, over traditional risk factors.

Conclusion

Women with different SBP trajectories were at varied risk of adverse maternal and fetal outcomes. Meanwhile, our study suggested that BP monitoring during pregnancy is necessary, especially for women with high SBP in early pregnancy or upward trajectory.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12884-021-03599-7.

Prevalence, placenta development, and perinatal outcomes of women with hypertensive disorders of pregnancy at Komfo Anokye Teaching Hospital

BACKGROUND

One of the most common medical problems associated with pregnancy is hypertension. Hypertensive disorders of pregnancy (HDP), which has been attributable to abnormal placentation may have adverse effects on both mother and foetus if left unchecked. The objective of this study was to determine the prevalence of this condition and its effect on placental morphology as well as maternal and perinatal outcomes.

MATERIALS AND METHODS

This was a prospective case-control study, conducted at Komfo Anokye Teaching Hospital (KATH), Ghana between February 2018 and July 2018. The progression of pregnancy in normotensive and hypertensive pregnant women, and the eventual perinatal outcomes were closely followed. Statistical analysis was performed using IMB-SPSS version 23. Associations were considered significant at p values of ≤ 0.05.

RESULTS

From a total of 214 deliveries recorded during the period of study, 84 (39.25%) were hypertensives. Forty four (52%) of the hypertensives had preeclampsia, 28 (33.3%) had gestational hypertension, 6 (7.1%) had eclampsia, 4 (4.8%) had chronic hypertension, and 2 (2.4%) had preeclampsia superimposed on chronic hypertension. The frequency of placental haematoma, placental infarction, and placental calcification in the normotensives were significantly (p = 0.001) lower than that of the hypertensives. The mean placental weight (p = 0.01), placental volume (p = 0.001), placental diameter (p = 0.03), and placental thickness (p = 0.001) of the normotensives were significantly higher than those of the hypertensives. The number of normotensives in whom labour was induced, who had their babies delivered by caesarean section, and who were admitted after they had given birth were significantly (p = 0.001) lower than that of hypertensives who underwent similar procedures. No stillbirths were recorded in the normotensives compared with four in the hypertensives. The number of babies delivered to the normotensives who were admitted to the NICU was significantly (p = 0.001) lower than those delivered by hypertensives.

CONCLUSION

There was a high prevalence of hypertensive disorders of pregnancy in the study site. Pregnant women who developed HDP are at a risk of developing placental abnormalities that adversely affected perinatal outcomes. These adverse effects can be curtailed by embarking on a vigorous health education drive.

Pregnancy-induced Cardiovascular Pathologies: Importance of Structural Components and Lipids

Pregnancy leads to adaptations for maternal and fetal energy needs. The cardiovascular system bears the brunt of the adaptations as the heart and vessels enable nutrient supply to maternal organs facilitated by the placenta to the fetus. The components of the cardiovascular system are critical in the balance between maternal homeostatic and fetus driven homeorhetic regulation. Since lipids intersect maternal cardiovascular function and fetal needs with growth and in stress, factors affecting lipid deposition and mobilization impact risk outcomes. Here, the cardiovascular components and functional derangements associated with cardiovascular pathology in pregnancy, vis-à-vis lipid deposition, mobilization and maternal and/or cardiac and fetal energy needs are detailed. Most reports on the components and associated pathology in pregnancy, are on derangements affecting the extracellular matrix and epicardial fat, followed by the endothelium, vascular smooth muscle, pericytes and myocytes. Targeted studies on all cardiovascular components and pathological outcomes in pregnancy will enhance targeted interventions.

Reference ranges and trajectories for blood pressure in pregnancy: findings from a follow-up study based on China Maternal and Newborn's Health Monitoring System

Objectives: This study aimed to establish normal blood pressure reference ranges across gestation and maternal characteristics.Methods: We conducted a follow-up study including 29,200 Chinese normal pregnant women. Multilevel restrictive cubic spline models were used to calculate normal blood pressure reference ranges among all population and stratified groups.Results: In all normal pregnancies, the normal reference range of systolic blood pressure were 93.94-118.74 mmHg(2.5^th-97.5^th) and 97.35-124.63 mmHg at 12 and 37 weeks gestation, respectively while 58.79-74.21 mmHg and 59.19-78.25 mmHg were for diastolic blood pressure at 12 and 37 weeks gestation, which differed in subgroups stratified by prepregnancy body mass index and maternal age.Conclusion: This study provides evidence for blood pressure management in Chinese pregnant women.

ACOG Practice Bulletin No. 212: Pregnancy and Heart Disease

Maternal heart disease has emerged as a major threat to safe motherhood and women's long-term cardiovascular health. In the United States, disease and dysfunction of the heart and vascular system as "cardiovascular disease" is now the leading cause of death in pregnant women and women in the postpartum period () accounting for 4.23 deaths per 100,000 live births, a rate almost twice that of the United Kingdom (). The most recent data indicate that cardiovascular diseases constitute 26.5% of U.S. pregnancy-related deaths (). Of further concern are the disparities in cardiovascular disease outcomes, with higher rates of morbidity and mortality among nonwhite and lower-income women. Contributing factors include barriers to prepregnancy cardiovascular disease assessment, missed opportunities to identify cardiovascular disease risk factors during prenatal care, gaps in high-risk intrapartum care, and delays in recognition of cardiovascular disease symptoms during the puerperium. The purpose of this document is to 1) describe the prevalence and effect of heart disease among pregnant and postpartum women; 2) provide guidance for early antepartum and postpartum risk factor identification and modification; 3) outline common cardiovascular disorders that cause morbidity and mortality during pregnancy and the puerperium; 4) describe recommendations for care for pregnant and postpartum women with preexisting or new-onset acquired heart disease; and 5) present a comprehensive interpregnancy care plan for women with heart disease.

Blood pressure measurement by oscillometric and auscultatory methods in normotensive pregnant women

OBJECTIVE

to compare blood pressure values obtained by auscultatory and oscillometric methods in different gestational periods, considering cuff width.

METHOD

it is a cross-sectional and quasi-experimental study approved by the Research Ethics Committee. The sample consisted of 108 low-risk pregnant women. Blood pressure measurements were performed in gestational periods of 10-14, 19-22 and 27-30 weeks.

RESULTS

The oscillometric device presented values similar to the auscultatory method in systolic blood pressure, but overestimated diastolic blood pressure. Underestimation of blood pressure occurred when using the standard width cuff rather than the correct width cuff in both measuring methods.

CONCLUSION

Verification of brachial circumference and use of adequate cuffs in both methods are indispensable to obtain reliable blood pressure values in pregnant women. We recommend performance of additional studies to evaluate diastolic blood pressure overestimation by the Microlife 3BTO-A.

Trends of blood pressure and heart rate in normal pregnancies: a systematic review and meta-analysis

BACKGROUND

Current reference ranges for blood pressure and heart rate throughout pregnancy have a poor evidence base.

METHODS

This is a systematic review and meta-analysis. We included studies measuring blood pressure or heart rate from healthy pregnant women within defined gestational periods of 16 weeks or less. We analysed systolic blood pressure, diastolic blood pressure and heart rate by gestational age. We assessed effects of measurement year and method.

RESULTS

We included 39 studies undertaken in 1967-2017, containing 124,349 systolic measurements from 36,239 women, 124,291 diastolic measurements from 36,181 women and 10,948 heart rate measurements from 8317 women. Mean (95% CI) systolic blood pressure was lowest at 10 weeks gestation, 110.4 (108.5, 112.3) mmHg, rising to 116.0 (113.6, 118.4) mmHg at 40 weeks, mean (95% CI) change 5.6 (4.0, 7.2) mmHg. Mean (95% CI) diastolic blood pressure was lowest at 21 weeks gestation, 65.9 (64.2, 67.7) mmHg; rising to 72.8 (71.0, 74.6) mmHg at 40 weeks, mean (95% CI) change 6.9 (6.2, 7.5) mmHg. Mean (95% CI) heart rate rose from 79.3 (75.5, 83.1) beats/min at 10 weeks to 86.9 (82.2, 91.6) beats/min at 40 weeks gestation, mean (95% CI) change 7.6 (1.8, 13.4) beats/min. Studies using manual measurement reported higher diastolic blood pressures than studies using automated measurement, mean (95 CI) difference 4.9 (0.8, 8.9) mmHg. Diastolic blood pressure increased by 0.26 (95% CI 0.10-0.43) mmHg/year. Including only higher-quality studies had little effect on findings, with heterogeneity remaining high (I2 statistic > 50%).

CONCLUSIONS

Significant gestational blood pressure and heart rate changes occur that should be taken into account when assessing pregnant women. Commonly taught substantial decreases in blood pressure mid-pregnancy were not seen and heart rate increases were lower than previously thought. Manual and automated blood pressure measurement cannot be used interchangeably. Increases in diastolic blood pressure over the last half-century and differences between published studies show contemporary data are required to define current normal ranges.

STUDY REGISTRATION

PROSPERO CRD42014009673.

Uterine perivascular adipose tissue is a novel mediator of uterine artery blood flow and reactivity in rat pregnancy

KEY POINTS

In vivo, uterine perivascular adipose tissue (PVAT) potentiates uterine artery blood flow in pregnant rats, although not in non-pregnant rats. In isolated preparations, uterine PVAT has pro-contractile and anti-dilatory effects on uterine arteries. Pregnancy induces changes in uterine arteries that makes them responsive to uterine PVAT signalling.

ABSTRACT

An increase in uterine artery blood flow (UtBF) is a common and necessary feature of a healthy pregnancy. In the present study, we tested the hypothesis that adipose tissue surrounding uterine arteries (uterine perivascular adipose tissue; PVAT) is a novel local mediator of UtBF and uterine artery tone during pregnancy. In vivo experiments in anaesthetized Sprague-Dawley rats showed that pregnant animals (gestational day 16, term = 22--23 days) had a three-fold higher UtBF compared to non-pregnant animals. Surgical removal of uterine PVAT reduced UtBF only in pregnant rats. In a series of ex vivo bioassays, we demonstrated that uterine PVAT had pro-contractile and anti-dilatory effects on rat uterine arteries. In the presence of PVAT-conditioned media, isolated uterine arteries from both pregnant and non-pregnant rats had reduced vasodilatory responses. In non-pregnant rats, these responses were mediated at the level of uterine vascular smooth muscle, whereas, in pregnant rats, PVAT-media reduced endothelium-dependent relaxation. Pregnancy increased adipocyte size in ovarian adipose tissue but had no effect on uterine PVAT adipocyte morphology. In addition, pregnancy down-regulated the gene expression of metabolic adipokines in uterine but not in aortic PVAT. In conclusion, this is the first study to demonstrate that uterine PVAT plays a regulatory role in UtBF, at least in part, as a result of its actions on uterine artery tone. We propose that the interaction between the uterine vascular wall and its adjacent adipose tissue may provide new insights for interventions in pregnancies with adipose tissue dysfunction and abnormal UtBF.

Serum Calcium and Magnesium Levels in Normal Ghanaian Pregnant Women: A Comparative Cross-Sectional Study

BACKGROUND:

Pregnancy is described as a normal physiologic state associated with various biochemical changes. Magnesium and calcium are essential macronutrients required for foetal growth. Complications associated with their deficiency during normal pregnancy include; low neonatal birth weight, pre-eclampsia, eclampsia and preterm labour. Changes in serum levels of magnesium and calcium in normal pregnancy have not been extensively studied among Ghanaian women.

AIM:

To determine the variation in serum magnesium and calcium levels with gestational age in normal pregnancy in Ghanaian women.

METHODS:

A hospital-based comparative cross-sectional study was conducted among 32 normal non-pregnant women (Group A) and 100 normal pregnant women (Group B) attending the clinic at the Korle-Bu Teaching hospital. The group B pregnant women were further divided into Group B1 (n = 33), Group B2 (n = 37) and Group B3 (n = 30) based on their pregnancy gestation as first, second and third trimester respectively. Blood samples were obtained from the antecubital vein of subjects and total serum calcium, magnesium, protein and albumin were estimated. Data obtained were analysed using SPSS for windows version 20. Analysis of variance (ANOVA) was employed to determine the statistical differences between the groups. A p-value of ≤ 0.05 was considered significant.

RESULTS:

Mean serum total calcium and magnesium in first, second and third trimester normal pregnant women were 2.14 ± 0.16, 2.13 ± 0.44, 2.13 ± 0.35 mmol/L and 0.77 ± 0.11, 0.77 ± 0.16 and 0.76 ± 0.14 mmol/L respectively. Mean serum total calcium and magnesium levels in non-pregnant women were 2.20 ± 0.16 and 0.80 ± 0.10 mmol/L respectively. There was a statistically non-significant difference in serum total calcium and magnesium between non-pregnant and normal pregnant women, with p-values of 0.779 and 0.566 respectively. Mean total serum protein and albumin in first, second and third-trimester normal pregnant women were 68.42 ± 10.37, 70.46 ± 6.84, 66.70 ± 7.83 g/L and 39.92 ± 3.22, 40.75 ± 8.06, 38.26 ± 3.02 g/L respectively. Mean total serum protein and albumin in non-pregnant women were 73.13 ± 7.02 and 42.94 ± 3.03 g/L respectively. Mean total serum protein and albumin levels were lower in pregnant women as compared to non-pregnant women with the difference being significant in the third trimester (p-values of 0.012 and 0.002).

CONCLUSION:

Total serum calcium and magnesium levels in normal pregnancy were non-significantly lower compared to non-pregnant women in Ghana. There was a reduction in total serum protein, and albumin levels during pregnancy with a significant reduction noticed during the third trimester compared to the non-pregnant state.

Hemodynamic and Electrocardiographic Aspects of Uncomplicated Singleton Pregnancy

Pregnancy is associated with significant changes in maternal hemodynamics, which are triggered by profound systemic vasodilation and mediated through the autonomic nervous system as well as the renin-angiotensin-aldosterone system. Vascular function changes to help accommodate an increase in intravascular volume due to blood volume expansion associated with pregnancy while maintaining the efficiency of ventricular-arterial coupling and diastolic perfusion pressure. The heart undergoes physiological (eccentric) hypertrophy due to increased volume load and cardiac stroke work, whereas the functional change of the left ventricle remains controversial. There are changes in cardiac electrical activity during pregnancy which can be detected in the electrocardiogram that are not related to disease. Sympathetic activation is a common phenomenon during uncomplicated pregnancy and may be a compensatory mechanism induced by profound systemic vasodilation and a decrease in mean arterial pressure. Despite marked sympathetic activation, vasoconstrictor responsiveness is blunted during uncomplicated pregnancy. There are race and ethnic differences in maternal hemodynamic adaptations to uncomplicated pregnancy, which may be attributed to differences in socioeconomic status or in prevalence rates of cardiovascular risk factors.

Echocardiographic Techniques of Deformation Imaging in the Evaluation of Maternal Cardiovascular System in Patients with Complicated Pregnancies

Cardiovascular diseases (CVD) represent the leading cause of maternal mortality and morbidity. Knowledge of CVD in women is constantly evolving and data are emerging that female-specific risk factors as complications of pregnancy are conditions associated with an increased risk for the long-term development of CVD. Echocardiography is a safe and effective imaging technique indicated in symptomatic or asymptomatic pregnant women with congenital heart diseases who require close monitoring of cardiac function. Deformation imaging is an echocardiographic technique used to assess myocardial function by measuring the actual deformation of the myocardium through the cardiac cycle. Speckle-tracking echocardiography (STE) is a two-dimensional (2D) technique which has been found to be more accurate than tissue Doppler to assess both left ventricular (LV) and right ventricular (RV) myocardial function. The use of 2D STE however might present some technical issues due to the tomographic nature of the technique and the motion in the three-dimensional space of the myocardial speckles. This has promoted the use of 3D STE to track the motion of the speckles in the 3D space. This review will focus on the clinical value of the new echocardiographic techniques of deformation imaging used to assess the maternal cardiovascular system in complicated pregnancies.

Trimester-Specific Weight Gain and Midpregnancy Diastolic Blood Pressure Rebound During Normotensive Pregnancy

The longitudinal exposure-response relationship between trimester-specific gestational weight gain (GWG) and blood pressure (BP) during pregnancy is not well understood. We retrospectively assessed 1112 uncomplicated, normotensive pregnant women whose body weight and BP were measured from 12⁺⁰ to 40⁺⁰ weeks of gestation from a hospital-based cohort. By using growth curve modeling, a J-shaped pattern dominated diastolic BP (DBP) changing dynamics, with a midpregnancy drop at 20⁺⁰ to 22⁺⁰ weeks followed by a rebound. Using group-based trajectory modeling, 3 distinctive trajectories of DBP were identified: high-J shaped (18.5%), moderate-J shaped (48.3%), and low-J shaped (33.1%), as well as 3 distinctive GWG trajectories: high increasing (14.7%), moderate increasing (48.6%) and low increasing (36.8%). A temporal coincidence between the maximal rate of GWG and DBP transition from its nadir to rebound was observed during 20⁺⁰ to 22⁺⁰ weeks. Moreover, women in the high-increasing GWG group had the highest probability of being in the high-J DBP group. The GWG rate during the late midsecond trimester (22⁺⁰ to 26⁺⁰ weeks) was consistently associated with an elevated DBP level: for every 200 g/wk increase, the multivariable-adjusted odds ratio was 1.27 (95% confidence interval, 1.13-1.43) for the trajectory shift to the high-J group and 1.20 (95% confidence interval, 1.07-1.35) for the occurrence of diastolic prehypertension after 37⁺⁰ weeks. Furthermore, adding a trimester-specific GWG rate (22⁺⁰ to 26⁺⁰ weeks) contributed to the incremental yield for the prediction of diastolic prehypertension after 37⁺⁰ weeks. Our results thus provide the timing and extent of gestational weight control relevant to the optimized BP level during pregnancy.

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

OBJECTIVE

To examine blood pressure (BP) differences and changes between and within ethnic Western European, South Asian, Middle Eastern, East Asian, African, and East European living in Norway, from early pregnancy to postpartum and to explore associations between BP and explanatory variables.

METHODS

This was a population-based cohort study of 811 healthy pregnant women, 59% had ethnic minority origin. Participants were from Western Europe, Eastern Europe, South Asia, East Asia, Middle East, and Africa. We performed ANOVA, generalized estimating equations linear regression and multiple linear regression analysis.

RESULTS

At 15 weeks' gestation, mean SBP were 4.9-7.0 mmHg lower and mean DBP 2.1-3.4 mmHg lower for the non-Europeans compared with Western Europeans. SBP increased in all non-European groups from 15 weeks' gestation to 14 weeks' postpartum (P < 0.01), but not in Europeans. Ethnic differences were further reduced postpartum, with only South Asians having lower mean SBP than Western Europeans (P < 0.01). The ethnic differences persisted after adjusting for age, family history of cardiovascular disease, prepregnancy BMI, and prepregnancy physical activity. Age, prepregnancy BMI, prepregnancy physical activity, postpartum weight retention, and breastfeeding were independently associated with postpartum BP (P < 0.05).

CONCLUSION

Pregnancy may have a more adverse effect on BP trajectories from early pregnancy to postpartum among non-European women compared with Western Europeans, despite their more favorable BP in early pregnancy.

Trajectory of blood pressure change during pregnancy and the role of pre-gravid blood pressure: a functional data analysis approach

The study aims to examine the blood pressure (BP) trajectory during pregnancy and its association with pre-gravid BP level. In a pre-conception cohort study, newly-married women in Liuyang, China underwent pre-gravid measurements and were followed throughout the pregnancy. BP was measured at pre-conception and again throughout pregnancy. The functional principal component analysis was used to examine the trajectory of BP changes during pregnancy. A total of 1282 women with a singleton pregnancy who had both pre-conception and gestational BP measurements performed were included in the final analysis. The results showed that BP decreased significantly in early pregnancy and increased thereafter, without BP drop around 20 weeks of gestation. Pre-gravid BP level was inversely associated with the BP drop in early pregnancy, such that women with higher pre-gravid BP had greater BP drop at the beginning, while women with the lowest pre-gravid BP level demonstrated no obvious BP drop throughout the entire pregnancy.

Relation of the Number of Parity to Left Ventricular Diastolic Function in Pregnancy

Left ventricular diastolic dysfunction (LVDD) has been relatively less studied than other cardiac changes during pregnancy. Previous studies revealed a mild diastolic deterioration during pregnancy. However, these studies did not evaluate the long-term effect of parity on left ventricular diastolic function. A comprehensive study evaluating the long-term effect of parity on diastolic function is required. A total of 710 women with various number of parity were evaluated through echocardiography to reveal the status of diastolic function. Echocardiographic parameters were compared among the women by parity number and categorized accordingly: none, 0 to 4 and 4< parity (grand multiparous). In nulliparous group, 19 women (23.2%) had grade 1 LVDD, and only 2 women (2.4%) had grade 2 LVDD. In women with a parity number of 0 to 4, 209 women (38.3%) had grade 1 LVDD, and only 17 women (3.1%) had grade 2 LVDD. In grand multiparous group, only 2 women (2.4%) did not have LVDD, and 12 women (14.6%) had grade 2 LVDD. None of the subjects had grade 3 or grade 4 LVDD. According to hierarchical logistic regression analysis, any grade of LVDD and grade 2 LVDD had the highest rates at parity category of > 4 parity and that had 21 and 5.8 times higher than nulliparous group, respectively. In conclusion, according to the present study, grand multiparity but not multiparity, severely deteriorates left ventricular diastolic function. Further studies are warranted to evaluate the risk of gradual diastolic dysfunction after each pregnancy.

Pulse Pressure Amplification and Arterial Stiffness in Low-Risk, Uncomplicated Pregnancies

Background:

Arterial stiffness, a composite indicator of vascular health and predictor of future cardiovascular (CV) disease and events, was assessed in low-risk, uncomplicated pregnancies.

Methods:

Women with low-risk pregnancy were recruited consecutively (recruitment across the 3 trimesters). Vessel hemodynamics and arterial stiffness were measured every 4 weeks from recruitment until delivery and at 6.5 weeks postpartum.

Results:

Sixty-three women (maternal age: 32.7 ± 4.9 years) with low-risk, uncomplicated pregnancy were recruited. Mean arterial pressure ( P = .04) and aortic pulse pressure ( P = .03) decreased during pregnancy, whereas heart rate gradually increased until delivery ( P = .0002) and decreased postpartum ( P = .06). Pulse pressure amplification (PPA) and carotid-to-radial pulse wave velocity initially decreased in the second trimester, followed by a steady increase until delivery ( P = .01 and P = .04, respectively). Interestingly, PPA sharply decreased postpartum ( P = .01). Augmentation index and the subendocardial viability ratio significantly increased postpartum ( P = .03 and .02, respectively).

Conclusion:

The PPA increased steadily after the second trimester and was sharply decreased postpartum in low-risk, uncomplicated pregnancy. Longer and larger longitudinal studies will evaluate changes in PPA and its potential as a marker of CV risk later in women’s life.

Blood pressure in healthy pregnancy and factors associated with no mid-trimester blood pressure drop: a prospective cohort study

BACKGROUND

The well-known mid-trimester drop in blood pressure (BP) during normal pregnancy was recently questioned.

OBJECTIVE

To describe longitudinal changes in BP during healthy pregnancies and to investigate factors associated with no mid-trimester drop in BP.

METHODS

A prospective cohort with 158 healthy pregnant women was followed up in a public health care center in Rio de Janeiro, Brazil. We used linear mixed-effects models to estimate longitudinal changes in systolic BP (SBP) and diastolic BP (DBP) during pregnancy. Poisson regression models were performed to identify factors associated with no mid-trimester drop in BP.

RESULTS

Significant mid-trimester increase in SBP (5.6 mm Hg; 95% confidence interval (CI) = 4.6-6.7) and DBP (4.4 mm Hg; 95% CI = 3.4-5.3) was observed in 44.3% and 39.9% of the sample, respectively. Women (37.1%) who had not a mid-trimester SBP drop still had a DBP drop. White skin color (incidence ratio (IR): 1.71; 95% CI = 1.22-2.39), family history of hypertension (IR: 1.93; 95% CI = 1.29-2.89), early pregnancy obesity (IR: 2.29; 95% CI = 1.27-4.11), outside temperature variation (IR: 1.45; 95% CI = 1.00-2.10), and gestational weight gain from the first to second trimester (IR: 1.71; 95% CI = 1.01-2.88 and IR: 2.32; 95% CI = 1.39-3.89 for second and third tertiles) were characteristics associated with no mid-trimester drop in SBP. The same characteristics were associated with no mid-trimester drop in DBP, except family history of hypertension and outside temperature variation.

CONCLUSIONS

Some women without a mid-trimester SBP drop still present a DBP drop. The different patterns of mid-trimester change in BP seem to be determined by preexisting and pregnancy-related factors.

Effect of external airflow resistive load on postural and exercise-associated cardiovascular and pulmonary responses in pregnancy: a case control study

BACKGROUND

Facial coverings (e.g., balaclavas, niqabs, medical/surgical masks, respirators, etc.), that impose low levels of airflow resistive loads, are worn by millions of pregnant women worldwide, but little data exist addressing their impact on pregnancy-associated cardiovascular and pulmonary responses.

METHODS

16 pregnant and 16 non-pregnant women were monitored physiologically (heart rate, blood pressure, mean arterial pressure, total peripheral resistance, stroke volume, cardiac output, oxygen saturation, transcutaneous carbon dioxide, fetal heart rate) and subjectively (exertion) for 1 h of mixed sedentary postural activity (sitting, standing) and moderate exercise (bicycle ergometer) with and without wearing N95 filtering facepiece respirators with filter resistive loads of 94.1 Pa (9.6 mm H2O) - 119.6 Pa (12.2 mm H2O) pressure.

RESULTS

The external airflow resistive loads were associated with increases in diastolic pressure (p = 0.004), mean arterial pressure (p = 0.01), and subjective exertion score (p < 0.001) of all study subjects. No significant differences were noted with the external resistive loads between the pregnant and non-pregnant groups for any cardiovascular, pulmonary and subjective variable over 1 h.

CONCLUSIONS

Low external airflow resistive loads, during combined sedentary postural activity and moderate exercise over 1 h, were associated with increases in the diastolic and mean arterial pressures of all study subjects, but pregnancy itself was not associated with any significant differences in physiologic or subjective responses to the external airway resistive loads utilized in the study.

Blood Pressure Variation Throughout Pregnancy According to Early Gestational BMI: A Brazilian Cohort

Background

The maternal cardiovascular system undergoes progressive adaptations throughout pregnancy, causing blood pressure fluctuations. However, no consensus has been established on its normal variation in uncomplicated pregnancies.

Objective

To describe the variation in systolic blood pressure (SBP) and diastolic blood pressure (DBP) levels during pregnancy according to early pregnancy body mass index (BMI).

Methods

SBP and DBP were measured during the first, second and third trimesters and at 30-45 days postpartum in a prospective cohort of 189 women aged 20-40 years. BMI (kg/m²) was measured up to the 13^th gestational week and classified as normal-weight (<25.0) or excessive weight (≥25.0). Longitudinal linear mixed-effects models were used for statistical analysis.

Results

A decrease in SBP and DBP was observed from the first to the second trimester (β_SBP=-0.394; 95%CI: -0.600- -0.188 and β_DBP=-0.617; 95%CI: -0.780- -0.454), as was an increase in SBP and DBP up to 30-45 postpartum days (β_SBP=0.010; 95%CI: 0.006-0.014 and β_DBP=0.015; 95%CI: 0.012-0.018). Women with excessive weight at early pregnancy showed higher mean SBP in all gestational trimesters, and higher mean DBP in the first and third trimesters. Excessive early pregnancy BMI was positively associated with prospective changes in SBP (β_SBP=7.055; 95%CI: 4.499-9.610) and in DBP (β_DBP=3.201; 95%CI: 1.136-5.266).

Conclusion

SBP and DBP decreased from the first to the second trimester and then increased up to the postpartum period. Women with excessive early pregnancy BMI had higher SBP and DBP than their normal-weight counterparts throughout pregnancy, but not in the postpartum period.

Microvascular remodelling in preeclampsia: quantifying capillary rarefaction accurately and independently predicts preeclampsia

BACKGROUND

Preeclampsia is a major cause of maternal and neonatal mortality and morbidity. The incidence of preeclampsia seems to be rising because of increased prevalence of predisposing disorders, such as essential hypertension, diabetes, and obesity, and there is increasing evidence to suggest widespread microcirculatory abnormalities before the onset of preeclampsia. We hypothesized that quantifying capillary rarefaction could be helpful in the clinical prediction of preeclampsia.

METHODS

We measured skin capillary density according to a well-validated protocol at 5 consecutive predetermined visits in 322 consecutive white women, of whom 16 subjects developed preeclampsia.

RESULTS

We found that structural capillary rarefaction at 20-24 weeks of gestation yielded a sensitivity of 0.87 with a specificity of 0.50 at the cutoff of 2 capillaries/field with the area under the curve of the receiver operating characteristic value of 0.70, whereas capillary rarefaction at 27-32 weeks of gestation yielded a sensitivity of 0.75 and a higher specificity of 0.77 at the cutoff of 8 capillaries/field with area under the curve of the receiver operating characteristic value of 0.82. Combining capillary rarefaction with uterine artery Doppler pulsatility index increased the sensitivity and specificity of the prediction. Multivariable analysis shows that the odds of preeclampsia are increased in women with previous history of preeclampsia or chronic hypertension and in those with increased uterine artery Doppler pulsatility index, but the most powerful and independent predictor of preeclampsia was capillary rarefaction at 27-32 weeks.

CONCLUSIONS

Quantifying structural rarefaction of skin capillaries in pregnancy is a potentially useful clinical marker for the prediction of preeclampsia.

Blood pressure measured in the clinic and at home during pregnancy among nulliparous and multiparous women: the BOSHI study

BACKGROUND

Hypertension during pregnancy can cause serious problems during delivery, such as stroke, premature delivery, or low birthweight. Nulliparity is believed to be a risk factor for hypertension during pregnancy. However, the relationship between parity and blood pressure determined at home during pregnancy is still unknown.

METHODS

We assessed the incidence of gestational hypertension or preeclampsia in 575 nulliparous and multiparous women. Also, we examined blood pressure measured in the clinic and at home among 530 normotensive pregnant women who received antenatal care at a maternity hospital in Japan. Clinic blood pressures (CBPs) were obtained by duplicate measurement at each antenatal care visit. The participants were also required to measure their own blood pressures every morning at home while they were pregnant. A linear mixed model was used for analysis of the blood pressure course throughout pregnancy.

RESULTS

A total of 315 nulliparous and 215 multiparous women were entered into this study (mean age, 30.1 ± 4.6 years and 33.0 ± 4.1 years, respectively). CBP levels during pregnancy among nulliparous women were significantly higher than among multiparous women (P = 0.02/P <0.0001 for systolic/diastolic blood pressure), whereas there were no significant differences in home blood pressure (HBP) levels during pregnancy between the two groups (P = 0.4/P = 0.2 for systolic/diastolic blood pressure).

CONCLUSIONS

HBP levels during pregnancy were shown not to differ between nulliparous and multiparous women, while CBP levels during pregnancy were higher among nulliparous than among multiparous women.