Second trimester ambulatory blood pressure in nulliparous pregnancy: a useful screening test for pre-eclampsia?

OBJECTIVE

To assess the effectiveness of second trimester 24-hour ambulatory blood pressure measurement as a screening test for pre-eclampsia.

DESIGN

Prospective interventional study.

SETTING

John Radcliffe Maternity Hospital, Oxford, and Queen Charlotte's and Chelsea Hospital, London.

SUBJECTS

One hundred and sixty-two normotensive nulliparous women recruited at hospital booking clinics.

INTERVENTION

Ambulatory blood pressure was measured at 18 and 28 weeks gestation using the TM2420 monitor.

MAIN OUTCOME MEASURE

The development of pre-eclampsia.

RESULTS

Awake systolic and mean arterial pressures were significantly increased (P < 0.02) at 18 weeks in those who later developed pre-eclampsia. Those differences were more apparent at 28 weeks at which time the diastolic pressure was also increased (P < 0.01). At both stages of gestation the higher readings were sustained during sleep so that the awake-sleep differences were similar in relation to each outcome. The group with incipient pre-eclampsia had a significantly faster heart rate at both 18 and 28 weeks (P < 0.002) The sensitivity in predicting pre-eclampsia for a mean arterial pressure of 85 mmHg or greater at 28 weeks was 65%, with a positive predictive value of 31%. The sensitivity and positive predictive value for a test combining a mean arterial pressure of 85 mmHg or greater and a heart rate of 90 bpm or greater were 53% and 45%, respectively.

CONCLUSION

Although second trimester ambulatory blood pressure is significantly increased in women who later develop pre-eclampsia, the predictive values for blood pressure alone are low. The efficiency of the test is increased by combining the awake ambulatory heart rate and blood pressure measurement together. If an effective method for preventing pre-eclampsia becomes available (commencing at 28 weeks gestation), then awake ambulatory blood pressure and heart rate may have some clinical value as a screening test.

Antigenic heterogeneity of human cytotrophoblast and evidence for the transient expression of MHC class I antigens distinct from HLA-G

Expression of MHC class I antigens on trophoblast populations in first trimester human chorionic villous tissue was assessed by immunohistology. Antibodies used were W6/32 which recognizes a non-polymorphic framework determinant of HLA- A, -B, -C, MHM5 specific for HLA-B, C and 4E and B23.1 which are specific for HLA-B. Syncytiotrophoblast and villous cytotrophoblast were negative with all the anti (HLA class I) antibodies tested. Interstitial trophoblast cells within the maternal decidua were identified with a new antibody, NDOG5, which is specific for extravillous cytotrophoblast. Double labelling showed that they bind W6/32 but not 4E, MHM5 or B23.1; consistent with the expression of the monomorphic HLA-G. In contrast the cytotrophoblast cells of the cell islands and cytotrophoblast shell, which also express the NDOG5 antigen, were positive with W6/32, 4E, MHM5 and B23.1. Cell column cytotrophoblast cells were negative with all four MHC class I antibodies. These results suggest that differentiation of cytotrophoblast from noninvasive to invasive forms is associated with transient expression of class I antigens other than HLA-G on cytotrophoblast shell and cell island cytotrophoblast.

Sera from women with unexplained infertility inhibit both mouse and human embryo growth in vitro

OBJECTIVES

To compare the effect of sera from women with reproductive disorders on the in vitro growth of mouse and human embryos up to the blastocyst stage and to determine the influence on human pregnancy outcome.

DESIGN

The growth of mouse embryos and in vitro fertilized human embryos up to the blastocyst stage was compared in sera from women with unexplained infertility, and these results were correlated with pregnancy outcome. Also the growth of mouse embryos in sera from women with a history of recurrent abortions was correlated with their pregnancy outcome. PATIENTS, SETTING: Women with unexplained infertility were attending the IVF Unit at the John Radcliffe Hospital, Oxford, United Kingdom. Women with a history of recurrent abortions were attending the high risk pregnancy unit at the same hospital.

MAIN OUTCOME MEASURES

Human embryo growth was monitored by daily morphological assessment and mouse embryo growth by both morphological assessment and tritiated thymidine uptake.

RESULTS

In 15 women with unexplained infertility, poor mouse embryo development correlated with poor human embryo quality and impaired blastocyst formation when cultured in the same serum, as well as failure to achieve a pregnancy. In 11 women with a history of recurrent abortion, inhibition of mouse embryo growth correlated with unsuccessful pregnancy outcome.

DISCUSSION

Assessment of both morphological development and cell proliferation in mouse embryos may be a useful test to determine the suitability of maternal sera for human IVF embryo culture, predicting pregnancy outcome and for categorizing women with reproductive disorders for future clinical management.

Distribution of cell adhesion molecules on CD56++, CD3-, CD16- large granular lymphocytes and endothelial cells in first-trimester human decidua

Human decidua exhibits a unique infiltrate of large granular lymphocytes (LGL) with a natural killer (NK) cell phenotype (CD56++, CD16-, CD3-). The mechanisms underlying the binding of circulating LGL to vascular endothelium in the decidua and their migration into the decidual stroma were investigated immunohistochemically in first-trimester decidua with antibodies against endothelial adhesion molecules and their counter-receptors on leukocytes. Decidual and peripheral blood LGL were also investigated by flow cytometry. In the immunohistochemical investigations, moderate to large numbers of lymphoid cells in the decidua were found to express the alpha 4 and alpha L integrin subunits, platelet endothelial cell adhesion molecule (PECAM) and intercellular adhesion molecule-1 (ICAM-1). PECAM and ICAM-1 were found on the endothelium of large numbers of decidual blood vessels of all types. Vascular cell adhesion molecule (VCAM), however, was found on the endothelium of only small to moderate numbers of arterioles and venules and a few capillaries, the latter being the main site of migration of leukocytes into the stroma. Weak staining for endothelial leukocyte adhesion molecule (ELAM) was seen only in a moderate number of blood vessels. Flow cytometry revealed expression of the alpha L integrin subunit by 72 +/- 10% and 97 +/- 3% of decidual and peripheral blood CD56+ LGL, respectively, of the alpha 4 integrin subunit by 85 +/- 7% and 90 +/- 5%, of PECAM by 40 +/- 12% and 30 +/- 15%, and of ICAM-1 by 22 +/- 10% and 1 +/- 1%.(ABSTRACT TRUNCATED AT 250 WORDS)

A randomised prospective study comparing the new vacuum extractor policy with forceps delivery

OBJECTIVE

To compare assisted vaginal delivery by forceps with delivery by vacuum extractor, where a new vacuum extractor policy was employed which dictated the cup to be used in specific situations.

DESIGN

Multicentre randomised controlled trial.

SETTING

Four district general hospitals in the West Midlands.

SUBJECTS

Six hundred-seven women requiring assisted vaginal delivery, of whom 296 were allocated to vacuum extractor delivery and 311 to forceps.

MAIN OUTCOME MEASURES

Delivery success rate, maternal perineal and vaginal injuries, maternal anaesthetic requirements, neonatal scalp and facial injuries.

RESULTS

Of the vacuum extractor group, 85% were delivered by the allocated instrument compared to 90% in the forceps group (odds ratio (OR) 0.64; 95% confidence intervals (CI) 0.4-1.04). However, more women in the vacuum extractor group were delivered vaginally (98%) than in the forceps group (96%). There were significantly fewer women with anal sphincter damage or upper vaginal extensions in the vacuum extractor group (11% vs 17%, OR 0.6; 95% CI, 0.38-0.97). There were significantly fewer women in the vacuum extractor group requiring epidural or spinal anaesthetics (25.4% vs 32.7%, OR 0.69; 95% CI 0.49-0.99) or general anaesthetics (1% vs 4%, OR 0.17; 95% CI 0.04-0.76). Although there were significantly more babies in the vacuum extractor group with cephalhaematomata (9% vs 3%, OR 3.3; 95% CI 1.4-7.4) there were fewer babies in the vacuum extractor group with other facial injuries. There were three babies in the forceps group with unexplained neonatal convulsions.

CONCLUSIONS

Assisted vaginal delivery using the new vacuum extractor policy is associated with significantly less maternal trauma than with forceps. Further studies are required to assess neonatal morbidity adequately.

Pre-eclampsia is associated with an increase in trophoblast glycogen content and glycogen synthase activity, similar to that found in hydatidiform moles

Pre-eclampsia is a placental disorder, but until now, biochemical details of dysfunction have been lacking. During an analysis of the oligosaccharide content of syncytiotrophoblast microvesicles purified from the placental chorionic villi of 10 primigravid women with proteinuric pre-eclampsia, we found an excess of glycogen breakdown products. Further investigation revealed a 10-fold increase in glycogen content (223 +/- 117 micrograms glycogen/mg protein), when compared with controls matched for gestational age at delivery (23 +/- 18 micrograms glycogen/mg protein) (P < 0.01). This was confirmed by examination of electron micrographs of chorionic villous tissue stained for glycogen. The increase in glycogen content was associated with 16 times more glycogen synthase (1,323 +/- 1,013 relative to 83 +/- 96 pmol glucose/mg protein per min) (P < 0.001), and a threefold increase in glycogen phosphorylase activity (2,280 +/- 1,360 relative to 700 +/- 540 pmol glucose/mg protein per min; P < 0.05). Similar changes in glycogen metabolism were found in trophoblast microvesicles derived from hydatidiform moles. Glycogen accumulation in villous syncytiotrophoblast may be a metabolic marker of immaturity of this cell which is unable to divide. The implications of these findings with regard to the pathogenesis of pre-eclampsia are discussed.

Communicating the significance of the fetal heart rate record to the user

Fetal heart rate (FHR) records should be presented as measurements derived from numerical analysis. Such analysis requires computerized systems. The Oxford system is the longest established and most tested of the systems available. It could provide the basis for a standardized approach to the numerical analysis of antepartum FHR records. Intrapartum FHR monitoring is of uncertain clinical value. It is premature to recommend standards for numerical analysis to upgrade the present methods of data presentation during labour. Once the patterns of abnormality are better defined numerically such standards will be mandatory because intrapartum FHR records cannot be interpreted reliably by eye.

Obstetric and neonatal outcome in fetuses with absent end-diastolic velocities of the umbilical artery: a case-controlled study

Absence of end-diastolic velocities (AEDV) is the most severe waveform abnormality detected by Doppler ultrasound examination of the umbilical artery. It is associated with fetal hypoxemia and acidemia. If AEDV predisposed to more neonatal complications, then it might be an indication for earlier delivery. This was investigated in 21 preterm fetuses with AEDV who were matched for gestational age at delivery with 21 with end-diastolic velocities. All fetuses were delivered electively before 36 weeks' gestation of mothers who were hypertensive. The fetal heart rate (FHR) variability, birthweight, and umbilical arterial blood pH were significantly lower in the AEDV group. However, the neonatal outcomes were similar except for less severe hyaline membrane disease and lower initial platelet counts in the AEDV group. At present, fetuses with umbilical arterial AEDV need not be delivered earlier than indicated by the FHR pattern, nor should neonatal management be altered on the basis of antenatal AEDV.

Fetal cerebral Doppler in the recognition of fetal compromise

OBJECTIVE

To establish reference ranges for the human fetal middle cerebral artery pulsatility index (MCA PI) for the local obstetric population, and to compare computerised antenatal fetal heart rate (FHR) analysis with the MCA PI as indicators of fetal compromise.

DESIGN

Prospective data collection for selected patients.

SETTING

High risk pregnancy unit of a teaching hospital.

SUBJECTS

Group 1 consisted of 18 healthy women with uncomplicated singleton pregnancies. Group 2 consisted of 27 women admitted to the high risk pregnancy unit over a 9 month period with intrauterine growth retardation and other related problems; all these women were delivered by prelabour caesarean section.

INTERVENTION

Serial Duplex sonography to determine fetal MCA PI in Groups 1 and 2. Serial FHR analysis using computerised numerical techniques in Group 2 only.

MAIN OUTCOME MEASURES

Serial MCA PI values from 24 to 39 completed weeks of gestation in Group 1. Comparison of serial MCA PI values with FHR analysis in relation to fetal outcome in Group 2.

RESULTS

In Group 1 the MCA PI diminished significantly as gestation advanced from 1.73 (SD 0.25) at 24 weeks to 1.38 (SD 0.26) at 39 weeks (P < 0.01). In Group 2 eleven babies were hypoxaemic at delivery: all had low MCA PI values while only nine had an abnormal FHR prior to delivery.

CONCLUSION

In normal pregnancy, there is a fall in the fetal MCA PI with advancing gestation which probably reflects a decreasing vascular resistance to fetal cerebral blood flow. Hypoxaemia at delivery appeared to be better recognised by the fetal MCA flow velocity waveform than the FHR analysis. This increased sensitivity, however, was achieved at the expense of a reduced specificity. Larger studies are needed to confirm the findings of this preliminary investigation.

Large fetal heart rate decelerations at term associated with changes in fetal heart rate variation

OBJECTIVE

The objective was to determine whether large antepartum decelerations in fetal heart rate were associated with a switch from high to low fetal heart rate variation, suggestive of a change in sleep state, and whether the variation predicted outcome.

STUDY DESIGN

Retrospective computerized analysis of 10,272 cardiotocographic records from 3998 patients at 37 to 42 weeks' gestation from four centers in England and Italy identified 140 good-quality records with large decelerations (more than 20 lost beats in area).

RESULTS

In otherwise normal cardiotocograms a large deceleration had a 40% chance of association with a downward change in fetal heart rate variation (69% when the deceleration exceeded 100 lost beats). The change resembled that occurring naturally with behavioral states. Uterine contractions did not always precede large decelerations. When they did, the lag time (peak of contraction-trough of deceleration) increased from 28 seconds (at 20 to 29 lost beats) to > 100 seconds with increase in deceleration area. Of patients with large decelerations 76% had a normal vaginal delivery.

CONCLUSION

Large decelerations near term, present in up to 5% of patients with otherwise normal fetal heart rate and variation, are often associated with a fall in fetal heart rate variation characteristic of a change in sleep state, without ominous significance.

The West Midlands epithelial ovarian cancer adjuvant therapy trial

In a multicentre prospective randomized controlled trial, single agent cisplatinum was compared with whole abdomino-pelvic moving strip radiotherapy in the management of Stage IC-III epithelial ovarian cancer patients who had no macroscopic residual disease after primary surgery. Over a 6-year period 40 eligible patients were recruited, 15 of whom had Stage III disease. The overall 5-year survival was 60% with no significant survival difference between the treatment groups. Acute toxicity was common in both arms and six (11%) patients experienced significant long term disability.

Noninvasive assessment of the maternal cerebral circulation by transcranial Doppler ultrasound during angiotensin II infusion

OBJECTIVE

To examine the relationship between experimentally induced increments in blood pressure and maternal middle cerebral artery flow velocity patterns measured by transcranial Doppler ultrasound (TCD).

DESIGN

Prospective experimental study.

SETTING

John Radcliffe Maternity Hospital, Oxford.

INTERVENTION

Middle cerebral artery flow velocity waveforms were measured using 2 MHz pulsed Doppler ultrasound via the temporal cranial approach at 28 weeks gestation before, during and 10 min following an angiotensin II infusion.

SUBJECTS

101 normotensive primiparous women at 28 weeks gestation.

RESULTS

A significant rise in blood pressure and fall in heart rate were demonstrated between pre-infusion and maximum angiotensin II infusion (maximum blood pressure) recordings. Simultaneous changes were observed in all flow velocity indices, shown as a decrease in systolic velocity and pulsatility index, and an increase in diastolic and mean velocity (P < 0.0001). These values all returned to baseline levels 10 min post infusion (P < 0.0001). Statistical analysis suggested that the change in flow velocity is related to the rise in blood pressure rather than the direct effect of angiotensin II on the cerebral circulation.

CONCLUSION

Transcranial Doppler can detect changes in the cerebral circulation associated with alterations in blood pressure during pregnancy. The technique needs to be evaluated further in hypertensive disease.

Approximate entropy, a statistic of regularity, applied to fetal heart rate data before and during labor

OBJECTIVE

To determine whether approximate entropy (ApEn), a new statistic of regularity, when applied to fetal heart rate (FHR) data antepartum or in labor, would offer an advantage over standard statistics of variation in predicting outcome.

METHODS

A large data base of antepartum FHR records collected in clinical practice over 10 years was available. Two data sets in labor were stored on disk in small computers interfaced to fetal monitors on-line. Outcomes were assessed using blood gas values on delivery and Apgar scores.

RESULTS

Antepartum, when the most favorable form of ApEn was used on 769 good-quality FHR records, the correlation with measurement of short-term variation was high. This was especially true when the fetal pulse interval variation fell below the normal range (less than 6 milliseconds short-term; r = 0.93) and in 20 other records with sinusoidal variation (r = 0.96). Approximate entropy varied with fetal sleep cycles and took longer to calculate than FHR variation. During the last hour of labor, in 319 records, there was no significant correlation between umbilical artery base deficit values on delivery and ApEn measurement. In 871 additional good-quality records of fetuses with normal outcome, the mean (+/- standard error [SE]) ApEn (0.95 +/- 0.005) was significantly greater than in 22 records (0.88 +/- 0.028) from fetuses with abnormal outcome (umbilical artery base deficit more than 12 mmol/L and Apgar score of 3 or less at 1 minute). However, consideration of the frequency distributions of these measurements showed that ApEn did not discriminate between normal and abnormal outcomes. The SD of fetal pulse intervals rose in labor whereas ApEn values fell, confirming that this new statistic of regularity differs from standard statistics of variation.

CONCLUSION

Approximate entropy offered no advantage over measurement of short-term FHR variation antepartum, and neither measurement predicted outcome in labor.

Spontaneous resolution of pre-eclampsia-related thrombocytopenia

OBJECTIVE

To observe the spontaneous resolution of pre-eclampsia-related thrombocytopenia.

DESIGN

A retrospective study.

SETTING

High Risk Pregnancy Unit, John Radcliffe Maternity Hospital, Oxford.

SUBJECTS

Thirty women with pre-eclampsia complicated by the HELLP/ELLP syndrome who did not receive any specific treatment for their thrombocytopenia.

INTERVENTION

Serial platelet counts throughout labour and the puerperium until the platelet counts returned to levels above 100 x 10(9)/l.

MAIN OUTCOME MEASURES

Time taken from delivery and platelet nadir for platelet counts to return to levels above 100 x 10(9)/l. The rate of recovery from the platelet nadir was measured by the slope of the serial platelet counts plotted against time.

RESULTS

The mean time until platelet count exceeded 100 x 10(9)/l was 67 h (SD 25) after delivery and 44 h (SD 17) from the platelet nadir. All women had counts above 100 x 10(9)/l by 111 h after delivery, and by 88 h after the platelet nadir. Although the time to recovery appeared to depend on the degree of thrombocytopenia, the rate of resolution did not.

CONCLUSION

These data can be used as a guide by clinicians as to the expected time course for postpartum resolution of pre-eclampsia-related thrombocytopenia.

Antenatal cardiotocogram quality and interpretation using computers

OBJECTIVE

To test the application in practice of computerized fetal heart rate (FHR) analysis in pregnancy.

DESIGN

Randomized distribution of subjects with computerized analysis automatically revealed or concealed.

SETTING

A district general hospital and a teaching hospital outside London.

SUBJECTS

2869 pregnant women studied within a year.

OUTCOME MEASURES

Quality and duration of the cardiotocogram; quantitative measurement of FHR variation; number of stillbirths.

RESULTS

With interactive advice to the operator, records were of improved quality (up to 28% without signal loss) with potentially much reduced recording time. The short-term FHR variation measured in the last records before intervention is reported for the first time.

CONCLUSION

The benefits of using the computers include improvement in record quality and saving of time. In addition, where interpretation depended on estimation of FHR variation there was prima facie evidence of observer misinterpretation; visual analysis was unreliable. A larger trial is now required with more rigorous constraints on intervention.

Short-term fetal heart rate variation, decelerations, and umbilical flow velocity waveforms before labor

OBJECTIVE

To determine the value of computerized antepartum measurements of short-term fetal heart rate (FHR) variation and decelerations as a predictor of outcome, and to compare these with measurements of the umbilical artery flow velocity waveform.

METHODS

Data were collected from 3563 high-risk patients for measurements of FHR variables (15,702 records) and outcome (intrauterine death or metabolic acidemia on delivery). Detailed analyses were made on 89 patients with one or more records in which short-term FHR variation was 3 milliseconds or less. Umbilical artery flow velocity waveforms were measured concurrently on 2441 occasions in 991 patients.

RESULTS

More than half of the patients with FHR variation of 3 milliseconds or less were identified before 31 weeks. When short-term FHR variation exceeded 3 milliseconds, there were no intrauterine deaths and only one instance of metabolic acidemia on cesarean delivery. When FHR variation fell below 2.6 milliseconds, 34% of the subjects had metabolic acidemia on cesarean or intrauterine death. The appearance or absence of decelerations was an unreliable guide to outcome. The correlation between FHR variation and the umbilical artery flow velocity waveform was low (r = 0.32). The population studied contained some patients without placental vascular disease or, in five with pre-eclampsia, without abnormal umbilical artery velocity waveforms but with grossly reduced FHR variation.

CONCLUSION

Reduction in short-term FHR variation, as measured by computer, reliably predicts fetal outcome and is a more general measure of fetal well-being than are umbilical artery flow velocities.

Immunological aspects of pre-eclampsia

The first pregnancy preponderance and apparent partner specificity of pre-eclampsia suggest that it might have an immune aetiology. The pathogenesis of pre-eclampsia is undefined although it is clear that it is a placental disorder. The maternal syndrome appears to be mediated by placental ischaemia secondary to spiral artery insufficiency. This leads to a hypothesis that pre-eclampsia is a two-stage disease. The first comprises processes that limit the size of the spiral arteries (poor placentation) or obstruct them (acute atherosis). Either or both may have immunological causes although there is no direct evidence. Factors limiting placentation could involve maternal immune intolerance of the fetal allograft, which in their most extreme expression could lead to immunologically mediated abortion. Thus pre-eclampsia may be part of a wider spectrum of pregnancy loss secondary to poor maternal immune accommodation of her genetically disparate fetus. The second stage involves the consequences of the ensuing placental ischaemia. The syndrome is currently tentatively ascribed to diffuse maternal endothelial dysfunction. There is less reason to invoke immunological mechanisms in the second stage although neutrophil activation could explain generalized endothelial damage. It should be clear that these conclusions are provisional and that the greatest need is for more investigation to eliminate the uncertainty which clouds our concepts.

Management of severe pre-eclampsia and eclampsia by UK consultants

OBJECTIVE

To determine the current management of severe pre-eclampsia and eclampsia in the United Kingdom.

DESIGN

One-page postal survey to all (1007) UK consultant obstetricians with questions about use of antihypertensive and anticonvulsant drugs in severe pre-eclampsia and eclampsia, other management strategies, definition of factors determining severity, protocol development and regional review.

RESULTS

688 replies (69.6% response rate). The antihypertensive drugs used were mainly oral labetalol (35%), oral methyl dopa (23%) and parenteral hydralazine (29%); diuretics were not used. Diazepam was the preferred drug in eclampsia. Very few consultants used magnesium sulphate (2%). Anticonvulsants were also prescribed by 85% of consultants to prevent fits; the drugs then preferred were diazepam (41%), phenytoin (30%) and chlormethiazole (24%). Two-thirds of consultants felt there was a need for trials to study the effectiveness of antihypertensive and anticonvulsant drugs. In a woman with proteinuric hypertension, 15% of consultants did not regard the development of headache as indicating severe pre-eclampsia. Consistent management practices were not associated with agreement about protocols. Regional review does not appear to have occurred.

CONCLUSION

Antihypertensive and anticonvulsant therapies are widely used but trials are considered necessary. Improvements in the management of women with severe pre-eclampsia or eclampsia might occur if UK obstetricians sought more collective opinion and undertook regional audit of protocols.