Maternal Mean Arterial Blood Pressure Research Articles

Validation of machine-learning model for first-trimester prediction of pre-eclampsia using cohort from PREVAL study.

Effective first-trimester screening for pre-eclampsia (PE) can be achieved using a competing-risks model that combines risk factors from the maternal history with multiples of the median (MoM) values of biomarkers. A new model using artificial intelligence through machine-learning methods has been shown to achieve similar screening performance without the need for conversion of raw data of biomarkers into MoM. This study aimed to investigate whether this model can be used across populations without specific adaptations. Previously, a machine-learning model derived with the use of a fully connected neural network for first-trimester prediction of early (< 34 weeks), preterm (< 37 weeks) and all PE was developed and tested in a cohort of pregnant women in the UK. The model was based on maternal risk factors and mean arterial blood pressure (MAP), uterine artery pulsatility index (UtA-PI), placental growth factor (PlGF) and pregnancy-associated plasma protein-A (PAPP-A). In this study, the model was applied to a dataset of 10 110 singleton pregnancies examined in Spain who participated in the first-trimester PE validation (PREVAL) study, in which first-trimester screening for PE was carried out using the Fetal Medicine Foundation (FMF) competing-risks model. The performance of screening was assessed by examining the area under the receiver-operating-characteristics curve (AUC) and detection rate (DR) at a 10% screen-positive rate (SPR). These indices were compared with those derived from the application of the FMF competing-risks model. The performance of screening was poor if no adjustment was made for the analyzer used to measure PlGF, which was different in the UK and Spain. Therefore, adjustment for the analyzer used was performed using simple linear regression. The DRs at 10% SPR for early, preterm and all PE with the machine-learning model were 84.4% (95% CI, 67.2-94.7%), 77.8% (95% CI, 66.4-86.7%) and 55.7% (95% CI, 49.0-62.2%), respectively, with the corresponding AUCs of 0.920 (95% CI, 0.864-0.975), 0.913 (95% CI, 0.882-0.944) and 0.846 (95% CI, 0.820-0.872). This performance was achieved with the use of three of the biomarkers (MAP, UtA-PI and PlGF); inclusion of PAPP-A did not provide significant improvement in DR. The machine-learning model had similar performance to that achieved by the FMF competing-risks model (DR at 10% SPR, 82.7% (95% CI, 69.6-95.8%) for early PE, 72.7% (95% CI, 62.9-82.6%) for preterm PE and 55.1% (95% CI, 48.8-61.4%) for all PE) without requiring specific adaptations to the population. A machine-learning model for first-trimester prediction of PE based on a neural network provides effective screening for PE that can be applied in different populations. However, before doing so, it is essential to make adjustments for the analyzer used for biochemical testing. © 2023 International Society of Ultrasound in Obstetrics and Gynecology.

Effect of transdermal nitroglycerin compared with sildenafil citrate on Doppler indices in intrauterine growth restriction

Objective This study aimed to compare the effect of sildenafil citrate on pulsatility index of uterine, umbilical and middle cerebral arteries to that of nitroglycerine in cases of intrauterine growth restriction (IUGR). Background IUGR is one of the most common and serious complications of pregnancy. Sildenafil citrate and nitroglycerine are emerging as potential candidates for the treatment of IUGR through improving uteroplacental blood flow. Participants and methods Ninety singleton pregnancies, with IUGR and abnormal uterine and umbilical arteries Doppler, were included in the study and randomized into three groups to receive either oral sildenafil citrate (50 mg), a transdermal nitroglycerine patch (10 mg), or placebo. Maternal mean arterial blood pressure and the pulsatility index (PI) of uterine (Ut.A), umbilical (UA) and fetal middle cerebral (MCA) arteries were measured before and two hours after application of drugs. Results A significant reduction of Ut.A-PI occurred after application of both sildenafil citrate (16.7%, P = 0.001) and nitroglycerine (18.7%, P = 0.001). UA-PI also showed a significant decrease with both sildenafil citrate (17.8%, P = 0.001) and nitroglycerine (17.03%, P = 0.001), with no significant difference between the two drugs. No changes were observed in Doppler velocimetry in the placebo group, and no significant change in MCA-PI was observed in any group. Maternal arterial blood pressure decreased significantly with administration of both sildenafil citrate and nitroglycerine. Conclusion Sildenafil citrate has an effect similar to nitroglycerine in improving Doppler indices and blood flow of uterine and umbilical arteries in growth-restricted fetuses.

Serum Adropin Levels in a Preeclampsia Like L-Name Rat Model Treated with Sildenafil Citrate

AbstractBackground: Preeclampsia, a hypertensive disorder of pregnancy, is detrimental to both mother and fetus. Sildenafil been proposed as a potential therapy to reduce blood pressure and improve uteroplacental perfusion in preeclamptic patients. Adropin is a novel secreted energy homeostasis protein regulating carbohydrate, lipid and protein metabolism, maternal adropin levels in Preeclampsia were still controversy.Aim of the Work: To evaluate serum levels of adropin in preeclampsia-like rat model and in preeclamptic rats treated with Sildenafil and to investigate their associations with some inflammatory, oxidative stress, and metabolic parameters.Material and Methods: 32 pregnant rats were divided randomly into four groups (n=8): Control group, sildenafil treated group, L-NAME group to induce pre-eclampsia and L-NAME with sildenafil treated group. In all groups, maternal Body Mass Index (BMI), placental weights, fetal weights, maternal mean arterial blood pressure (MAP), total urinary proteins, serum glucose, insulin and calculated Homeostatic Model Assessment of Insulin Resistance index (HOMA-IR), serum urea, creatinine, Triglycerides (TGs), Total Cholesterol (TC), Low Density Lipoproteins-cholesterol (LDL-c), High Density Lipoproteins-cholesterol (HDL-c), C Reactive Protein (CRP), Endothelin-1 (ET-1), and adropin were measured, also placental Malondialdehyde (MDA) levels, and activities of the antioxidant enzymes Superoxide Dismutase (SOD) and glutathione peroxidase (GSH) in placental homogenates were determined plus histopathological examination of placental sections were done.Results: L-NAME induced preeclampsia in rats and they showed significant increase in MAP, total urinary proteins, serum levels of glucose, insulin, calculated HOMA-IR, serum urea, creatinine, CRP, ET-1, TGs, TC, LDL-c, adropin and placental tissue MDA with significant reduction in maternal BMI, placental weights, fetal weights, serum HDL-c and placental tissue SOD and GSH activities as compared to other groups, additionally, L-NAME treated and L-NAME + SILD treated groups revealed positive significant correlations between adropin levels and MAP, total urinary proteins, serum levels of urea, creatinine, CRP, ET-1, TGs, TC, LDL-c, and placental tissue MDA, however they showed negative corre-lations between adropin and BMI, placental weights, fetal weights, serum HDL-c and placental tissue SOD and GSH activities.Conclusion: Increased maternal adropin levels in preec-lampsia like model in rats might represent a regulatory feed-back mechanism against endothelial placental dysfunction, insulin resistance, inflammation and oxidative stress which associated with preeclampsia, hence identify it as a potentially protective agent against preeclampsia development. Sildenafil ameliorates preeclampsia symptoms, inflammation and oxi-dative stress in a rat model of preeclampsia.

Clinical Implications

HomeHypertensionVol. 68, No. 6Clinical Implications Free AccessResearch ArticlePDF/EPUBAboutView PDFView EPUBSections ToolsAdd to favoritesDownload citationsTrack citationsPermissions ShareShare onFacebookTwitterLinked InMendeleyReddit Jump toFree AccessResearch ArticlePDF/EPUBClinical Implications Originally published1 Dec 2016https://doi.org/10.1161/HYPERTENSIONAHA.116.08492Hypertension. 2016;68:1321Cardiovascular Health and Masked Hypertension (p 1475)Download figureDownload PowerPointPrevious data from the Jackson Heart Study indicate that the prevalence of masked hypertension exceeds 50% in African Americans. Masked hypertension is associated with 2× the risk for cardiovascular disease. Data suggest that individuals with prehypertension have a high probability of having prevalent masked hypertension. Despite the importance of masked hypertension on cardiovascular outcomes, there have been few studies investigating risk factors for masked hypertension. Identifying modifiable risk factors for masked hypertension may provide an approach to prevent its development and reduce its prevalence. In the current study, Bromfield et al report that better cardiovascular health (ideal levels of body mass index, physical activity, nonsmoking, diet, clinic blood pressure, total cholesterol, and fasting glucose) was associated with a lower prevalence of masked daytime, nighttime, and 24-hour hypertension, and any masked hypertension were less prevalent among participants with. These results provide evidence that improving and maintaining cardiovascular health may lower the probability of having masked hypertension in African Americans. Although randomized clinical trials are needed to determine the efficacy of lifestyle interventions on delaying or preventing masked hypertension, clinicians should continue to encourage their patients to improve their cardiovascular risk factors through lifestyle modification, specifically by improving physical activity and diet and stopping cigarette smoking that can result in lower clinic blood pressure levels and maintain better cardiovascular health.Fetal Imprinted Genes and Maternal Blood Pressures (p 1459)Download figureDownload PowerPointEpidemiological studies suggest that gestational hypertension has both environmental and genetic pathogenic components. Defining its genetic risk factors may lead to improvements in pregnancy risk assessment and novel therapeutic targets. Known maternal genetic risk variants only account for a small fraction of the total genetic risk of gestational hypertension. The fetal genome may also contribute to that risk. Petry et al tested fetal variants in imprinted genes for associations with maternal blood pressure in pregnancy because these genes are thought to mediate the separate reproductive genetic needs of each parent. Using 2 birth cohorts from Cambridge, United Kingdom, they found 7 variants that were significantly associated with maternal blood pressure in the second half of pregnancy. In meta-analyses with additional independent data from the Hyperglycemia and Adverse Pregnancy Outcome Study, one of these variants, maternally transmitted fetal rs10139403, was associated with maternal mean arterial blood pressure at the genome-wide level—the first such finding of its kind. A composite fetal imprinted gene allele score constructed from the 7 key variants was associated with both maternal mean arterial blood pressure in the second half of pregnancy at the genome-wide level (explaining up to 8.7% of its variance) and gestational hypertension (each additional risk allele contributing an additional 50% to the risk). These data support the concept that fetal imprinted genes are related to the development of gestational hypertension.Medication Use in Resistant Hypertension, 2008 to 2014 (p 1349)Download figureDownload PowerPointCurrent recommendations for treatment-resistant hypertension (TRH) include optimizing medical therapy such as thiazide diuretics and aldosterone antagonists. But the extent to which such recommendations have been implemented is not well studied, and little is known about longitudinal trends in antihypertensive use, generally, among patients with TRH. We analyzed antihypertensive use in US adults (aged 18–65 years) with apparent TRH, defined as the concurrent use of ≥4 antihypertensive agents, from July 2008 to December 2014 using Marketscan commercial claims data. Over this time period, thiazide diuretic use was generally stable and prevalent in >80% of TRH episodes. Hydrochlorothiazide predominated among thiazides for all time periods, whereas chlorthalidone use increased modestly from 3.8% to 6.3% of all TRH episodes from 2008 to 2014. Aldosterone antagonist prevalence increased by 2.9% (7.3%–10.2%) over the same time period, driven almost exclusively by greater spironolactone use (Figure). Likewise, dihydropyridine calcium channel blocker and β-blocker use increased over the study period, whereas angiotensin-converting enzyme inhibitor use decreased. Concurrent angiotensin-converting enzyme inhibitor and angiotensin receptor blocker use declined from 17.7% (2008) to 6.3% (2014) of TRH episodes, whereas the use of preferred 3-drug regimens (diuretic, dihydropyridine calcium channel blocker, and ACE-I or angiotensin receptor blocker, but not both) increased from 50.8% to 64.6%. Our results highlight persistent, infrequent use of recommended therapies and suggest a need for increased efforts targeting evidence-based approaches. Previous Back to top Next FiguresReferencesRelatedDetails December 2016Vol 68, Issue 6 Advertisement Article InformationMetrics © 2016 American Heart Association, Inc.https://doi.org/10.1161/HYPERTENSIONAHA.116.08492 Originally publishedDecember 1, 2016 PDF download Advertisement

Ondansetron Preloading with Crystalloid Infusion Reduces Maternal Hypotension during Cesarean Delivery

The aim of the article was to investigate the effect of ondansetron preloading with crystalloid infusion after spinal anesthesia during cesarean delivery. A total of 66 parturient women scheduled for elective caesarean sections were randomly assigned to two groups. Five minutes before spinal anesthesia, Group O patients were injected with 4 mg of ondansetron, while Group S patients were injected with 5 mL physiological saline. Maternal blood pressure and heart rate were measured at 2 minute intervals for 30 minutes. After delivery, umbilical cord blood samples were analyzed. Maternal hypotension and nausea were significantly lower in ondansetron-treated patients versus placebo (p = 0.011 vs. 0.004). Umbilical venous pH was significantly higher in ondansetron-treated patients (p = 0.006), while partial pressure of carbon dioxide (Pco 2) was significantly lower (p = 0.002). Decreases in maternal systolic and mean arterial blood pressures were significantly lower in ondansetron-treated patients (p = 0.008 vs. 0.025), with less requirement for phenylephrine administration compared with controls (p = 0.029). Ondansetron preloading combined with crystalloid infusion significantly reduced hypotension and nausea, while improving acid-base status, as well as reducing vasoconstrictor use.

Maternal Characteristics, Mean Arterial Pressure and Serum Markers in Early Prediction of Preeclampsia

ObjectivesIn a previous study, we have described the predictive value of first-trimester Pregnancy-Associated Plasma Protein-A (PAPP-A), free β-subunit of human Chorionic Gonadotropin (fβ-hCG), Placental Growth Factor (PlGF) and A Disintegrin And Metalloprotease 12 (ADAM12) for early onset preeclampsia (EO-PE; delivery <34 weeks). The objective of the current study was to obtain the predictive value of these serum makers combined with maternal characteristics and first-trimester maternal mean arterial blood pressure (MAP) in a large series of patients, for both EO-PE and late onset PE (LO-PE; delivery ≥ 34 weeks).MethodsThis was a nested case-control study, using stored first-trimester maternal serum from women who developed EO-PE (n = 68) or LO-PE (n = 99), and 500 uncomplicated singleton pregnancies. Maternal characteristics, MAP, and pregnancy outcome were collected for each individual woman and used to calculate prior risks for PE in a multiple logistic regression model. Models containing prior PE risks, serum markers, and MAP were developed for the prediction of EO-PE and LO-PE. The model-predicted detection rates (DR) for fixed 10% false-positive rates were calculated for EO-PE and LO-PE with or without the presence of a small-for-gestational age infant (SGA, birth weight <10th centile).ResultsThe best prediction model included maternal characteristics, MAP, PAPP-A, ADAM12, and PlGF, with DR of 72% for EO-PE and 49% for LO-PE. Prediction for PE with concomitant SGA was better than for PE alone (92% for EO-PE and 57% for LO-PE).ConclusionFirst-trimester MAP, PAPP-A, ADAM12, and PlGF combined with maternal characteristics and MAP are promising markers in the risk assessment of PE, especially for EO-PE complicated by SGA.

OS087. Maternal characteristics, mean arterial pressure and PLGF in early prediction of preeclampsia

In a previous study, we described the predictive value of first-trimester pregnancy-associated plasma protein-A (PAPP-A), free beta-subunit of human chorionic gonadotrophin (fb-hCG), Placental Growth Factor (PlGF) and A Desintegrin And Metalloproteinase 12 (ADAM12) for early onset preeclampsia (delivery <34 weeks) [1]. The objective of the current study was to obtain the predictive value of these serum makers, for both early onset PE (EOPE) and late onset PE (LOPE), combined with maternal characteristics and first-trimester maternal mean arterial blood pressure (MAP). This was a nested case-control study, using stored first-trimester maternal serum from 167 women who subsequently developed PE, and 500 uncomplicated singleton pregnancies which resulted in a live birth =>37 weeks. Maternal characteristics (i.e. medical records, parity, weight, length) MAP and pregnancy outcome (i.e. gestational age at delivery, birthweight, fetal sex) were collected for each individual and used to calculate prior risks for PE in a multiple logistic regression model. MAP values and marker levels of PAPP-A, fb-hCG, PlGF and ADAM12 were expressed as multiples of the gestation-specific normal median (MoMs). Subsequently, MoMs were log-transformed and compared between PE and controls using Student's t-tests. Posterior risks were calculated using different combinations of variables;(1) maternal characteristics, serum markers, and MAP separately (2) maternal characteristics combined with serum markers or MAP (3) maternal characteristics combined with serum markers and MAP. The model-predicted detection rates (DR) for fixed 10% false-positive rates were obtained for EOPE and LOPE with or without intra-uterine growth restriction (IUGR,birth weight <10th centile). The maternal characteristics: maternal age, weight, length, smoking status and nulliparity were discriminative between PE and control groups and therefore incorporated in the multiple logistic regression model. MoM MAP was significantly elevated (1.10 p<0.001; 1.07 p<0.001) and MoM PlGF was significantly reduced (0.95 p=0.016; 0.90 p=0.029) in the EOPE and LOPE group, respectively. The differences in markers for IUGR groups were larger. The estimated DRs of the three different models are presented in the table. This study demonstrates that first-trimester MAP and PlGF combined with maternal characteristics are promising markers in risk assessment for PE. Combination of markers proved especially useful for risk assessment for term PE. Detection rates were higher in the presence of IUGR.

Maternal Hypotension During Elective Cesarean Section and Short-term Neonatal Outcome

Objective To investigate the extent and risk factors for hypotension among women undergoing elective cesarean section, and whether maternal hypotension has any impact on perinatal infant outcome. Study Design Retrospective analysis of data on 919 mother-infant pairs after elective cesarean section that involved the use of regional anesthetic. Data collection included information on maternal blood pressure during the cesarean section procedure and any infant perinatal complications. Results Nearly one-half of the mothers underwent a decrease in their mean arterial blood pressure by ≥30%. The risk factors for hypotension included preoperative hypertension, older age, type of spinal anesthesia, and a higher infant birthweight. A drop in the maternal mean arterial blood pressure exceeding 30% or even 50% compared with the preoperative value was not found to predict any perinatal complications. Conclusion Despite a very high prevalence of maternal hypotension during cesarean sections, term infants tend to tolerate this placental blood perfusion challenge without any major sequel.

Maternal hypotension during elective cesarean section and short-term neonatal outcome

To investigate the extent and risk factors for hypotension among women undergoing elective cesarean section, and whether maternal hypotension has any impact on perinatal infant outcome. Retrospective analysis of data on 919 mother-infant pairs after elective cesarean section that involved the use of regional anesthetic. Data collection included information on maternal blood pressure during the cesarean section procedure and any infant perinatal complications. Nearly one-half of the mothers underwent a decrease in their mean arterial blood pressure by > or =30%. The risk factors for hypotension included preoperative hypertension, older age, type of spinal anesthesia, and a higher infant birthweight. A drop in the maternal mean arterial blood pressure exceeding 30% or even 50% compared with the preoperative value was not found to predict any perinatal complications. Despite a very high prevalence of maternal hypotension during cesarean sections, term infants tend to tolerate this placental blood perfusion challenge without any major sequel.

Significance of retrograde diastolic uterine artery blood flow during regional anesthesia in instrumented pregnant sheep

We studied the interactions between uterine and placental hemodynamics during maternal hypotension in chronically instrumented fetal sheep. In addition, we investigated maternal hemodynamic characteristics, fetoplacental hemodynamics and fetal acid-base status when a retrograde diastolic uterine artery blood flow pattern is present during maternal hypotension. Invasive maternal and fetal hemodynamic parameters, uterine (Q(UtA)) and placental (Q(UA)) volume blood flows and acid-base values were examined in 24 chronically instrumented sheep at baseline and during epidural-induced maternal hypotension at 117-132 (term 145) days of gestation. Uterine artery blood flow velocity waveforms were obtained by Doppler ultrasonography. Maternal hypotension decreased Q(UtA) without affecting Q(UA). During hypotension, eight out of 24 sheep demonstrated a retrograde diastolic blood flow velocity waveform pattern in the uterine artery. Maternal systolic, diastolic and mean arterial blood pressures were significantly lower in the retrograde group than in the antegrade group. No statistically significant differences in Q(UtA), Q(UA) and fetal blood gas values were detected between the two groups during hypotension. An acute decrease in uterine artery volume blood flow during maternal hypotension is not compensated by increased placental volume blood flow. A retrograde diastolic blood flow pattern in the uterine artery is related to lower maternal arterial pressures, especially during diastole. A uterine artery retrograde diastolic blood flow pattern does not have any additional detrimental short-term effects on fetal acid-base status.

Increased fetal blood pressure response to maternal norepinephrine after pharmacological inhibition f norepinephrine uptake in pregnant sheep

Norepinephrine (NE) is elevated in pregnancies complicated by preeclampsia (PE). Specific uptake of NE by the NE transporter (NET) plays a central role as regulator of NE levels. Expression of NET is reduced in placentas from PE pregnancies. To study adverse fetal effects of reduced NET expression on the placental buffering capacity, the NET was pharmacologically blocked by a specific uptake inhibitor reboxetine. We evaluated the effect of NE uptake inhibition on maternal and fetal arterial blood pressure responses to increasing maternal doses of NE in 10 chronically prepared fetal sheep. Arterial blood pressure was monitored continuously during increasing doses of i.v. NE. NET inhibition increased both fetal and maternal mean arterial blood pressure (p < 0.001, respectively). Reuptake by NET appears to be a mechanism protecting the fetus from NE. A reduced uptake capacity in preeclamptic pregnancies due to reduced NE uptake may lead to increased fetal arterial blood pressure.

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Infusion of exogenous platelet-activating factor produces intrauterine growth restriction in the rat.

To determine the impact of exogenous platelet-activating factor (PAF) on pregnancy outcome in the rat. Carbamyl-PAF (0.05, 0.5, or 5.0 microg/kg per hour) or vehicle was infused intravenously for 7 days by osmotic pump into timed pregnant rats. Infusion was begun on day 14 of a 22-day gestation. Maternal mean arterial blood pressures were measured on days 1, 4, and 7 of the infusion. On gestational day 21 (PAF infusion day 7), fetal and placental weights and viability were evaluated at hysterotomy. Uterine and placental PAF receptor expression was analyzed by reverse transcription-polymerase chain reaction and agarose gel electrophoresis. Data were analyzed by analysis of variance, chi(2), or the Mann-Whitney U test as appropriate. Fetal weights were dose-dependently lower than control, by 19% and 35%, respectively, at dosages of 0.5 and 5.0 microg/kg per hour (P < .001) but were not affected at the 0.05 microg/kg per hour dose of carbamyl-PAF. Placental weights were significantly lower at all doses (P < .001). Fetal demise was dose-dependently higher and was significantly different from the control group at the 0.5 and 5.0 microg/kg per hour doses of carbamyl-PAF (P < .0001). Maternal mean arterial pressures were not altered by these doses of carbamyl-PAF. PAF receptors were expressed abundantly in both uterus and placenta. Exogenous PAF produces dose-dependent fetal growth restriction in the rat. Placental growth is particularly sensitive to PAF and, coupled with the dose-dependent decline in fetal growth, suggests a dose-dependent decline in function. An elevated level of PAF is detrimental to fetal growth and well-being in the rat.

P79Maternal ophthalmic artery Doppler velocimetry in type 1 diabetes during pregnancy

BackgroundOur purpose was to evaluate whether maternal ophthalmic artery pulsatility index (PI) in normotensive pregnancies with type 1 diabetes is different from that in normal normotensive pregnancies.MethodThe ophthalmic artery in 15 normal normotensive pregnant women, and 13 normotensive pregnant women with type 1 diabetes was studied once with colour Doppler flow imaging and pulsed Doppler ultrasonography after 16 weeks gestation. The heart rate, mean arterial blood pressure, and ophthalmic artery PI were calculated in each group.ResultsThe PI (1.94 ± 0.45) in normotensive pregnant women with type 1 diabetes was significantly lower than that (2.73 ± 0.32) in normal normotensive pregnant women (P &lt; 0.0001). There was no significant difference in maternal heart rate or mean arterial blood pressure between the two groups.ConclusionThese results suggest that vascular resistance in the maternal orbital circulation is reduced in pregnancies with type 1 diabetes that are normotensive. The lower PI in pregnant women with type 1 diabetes should be interpreted as orbital vascular vasodilatation, indicating orbital hyperperfusion or hyperaemia.

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Maternal ophthalmic artery doppler velocimetry in type 1 diabetes during pregnancy.

Our purpose was to evaluate whether maternal ophthalmic artery pulsatility index (PI) in normotensive pregnancies with type 1 diabetes is different from that in normal normotensive pregnancies. The ophthalmic artery in 15 normal normotensive pregnant women, and 13 normotensive pregnant women with type 1 diabetes was studied once with colour Doppler flow imaging and pulsed Doppler ultrasonography after 16 weeks gestation. The heart rate, mean arterial blood pressure, and ophthalmic artery PI were calculated in each group. The PI (1.94 +/- 0.45) in normotensive pregnant women with type 1 diabetes was significantly lower than that (2.73 +/- 0.32) in normal normotensive pregnant women (P < 0.0001). There was no significant difference in maternal heart rate or mean arterial blood pressure between the two groups. These results suggest that vascular resistance in the maternal orbital circulation is reduced in pregnancies with type 1 diabetes that are normotensive. The lower PI in pregnant women with type 1 diabetes should be interpreted as orbital vascular vasodilatation, indicating orbital hyperperfusion or hyperaemia.

Calcium channel blockade (isradipine) in treatment of hypertension in pregnancy: A randomized placebo-controlled study

OBJECTIVE: Our purpose was to study the effects of isradipine, a dihydropyridine calcium channel blocker, on mother and fetus in the treatment of hypertensive disorders of pregnancy. STUDY DESIGN: The investigation was performed as a two-group, parallel, double-blind multicenter study of isradipine versus placebo. Fifty-four women were randomized to treatment with isradipine slow-release capsules given orally 5 mg twice a day and 57 to a placebo group. RESULTS: Isradipine lowered the maternal mean arterial blood pressure effectively in women with nonproteinuric hypertension but did not do so in women with proteinuria at recruitment or appearing during treatment. Blood flow in the umbilical artery and maternal renal and liver function were not influenced by treatment. Isradipine had few side effets and was well tolerated. CONCLUSION: Calcium channel blockade with isradipine is effective for treatment of nonproteinuric hypertension but not in preeclampsia.

The effect of nicardipine on maternal and fetal hemodynamics and uterine blood flow in chronically instrumented pregnant goats.

This study was designed to clarify the maternal and fetal hemodynamics of nicardipine (0.02 mg/kg) administered intravenously to unanesthetized, chronically instrumented pregnant goats. Nicardipine produced a significant increase in maternal heart rate and cardiac output, and a significant decrease in maternal mean arterial blood pressure and systemic vascular resistance. These changes persisted for about 30 minutes. There were no consistent changes in maternal pulmonary hemodynamics. Uterine arterial blood flow (UBF) decreased significantly (about 15%) after 5 minutes of the injection and returned to the control value within 30 minutes. A significant correlation between the decreases in UBF and maternal diastolic blood pressure was observed after 5 minutes of the injection. The fetal heart rate, blood pressure and acid-base status did not change after the injection of nicardipine. These observations of pregnant goats suggest that nicardipine might be a useful agent for the treatment of acutely hypertensive crises in pregnant patients.

The effect of smoking on the resistance index of the umbilical artery and the middle cerebral artery

23 healthy smokers with uneventful singleton pregnancies underwent Doppler-flow measurements of the foetal umbilical artery and middle cerebral artery before and ten minutes after smoking one cigarette. In both arteries the resistance indices (RI) did not change significantly. Maternal mean arterial blood pressure and heart rate increased significantly after the smoking of the cigarette. Neither the group with an RI increase of greater than or equal to 5% in the foetal umbilical artery (n = 7) nor the group with an increase of the RI in the foetal umbilical artery and, at the same time, a decrease of the RI in the arteria cerebri media (n = 5), showed a significant difference concerning maternal haemodynamic parameters and the number of cigarettes smoked before and during pregnancy. The results suggest, that the smoking of one cigarette in uneventful pregnancy does not produce acute haemodynamic effects in the foetus.

Fetal and maternal plasma atrial natriuretic factor responses to angiotensin II infusion

Plasma atrial natriuretic factor and angiotensin II have opposing actions in the regulation of body fluid homeostasis and systemic blood pressure. Angiotensin II infusions stimulate atrial natriuretic factor release in some, but not all, studies in adult mammals. To examine the response during the perinatal period, graded intravenous angiotensin II infusions were administered to four chronically instrumented pregnant ewes and fetuses (132 ± 1 days of gestation). Fetuses received successive 20-minute intravenous angiotensin II infusions at 25, 50, and 100 ng/kg/min. After a 90-minute recovery, maternal ewes received successive 20-minute angiotensin II infusions (5, 10, and 25 ng/kg/min). During the fetal infusions, mean (± SEM) fetal arterial blood pressure (47 ± 2 to 61 ± 2 mm Hg, p < 0.05) and heart rate (155 ± 16 to 196 ± 36 beats/min, p < 0.05) increased, although there was no change in maternal measured parameters. In response to the maternal infusion, maternal mean arterial blood pressure increased (92 ± 7 to 110 ± 8 mm Hg, p < 0.05) and maternal heart rate decreased (136 ± 4 to 125 ± 2 beats/min, p < 0.05) without change in fetal parameters. Fetal plasma atrial natriuretic factor levels (210 ± 27 to 664 ± 250 pg/ml, p < 0.05) significantly increased during the fetal angiotensin II infusions in spite of no change in maternal plasma atrial natriuretic factor (85 ± 21 to 124 ± 22 pg/ml) during the maternal angiotensin II infusions. These findings indicate that similar increases in systemic blood pressure in response to angiotensin II infusions stimulate increased fetal, but not maternal, plasma atrial natriuretic factor. (AM J OBSTET GYNECOL 1991;165:1635-41.)