Regional circulatory contributions to increased systemic vascular conductance of pregnancy

Latest Concepts in Endodontic Management of Pregnant Patients

Pregnant patients and how to manage their treatments is one of the most important challenges in endodontic practice. Endodontic treatment on pregnant women is sometimes an emergency condition to control toothache due to irreversible pulpitis and odontogenic infection. Tooth decay, oral health, local and general anesthesia, analgesics, antibiotic prescription, drug interactions, and X-ray radiation are the most important considerations that may impact treatment planning and endodontic practice in pregnancy. The aim of this article is to notify and explain the latest concepts in the endodontic management of pregnant patients.

ASPRE trial: effects of aspirin on mean arterial blood pressure and uterine artery pulsatility index trajectories in pregnancy

OBJECTIVES

The mechanism by which aspirin prevents pre-eclampsia is poorly understood, and its effects on biomarkers throughout pregnancy are unknown. We aimed to investigate the effects of aspirin on mean arterial pressure (MAP) and mean uterine artery pulsatility index (UtA-PI) using repeated measures from women at increased risk of preterm pre-eclampsia.

METHODS

This was a longitudinal secondary analysis of the Combined Multimarker Screening and Randomized Patient Treatment with Aspirin for Evidence-Based Pre-eclampsia Prevention (ASPRE) trial using repeated measures of MAP and UtA-PI. In the trial, 1620 women at increased risk of preterm pre-eclampsia were identified using the Fetal Medicine Foundation algorithm at 11 + 0 to 13 + 6 weeks, of whom 798 were randomly assigned to receive 150 mg/day aspirin and 822 were assigned to receive placebo daily from 11-14 weeks to 36 weeks of gestation or delivery, whichever came first. MAP and UtA-PI were measured at baseline and follow-up visits at 19-24, 32-34 and 36 weeks of gestation. Generalized additive mixed models with treatment by gestational age interaction terms were used to investigate the effects of aspirin on MAP and UtA-PI trajectories over time.

RESULTS

Among 798 participants in the aspirin group and 822 in the placebo group, there were 5951 MAP and 5942 UtA-PI measurements. Trajectories of raw and multiples of the median (MoM) values of MAP did not differ significantly between the two groups (MAP MoM analysis: P-value for treatment by gestational age interaction, 0.340). In contrast, trajectories of raw and MoM values of UtA-PI showed a significantly steeper decline in the aspirin group than in the placebo group, with the difference mainly driven by a more pronounced reduction before 20 weeks of gestation (UtA-PI MoM analysis: P-value for treatment by gestational age interaction, 0.006).

CONCLUSIONS

In women at increased risk of preterm pre-eclampsia, 150 mg/day aspirin initiated in the first trimester does not affect MAP but is associated with a significant decrease in mean UtA-PI, particularly before 20 weeks of gestation. © 2023 The Authors. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of International Society of Ultrasound in Obstetrics and Gynecology.

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.

Pregnancy and Dentistry: A Literature Review on Risk Management during Dental Surgical Procedures

Background: Pregnancy is a unique moment in a woman’s life, accompanied with several physiologic changes that have an impact on oral health. Aim of the study: The purpose of the present study was to conduct a critical review of published literature regarding pregnancy and dentistry, the most frequent oral diseases that are encountered during pregnancy, their correlation to adverse pregnancy events, and safe dental treatments that can be performed during pregnancy. Methods: A Medline/COCHRANE search was carried using specific keywords and MeSH terms, combined with the boolean operators “OR” and “AND”. Results: The search led to 146 publications including guidelines, meta-analyses, systematic and non-systematic reviews, published between 2000 and 2021. Discussion and conclusions: Due to the increased inflammatory and immune body response that characterizes pregnancy, periodontal conditions are often aggravated during pregnancy and periodontal disease encountered frequently in pregnant patients. There are conflicting study results in the literature regarding the association between periodontitis and adverse pregnancy outcomes. Periodontal treatment did not show a significant reduction in the adverse outcomes. Many dentists, often due to lack of information, are reluctant to provide dental treatment to pregnant women. However, preventive and restorative dental treatment is safe during pregnancy. Diagnostic radiographs may be performed after the first trimester if absolutely necessary. Analgesics (such as paracetamol) and anesthetics (such as lidocaine) are also considered safe. In case of infection, antibacterial drugs such as amoxicillin, ampicillin, and some cephalosporines and macrolides can also be prescribed. Organogenesis takes place in the first trimester, the time during which the fetus is susceptible to severe malformations (teratogenesis). The ideal time to perform dental treatment is the second trimester (week 17 to 28). However, acute pain or infections make the intervention of the dentist absolutely necessary and emergency treatment can be performed during the whole pregnancy period.

The thrill of the paper, the agony of the review

The process of first writing a scientific paper and then responding to reviewer comments can be challenging and sometimes-some might say often-frustrating. In this personal view, I recount some of my experiences as an author, and I offer some strategies to write a paper and to then respond to comments from the people who reviewed it.

Cardiovascular Complications of Pregnancy

Pregnancy causes significant metabolic and hemodynamic changes in a woman's physiology to allow for fetal growth. The inability to adapt to these changes might result in the development of hypertensive disorders of pregnancy (hypertension, preeclampsia or eclampsia), gestational diabetes and preterm birth. Contrary to previous beliefs these complications are not limited to the pregnancy period and may leave permanent vascular and metabolic damage. There is in addition, a direct association between these disorders and increased risk of future cardiovascular disease (CVD, including hypertension, ischemic heart disease, heart failure and stroke) and diabetes mellitus. Despite abundant evidence of this association, women who present with these complications of pregnancy do not receive adequate postpartum follow up and counseling regarding their increased risk of future CVD. The postpartum period in these women represents a unique opportunity to intervene with lifestyle modifications designed to reduce the development of premature cardiovascular complications. In some cases it allows early diagnosis and treatment of chronic hypertension or diabetes mellitus. The awareness of this relationship is growing in the medical community, especially among obstetricians and primary care physicians, who play a pivotal role in detecting these complications and assuring appropriate follow up.

Statement on pregnancy in pulmonary hypertension from the Pulmonary Vascular Research Institute

Pregnancy outcomes in patients with pulmonary hypertension remain poor despite advanced therapies. Although consensus guidelines recommend against pregnancy in pulmonary hypertension, it may nonetheless occasionally occur. This guideline document sought to discuss the state of knowledge of pregnancy effects on pulmonary vascular disease and to define usual practice in avoidance of pregnancy and pregnancy management. This guideline is based on systematic review of peer-reviewed, published literature identified with MEDLINE. The strength of the literature was graded, and when it was inadequate to support high-level recommendations, consensus-based recommendations were formed according to prespecified criteria. There was no literature that met standards for high-level recommendations for pregnancy management in pulmonary hypertension. We drafted 38 consensus-based recommendations on pregnancy avoidance and management. Further, we identified the current state of knowledge on the effects of sex hormones during pregnancy on the pulmonary vasculature and right heart and suggested areas for future study. There is currently limited evidence-based knowledge about both the basic molecular effects of sex hormones and pregnancy on the pulmonary vasculature and the best practices in contraception and pregnancy management in pulmonary hypertension. We have drafted 38 consensus-based recommendations to guide clinicians in these challenging topics, but further research is needed in this area to define best practices and improve patient outcomes.

The treatment of hypertension during pregnancy: when should blood pressure medications be started?

Hypertensive pregnancy disorders (HPD) are important causes of maternal and fetal morbidity and mortality worldwide. In addition, a history of HPD has been associated with an increased risk for maternal cardiovascular disease later in life, possibly because of irreversible vascular and metabolic changes that persist beyond the affected pregnancies. Therefore, treatment of HPD may not only improve immediate pregnancy outcomes, but also maternal long-term cardiovascular health. Unlike the recommendations for hypertension treatment in the general population, treatment recommendations for HPD have not changed substantially for more than 2 decades. This is particularly true for mild to moderate hypertension in pregnancy, defined as a blood pressure of 140-159/90-109 mm Hg. This review focuses on the goals of therapy, treatment strategies, and new developments in the field of HPD that should be taken into account when considering blood pressure targets and pharmacologic options for treatment of hypertension in pregnant women.

Role of the AT2 receptor in modulating the angiotensin II contractile response of the uterine artery at mid-gestation

INTRODUCTION

During human pregnancy, circulating concentrations of components of the renin-angiotensin system increase, but pressor refractoriness to angiotensin II (Ang-II) is observed. Given the importance of the Ang-II pressor response in deciding susceptibility to preeclampsia and of the Ang-II system for controlling uterine vasoreactivity, we sought to address the effects of pregnancy on the reactivity of the isolated uterine artery (UA) in mice.

MATERIALS AND METHODS

Blood pressure was measured throughout pregnancy in awake C57BL/6J mice. UA segments were isolated from three groups of animals (non-pregnant, mid [day 12-13] and late [day 18-19] gestation) and studied by wire myography.

RESULTS

UA diameters, KCl-mediated responses, and acetylcholine-dependent vasorelaxation were greater at mid and late gestation than in non-pregnant animals. Ang-II responses were also greater during pregnancy, with an increased contraction in response to AT2 receptor blockade at mid-gestation. AT1 receptor blockade abolished the Ang-II response in all groups.

CONCLUSIONS

Study findings are consistent with the possibility that AT2 receptor-mediated vasodilatation plays a role in modulating Ang-II contractile responses in pregnancy.

Autonomic circulatory control during pregnancy in humans

Pregnancy is associated with dramatic alterations in maternal hemodynamics, which begin as early as 4 to 5 weeks of gestation. It has been proposed that these changes occur through autonomic control mechanisms, but the actual role of the autonomic nervous system in pregnancy is poorly understood. Here, we review what is known about the hemodynamic adaptation, changes in vascular endothelial function, sympathetic neural control and vascular responsiveness in pregnancy, and baroreflex function during pregnancy in humans. However, whether and how the sympathetic nervous system plays a role in hemodynamic homeostasis during EARLY human pregnancy remains completely unknown. Understanding the pathophysiology underlying autonomic control of maternal hemodynamics may be particularly important for prevention of cardiovascular complications during pregnancy and may improve risk stratification and prevention of cardiovascular disease for women well beyond the postpartum period.

Maternal cardiovascular changes during pregnancy and postpartum in mice

Genetically altered mice may provide useful models for exploring cardiovascular regulation during pregnancy and postpartum if changes in mice mimic humans. We found in awake ICR (CD-1) mice at 17.5 days gestation that hematocrit was reduced 18%, and the pressor response to intravenous angiotensin II was reduced ~33%. Arterial pressure in awake mice was 12% lower in early pregnancy (3.5 days) than late pregnancy (17.5 days) and postpartum (3 and 17 days after delivery), whereas heart rate was 10-20% higher in the peripartum period (17.5 days gestation and 3 days postpartum). In late pregnancy, cardiac output under isoflurane anesthesia was 64% higher than in nonpregnant mice, due to a 37% increase in stroke volume and a 17% increase in heart rate. All changes P < 0.05. We conclude that, as in humans, mice exhibit hypotension in early pregnancy, and a blunted pressor response to angiotensin II, a decrease in hematocrit, and a marked increase in cardiac output in late pregnancy.

Mechanisms regulating angiotensin II responsiveness by the uteroplacental circulation

Pregnancy is associated with increases in cardiac output and uterine blood flow (UBF) and a fall in systemic vascular resistance. In ovine pregnancy, UBF rises from approximately 3% of cardiac output to approximately 25% at term gestation, reflecting a >30-fold rise in UBF by term. This increase in UBF supports exponential fetal growth during the last trimester and maintains fetal well-being by providing excess oxygen and nutrient delivery. These hemodynamic changes are associated with numerous hormonal changes, including increases in placental steroid hormones and enhanced activation of the renin-angiotensin and sympathetic nervous systems, all of which are believed to modulate systemic and uterine vascular adaptation and vascular reactivity. Systemic pressor responses to infused ANG II are attenuated in normotensive pregnancies and the uteroplacental vasculature is even less sensitive, suggesting development of mechanisms to maintain basal UBF and permit the rise in UBF necessary for fetal growth and well-being. The effects of ANG II on the uteroplacental vasculature are reviewed, and the mechanisms that may account for attenuated vascular sensitivity are examined, including ANG II metabolism, vascular production of antagonists, ANG II-receptor subtype expression, and the role of indirect mechanisms.

Angiotensin II indirectly vasoconstricts the ovine uterine circulation

The uterine vasculature of women and sheep predominantly expresses type 2 ANG II receptors that do not mediate vasoconstriction. Although systemic ANG II infusions increase uterine vascular resistance (UVR), this could reflect indirect mechanisms. Thus we compared systemic and local intra-arterial ANG II infusions in six near-term pregnant and five ovariectomized nonpregnant ewes to determine how ANG II increases UVR. Systemic ANG II dose-dependently (P > 0.001) increased arterial pressure (MAP) and UVR and decreased uterine blood flow (UBF) in pregnant and nonpregnant ewes; however, nonpregnant responses exceeded pregnant (P < 0.001). In contrast, local ANG II infusions at rates designed to achieve concentrations in the uterine circulation comparable to those seen during systemic infusions did not significantly decrease UBF in either group, and changes in MAP and UVR were absent or markedly attenuated. When MAP rose during local ANG II, which only occurred with doses > or =2 ng/ml, increases in MAP were delayed more than twofold compared with responses during systemic ANG II infusions and always preceded decreases in UBF, resembling that observed during systemic ANG II infusions. These observations demonstrate attenuated uterine vascular responses to systemic ANG II during pregnancy and suggest that systemic ANG II may increase UVR through release of another potent vasoconstrictor(s) into the systemic circulation.