Uterine Artery Flow Velocity Waveforms Research Articles

Low placental growth factor levels and high soluble endoglin levels at 26–31 weeks of gestation precede light placenta with and without relatively heavy infant, respectively: A retrospective cohort study

Our aim was to examine whether serum levels of placental growth factor (PlGF) and soluble endoglin (sEng) at 19-25 and 26-31 weeks of gestation were associated with the occurrence of the 9-block categorization of placenta weight (PW) and fetal/placenta ratio (F/P ratio). We performed a retrospective cohort study in 1391 women with singleton pregnancy. Serum levels of PlGF and sEng were measured by enzyme immunosorbent assay. A light placenta was defined as PW ZS < -1.28 SD. Based on the PW (light, normal, and heavy) and F/P ratio (relatively heavy, balanced growth, and relatively small), 9-block categorization were performed. Multivariable logistic regression analyses were performed. Low PlGF at 26-31 weeks was an independent risk factor for the birth of infants belonging to Block A (light placenta and relatively heavy infant), after adjusting for prepregnancy body mass index and serum levels of sEng. High sEng at 26-31 weeks was an independent risk factor for the birth of infants belonging to Block D (light placenta and balanced growth of infant), after adjusting for past history of either preeclampsia or gestational hypertension, high pulsatility index of uterine artery flow velocity waveforms in the second trimester, and serum level of PlGF. Low PlGF levels at 26-31 weeks of gestation may precede a light placenta and relatively heavy infant (Block A), and high sEng levels at 26-31 weeks of gestation may precede a light placenta and balanced growth of infant (Block D).

Uterine artery flow velocity waveform (FVW) type and subednometrial vascularity in recurrent pregnancy loss

Purpose: To assess the subendometrial and uterine artery blood flow and pattern of the waveform of the uterine artery in cases of recurrent pregnancy loss compared with normal controls.Subjects and methods: Fifty women with a history of two or more successive pregnancy losses were investigated by Doppler transvaginal ultrasound to assess the subendometrial blood flow resistance index (RI), type of Doppler waveform of the uterine artery, and uterine artery pulsatility index (PI) in the mid-luteal phase. Fifty normal women acted as controls.Results: Subendometrial blood flow RI and uterine artery PI were higher in cases than controls. The majority of cases of recurrent pregnancy loss had a waveform pattern of A, or loss of diastolic flow, whereas the controls were mainly C wave.Conclusions: Some sort of endometrial and subendometrial ischemia can be suggested in cases of recurrent pregnancy loss, waveform pattern of uterine artery changes may be used to monitor changes in vascularity of endometrium if vascular enhancers are given in such cases.

Uterine artery flow velocity waveforms before and after delivery in hypertensive disorders of pregnancy near term

ABSTRACT Objective: To compare the uterine artery pulsatility index (UtAPI-AP) before labor and immediate postpartum (UtAPI-PP) in hypertensive disorders of pregnancy (HTNP) and normotensives near term. Methods: Pregnancies ≥36 weeks admitted for labor induction in our institution from October 2015 to October 2017 were included. We excluded active labor, multiple gestations, fetal demise, and those with inadequate uterine artery sampling. Our primary outcome was to compare the UtAPI-AP and UtAPI-PP between subjects with HTNP (gestational hypertension, preeclampsia with and without severe features) and normotensive participants. Our secondary outcomes were to compare the UtAPI-AP and UtAPI-PP by subgroups (severe HNTP, non-severe HTNP, and controls) and the UtAPI-PP in participants while on MgSO4 and after its discontinuation. A linear regression model was applied to test the above associations. A P < .05 was considered significant. Results: We included 108 women (HTNP = 71; controls = 37). The UtAPI-AP was higher in the HTNP group (.85 ± .3 vs. .71 ± .2; P < .001); however, the UtAPI-PP was not different between groups (1.11 ± .3 vs. 1.16 ± .4; P = .46). The UtAPI-AP was higher in the severe HTNP group than controls (P = .004), but there was no significant difference in the UtAPI-PP between subgroups. Our results remained unchanged after adjusting for confounders. The UtAPI while on MgSO4 and after its discontinuation was similar (P = >.99). Conclusion: The increased UtAPI in patients with HTNP resolves soon after delivery. MgSO4 does not seem to have an effect on the UtAPI postpartum.

Uterine artery flow velocity waveform, arterial flow indices, follicular dynamics, and sex hormones during preovulatory period in synchronized ovulatory cycle of Bos indicus beef cows

A greater understanding of the uterine artery’s (UtA) biology is essential to the increase in female reproductive abilities. The UtA flow velocity waveform, blood flow volume (BFV), pulsatility and resistance indices (PI and RI), blood flow velocities, dynamics of the dominant follicle (DF), and estradiol (E2) and progesterone (P4) levels in an induced ovulatory cycle were evaluated in Thai native cattle. Twenty cows were induced with synchronized ovulation through a P4-releasing device, from Day −9 to Day −4, concurrent with the administration of two doses of a gonadotropin-releasing hormone on Day −9 and Day −1, and two doses of prostaglandin F2α on Day −4 and 8 h later. Day 0 was designated as the day of ovulation. The cows underwent Doppler sonographic determination and blood collection from Day −4 to Day 0. The cows were classified in the non-ovulating (n = 5) and ovulating groups (n = 15). The ovulating cows presented higher BFV values, blood flow velocities, DF growth rates, and E2 levels; yet lower PI values and P4 concentrations, than those of the non-ovulating cows. The BFV values and the blood flow velocities were greater, but the RI and PI values were lower in the ovulatory side UtA than in the contraovulatory side UtA. The BFV values were positively correlated with blood flow velocities, DF growth rates and E2 concentrations in the ovulating cows; confirming the importance of UtA blood flow, follicular growth, and E2-vasodilation during preovulatory phase in the induced ovulatory cycle of Bos indicus beef cows.

First‐trimester uterine artery Doppler and adverse pregnancy outcome: a meta‐analysis involving 55 974 women

To determine the accuracy with which uterine artery Doppler in the first trimester of pregnancy predicts pre-eclampsia and fetal growth restriction, particularly early-onset disease. We searched MEDLINE (1951-2012), EMBASE (1980-2012) and the Cochrane Library (2012) for relevant citations without language restrictions. Two reviewers independently selected studies that evaluated the accuracy of first-trimester uterine artery Doppler to predict adverse pregnancy outcome and performed data extraction to construct 2 × 2 tables. We synthesized sensitivity and specificity for various Doppler indices using a bivariate random-effects model. From 1866 citations, we identified 18 studies (55,974 women). The sensitivity and specificity of abnormal uterine artery flow velocity waveform (FVW) in the prediction of early-onset pre-eclampsia were 47.8% (95% CI: 39.0-56.8) and 92.1% (95% CI: 88.6-94.6), and in the prediction of early-onset fetal growth restriction were 39.2% (95% CI: 26.3-53.8) and 93.1% (95% CI: 90.6-95.0), respectively. The sensitivities for predicting any pre-eclampsia and fetal growth restriction were 26.4% (95% CI: 22.5-30.8) and 15.4% (95% CI: 12.4-18.9), respectively, and the specificities were 93.4% (95% CI: 90.4-95.5%) and 93.3% (95% CI: 90.9-95.1), respectively. The number needed to treat (NNT) with aspirin to prevent one case of early-onset pre-eclampsia fell from 1000 to 173 and from 2500 to 421 for background risks varying between 1% and 0.4%, respectively. First-trimester uterine artery Doppler is a useful tool for predicting early-onset pre-eclampsia, as well as other adverse pregnancy outcomes. Based on the NNT, abnormal uterine artery Doppler in low-risk women achieves a sufficiently high performance to justify aspirin prophylaxis in those who test positive.

ISUOG Practice Guidelines: use of Doppler ultrasonography in obstetrics

<scp>ISUOG</scp> Practice Guidelines: use of Doppler ultrasonography in obstetrics

Analysis of perinatal outcome by combination of first trimester maternal plasma homocysteine with uterine artery Doppler velocimetry

To analyse the pregnancy outcome by combining plasma homocysteine with uterine artery Doppler velocimetry at 11 to 14 weeks of gestation. A prospective cohort study with 103 healthy pregnant women. Uterine artery Doppler velocimetry was performed at between 11 and 14 weeks of gestation. Abnormal blood flow was defined as average pulsatility index >1.5 and presence of unilateral or bilateral diastolic notch. Doppler scores were calculated by a modified scoring method of uterine artery flow velocity waveforms. Serum for measurement of homocysteine, vitamin B(12) and folate levels were collected when the ultrasonographic measurement was performed. Pre-eclampsia developed in five, gestational hypertension in three, intrauterine growth restriction in two and preterm birth in eight patients. There was a significant difference between mean plasma homocysteine levels at different Doppler scores (p<0.001) and a weak positive correlation between Doppler scores and occurrence of pregnancy complications (r(s) = 0.232, p<0.05). Mean homocysteine level increased with increasing Doppler scores. Any uterine artery abnormality had a sensitivity of 88.9% in predicting obstetric complications. Addition of hyperhomocytenemia to Doppler scores did not change the sensitivity. Maternal serum homocysteine level is increased in 11 to 14 weeks of gestation that is complicated with pre-eclampsia, gestational hypertension, intrauterine growth restriction and preterm birth. Addition of homocysteine determination to uterine artery Doppler in the first trimester does not add any advantage in predicting adverse perinatal outcome.

Uterine artery flow velocity waveforms during uterine contractions: Differences between oxytocin‐induced contractions and spontaneous labor contractions

To clarify the effects on uterine arterial flow velocity waveforms of uterine contractions following oxytocin infusion and during spontaneous labor. Uterine arterial flow velocity waveforms were obtained by pulsed Doppler methods from 22 women during an oxytocin challenge test (OCT), 26 women during oxytocin-induced labor, and 40 women during spontaneous labor. Mean resistance index (RI) for bilateral arteries was used for analyses. After the onset of labor, flow velocity waveforms were assessed according to cervical dilatation. During OCT, Doppler flow velocimetry was performed when three uterine contractions occurred per 10-min period. RI values did not differ significantly between induced and spontaneous labor during relaxations at any level of cervical dilatation. However, during contractions, RI was significantly higher for induced labor than for spontaneous labor. Absence or reversal of flow was more frequent in the OCT group than in the induced labor group (P < 0.0001). However, no significant differences were found between spontaneous and induced labor groups. Interactions between the contracting uterine body and the relaxing lower segment in oxytocin-induced labor might be associated with differences in uterine arterial flow during contraction between oxytocin-induced and spontaneous labor. However, changes in the intensity of uterine contractions during labor progression might differ between oxytocin-induced and spontaneous labor.

OP23.08: The effects of intrapartum continuous epidural analgesia on uterine artery flow velocity waveforms

Objectives: To evaluate the usefulness of a novel software to assess on three-dimensional (3D) ultrasound volumes the progression of the fetal head in the second stage of labour. Methods: a software (L&D) was developed as an application of the program 4D view (GE Healthcare, Zipf, Austria) with the purpose to help the evaluation of fetal head progression by serial ultrasound volumes obtained with a translabial approach throughout the second stage of labour. Volumes can be aligned by usign the pubic bone as reference. In the longitudinal plane of the pelvis, the head contour can be traced and the angle formed by the head and the antero-posterior diameter (head direction) can be measured. In the transverse plane of the pelvis, the angle formed by the midline with the anteroposterior axis of the posterior (head rotation) can also be measured. Subsequent volumes can be superimposed to demonstrate visually the progression of the head contour, modification of the head direction and head rotation. Between november 2007 and january 2008 serial ultrasound volumes were obtained in labouring patients, stored and subsequently evaluated with the L&D software Results: A total of 15 volumes from 9 patients were analyzed. Superimposition of serial volumes allowed to visualize the progression of the fetal head. With increasing station, the parietal line angle increased and the midline angle decreased. Conclusions: Using 3D ultasound and a novel software the progression of the second stage of labour can be directly visualized. Measurement of angles (head direction and rotation) could also prove useful, as they provide a quantitative estimate of the progression. These tools may support and facilitate the clinical diagnosis of normal and abnormal labour.

Screening for pre‐eclampsia and fetal growth restriction by uterine artery Doppler and PAPP‐A at 11–14 weeks' gestation

To assess the role of maternal demographic characteristics, uterine artery Doppler velocimetry, maternal serum pregnancy-associated plasma protein-A (PAPP-A) and their combination in screening for pre-eclampsia and small-for-gestational age (SGA) fetuses at 11-14 weeks. This was a prospective study of 878 consecutive women presenting for a routine prenatal ultrasound examination at 11-14 weeks. Pulsed wave Doppler was then used to obtain uterine artery flow velocity waveforms and the mean pulsatility index (PI) of the uterine arteries was calculated. Maternal serum samples for PAPP-A were assayed. Along with maternal history, these measurements were compared in their ability to predict adverse outcome, defined as pre-eclampsia and/or SGA and/or placental abruption. Mean uterine artery PI > or = 95(th) centile and PAPP-A < or = 10(th) centile each predicted 23% of the women that developed pre-eclampsia and 43% of cases of placental abruption. For SGA < or = 5(th) centile, mean uterine artery PI > or = 95(th) centile predicted 23% of cases and PAPP-A < or = 10(th) centile predicted 34%. Independent predictors for subsequent development of pre-eclampsia were increased mean uterine artery PI > or = 95(th) centile (OR, 2.76; 95% CI, 1.11-6.81) and maternal history of pre-eclampsia/hypertension (OR, 50.54; 95% CI, 10.52-242.73). The predicting factors for SGA < or = 5(th) centile were increased mean uterine artery PI > or = 95(th) centile (OR, 2.0; 95% CI, 1.07-3.74) and low PAPP-A (OR, 0.43; 95% CI, 0.20-0.93). Increased uterine artery PI was the only independent factor in the prediction of placental abruption (OR, 8.49; 95% CI, 2.78-25.94). The combination of uterine artery PI and maternal history of pre-eclampsia/hypertension was better than was using uterine artery Doppler alone in predicting pre-eclampsia. Similarly, for the prediction of SGA < or = 5(th) centile, combining uterine artery Doppler and maternal serum PAPP-A was better than was uterine artery Doppler alone. In both cases, the difference approached statistical significance. The combination of maternal history with abnormal uterine artery Doppler and low PAPP-A level at 11-14 weeks achieves better results than does either test alone in the prediction of pre-eclampsia and SGA.

Uterine artery Doppler velocimetry for the detection of adverse obstetric outcomes in patients with elevated mid‐trimester β‐human chorionic gonadotrophin

The aim of this study is to review the clinical usefulness of Doppler velocimetry of the uterine artery for the detection of adverse obstetric outcome in a population of women with elevated mid-trimester serum beta-human chorionic gonadotrophin (betahCG). Women with an unexplained elevated mid-trimester betahCG level (> or = 4.0 multiples of the median) are offered uterine artery Doppler assessment at 22-24 weeks of gestation. We have audited the clinical usefulness of this practice by reviewing the prevalence of the adverse outcomes of gestational hypertension, intrauterine growth restriction (IUGR) and preterm birth and the predictive capacity of the test when applied to this subgroup of high-risk patients. Sixty-two women had an elevated serum betahCG and underwent Doppler study of uterine artery flow velocity waveform. Notching afforded better predictive utility for any outcome than the resistance index alone or in combination with notching. For a composite adverse outcome of any or all of gestational hypertension, birthweight < or = 10th centile, and preterm delivery, the presence of a uterine notch alone had sensitivity of 30.7% and specificity of 93.8%. For the identification of severe fetal growth restriction (< 5th centile) and/or preeclampsia, the presence of a notch offered a sensitivity of 50%, specificity of 96.3%, a positive likelihood ratio of 13.5, and a negative likelihood ratio of 0.5. The identification of uterine artery notching by means of Doppler ultrasound as a component of the surveillance of women with unexplained elevated betahCG levels significantly improves the prediction of preeclampsia and/or severe IUGR, although the low prevalence of 13% of these adverse outcomes limits the usefulness of the test in routine clinical practice.

Delayed normalisation of uterine artery doppler waveforms is not a benign phenomenon

Objective: To evaluate the pregnancy outcome in patients with abnormal uterine artery Doppler flow velocity waveforms (FVW’s) at 19–21 weeks, which were subsequently normal by 24–26 weeks, and to study the effect of low-dose aspirin on these waveforms. Design: The study group consisted of 49 patients who had abnormal uterine artery flow velocity waveforms (FVW’s) at 19–21 weeks. These women were initially commenced on 100 mg slow-release aspirin at 20 weeks, which was discontinued at the follow-up visit, after confirming normal uterine artery Doppler FVW. The control group consisted of 730 patients with normal uterine artery Doppler waveforms at 19–21 weeks. The main outcome measures were: small for gestational age (SGA) <10th centile, pre-eclampsia, placental abruption, and perinatal mortality rate (PMR). Results: When compared with the control group, the study group had an increased risk of placental abruption (2% versus 0.27%, P=0.05) 95% Confidence Intervals CI=0.01–0.13), low birth weight (3087 versus 3383 gm, P=0.0003), SGA <10th centile (32.7% versus 11.9%, P≤0.0001, CI=0.14–0.5), and PMR (2/49 versus 1/730, P<0.0001, CI=0.003–0.37). Conclusions: These findings suggest that delayed normalisation of the uterine artery Doppler waveform is not a benign phenomenon. This subgroup of patients is at increased risk of pregnancy complications, in particular SGA and placental abruption. These patients could benefit from serial ultrasound scans in the third trimester to evaluate fetal growth and well-being. Aspirin does not appear to play a major part in modifying uterine artery blood flow.

Uterine artery blood flow velocity waveforms during uterine contractions.

No quantitative or qualitative Doppler velocimetry classification of vascular flow resistance covering all stages of forward and reversed flows exists. The objective of this study was to characterize uterine artery (UtA) flow velocity waveforms (FVWs) obtained during an oxytocin challenge test (OCT) and compare them to FVWs in spontaneous normal labor. Uterine artery Doppler velocimetry was performed during and between uterine contractions in 61 high-risk pregnancies subjected to an OCT and in 20 normal pregnancies undergoing spontaneous labor. FVWs were classified relative to the presence of forward/absent/reversed flow during systole and diastole, and the time-averaged flow velocity over the heart cycle. Eleven different FVW classes were identified. No relationship between FVWs recorded during uterine inertia and contractions was found (P >/= 0.2). In both groups, only forward FVWs were recorded between contractions, whereas during contractions flow reversal was more common in the OCT group (P </= 0.002). In cases of predominantly reversed flow, a reciprocal relationship to FVW classes recorded in the contralateral artery was found. UtA FVW patterns recorded during uterine contractions were not predicted by flow patterns recorded during uterine inertia. Reversal of flow direction was more common during oxytocin-induced uterine contractions than during spontaneous contractions. In cases of predominantly reversed flow, domains of the uterus may be supplied by blood from the contralateral UtA. These observations give new insights into the circulatory dynamics of the uterus during labor, and also point to a possible vasoconstrictory effect in the UtAs of oxytocin at high concentrations.

Predicting risk of pre-eclampsia by quantitative assessment of diastolic notch in uterine artery flow velocity waveform

International Journal of Gynecology & ObstetricsVolume 70, Issue S4 p. D150-D150 Ultrasound Predicting risk of pre-eclampsia by quantitative assessment of diastolic notch in uterine artery flow velocity waveform A. Ohkuchi, A. OhkuchiSearch for more papers by this authorH. Minakami, H. MinakamiSearch for more papers by this authorH. Mori, H. MoriSearch for more papers by this authorT. Nakano, T. NakanoSearch for more papers by this authorM. Tateno, M. TatenoSearch for more papers by this authorI. Sato, I. SatoSearch for more papers by this author A. Ohkuchi, A. OhkuchiSearch for more papers by this authorH. Minakami, H. MinakamiSearch for more papers by this authorH. Mori, H. MoriSearch for more papers by this authorT. Nakano, T. NakanoSearch for more papers by this authorM. Tateno, M. TatenoSearch for more papers by this authorI. Sato, I. SatoSearch for more papers by this author First published: 11 December 2003 https://doi.org/10.1016/S0020-7292(00)84702-5AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat No abstract is available for this article. Volume70, IssueS42000Pages D150-D150 RelatedInformation

The effect of isosorbide dinitrate on placental blood flow and maternal blood pressure in women with pregnancy induced hypertension

The effect of isosorbide dinitrate (ISDN) on maternal and fetal circulation was assessed in 23 women with pregnancy induced hypertension (PIH). A double-blind randomized design was employed. Each woman was given a sublingual tablet of ISDN (5 mg) or placebo. Maternal blood pressure (BP) and heart rate (HR) were measured before and every 2 min after the medication or placebo, for a total of 20 min. Flow velocity waveforms in the uterine and umbilical arteries were recorded at the same time periods, using pulsed Doppler ultrasound. The ratio of peak systolic to end-diastolic flow velocity (S/D) in those vessels was calculated. After ISDN mean maternal BP fell from 103 ± 1.8 mm Hg to 90.5 ± 2.9 mm Hg at 14 min ( P < .0001) and mean maternal HR increased from 97.3 ± 3.8 beats/min to 115.7 ± 3.5 beats/min at 12 min ( P < .0001). The mean S/D in the umbilical artery fell from 3.07 ± 0.33 to 2.58 ± 0.23 at 8 min ( P < .0007). The mean S/D in the uterine artery fell from 3.27 ± 0.6 to 2.38 ± 0.28 at 10 min ( P < .0001). In seven of 12 women with an early diastolic notch in the uterine artery flow velocity waveform the notch diminished or disappeared within the first 6 min after the medication. No significant change in any of the measured parameters was observed in the placebo group. Our finding that ISDN altered maternal and fetal hemodynamics in PIH lends support to the further exploration of nitric oxide donors in the treatment and prevention of pregnancy induced hypertension.

The Influence of the Maternal Heart Rate on the Uterine Artery Pulsatility Index in the Pregnant Ewe

We investigated the influence of the maternal heart rate on the uterine artery pulsatility index in pregnant ewes. We used an external pacemaker to alter the heart rate of 5 pregnant ewes at 16–17 weeks of pregnancy and examined the effect of changes in the maternal heart rate on the uterine artery flow velocity waveforms and the pulsatility index, as determined by Doppler velocimetry. The uterine artery pulsatility index showed a significant negative correlation with the maternal heart rate. There were no significant changes in other hemodynamic parameters. The maternal heart rate had a significant influence on the uterine artery pulsatility index.

Significance of a diastolic notch in the uterine artery flow velocity waveform induced by uterine embolisation in the pregnant ewe.

To investigate the relation between placental embolisation and the diastolic notch in the uterine artery flow velocity waveform of pregnant ewes under general anaesthesia. Seven pregnant ewes at a gestation 16 to 17 weeks were anaesthesized and microbeads of gelfoam were injected into the uterine artery; changes in the uterine circulation were assessed by Doppler velocimetry. Gelfoam embolisation reduced uterine blood flow in a dose-dependent manner, from a mean (95%, CI) of 568 mL/min (495-641) to 159 mL/min (131-187) after the injection of 30 mg of gelfoam, and increased the uterine vascular resistance from 135 mmHg x min x L(-1)(103-167) to 498 mmHg x min x L(-1) (422-574). A diastolic notch in uterine artery flow velocity waveform was observed after 20 mg to 25 mg of gelfoam in two ewes and after injection of 30 mg of gelfoam in all seven animals. Injection of 30 mg of gelfoam increased the pulsatility index to 2.4 (1.9-2.9) from 0.6 (0.5-0.7). The mean uterine vascular resistance at the time of the appearance of a diastolic notch was 414 mmHg x min x L(-1)(377-451). These findings suggest that an elevated pulsatility index and the presence of a diastolic notch in the uterine artery flow velocity waveform are indicators of increased uterine vascular resistance and impaired uterine circulation.

Unexpected effect of a nitric oxide donor on uterine artery Doppler velocimetry in oligomenorrheic women with polycystic ovaries.

We compared uterine artery vascular responses following administration of the nitric oxide donor glyceryl trinitrate to ten women with oligomenorrhea and ultrasound evidence of polycystic ovaries with those of nine women with a normal menstrual cycle and ultrasonically normal ovaries. Mean arterial blood pressure, pulse rate and uterine artery flow velocity waveforms were recorded before and 60-75 min after glyceryl trinitrate patch application. The pulsatility index and resistance index were calculated to describe changes in impedance to flow in the uterine artery. Peak systolic and time-averaged velocities were also measured. Pretreatment median arterial pressure was higher in women with polycystic ovaries (90 mmHg) compared to those with regular cycles (80 mmHg) (p < 0.05). No differences were found in pulse rate and uterine artery blood flow indices between the two groups. After glyceryl trinitrate patch administration, there was no change in blood pressure or pulse rate in either group. In women with polycystic ovaries, there was an increase in uterine artery resistance index (0.93 to 1.00; p < 0.05) and pulsatility index (3.77 to 4.99; p < 0.05) and a decrease in peak systolic (36.8 to 32.3 cm/s; p < 0.05) and time-averaged maximum (8.5 to 5.0 cm/s; p < 0.05) velocities. Uterine artery Doppler parameters remained unchanged in women with normal cycles. Uterine artery vascular responses to the nitric oxide donor glyceryl trinitrate are different in women with normal cycles compared to oligomenorrheic women with polycystic ovaries. This may be relevant to an understanding of the pathophysiology underlying the higher risk of cardiovascular morbidity and mortality associated with polycystic ovarian syndrome.

The effect of nitric oxide on uterine and umbilical artery flow velocity waveform in pre-eclampsia

We compared the flow velocity waveforms of uterine and umbilical arteries in normotensive and pre-eclamptic patients at mid-gestation. In a randomised controlled trial we tested the effects of isosorbide dinitrate (ISDN, nitric oxide donor) patch therapy on the flow velocity waveform of pre-eclamptic patients at mid-gestation. The resistance indices (RI) of human uterine and umbilical arteries were higher in pre-eclamptic patients compared to the normotensive patients. ISDN patch therapy significantly reduced the increased RI values of the umbilical artery in pre-eclamptic patients without any change in systemic blood pressures, but the RI values of the uterine artery were not significantly attenuated. The change in RI values of the umbilical artery might be due to the improvement of end-diastolic flow velocity. These results suggest that the feto-placental circulation is impaired in pre-eclampsia, perhaps due to the disturbance of the endothelium-dependent vaso-relaxation system, and that ISDN therapy may improve the impaired endothelium dependent nitric oxide system.

Prediction of Pre-Eclampsia by Abnormal Uterine Doppler Ultrasound and Modification by Aspirin

Objective To assess the effect of low dose aspirin on severe pre-eclampsia when given to women identified as high risk by abnormal uterine artery Doppler ultrasound. Design Women with abnormal uterine artery flow velocity waveforms were recruited to the CLASP trial at 24 weeks. Abnormal uterine artery waveforms, with a high resistance index or an early diastolic notch, were identified at the 18–22 week anomaly scan and confirmed at 24 weeks. Of those women with persistently abnormal waveforms, 63 agreed to enter the CLASP trial. Three women were lost to follow up and five did not comply. Thus, 60 were randomised: 29 to placebo and 31 to low dose aspirin (60 mg daily) and analysis by intention to treat is reported. Results There were nine cases (29%) of pre-eclampsia in the aspirin group and twelve (41%) in the placebo group (odds ratio (OR) 0.58, confidence interval (CI) 0.2–1.69, P = 0.32). Severe pre-eclampsia developed in four women in the aspirin group and eleven women in the placebo group (OR 0.24, CI 0.07–0.88, P = 0.03) and intrauterine growth retardation occurred in eight cases in the aspirin group and twelve in the placebo group (OR 0.49, CI 0.17–1.47). The mean birthweight and gestation at delivery were 2.69 kg and 38.5 weeks in the aspirin group and 2.38 kg and 37.4 weeks in the placebo group, neither of which were statistically significant using the unpaired t test; P = 0.09 and P = 0.23, respectively. Conclusions In high risk pregnancy low dose aspirin commenced at 24 weeks may reduce the incidence of severe pre-eclampsia.