Heart rate and blood pressure in infants of pre-eclamptic mothers during the first hour of life

Assessment of the Cardiovascular Risk Profile of Infants Exposed to Pre-eclampsia in-utero: A Prospective Case-Control Study in South African Children of African Ancestry

Background: It has been reported that maternal gestational environment may be programmed to have a significant impact on foetal and offspring health later in life. Studies have shown that children born to pre-eclamptic mothers are prone to obesity, hypertension, and diabetes in their adult life. However, such findings are yet to be established in an African population. This protocol is for a study aiming to investigate the relationship between pre-eclampsia (PE) and cardiovascular risk in children born to pre-eclamptic mothers in a South African population of African descents.

Methods: A prospective case-control design will be employed to recruit pre-eclamptic and normotensive pregnant women and their offspring after birth. Pregnant women will be assessed for cardiovascular risk factors including PE, obesity, haemodynamics, lipids, glycaemic indices, oxidative stress, and vascular function at 30 weeks of gestation. The cardiovascular risk profile of their offspring will be assessed at birth and 6 weeks later. The difference in cardiovascular risk profile between children born to the pre-eclamptic and normotensive mothers will be compared and the correlation between maternal and offspring cardiovascular risks will be investigated.

Discussion: This will be the first prospective study to assess the in-utero effect of cardiovascular risk in offspring born to pre-eclamptic women of African ancestry. It is expected that findings from this study will provide information on the cardiovascular effect of in-utero exposure to PE in a population of African ancestry. This knowledge will advise policy on the management of women with PE with a view of protecting cardiovascular health in offspring.

Effect of Early-Onset Preeclampsia on Offspring's Blood Pressure during the First Month of Life

OBJECTIVE

To explore the effect of early-onset preeclampsia on the blood pressure of offspring during the first month of life.

STUDY DESIGN

This prospective case-control study included 106 neonates of mothers with early-onset preeclampsia (developing at <34 weeks of gestation) and 106 infants of normotensive mothers, matched 1-to-1 for sex and gestational age. Serial blood pressure measurements were obtained on admission, daily for the first postnatal week, and then weekly up to the fourth week of life.

RESULTS

There were no differences in blood pressure values on admission and the first day of life between cases and controls. Conversely, infants exposed to preeclampsia had significantly higher systolic (SBP), diastolic (DBP), and mean blood pressure (MBP) on the subsequent days up to the fourth postnatal week (P <.001-.033). Multiple regression analyses with adjustment for sex, gestational age, antenatal corticosteroid use, and maternal antihypertensive medication use confirmed the foregoing findings (P <.001-.048). Repeated-measures ANOVA also identified preeclampsia as a significant determinant of trends in SBP, DBP, and MBP during the first month of life (F = 16.2, P < .001; F = 16.4, P < .001; and F = 17.7, P < .001, respectively).

CONCLUSIONS

Infants of mothers with early-onset preeclampsia have elevated blood pressure values throughout the neonatal period compared with infants born to normotensive mothers.

Osteoprotegerin and RANKL serum concentrations in neonates of mothers with early-onset pre-eclampsia: comparison with neonates of normotensive mothers

BACKGROUND

Pre-eclampsia is a known risk factor for long-term cardiovascular complications. Osteoprotegerin (OPG) and the receptor activator of nuclear factor κB ligand (RANKL) have been implicated in the pathogenesis of cardiovascular disease. The OPG-RANKL axis function is also altered in pregnant women with pre-eclampsia, but there is lack of data regarding OPG and RANKL concentrations in their neonates.

AIMS

To examine the effects of early-onset pre-eclampsia on OPG and RANKL serum concentrations at birth, taking into account the influence of various perinatal factors.

STUDY DESIGN

OPG and RANKL serum concentrations were measured in 28 premature newborns of mothers with early onset pre-eclampsia, and in 28 preterm and 28 full-term neonates of normotensive mothers (control groups).

RESULTS

Neonates of pre-eclamptic mothers had higher OPG and lower RANKL levels compared to both control groups (Kruskal-Wallis P < 0.0001 and P = 0.014, respectively). Regression analysis showed that pre-eclampsia (P < 0.0001), birth weight z-score (P = 0.048) and antenatal steroid administration (P = 0.034) were significant determinants of OPG levels. Multivariable regression analysis also showed that pre-eclampsia was an independent predictor of increased diastolic and mean blood pressure in these neonates.

CONCLUSIONS

Early-onset pre-eclampsia affects OPG concentrations at birth and is an independent predictor of increased blood pressure in the offspring. Our findings suggest that altered OPG-RANKL axis function may be one of the mechanisms of cardiovascular 'programming' in fetuses exposed to pre-eclampsia.

Preeclampsia As Modulator of Offspring Health

A balanced intrauterine homeostasis during pregnancy is crucial for optimal growth and development of the fetus. The intrauterine environment is extremely vulnerable to multisystem pregnancy disorders such as preeclampsia, which can be triggered by various pathophysiological factors, such as angiogenic imbalance, immune responses, and inflammation. The fetus adapts to these conditions by a mechanism known as developmental programming that can lead to increased risk of chronic noncommunicable diseases in later life. This is shown in a substantial number of epidemiological studies that associate preeclampsia with increased onset of cardiovascular and metabolic diseases in the later life of the offspring. Furthermore, animal models based predominantly on one of the pathophysiological mechanism of preeclampsia, for example, angiogenic imbalance, immune response, or inflammation, do address the susceptibility of the preeclamptic offspring to increased maternal blood pressure and disrupted metabolic homeostasis. Accordingly, we extensively reviewed the latest research on the role of preeclampsia on the offspring's metabolism and cardiovascular phenotype. We conclude that future research on the pathophysiological changes during preeclampsia and methods to intervene in the harsh intrauterine environment will be essential for effective therapies.

Preeclampsia: effect on newborn blood pressure in the 3 days following preterm birth: a cohort study

Maternal hypertension and preeclampsia are associated with greater risk of hypertension in childhood, and cardiovascular events in adulthood. However, whether preeclampsia affects blood pressure (BP) in the newborn period is unclear. Previous neonatal studies were based on small sample sizes, very low birth weight or gestational age or limited duration (h). To delineate hemodynamic repercussions of maternal preeclampsia on preterm infants (gestational ages ⩾29 weeks) with/without intrauterine growth restriction (IUGR) in the first 3 postnatal days, we conducted a single-centre retrospective cohort study of singleton births at 29-35 weeks of gestation in Montreal, Canada, from 2008 to 2011. Data were obtained from medical charts. Exclusion criteria included congenital anomalies, infections, pre-pregnancy maternal hypertension and gestational diabetes. IUGR was defined as birth weight <10th percentile. Of the 338 eligible neonates, 230 were included: 75 preeclampsia-IUGR, 72 preeclampsia-only and 83 controls. The preeclampsia-IUGR group had longer gestations than the preeclampsia-only or control groups (32.4±1.8 vs. 31.3±1.6 vs. 31.7±1.6 weeks, respectively; P<0.001). Mean BPs increased over the first 3 days for all newborns (P<0.001). Infants with preeclampsia-associated IUGR had the highest systolic and diastolic BPs, even after adjustment for birth weight, and preeclampsia-only the next highest. Systolic BP progression showed significant differences between groups (P<0.05). We conclude that impact of preeclampsia on children blood pressure was manifest within days of birth, over and above coexisting IUGR. Long-term cardiovascular follow-up and targeted preventive strategies are advised for this underrecognized high-risk population.

Determinants of neonatal blood pressure

Blood pressure (BP) measurements have been increasingly used across neonatal intensive care units to determine and monitor hemodynamic status in neonates. A number of studies have attempted to derive normative blood pressure data in both preterm and term infants. However, this still remains a complex process, as several maternal and neonatal factors influence neonatal blood pressure. Maternal conditions, including hypertension and preeclampsia, seem to have some impact on neonatal BP, while maternal drugs, in particular antenatal steroids, seem to have a strong influence. Among the neonatal factors, gestational age, post-conceptual age and weight seem to have the strongest influence. The paucity of data on the short and long term effects of maternal conditions and medication on neonatal BP requires further research.

Pre-eclampsia and offspring cardiovascular health: mechanistic insights from experimental studies

Pre-eclampsia is increasingly recognized as more than an isolated disease of pregnancy. Women who have had a pregnancy complicated by pre-eclampsia have a 4-fold increased risk of later cardiovascular disease. Intriguingly, the offspring of affected pregnancies also have an increased risk of higher blood pressure and almost double the risk of stroke in later life. Experimental approaches to identify the key features of pre-eclampsia responsible for this programming of offspring cardiovascular health, or the key biological pathways modified in the offspring, have the potential to highlight novel targets for early primary prevention strategies. As pre-eclampsia occurs in 2–5% of all pregnancies, the findings are relevant to the current healthcare of up to 3 million people in the U.K. and 15 million people in the U.S.A. In the present paper, we review the current literature that concerns potential mechanisms for adverse cardiovascular programming in offspring exposed to pre-eclampsia, considering two major areas of investigation: first, experimental models that mimic features of the in utero environment characteristic of pre-eclampsia, and secondly, how, in humans, offspring cardiovascular phenotype is altered after exposure to pre-eclampsia. We compare and contrast the findings from these two bodies of work to develop insights into the likely key pathways of relevance. The present review and analysis highlights the pivotal role of long-term changes in vascular function and identifies areas of growing interest, specifically, response to hypoxia, immune modification, epigenetics and the anti-angiogenic in utero milieu.

Antenatal dexamethasone and renal vascular resistance in preterm infants

OBJECTIVE

To compare vascular resistance, renal volume and insulin levels in preterm infants with and without antenatal steroids.

METHODS

We studied 61 preterm infants (37 with (group A) and 24 without antecedent of antenatal steroids (group B)). We measured insulin levels at birth in cord blood samples. Ultrasound measurements to evaluate renal arteries resistance index and renal volume were performed during the first 72 h of birth.

RESULTS

Preterm infants from group A tended to have lower weight and gestational age than those from group B. Resistance index in renal arteries was lower in preterm infants with steroid therapy compared with group B (right renal artery 0.73 vs. 0.80; P=0.001, and left renal artery 0.75 vs. 0.79; P=0.01, respectively). Renal volume and insulin levels were not different between the groups. In the multiple regression analysis for factors associated with resistance index of renal arteries, only antenatal steroids use was included in the model (R2=0.13; P=0.003 and R2=0.10; P=0.01 for left and right renal arteries, respectively).

CONCLUSION

Antenatal dexamethasone in preterm infants during the first 72 h of birth seems to decrease resistance index in renal arteries without affecting renal volume and insulin levels.

Maternal and neonatal influences on, and reproducibility of, neonatal aortic pulse wave velocity

Aortic pulse wave velocity (aPWV), a noninvasive measure of vascular stiffness, is an independent predictor of cardiovascular disease both before and in overt vascular disease. Its characteristics in early life and its relationship to maternal factors have hardly been studied. To test the hypothesis that infant aPWV was positively related to maternal anthropometry and blood pressure (BP) at 28 weeks gestation, after adjusting for neonatal anthropometry and BP, 148 babies born in Manchester were measured 1 to 3 days after birth. A high reproducibility of aPWV, assessed in 30 babies within 3 days of birth, was found with a mean difference between occasions of -0.04 m/s (95% CI: -0.08 to 0.16 m/s). Contrary to our hypothesis, a significant inverse relation was found between neonatal aPWV (mean: 4.6 m/s) and maternal systolic BP (mean: 108.9 mm Hg; r=-0.57; 95% CI: -0.67 to -0.45) but not maternal height nor weight. Neonatal aPWV was positively correlated with birth length, birth weight, and systolic BP. In multiple regression, neonatal aPWV remained significantly inversely associated with maternal systolic BP (adjusted beta coefficient: -0.032; 95% CI: -0.040 to -0.024; P<0.001), after adjustment for maternal age, birth weight, length, and neonatal BP (all independently and positively related to aPWV) and for gestational age, maternal weight, and height (unrelated). These results suggest that infant aPWV may be a useful index of infant vascular status, is less disturbing to measure than infant BP, and is sensitive to the gestational environment marked by maternal BP.

Effect of preeclampsia on blood pressure in newborn very low birth weight infants

OBJECTIVE

To test the hypothesis that very low birth infants born to mothers with preeclampsia have higher blood pressure over the first week of life than infants whose mothers did not have preeclampsia.

METHOD

Infants born at<1,350 g who survived at least one week were stratified by gestational age ( <or= 28 weeks and >or= 29 completed weeks) and grouped by the presence or absence of preeclampsia. Highest and lowest systolic and mean and diastolic blood pressures were recorded for each of the first seven days of life. Serial blood pressures were analyzed by repeated measures ANOVA: The presence of hypertension (defined as >or= 3 days with the highest systolic blood pressure>90th percentile for gestational age stratum and day-specific range) was analyzed by binary logistic regression.

RESULTS

Infants >or= 29 weeks gestational age born to mothers with preeclampsia had higher blood pressures than did controls. Infants <or= 28 weeks gestational age born to preeclamptic and non-preeclamptic mothers had similar blood pressures. In the combined cohort, hypertension was not more prevalent among infants born to women with preeclampsia.

CONCLUSIONS

Preeclampsia is associated with higher blood pressure in very low birth weight neonates who are >or= 29 weeks gestation. The long-term significance of this finding is not known.

Blood pressure in the very low birth weight neonate

Few aspects of management of very low birth weight (VLBW; <1500 g) neonates have generated as much controversy as the assessment of blood pressure (BP) and need for treatment of perceived abnormalities of this physiologic variable. The approach to this problem may differ greatly among various institutions and even among clinicians within a given center. The purpose of this manuscript is to review available information regarding physiologic determinants and measurement of BP in VLBW neonates, normative data for BP, clinical factors that may affect BP in these at-risk neonates and studies in which presumed abnormalities of BP resulted in adverse clinical outcomes. Options for treatment of low BP in VLBW neonates also will be discussed.

Control of blood pressure and the distribution of blood flow

Systemic blood pressure (BP) is the product of cardiac output and total peripheral resistance. Cardiac output is controlled by the heart rate, myocardial contractility, preload, and afterload. Vascular resistance (vascular hindrance × viscosity) is under local autoregulation and general neurohumoral control through sympathetic adrenergic innervation and circulating catecholamines. Sympathetic innovation predominates in organs receivingflowin excess of their metabolic demands (skin, splanchnic organs, kidney), while innervation is poor and autoregulation predominates in the brain and heart. The distribution of blood flow depends on the relative resistances of the organ circulations. During stress (hypoxia, low cardiac output), a raise in adrenergic tone and in circulating catecholamines leads to preferential vasoconstriction in highly innervated organs, so that blood flow is directed to the brain and heart. Catecholamines also control the levels of the vasoconstrictors renin, angiotensin II, and vasopressin. These general principles also apply to the neonate.