Routine formal fetal movement counting and risk of antepartum late death in normally formed singletons

Biophysical profile for fetal assessment in high risk pregnancies

BACKGROUND

A biophysical profile (BPP) includes ultrasound monitoring of fetal movements, fetal tone and fetal breathing, ultrasound assessment of liquor volume with or without assessment of the fetal heart rate. The BPP is performed in an effort to identify babies that may be at risk of poor pregnancy outcome, so that additional assessments of wellbeing may be performed, or labour may be induced or a caesarean section performed to expedite birth.

OBJECTIVES

To assess the effects of the BPP when compared with conventional monitoring (CTG only or MBPP) on pregnancy outcome in high-risk pregnancies.

SEARCH STRATEGY

We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (October 2007), CENTRAL (The Cochrane Library 2006, Issue 4), MEDLINE (1966 to November 2006), EMBASE (1974 to November 2006) and CINAHL (1980 to November 2006).

SELECTION CRITERIA

Randomised and quasi-randomised controlled trials involving a comparison of fetal BPP with other forms of antepartum fetal assessment in women with high-risk pregnancies.

DATA COLLECTION AND ANALYSIS

Two authors independently assessed eligibility, quality and extracted data.

MAIN RESULTS

We included five trials, involving 2974 women. Most trials were not of high quality. Although the overall incidence of adverse outcomes was low, available evidence from randomised controlled trials does not support the use of BPP as a test of fetal wellbeing in high-risk pregnancies. We found no significant differences between the groups in perinatal deaths (relative risk (RR) 1.33, 95% confidence interval (CI) 0.60 to 2.98) or in Apgar score less than seven at five minutes (RR 1.27, 95% CI 0.85 to 1.92). Combined data from the two high-quality trials suggest an increased risk of caesarean section in the BPP group RR 1.60, 95% CI 1.05 to 2.44, n = 280, interaction test P = 0.03. However, the number of participating women was relatively small (n = 280). Therefore, additional evidence is required in order to be definitive regarding the efficacy of this test in high-risk pregnancies. Furthermore, the impact of the BPP on other interventions, length of hospitalisation, serious short-term and long-term neonatal morbidity and parental satisfaction requires further evaluation.

AUTHORS' CONCLUSIONS

At present, there is insufficient evidence from randomised trials to support the use of BPP as a test of fetal wellbeing in high-risk pregnancies.

Maternal risk factors associated with fetal death during antenatal care in low-resource tertiary hospitals

BACKGROUND

Data on maternal characteristics that could predict antepartum fetal death in women receiving antenatal care in resource-constrained settings are limited.

AIMS

To identify maternal sociodemographic and clinical risk factors for antepartum fetal death among women receiving antenatal care in a developing country setting.

METHODS

Case-control analyses of risk factors in the occurrence of singleton fetal death before labour at two university hospitals in south-west Nigeria over 4-5 years. A total of 46 cases and 184 controls were compared for 31 sociodemographic and clinical risk factors. Unconditional multivariate logistic regression analysis was applied to determine independent risk factors. Level of significance was set at P < 0.05.

RESULTS

The incidence of antepartum fetal death among women receiving antenatal care was 10.8 per 1000 total births during the period. Significant risk factors at univariate level include proteinuria, pregnancy-induced hypertension, pre-existing hypertension, reduced weight gain per week, previous antepartum fetal death, antepartum haemorrhage, previous miscarriage, symphysiofundal height-gestational age disparity = 4 cm and perception of reduced fetal movements. The independent risk factors were proteinuria (adjusted OR 4.23, CI: 1.57-11.42), pregnancy-induced hypertension (adjusted OR 8.24, CI: 3.01-22.51) and perceived reduction in fetal movements (adjusted OR 7.17, CI: 1.57-45.76).

CONCLUSIONS

The identified factors should serve as potential targets for antenatal interventions to prevent antepartum fetal death in these institutions. Awareness of these factors should stimulate appropriate risk assessment geared towards the prevention of antepartum fetal deaths by clinicians in these centres and centres in similar setting.

Stillbirth

In the UK, about one in 200 infants is stillborn, and rates of stillbirth have recently slightly increased. This recent rise might reflect increasing frequency of some important maternal risk factors for stillbirth, including nulliparity, advanced age, and obesity. Most stillbirths are related to placental dysfunction, which in many women is evident from the first half of pregnancy and is associated with fetal growth restriction. There is no effective screening test that has clearly shown a reduction in stillbirth rates in the general population. However, assessments of novel screening methods have generally failed to distinguish between effective identification of high-risk women and successful intervention for such women. Future research into stillbirth will probably focus on understanding the pathophysiology of impaired placentation to establish screening tests for stillbirth, and assessment of interventions to prevent stillbirth in women who screen positive.

Fetal movement counting for assessment of fetal wellbeing

BACKGROUND

Fetal movement counting is a method by which a woman quantifies the movements she feels to assess the condition of the baby. The purpose is to try to reduce perinatal mortality by alerting caregivers when the baby might have become compromised. This method may be used routinely, or only in women who are considered at increased risk of complications in the baby. Some clinicians believe that fetal movement counting is a good method as it allows the clinician to make appropriate interventions in good time. On the other hand, fetal movement counting may cause anxiety to women.

OBJECTIVES

To assess outcomes of pregnancy where fetal movement counting was done routinely, selectively or was not done at all; and to compare different methods of fetal movement counting.

SEARCH STRATEGY

We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (30 September 2006), the Cochrane Central Register of Controlled Trials (The Cochrane Library) and the reference lists of relevant papers.

SELECTION CRITERIA

Randomised controlled trials. Trials were excluded where allocation concealment was inadequate and no measures were taken to prevent bias were excluded. The interventions included routine fetal movement counting, selective fetal movement counting, and studies comparing different fetal assessment methods.

DATA COLLECTION AND ANALYSIS

We assessed the methodological quality of included studies and extracted data from studies.

MAIN RESULTS

Four studies, involving 71,370 women, were included in this review; 68,654 in one cluster-randomised trial. All four trials compared formal fetal movement counting. Two trials compared different types of counting with each other; one with no formal instruction, and one with hormonal analysis. Women in the formal fetal movement counting group had significantly fewer visits to the hospital antenatally than those women randomised to hormone analysis (relative risk (RR) 0.26, 95% confidence interval (CI) 0.20 to 0.35), whereas there were fewer Apgar scores less than seven in five minutes for women randomised to hormone analysis (RR 1.72, 95% CI 1.01 to 2.93). There was a significantly higher compliance with the Cardiff 'count to ten' method than with the formal fetal movement counting method (RR 0.25, 95% CI 0.19 to 0.32).All other outcomes reported were non significant.

AUTHORS' CONCLUSIONS

This review does not provide enough evidence to influence practice. In particular, no trials compared fetal movement counting with no fetal movement counting. Robust research is needed in this area.

Etiology and prevention of stillbirth

OBJECTIVE

This is a systematic review of the literature on the causes of stillbirth and clinical opinion regarding strategies for its prevention.

STUDY DESIGN

We reviewed the causes of stillbirth by performing a Medline search limited to articles in English published in core clinical journals from January 1, 1995, to January 1, 2005. Articles before this date were included if they added historical information relevant to the topic. A total of 1445 articles obtained, 113 were the basis of this review and chosen based on the criterion that stillbirth or fetal death was central to the article.

RESULTS

Fifteen risk factors for stillbirths were identified and the prevalence of these conditions and associated risks are presented The most prevalent risk factors for stillbirth are prepregnancy obesity, socioeconomic factors, and advanced maternal age. Biologic markers associated with increased stillbirth risk are also reviewed, and strategies for its prevention identified.

CONCLUSION

Identification of risk factors for stillbirth assists the clinician in performing a risk assessment for each patient. Unexplained stillbirths and stillbirths related to growth restriction are the 2 categories of death that contribute the most to late fetal losses. Late pregnancy is associated with an increasing risk of stillbirth, and clinicians should have a low threshold to evaluate fetal growth. The value of antepartum testing is related to the underlying risk of stillbirth and, although the strategy of antepartum testing in patients with increased risk will decrease the risk of late fetal loss, it is of necessity associated with higher intervention rates.

[Decreased fetal movements in the third trimester: what to do?]

OBJECTIVE

To appreciate at the end of pregnancy, in a low-risk pregnant population, the interest of a screening for fetal well-being in case of decreased fetal movements. To define the most adapted screening.

PATIENTS AND METHODS

Retrospective study over a complete year of the patients having consulted in the same center for decreased fetal movements and subjected to the same screening for fetal activity in hospitalization during 48 hours. This screening included a study of fetal heart rate repeated three times a day, a fetal biophysical profile scoring, an umbilical artery Doppler, a Kleihauer-Betke testing, and an amnioscopy.

RESULTS

One hundred and sixty patients were identified, representing 6.1% of pregnancies followed in the center. There was no relation between the age, the parity of the patients and the probability to consult for a decrease of fetal movements. Nevertheless the antecedents of pathological pregnancy or fetal malformation were frequent. Twenty-one percent of the deliveries were induced for a global rate of 18% in the center. Twenty-eight percent of the patients had a cesarean section for a global rate of 22.8%. Five percent of fetuses were at risk for prenatal asphyxia on the data of the screening. Fetal heart rate was abnormal in 3.75% of cases, fetal biophysical profile score pathological in 3.1% of cases. Just one umbilical Doppler was highly pathological. No meconium amniotic fluid was found. Two Kleihauer-Betke tests were disturbing. At the time of delivery, 28% of fetuses presented a funicular abnormality, 4.3% a severe growth restriction, 4.3% a malformation. One child only had an anemia. There was no perinatal mortality.

DISCUSSION AND CONCLUSION

Screening for fetal vitality remains necessary in case of decreased fetal movements. It has to associate the study of fetal heart rate and the fetal biophysical profile with a Kleihauer-Betke testing. In a low-risk pregnant population, the study of fetal Doppler velocimetry is not profitable. Amnioscopy presents not enough interest. It is necessary to insist with the patients on the necessity of consulting in case of decreased fetal movements even in the approach of the term.

Decreased fetal movements: background, assessment, and clinical management

A reduction or cessation of fetal movements (FMs) is frequently reported by pregnant women and causes concern and anxiety. However, the clinical significance of a history of reduced FMs remains unclear, and the assessment and management of these pregnancies is controversial. This article is a review of the literature on decreased FMs found in medline and the cochrane library using the search phrases: decreased FMs, perinatal outcome, FM monitoring, and fetal assessment. Formal counting of FMs by the pregnant woman could possibly identify the fetuses, which are at risk of compromise, thus allowing for appropriate action. However, the benefit of this intervention has not been definitely proven. Cardiotocography, umbilical/uterine artery Doppler velocimetry, and ultrasonography have been used for antepartum fetal assessment in pregnancies with decreased FMs, but the evidence of a clinical benefit is limited. The effects of fetal assessment with vibroacoustic stimulation and biophysical profile are unknown and should be further evaluated. Present recommendations on the management of pregnancies with decreased FMs are based on limited and inconsistent scientific evidence. There is a need for further well-designed studies in order to provide evidence-based guidelines in the future.

Assessing fetal health

Fetal surveillance significantly reduces the incidence of fetal loss, perinatal morbidity and maternal distress. Obstetricians traditionally classify pregnancies as 'low' or 'high risk' and apply various methods of fetal surveillance in the latter group. However, the majority of stillbirths now occur in 'low-risk' women. This seemingly anomalous observation emphasises the need to develop more effective ways of identifying 'at-risk' fetuses in 'low-risk' women. This chapter describes and critically evaluates eleven currently available tools for fetal surveillance. It also reviews the criteria for ascribing risk status in pregnancy and suggests a pragmatic approach to health assessment in normally formed fetuses for each group. It does not address fetal surveillance during labour and delivery.

Mounting a community-randomized trial: sample size, matching, selection, and randomization issues in PRISM

This paper discusses some of the processes for establishing a large cluster-randomized trial of a community and primary care intervention in 16 local government areas in Victoria, Australia. The development of the trial in terms of design factors such as sample size estimates and the selection and randomization of communities to intervention or comparison is described. The intervention program to be implemented in Program of Resources, Information and Support for Mothers (PRISM) was conceived as a whole community approach to improving support for all mothers in the first 12 months after birth. A cluster-randomized trial was thus the design of choice from the outset. With a limited number of communities available, a matched-pair design with eight pairs was chosen. Sample size estimates, adjusting for the cluster randomization and the pair-matched design, showed that with eight pairs, on average, 800 women from each community would need to respond to provide sufficient power to determine a 3% reduction in the prevalence of maternal depression 6 months after birth-a reduction deemed to be a worthwhile impact of the intervention to be reliably detected at 80% power. The process of selecting suitable communities and matching them into pairs required careful collection of data on numbers of births, size of the local government areas (LGAs), and an assessment of the capacity of communities to implement the intervention. Ways of dealing with boundary issues associated with potential contamination are discussed. Methods for the selection of feasible configurations of sets of pairs and the ultimate allocation to intervention or comparison are provided in detail. Ultimately, all such studies are a balancing act between selecting the minimum number of communities to detect a meaningful outcome effect of an intervention and the maximum size budget and other resources allow.

A kick from within--fetal movement counting and the cancelled progress in antenatal care

Interest for maternal fetal movement counting as a method of screening for fetal well-being boomed during the 1970's and 1980's. Several reports demonstrated that the introduction of counting charts significantly reduced stillbirth rates. However, in 1989, a large study appeared in The Lancet that annihilated research in this field by deeming charts ineffective. In retrospect, it seems evidence was lacking. This review revisits the subject of the significance of fetal movement counting in predicting outcome and reducing stillbirth rates. A structured search was performed to identify studies relating to pregnancy outcome and its association with maternal perception of fetal movements. Suspected preliminary or redundant material was excluded. Only publications from Western countries dating from after 1970 were included. Twenty-four studies were identified. Available data demonstrate that reduced fetal movements are associated with adverse pregnancy outcome, both in high and low risk pregnancies. Increased vigilance towards maternal perception of movements (e.g. by performing movement counting studies) reduces stillbirth rates, in particular stillbirths deemed avoidable. While screening for fetal well-being by maternal fetal movement counting can reduce fetal mortality rates, a resurrection in research activity is urgently needed to optimize its benefits.

Multiple assessment techniques evaluate antepartum fetal risks

As technology has advanced, the field of antepartum fetal evaluation has grown. As reviewed here, a variety of options are available for use in the complicated pregnancy, including application of fetal heart rate monitoring techniques, noninvasive assessment of amniotic fluid volume, sonographic evaluation of fetal behavior, and Doppler assessment of fetal blood flow. It remains unclear which test is the best for any particular situation. The NST is the simplest test to perform but has a higher false-positive rate than the biophysical profile or the CST. These two tests also appear to demonstrate superior sensitivity, at the expense of increased testing time and cost. The application of vibroacoustic stimulation improves the specificity of the NST, while the addition of a sonographic assessment of amniotic fluid volume increases sensitivity and creates an acceptable alternative as a primary test. The limited biophysical profile, with the NST component initially omitted, provides some savings in time and cost without apparent loss of sensitivity or specificity when compared with the full profile. Ultimately, while one particular technique of fetal assessment may never prove to be the best, certain techniques may have advantages over others in particular clinical situations. Umbilical artery Doppler velocimetry appears to be a useful adjunct to other forms of testing, especially in the pregnancy at risk for intrauterine growth restriction and pre-eclampsia. Recent data have shown the biophysical profile predicts the onset of amnionitis in the setting of preterm premature rupture of membranes (PROM). The sonographic assessment of amniotic fluid volume is particularly important in the serial evaluation of the pregnancy complicated by fetal growth restriction. As new technology leads to innovative forms of testing, it is expected that these new tests of fetal status will similarly add to, rather than replace, the existing items in our armamentarium.

PGE2 induction of labor for consistent decreased perception of fetal movements at term

OBJECTIVES

To determine the effects of labor induction with vaginal prostaglandin E2 (PGE2) on mode of delivery and immediate neonatal outcome in women with consistent decreased perception of fetal movements at term.

METHODS

The study group consisted of 115 women with consistent perception of decreased fetal movements admitted for induction of labor at term. Findings were compared with those of 510 women with normal spontaneous onset of labor. Women with previous cesarean section (CS) were excluded from both the study and control groups.

RESULTS

The rate of CS was higher in the study group (14.8%) than in the control group (9%) (not significant). The rates of low 5-min Apgar score (<or=7) and CS performed for non-reassuring fetal heart rate were two-fold higher in the study group than in the control group (2.6% vs. 1.2%, and 6.1% vs. 3.1%, respectively, not significant in both).

CONCLUSION

Induction of labor with PGE2 is successful in approximately 85% of the patients with decreased perception of fetal movements at term and apparently with no serious maternal or fetal complications. However, these pregnancies might be at higher risk of perinatal complications. We suggest that active labor induction may be currently considered as the preferred strategy in these pregnancies. Large prospective randomized studies on maternal and neonatal outcome are needed to clarify this issue.

Security associated with pregnancy and childbirth--experiences of pregnant women

The aim of this study was to describe security associated with pregnancy and childbirth. Security was described as a human need and as human value. Data were collected in semi-structured interviews in two maternity health care clinics. Data interpretation was based on the method of content analysis. A convenience sample of 20 volunteer Finnish women was interviewed during pregnancy. The elements creating security associated with pregnancy and childbirth were maternity health care, social support, sense of control, and attitudes. The feeling of security was manifested in different resources, feelings and behavior. If the feeling of security associated with pregnancy and childbirth was impaired, the participants would resort to their network of social support, contact health care or social welfare services, or try to achieve a sense of security by their own resources. Feeling secure during pregnancy influences the pregnant woman's resources, feelings and behavior. It is important that professionals in maternity health care talk with the client about issues that influence her individually-experienced security associated with pregnancy and childbirth. These include examination of the client's network of social support and informing the client about the health care and social welfare services available.

Methodological considerations on the design and analysis of an equivalence stratified cluster randomization trial

The World Health Organization and collaborating institutions in four developing countries have conducted a multi-centre randomized controlled trial, in which clinics were allocated at random to two antenatal care (ANC) models. These were the standard 'Western' ANC model and a 'new' ANC model consisting of tests, clinical procedures and follow-up actions scientifically demonstrated to be effective in improving maternal and newborn outcomes. The two models were compared using the equivalence approach. This paper discusses the implications of the equivalence approach in the sample size calculation, analysis and interpretation of results of this cluster randomized trial. It reviews the ethical aspects regarding informed consent, concluding that the Zelen design has a place in cluster randomization trials. It describes the estimation of the intracluster correlation coefficient (ICC) in a stratified cluster randomized trial using two methods and reports estimates of the ICC obtained for many maternal, newborn and perinatal outcomes. Finally, it discusses analytical problems that arose: issues encountered using a composite index, heterogeneity of the intervention effect across sites, the choice of the method of analysis and the importance of efficacy analyses. The choice of the clustered Woolf estimator and the generalized estimating equations (GEE) as the methods of analysis applied is discussed.

Fetal movement counts

Monitoring fetal movement serves as an indirect measure of central nervous system integrity and function. The coordination of whole body movement in the fetus, which requires complex neurologic control, is similar to the coordination of movement in the preterm newborn infant. Short-term observations of the fetus are best performed using real-time ultrasound imaging or Doppler ultrasound. Daily fetal kick counting by the compliant gravida is a worthwhile adjunct in determining the need for fetal surveillance tests in the office and in predicting abnormal FHR patterns and perhaps impending stillbirth. Monitoring has its greatest value when placental insufficiency is long-standing; its routine role in low-risk pregnancies requires further clinical investigation. The presence of a vigorous fetus is reassuring. Perceived inactivity requires a reassessment of any underlying antepartum complication and a more precise evaluation by FHR testing or real-time ultrasonography before delivery is considered.

Zelen randomization: attitudes of parents participating in a neonatal clinical trial

Recruitment to randomized controlled trials can be difficult for all parties involved. An alternative to the standard process has been suggested for trials in which the control group receives standard treatment or nontreatment. In this approach (the Zelen design), randomization precedes consent, which is only sought from those allocated to the experimental arm of a trial. The control group is thus unaware that randomization has taken place. As a controversial method, this approach has been often suggested but rarely used. Here we describe how 44 parents recruited to a difficult neonatal trial that used conventional randomization reacted to the idea of Zelen randomization. The arguments they gave for and against the method pertain to four areas: the giving or withholding of information, the effect on decision making, the use of data without parental knowledge, and the long-term impact for parents. The parents were evenly divided in accepting or rejecting the method. Further analysis showed that those rejecting Zelen randomization were more likely to be parents of infants allocated to the control group. This suggests that those from whom consent would not be sought, the group that this approach is primarily meant to protect, are most likely to find it unacceptable.

Antepartum testing

Among the methods of antepartum testing in use today, the nonprovocative tests (NST, BPP, MBPP) are safe and effective for use in ambulatory settings. Outpatient or office utilization of the CST is limited by the need for intravenous access (when oxytocin is used) and by the potential for uterine hyperstimulation and resultant acute FHR abnormalities. Regardless of the method of testing used, large studies have confirmed that the fetal death rate among patients undergoing antepartum testing is significantly lower than that in the general, untested population. This is a particularly encouraging observation in view of the fact that antepartum testing is used almost exclusively in complicated pregnancies at highest risk for poor outcome. In the future, protocols using adjunctive testing methods (fetal movement counting, fetal movement profile, Doppler velocimetry) in combination with standard methods (CST, NST, BPP, MBPP) may further reduce the incidence of fetal death in high-risk populations. At present, the beneficial effects of antepartum testing have created a situation in which the likelihood of fetal death in high-risk, tested populations is lower than that in low-risk, untested populations. This paradox will force us to consider the option of routine antepartum testing in all pregnancies.

Assessment of fetal health should be based on maternal perception of clusters rather than episodes of fetal movements

OBJECTIVE

To determine the level of correlation between mother and machine detected episodes and clusters of fetal movements and their association with fetal heart rate acceleration.

METHODOLOGY

An observational study conducted on health pregnant women between 29-40 weeks gestation who were admitted in spurious labour to the Department of Obstetrics and Gynaecology, National University Hospital, Republic of Singapore. A continuous record of fetal heart rate and fetal movement was obtained using the fetal actocardiograph. Fetal movements felt by mother were also noted. If a continuous series of fetal movements were perceived over a period of 15 secs or more it was termed clusters of fetal movement. The presence or absence of acceleration in relation to these movements were noted.

RESULTS

There was a highly significant correlation between mother and machine in detection of clusters of fetal movements (r = 0.77, p < 0.001); for episodes of fetal movements, the correlation was weaker (r = 0.23, p < 0.05). All clusters of fetal movements perceived by the mother were recorded by the machine and were associated with fetal heart rate accelerations. Two or more accelerations within 3 minutes of the fetal movements were seen with 87.8% of clusters felt by mother compared with 66.7% detected by the machine (p = 0.01). In the 2,263 minutes of recording in 42 women, a cluster of fetal movements was felt at least every 25 minutes by the mother.

CONCLUSION

Maternal perception of 1 or 2 clusters of fetal movements in 30 to 60 minutes may be as reliable as a non-stress test in reassuring good health. It would be less time consuming than the traditional count to 10 fetal movement chart and a more reliable indicator of fetal health than counting episodes of fetal movements. Thus, our study suggests that clusters rather than episodes of fetal movements should be considered for evaluating fetal health based on fetal movements.

The psychological effects of counting fetal movements

By identifying a change in fetal activity state, fetal movement counting may help to reduce the possibility of stillbirth. Concern has arisen that such a focus on fetal activity may cause undue maternal anxiety. A prospective, controlled trial was conducted to determine whether fetal movement counting induced anxiety or other deleterious psychological effects in low-risk primigravidas. A sample of 613 healthy pregnant women was randomly assigned at 28 weeks' gestation to fetal movement counting, sleep recording, or a nonrecording control group. State and trait of anxiety, belief in sources of personal control, and attitudes toward pregnancy and infant were assessed at 28 and 37 weeks' gestation. Participation rates were high (91.4%) across all groups. Most women (90%) assigned to count fetal movements did so on a daily basis (95% of days). No significant changes in psychological status occurred in the three groups as a result of self-monitoring conditions. Independent of group assignment, all women showed a slight increase in transient state and decrease in trait of anxiety from 28 to 37 weeks. Internal locus of control and positive attitudes toward the infant increased slightly, and feelings of well-being decreased slightly for all women. It was concluded that women are willing to record fetal activity, and that fetal movement counting does not cause deleterious psychological effects in low-risk pregnant women.

A case-control study of unexplained antepartum stillbirths

OBJECTIVE

To ascertain factors that will identify women who are at increased risk of unexplained antepartum stillbirth.

DESIGN

Matched case-control study. The cases and controls were initially analysed as a whole group and again after dichotomizing into those of low birthweight (< 2500 g) and those of normal birthweight (> or = 2500 g).

SETTING

Western Australia 1980-1983.

SUBJECTS

Unexplained antepartum stillbirths of > or = 1000 g birthweight (cases) and liveborn infants individually matched for year of birth, plurality, sex and birthweight of infant and race of mother (controls).

RESULTS

The case pregnancies had more polyhydramnios (OR 10.83, 95% CI 2.41-48.69) and cord problems (OR 6.57 95% CI 1.36-31.75) than the controls but, paradoxically, other obstetric and medical complications were less common in the cases. The association with polyhydramnios persisted when the analysis was confined to those with low birthweight. With normal birthweight fetal distress was more frequent in the cases (OR 3.65 95% CI 1.36-9.80) but there were few other differences.

CONCLUSIONS

The clinical and diagnostic systems currently in use are unable to identify many fetuses at risk of death. Decreases in the rate of unexplained antepartum stillbirths await the discovery of new preventable causes, or of innovations in clinical or laboratory aspects of obstetric care.

The epidemiological characteristics of unexplained antepartum stillbirths

All antepartum stillbirths weighing 1000 g or more born in Western Australia from 1980 to 1983 were categorised as 'unexplained' or 'explained' based on information from Perinatal Death Certificates. Using data from hospital and doctors' antenatal records a number of variables in each stillbirth category were compared by unconditional logistic regression. Significant differences were observed between the two groups in medical disorders and abnormalities of pregnancy, thus confirming our classification system. Compared with mothers of 'explained' antepartum stillbirths, mothers of unexplained antepartum stillbirths tended to have younger ages at delivery and had associated lower parity, more antenatal visits to the medical practitioner, fewer hospital admissions, a greater chance of having received care by a general practitioner than by a specialist obstetrician and were of more advanced gestation at the time of diagnosis. The results of this study indicate that the epidemiological characteristics of pregnancies resulting in unexplained antepartum stillbirths differ from those resulting in explained antepartum stillbirths. This suggests that unexplained antepartum stillbirths are not merely the result of inadequate obstetrical management but consist of a series of fetal disease states which are not currently amenable to detection.

An evaluation of the importance of formal, maternal fetal movement counting as a measure of fetal well-being

Maternal perception of fetal movements has, over the years, become recognised as a valuable tool for early detection of fetal compromise. Several studies published in the mid-1970s have demonstrated that a reduction or cessation in maternally perceived fetal movements may precede antepartum late fetal death by a day or longer. From these findings formal fetal movement counting emerged as a valuable, non-invasive method of assessing fetal well-being; the belief being that clinical actions taken on the basis of reduced fetal movement counting may prevent antepartum death or morbidity. Conversely, more recent studies have failed to demonstrate that there is a beneficial effect of a formal, fetal movement counting policy on antepartum death. It is not disputed that fetal movements are of clinical importance but it seems that routine daily counting of fetal movements by women followed by appropriate action when movements are reduced offers no advantages over formal inquiry about fetal movements during standard antenatal care. Thus, the application of formal, maternal fetal movement counting as a method of fetal surveillance to reduce late antepartum death must be questioned.

Antepartum cardiotocographic surveillance of patients with diminished fetal movements

Over a 9-year period, 2,601 women had antenatal cardiotocography (CTG) performed after reporting diminished fetal movements. This series represented 5.6% of the total hospital population and 16.1% of those having antenatal CTG performed. The perinatal mortality rate (0.8%) and major fetal malformation rate (2.2%) were lower than in the hospital population (1.1% and 4.5% respectively). The incidence of abnormal CTG tracings was lower in the 1,390 women with diminished movements alone (6.4%) compared with the 1,211 who had additional antenatal complications (10.2%, p less than 0.001). Likewise the incidences of critical fetal reserve CTG and perinatal mortality were significantly lower in the group without additional complications (0.3% and 0.5%) compared with those with additional complications (1.7% and 1.2% respectively). The 24 patients with critical fetal reserve CTG were promptly delivered (19 by Caesarean section) with favourable results in 19, cerebral palsy in 1, and 4 perinatal deaths - 2 of these deaths resulted from intrauterine hypoxia (table 3, Cases 12 and 15). There were 17 perinatal deaths in cases where the CTG was satisfactory (13) or showed reduced reserve (4); 9 of these were unavoidable as a result of major malformations or other lethal conditions. The other 8 deaths resulted from hypoxia, including 4 in pregnancies at or beyond 37 weeks' gestation (table 3, Cases 6-9), illustrating that delivery is warranted in women with diminished fetal movements when conditions are favourable even when the CTG is satisfactory. Cardiotocography is useful in the management of patients with diminished fetal movements.

Cluster randomization in large public health trials: the importance of antecedent data

Large-scale public health trials are often randomized by geographic or administrative clusters, for reasons of financial or organizational exigency. In this paper, we deal with the situation where the dependent variable is a count of events, such as mortality from, or incidence of a given disease. Simulation results show that this design may decrease power by more than 50 per cent. The lost power can largely be replaced by incorporating information on the dependent variable, within clusters, before the start of the trial. The pretrial and trial data can be analysed by negative trinomial models.

Maternal perception of decreased fetal movement as an indication for antepartum testing in a low-risk population

Maternal perception of decreased fetal movement has traditionally been used as an indication for fetal testing in high-risk patients. Two hundred ninety-two low-risk patients who presented with a complaint of decreased fetal movement were studied to determine the incidence of adverse outcome and need for further testing. Initial testing included a nonstress test and ultrasonographic examination. Five (1.7%) of the study group had fetal death on initial examination and 4.4% of patients required immediate delivery because of abnormal maternal or fetal evaluation. An additional 5.8% had abnormal fetal heart rate tracings that necessitated follow-up. Fifty-two percent of patients with normal initial evaluations underwent additional testing. There were no significant differences between patients undergoing additional testing, patients having no additional testing, and a low-risk nontested group with regard to adverse outcome. Fetal surveillance is indicated in low-risk patients with decreased fetal movement. Additional testing of patients with a normal initial evaluation and no further complaint of decreased fetal movement may not be necessary.

Fetal movements; factors affecting their perception

We prospectively recorded placental site, maternal weight and parity in 182 patients reporting decreased fetal movements and compared these with controls. Reports of decreased fetal movements were 2.10 times (95% CI 1.51-2.92) as likely in association with an anterior placenta and 1.81 times (95% CI 1.20-2.93) and 2.61 times (95% CI 1.26-5.40) as likely in mothers weighing over 80 and 90 kg, respectively, but there was no association with parity. Decreased perception of fetal movements is more likely to have serious implications in thin women with a posterior placenta. Our findings also suggest that the sensation of fetal movements arises from pressure against body wall structures rather than the uterus or peritoneum.

The work of the National Perinatal Epidemiology Unit. One example of technology assessment in perinatal care

This article describes one approach to assessing the effects of perinatal care--that adopted by the National Perinatal Epidemiology Unit in Oxford, England. The unit's research has been based primarily on a combination of simple, descriptive analyses of observational data and statistically robust analyses of evidence derived from randomized controlled trials.