A modification of the uterine artery restriction technique in the guinea pig fetus produces asymmetrical ultrasound growth.

AIMS: To evaluate the use of diathermy ablation of branches of the uterine artery to produce growth restriction in the fetal guinea pig, and to compare this new approach with the more conventional use of uterine artery ligation. The development of growth restriction was documented by measuring fetal biparietal diameter (BPD) and the resistance index (RI) of the umbilical artery blood flow velocity waveform. METHODS: At 30-35 days of gestation (term=70 days), one uterine artery was ligated in 29 sows. In another 16 sows, branches of one uterine artery were ablated using diathermy. Fetuses in contralateral horns were used as controls. Ultrasound measurements were made weekly, and at 59-69 days of gestation animals were euthanased to determine fetal position in utero as well as fetal and placental weights. In some fetuses, brain and liver weights were also recorded. RESULTS: Both surgical techniques resulted in similar reductions in fetal body and placental weights. The number of fetuses surviving to term was greater in the diathermy group (53%) compared to the ligation group (22%) (P<0.05). Results from these two groups were combined and referred to as "treated" fetuses. The brain/liver weight ratio was increased by 245% in the treated fetuses compared to control fetuses. Ultrasound measures of BPD in the treated fetuses were within the normal range. The mean RI of the treated group showed a slight but significant increase near term compared to the mean RI of the normal range. CONCLUSION: We have shown that the diathermy technique produces asymmetrical fetal growth restriction (with normal head size) in the guinea pig to the same extent as the conventional ligation technique. It is associated with a lower fetal mortality rate and therefore should be the preferred method. The minimal increase in umbilical artery resistance index only at the end of gestation amongst the intrauterine growth restriction (IUGR) fetuses suggests that an obliterative vasculopathy in the umbilical circulation is not the cause of growth failure when there is maternal uteroplacental restriction.

Egr-1 transcription activation exists in placental endothelium when vascular disease is present.

OBJECTIVE: To seek evidence of early vascular injury in the placental villous microcirculation in placental insufficiency identified by a high-resistance umbilical Doppler study by examining for expression of fibroblast growth factor receptor-1 (FGFR-1), its transcription factor, early growth response factor-1 (Egr-1) and plasma fibroblast growth factor-2 (FGF-2). DESIGN: Case-control study. SETTING: University teaching hospital. SAMPLE: Placentas and umbilical vein blood were collected at delivery from 12 women with normal pregnancy delivered at term and 14 with placental vascular disease defined by an abnormal umbilical artery Doppler study. METHODS: Microvascular endothelial cells were isolated from fresh human placentas using collagenase digestion and Dynabeads coated with monoclonal antibody against CD31. RNA was extracted from the isolated endothelial cells. The messenger RNA (mRNA) expression of FGFR-1 and Egr-1 production were assessed by reverse transcription polymerase chain reaction and factored relative to 18S ribosomal RNA. To confirm that FGF-2 was playing a significant role in this microvascular endothelial cell injury in the placenta, we also measured the soluble fraction of FGF-2 in fetal plasma from same groups of pregnancies using an enzyme-linked immunosorbent assay. MAIN OUTCOME MEASURES: Microvascular endothelial cells expression of Egr-1mRNA, FGFR-1 mRNA and presence of soluble FGF-2 in fetal plasma. RESULTS: The soluble level of FGF-2 in the fetal placental circulation from pregnancy with placental vascular disease was increased when compared with normal pregnancy (median 10.15 pg/ml and interquartile range 5.34-21.83 pg/ml versus 4.46 pg/ml and 3.69-5.66 pg/ml; P < 0.05). Microvascular endothelial cells from the placental villi with placental vascular disease showed upregulation of both FGFR-1 mRNA expression (median 0.72 and interquartile range 0.40-1.64 versus 0.34 and 0.19-0.71; P<0.05) and Egr-1 expression (median 0.79 and interquartile range 0.27-1.86 versus 0.23 and 0.17-0.67; P<0.05) in comparison with normal pregnancy. CONCLUSIONS: Endothelial cells from the placental villi are upregulated for expression of Egr-1 transcription factor gene in placental vascular disease. The FGFR-1 activation and increase in FGF-2 in the fetal circulation are known to be very early features of the response of endothelium to injury. Egr-1 is a promoter of many key pathophysiologically relevant target genes, which influence the development of subsequent vascular lesions. This change may occur before the pathological features recognised on microscopy.

Sexual behaviour and social class in Australian women.

Sexual behaviour is determined by social, cultural and personal factors. Sexual behaviour studies have been conducted in many countries. However, information from Australia is limited. This study was conducted in Obstetrics Department, Westmead Hospital, Sydney. Questionnaire-derived demographic and behavioural characteristics for public and private patients were compared using bivariate and logistic regression analyses. Of the patients, 3036 were public, and 595 private. On bivariate analysis some significant differences were private patients more likely to be born in Australia and have a higher education level whereas public patients were more likely to have had a greater number of lifetime sexual partners and younger age at first sex. Public patients were more likely to be herpes simplex virus type 2 (HSV-2) antibody positive (12%) than private patients (6%). On logistic regression significant variables included country of birth, being HSV-2 antibody positive, and age at first sex. A number of sexual and social variables were significantly different, comparing patients in the public and private sectors. Evaluation of interventions to reduce the sexual risk to women in the public sector should be considered, including encouraging young women to delay their sexual debut, and reducing the number of sexual partners.

Sexual and demographic risk factors for herpes simplex type 1 and 2 in women attending an antenatal clinic.

OBJECTIVE: To establish risk factors for the presence of HSV-2 and HSV-1 infections in pregnant women. DESIGN, POPULATION, AND SETTING: A prospective study of 3306 women attending the antenatal department Westmead Hospital, Sydney, between June 1995 and April 1998. METHODS: Women completed a self administered questionnaire to establish risk factors for the presence of HSV-2 and HSV-1. Sera were tested for antibodies to HSV-2 and HSV-1. Data were analysed using SPSS and SAS. MAIN OUTCOME MEASURES: Seroprevalence of and risk factors for HSV-2 and HSV-1. RESULTS: 375 (11.3% (95% CI 10.3-12.5)) women were HSV-2 antibody positive. Increasing age, Asian country of birth, lower education level, public hospital status, confirmed genital herpes, a partner with genital herpes, early age of first sex, more than one lifetime sexual partner, and previous chlamydia infection were independently associated with HSV-2 seropositivity. Of 408 women tested for HSV-1 antibodies, 323 (79.2% (95% CI 74.9-83.0)) were positive. Oral herpes, oral blisters or sores, and being HSV-2 seropositive were independently associated with HSV-1 seropositive status. When the logistic regression model was rerun without HSV-2 status, parity of two or more and one or more sexual partners in the past 3 months were significant predictors of HSV-1 seropositivity. CONCLUSIONS: The presence of antibodies to HSV-2 and HSV-1 is related to a number of sexual and demographic risk factors. Public health campaigns directed at encouraging young people to delay the onset of sexual activity and reduce the number of sexual partners need to be evaluated. However, the possible availability of an HSV-2 vaccine that is able to protect over 70% of women offers the best hope for control of genital herpes.

Antenatal prediction of hypertrophic pyloric stenosis.

This is the first reported case where the diagnosis of hypertrophic pyloric stenosis (HPS) was entertained in the antenatal period and the neonate was followed up in the postnatal period on a prospective basis until the HPS became manifest.

A new and simple Doppler method for measurement of fetal cardiac isovolumetric contraction time.

OBJECTIVES: The fetal cardiac isovolumetric contraction time is defined as the interval between mitral valve closure and aortic valve opening. The objective of this study was to develop a simple and reliable Doppler method for measuring fetal isovolumetric contraction time using a digital filtering and processing system. METHODS: Cardiac Doppler signals were recorded from 40 fetuses at 18-40 weeks' gestation using a continuous-wave ultrasound transducer. The raw signal was digitized, filtered and divided into five different frequency ranges: 250-375, 375-500, 500-750, 750-1000 and 1000-1500 Hz. To determine the most suitable filter setting for detecting mitral valve closure and aortic valve opening signals, we examined whether they were detected clearly in each filter range. RESULTS: Both mitral valve closure and aortic valve opening signals were detected clearly in the 500-1000 Hz range. The atrioventricular flow and outflow noises in the 250-500 and 1000-1500 Hz ranges helped us to identify the signals. It was found that dividing the raw signals into three ranges of 250-500, 500-1000 and 1000-1500 Hz was the most suitable digital-filter setting for measuring isovolumetric contraction time. CONCLUSIONS: We have developed a simple Doppler method for measuring fetal isovolumetric contraction time. The advent of digital processing has simplified the equipment and the simultaneous multidisplay of three different filtered signals enables easy and accurate measurement.

Misoprostol versus dinoprostone for cervical priming prior to induction of labour in term pregnancy: a randomised controlled trial.

A prospective randomised controlled trial was performed to compare the efficacy and safety of intravaginal misoprostol to that of intravaginal dinoprostone when used for cervical priming prior to the induction of labour; 126 women were recruited to the study and randomised to receive either intravaginal dinoprostone (n = 63) or misoprostol (n = 63) for cervical priming prior to induction of labour. The mean time from insertion of the priming agent to vaginal delivery was significantly shorter in the misoprostol group (925.8 versus 1577.6 minutes), the mean duration of the active length of labour was significantly shorter in the misoprostol group (353.7 versus 496.8 minutes) and more women in the misoprostol group delivered in less than 12 hours (92% versus 76.5%). Women in the misoprostol group were less likely to require a repeated dose of prostaglandin for cervical priming and less likely to require oxytocin for augmentation of labour. There was no difference in the number of women who were delivered vaginally or by Ceasarean section between the two groups. More women developed hyperstimulation during labour in the misoprostol group; however there was no difference between the groups in neonatal outcome in respect to low cord pH or Apgar score at delivery or admission to the neonatal special care nursery.

The fetal cardiac isovolumetric contraction time in normal pregnancy and in pregnancy with placental vascular disease: the first clinical report using a new ultrasound technique.

OBJECTIVE: To study the fetal cardiac isovolumetric contraction time in normal and complicated pregnancies with placental vascular disease using a newly developed digital Doppler cardiography system. DESIGN: A preliminary case-control study. SETTING: Tertiary referral hospital. SAMPLE: One hundred and sixteen normal fetuses (20 to 40 weeks) and 55 complicated pregnancies with placental vascular disease as documented by a high systolic: diastolic ratio in the umbilical artery Doppler flow study. METHOD: A digital Doppler cardiography system with a high sampling rate (4,000 Hz) was used to detect the fetal cardiac valvular movements. The isovolumetric contraction time was measured as the interval between the mitral valve closing and the aortic valve opening with a built-in scale device. RESULTS: In normal pregnancy the isovolumetric contraction time remained remarkably constant with gestation and fetal heart rate. Comparison between clinical outcome and the isovolumetric contraction time of the complicated fetuses who were born within a week after the last determination of the isovolumetric contraction time revealed a strong correlation between prolonged isovolumetric contraction time duration and abnormalities in the perinatal course (non-reactive fetal heart rate pattern, low pulsatility index in the fetal middle cerebral artery Doppler flow and low birthweight infant). CONCLUSIONS: The isovolumetric contraction time is constant with gestation and fetal heart rate in normal pregnancy. In the presence of placental vascular disease a prolonged fetal isovolumetric contraction time predicts adverse outcome.

Ultrasound measurement of biparietal diameter and umbilical artery blood flow in the normal fetal guinea pig.

BACKGROUND AND PURPOSE: Measurement of the biparietal diameter (BPD) by use of B-mode ultrasound provides a useful means for assessment of gestational age and brain growth in humans during pregnancy. Recording of flow velocity waveforms from the umbilical artery, using Doppler ultrasound, is used to assess development of the fetal placental circulation. We sought to measure these ultrasound parameters during normal pregnancy in the guinea pig and develop normative data. METHODS: Measurements of BPD were made on 205 fetuses of various gestational ages; 114 fetuses had 2 or more serial studies performed (total n = 474). RESULTS: BPD increased from 0.806cm at 22 to 26 days, to 1.922cm at term (69 days), (y = -0.00043x2 + 0.06881x - 0.75941, with an r value of 0.995, where x = days' gestation, y = biparietal diameter [cm]). Umbilical artery flow velocity waveform resistance index (RI) decreased as gestation advanced (y = -0.012x + 1.294 with an r value of 0.887, where x = days gestation, y = RI) reflecting expansion of the placental vascular bed. CONCLUSIONS: It is possible to use ultrasound to study pregnancy in the guinea pig. The BPD may be used to estimate gestational age. Resistance to blood flow in the placenta may be assessed using the RI derived from the umbilical artery flow velocity waveform.

Neonatal herpes prevention: a minor public health problem in some communities.

BACKGROUND: Neonatal herpes is a condition with high morbidity and mortality. The greatest risk occurs when the mother acquires herpes simplex virus (HSV) towards the end of pregnancy. A study from Seattle has suggested that the risk of acquisition of HSV during pregnancy was 3.7%. In Australia, HSV-2 infection is less common in pregnant women than in the United States. Consequently we conducted a study to establish HSV seroprevalence and the rate of HSV seroconversion in this population. METHODS: The study was conducted at Westmead Hospital, Sydney, between June 1995 and April 1998. Women completed a questionnaire covering risk factors for the acquisition of genital herpes. A serum sample during pregnancy and a specimen of cord blood were obtained and tested for antibodies to HSV-2 using a type specific indirect enzyme linked immunosorbent assay (ELISA). Equivocal results were resolved by western blot. A subset of the paired sera was tested for antibodies to HSV-1. The data were analysed using SPSS. RESULTS: 326 of the 2616 (12.5%) women were HSV-2 seropositive. Three women (0.15%) acquired HSV-2 infection during pregnancy. None of the three babies of these mothers developed neonatal herpes. 416 maternal cord pairs were tested for HSV-1 antibodies and 330 (79.3%) were positive. No HSV-1 seroconversions occurred. CONCLUSIONS: In this population, HSV acquisition was uncommon (0.34% per year) and neonatal herpes was rare. A cost effective analysis suggested that type specific serology to screen pregnant women and their partners in low prevalence communities was not cost effective.

Elevated circulating homocyst(e)ine levels in placental vascular disease and associated pre-eclampsia.

We examined the hypothesis that hyperhomocyst(e)inaemia in the maternal or fetal circulation is associated with placental vascular disease with either the maternal syndrome of pre-eclampsia and/or fetal syndrome of growth restriction. Maternal plasma homocyst(e)ine levels were significantly higher in pregnancies complicated by pre-eclampsia, pregnancies with evidence of umbilical placental vascular disease, and pregnancies with both complications compared with the normal pregnancy group. In the fetal circulation mean plasma homocyst(e)ine concentration was significantly higher in the pre-eclampsia group compared with the normal group. The results suggest that hyperhomocyst(e)inaemia may be a risk marker for placental vascular disease and maternal pre-eclampsia. The elevated fetal plasma homocyst(e)ine concentrations, found only in the group of pregnancies with pre-eclampsia in the absence of umbilical placental vascular disease, may be due to an effect of placental vascular disease on homocyst(e)ine transfer from the maternal to fetal circulation.

Is an atherogenic lipoprotein profile in the fetus a prerequisite for placental vascular disease?

OBJECTIVE: To measure the blood apolipoprotein A-1 and apolipoprotein B in the fetal circulation in normal pregnancy and in pregnancy with evidence of vascular disease in the fetal umbilical placental circulation defined in the antenatal period by Doppler ultrasound study. DESIGN: An observational study to compare fetal plasma apolipoprotein levels in normal and complicated pregnancy. SETTING: A university hospital tertiary referral obstetric unit. SAMPLES: Umbilical vein blood was collected at delivery from 22 normal fetuses delivered by elective caesarean section for non fetal reasons and 30 fetuses with evidence of umbilical placental vascular disease identified antenatally by Doppler ultrasound study. METHODS: Plasma apolipoprotein A-1 and B were determined using an enzyme-linked immunosorbent assay (ELISA) methods. MAIN OUTCOME MEASURES: Fetal plasma levels of apolipoprotein A-1 and B were measured. RESULTS: There was a significantly lower level of fetal plasma apolipoprotein A-1 in placental insufficiency [placental insufficiency vs normal pregnancy, median 0.30 g/L (interquartile range 0.24, 0.39 g/L) vs 0.35 g/L (0.31, 0.42 g/L), P = 0.045]. In contrast, the levels of fetal plasma apolipoprotein B in placental insufficiency [0.20 g/L (0.17, 0.26 g/L)] were significantly increased compared with normal pregnancy [0.16 g/L (0. 14, 0.20 g/L), P = 0.03]. The ratio of fetal plasma apolipoprotein B to A-1 was also substantially higher in placental insufficiency [0.68 (0.55, 0.83)] than in normal pregnancy [0.45 (0.36, 0.60), P = 0.0003]. CONCLUSIONS: Our study has demonstrated that levels of fetal plasma apolipoprotein A-1, apolipoprotein B and the ratio of apolipoprotein B to A-1 were altered in the fetuses who are victims of umbilical placental insufficiency in the same direction as in adults associated with a high risk of atherogenesis.

Genotype dependent and cigarette specific effects on endothelial nitric oxide synthase gene expression and enzyme activity.

We explored the interactive effects of endothelial nitric oxide synthase (eNOS) genotypes and cigarette smoking on protein levels and enzyme activity in 33 postpartum placentas. Whilst the eNOS protein levels were lower in the rare allele (0.48+/-0.11, n=9 vs. 1. 05+/-0.10, n=24, P<0.01), the eNOS enzyme activity was about 7-fold higher in the rare allele (4556.2+/-255.4 vs. 621.8+/-180.5 cpm/mg/min, P<0.01). Smokers had lower eNOS protein levels (1.07+/-0. 09 vs. 0.50+/-0.19, P<0.05) in both alleles. It reduced the eNOS activities only in the rare allele (non-smokers: 6143.8+/-251.2, n=5, smokers: 2968.5+/-259.4, n=4, 52% reduction, P<0.01). We conclude that associations between eNOS polymorphism and protein levels and enzyme activities are modifiable by smoking, the effects of smoking are dependent on the eNOS genotypes.

Changes of resistance to activated protein C in the course of pregnancy and prevalence of factor V mutation.

The purpose of this study was to examine the changes in activated protein C (APC) anticoagulant activity during pregnancy and determine whether changes in APC could contribute to thrombosis in the placental bed in preeclampsia. We measured APC anticoagulant activity in 150 women with a normal pregnancy and 50 women with preeclampsia. There was a significant reduction in the mean APC sensitivity ratio (APC-SR) during pregnancy (p<0.001). APC resistance in preeclampsia was significantly higher than in normal pregnancy (p<0.01). Amongst women with APC resistance the presence of the factor V Leiden mutation was significantly higher in the preeclampsia group than in the normal pregnancy group (p<0.01). It seems that both factor V Leiden mutation and APC resistance may be associated with the development of preeclampsia. These results suggest that APC resistance may be an important mechanism underlying placental bed pathology in pregnancy and may be associated with an increased tendency to develop preeclampsia in some women. Assay of APC resistance and factor V Leiden mutation should be performed in women with preeclampsia.