ST waveform analysis versus cardiotocography alone for intrapartum fetal monitoring: a meta-analysis of randomized trials.

OBJECTIVE: To estimate the effectiveness of intrapartum ST waveform analysis (STAN) versus cardiotocography (CTG) alone in prevention of metabolic acidosis. STUDY DESIGN: Meta-analysis of randomized trials comparing intrapartum fetal monitoring utilizing STAN with CTG versus CTG alone. Primary outcome was neonatal metabolic acidosis, defined as umbilical arterial pH <7.05 and base deficit >12 mmol/L. RESULTS: Five randomized trials including 15,303 singletons, vertex, term, or near-term pregnancies met inclusion criteria and were analyzed. Compared with CTG alone, STAN with CTG was associated with similar incidences of metabolic acidosis (0.81% versus 1.12%, relative risk [RR] 0.80; 95% confidence interval [CI] 0.44 to 1.47), perinatal death, neonatal encephalopathy, Apgar score <7 at 5 minutes, admission to neonatal intensive care unit, and cesarean delivery. Operative vaginal delivery (OVD) was lower in the STAN with CTG compared with CTG alone (13.56% versus 15.20%; RR 0.89; 95% CI 0.83 to 0.97). CONCLUSION: There is no difference in perinatal outcomes between STAN with CTG compared with CTG alone, except for lower rate of OVD.

Cost-effectiveness of cardiotocography plus ST analysis of the fetal electrocardiogram compared with cardiotocography only.

OBJECTIVE: To assess the cost-effectiveness of addition of ST analysis of the fetal electrocardiogram (ECG; STAN) to cardiotocography (CTG) for fetal surveillance during labor compared with CTG only. DESIGN: Cost-effectiveness analysis based on a randomized clinical trial on ST analysis of the fetal ECG. SETTING: Obstetric departments of three academic and six general hospitals in The Netherlands. Population. Laboring women with a singleton high-risk pregnancy, a fetus in cephalic presentation, a gestational age >36 weeks and an indication for internal electronic fetal monitoring. METHODS: A trial-based cost-effectiveness analysis was performed from a health-care provider perspective. MAIN OUTCOME MEASURES: Primary health outcome was the incidence of metabolic acidosis measured in the umbilical artery. Direct medical costs were estimated from start of labor to childbirth. Cost-effectiveness was expressed as costs to prevent one case of metabolic acidosis. RESULTS: The incidence of metabolic acidosis was 0.7% in the ST-analysis group and 1.0% in the CTG-only group (relative risk 0.70; 95% confidence interval 0.38-1.28). Per delivery, the mean costs per patient of CTG plus ST analysis (n= 2 827) were €1,345 vs. €1,316 for CTG only (n= 2 840), with a mean difference of €29 (95% confidence interval -€9 to €77) until childbirth. The incremental costs of ST analysis to prevent one case of metabolic acidosis were €9 667. CONCLUSIONS: The additional costs of monitoring by ST analysis of the fetal ECG are very limited when compared with monitoring by CTG only and very low compared with the total costs of delivery.

[Fibronectin test in threatened preterm labour: cost-saving but not yet widely implemented in the Netherlands]. / Fibronectinetest bij dreigende vroeggeboorte.

OBJECTIVE: Analysis of national implementation of the foetal fibronectin test in the diagnostics of threatened preterm labour in the Netherlands, and indication of the possible obstacles and consequences of implementation or no implementation. DESIGN: National questionnaire, retrospective cohort study and cost-effectiveness calculation. METHODS: We approached all hospitals in the Netherlands (n = 86) with a questionnaire on use of the fibronectin test. We also collected data on women who were referred to the Academic Medical Center (AMC), a tertiary care centre in Amsterdam, with symptoms of threatened preterm labour. We investigated whether the referred patients gave birth within 7 days, and whether unnecessary transfer to a centre with a neonatal intensive care unit (NICU) could have been avoided by implementation of the fibronectin test in the referring hospital. RESULTS: The fibronectin test was used in 34% of the hospitals and an additional 17% were in the process of implementation. The most important reasons not to use the fibronectin test were of a financial nature (50%). The cohort study included 96 women who were referred from secondary care. In our cohort, 36% of all transfers could have been avoided by implementation of the fibronectin test in secondary care. CONCLUSION: The fibronectin test can greatly reduce overtreatment and unnecessary transfer in threatened preterm labour, but implementation remains limited. Costs of the test are an obstacle for the referring hospitals, while implementation prevents unnecessary transport, admission and treatment of pregnant women, giving a potential saving of at least EUR 1,027,930 per year. Inclusion in the Netherlands Society for Obstetrics and Gynaecology (Nederlandse Vereniging voor Obstetrie en Gynaecologie, NVOG) guidelines would be a first step towards wider implementation. Slow implementation exemplifies a more widespread problem: the current reimbursement system does not stimulate such cost-saving innovations.

Intrapartum oximetry of the fetus.

Fetal monitoring during labor aims to identify fetal problems which, if uncorrected, may result in morbidity or death. A nonreassuring or abnormal fetal heart rate trace by cardiotocography (CTG) does not necessarily equate with fetal hypoxia and/or acidosis. However, in the absence of more objective data, the use of CTG often results in variable, but inappropriately high, operative delivery rates (forceps, vacuum, or cesarean delivery) for nonreassuring fetal status in many hospitals. The addition of fetal pulse oximetry (FPO) has the potential to improve the assessment of fetal well-being during labor. In this review we consider several aspects of FPO. Several factors, such as sensor to skin contact, uterine contractions, fetal hair, and caput succedaneum, influence the performance and use of FPO. Issues such as clinicians' perspectives of FPO sensor placement, maternal perspectives of FPO during labor, and an economic analysis have all favored FPO. Several randomized controlled trials (RCTs) of FPO reported a reduction in cesarean delivery for nonreassuring fetal status when FPO was added to conventional CTG monitoring, with no difference in overall cesarean delivery rates. One large RCT reported no difference in mode of birth for any indication. Several issues relevant to the future of FPO have been addressed by these RCTs, the major issue being that it makes no difference to cesarean rates. It may be argued that FPO has a valid clinical use in monitoring the fetus with congenital heart block. Additionally, in situations of nonreassuring fetal status and dystocia, FPO may provide the necessary reassurance until adequate resources for cesarean delivery are available.

A randomised clinical trial on cardiotocography plus fetal blood sampling versus cardiotocography plus ST-analysis of the fetal electrocardiogram (STAN) for intrapartum monitoring.

BACKGROUND: Cardiotocography (CTG) is worldwide the method for fetal surveillance during labour. However, CTG alone shows many false positive test results and without fetal blood sampling (FBS), it results in an increase in operative deliveries without improvement of fetal outcome. FBS requires additional expertise, is invasive and has often to be repeated during labour. Two clinical trials have shown that a combination of CTG and ST-analysis of the fetal electrocardiogram (ECG) reduces the rates of metabolic acidosis and instrumental delivery. However, in both trials FBS was still performed in the ST-analysis arm, and it is therefore still unknown if the observed results were indeed due to the ST-analysis or to the use of FBS in combination with ST-analysis. METHODS/DESIGN: We aim to evaluate the effectiveness of non-invasive monitoring (CTG + ST-analysis) as compared to normal care (CTG + FBS), in a multicentre randomised clinical trial setting. Secondary aims are: 1) to judge whether ST-analysis of fetal electrocardiogram can significantly decrease frequency of performance of FBS or even replace it; 2) perform a cost analysis to establish the economic impact of the two treatment options. Women in labour with a gestational age > or = 36 weeks and an indication for CTG-monitoring can be included in the trial. Eligible women will be randomised for fetal surveillance with CTG and, if necessary, FBS or CTG combined with ST-analysis of the fetal ECG. The primary outcome of the study is the incidence of serious metabolic acidosis (defined as pH < 7.05 and Bdecf > 12 mmol/L in the umbilical cord artery). Secondary outcome measures are: instrumental delivery, neonatal outcome (Apgar score, admission to a neonatal ward), incidence of performance of FBS in both arms and cost-effectiveness of both monitoring strategies across hospitals. The analysis will follow the intention to treat principle. The incidence of metabolic acidosis will be compared across both groups. Assuming a reduction of metabolic acidosis from 3.5% to 2.1 %, using a two-sided test with an alpha of 0.05 and a power of 0.80, in favour of CTG plus ST-analysis, about 5100 women have to be randomised. Furthermore, the cost-effectiveness of CTG and ST-analysis as compared to CTG and FBS will be studied. DISCUSSION: This study will provide data about the use of intrapartum ST-analysis with a strict protocol for performance of FBS to limit its incidence. We aim to clarify to what extent intrapartum ST-analysis can be used without the performance of FBS and in which cases FBS is still needed. TRIAL REGISTRATION NUMBER: ISRCTN95732366.

The fetal acoustic stimulation test: a reliable and cost effective method of antepartum fetal monitoring.

RATIONALE: A healthy foetus, if exposed to external sound stimulation, often responds with vigorous movements which can be felt by the mother. A hypoxic foetus usually does not show this response. OBJECTIVES: To evaluate the fetal acoustic stimulation test (FAST) in antepartum fetal monitoring. DESIGN AND SETTING: Prospective interventional study carried out at the Teaching Hospital, Galle. METHOD: An initial non-stress test (NST) followed by a FAST using the Corometric model 146 was carried out in 423 high risk pregnant women. The response to FAST was assessed and compared with the NST. A repeat NST was recorded in women who had an initial non-reactive NST. The results of the NST and FAST were compared with the fetal outcome if the woman delivered within 24 hours. OUTCOME MEASURES: Maternal perception of fetal movements after FAST, results of NST before and after FAST, and the babies' 5 minute Apgar scores if delivered within 24 hours of the FAST. RESULTS: Of the women, 349 (82.5%) noticed fetal movements after FAST. Of the 167 women who complained of absent or reduced fetal movements, 67% felt fetal movements after FAST. Ninety one had a nonreactive NST and 43 (47%) became reactive after FAST. Compared to the NST, the FAST had less sensitivity (93% vs 100%, p = 0.01), better specificity (79% vs 45%, p = 0.001), better positive predictive value (67% vs 50%, p = 0.02), similar negative predictive values (96% vs 100%, p > 0.05) and better accuracy (83% vs 69%, p = 0.03) in predicting neonatal asphyxia (5 minute Apgar score < 7) if the baby was delivered within 24 hours after the test. CONCLUSION: The FAST is a reliable, cost effective screening test for antepartum fetal monitoring. It significantly reduces the false positive (non-reactive) NST and has a good negative predictive value.

Cost-minimization analysis of domiciliary antenatal fetal monitoring in high-risk pregnancies.

OBJECTIVE: To compare safety and cost-effectiveness of domiciliary antenatal fetal monitoring (cardiotocography and obstetric surveillance) with in-hospital monitoring in high-risk pregnancies. METHODS: From September 1992 to June 1994, 150 consecutive women with high-risk pregnancies, who would otherwise be monitored in the hospital, entered a randomized controlled trial of in-hospital (n = 74) or domiciliary (n = 76) monitoring. The main outcome measures were neonatal safety (Prechtl neurologic optimality score, the proportion of non-optimals) and cost-effectiveness. To test a two-point difference in mean Prechtl scores (two-tailed o = .05. 1-beta = .80), 150 women were needed. Safety and cost-effectiveness were analyzed according to intention to treat. Conditional on the safety outcomes, a cost-minimization analysis based on actual resource use was performed. Uncertainty of results was explored by sensitivity analyses. RESULTS: Neonatal outcomes were equal. No cost-shifting between the antenatal and postpartum period occurred. Substituting domiciliary for in-hospital monitoring reduced mean (standard deviation) antenatal costs from $3558 ($2841) to $1521 ($1459) per woman (P < .001). If costs were varied by the addition of 50%, costs were still reduced. The magnitude of the reduction was sensitive to the costs of hospital care and less sensitive to the costs of domiciliary monitoring. CONCLUSION: Domiciliary monitoring is safe and reduces costs by one-half. The technique seems transferable to other settings but local circumstances may sometimes hamper its dissemination.

Hygroscopic cervical dilators and prostaglandin E2 gel for preinduction cervical ripening. A randomized, prospective comparison.

A randomized, prospective study compared the safety and efficacy of hygroscopic cervical dilators (36 patients) with intracervical prostaglandin E2 (PGE2) gel (38 patients) in preinduction cervical ripening. Maternal age, gestational age and parity were similar in both groups. Both groups had similar cervical Bishop scores upon admission. The change in the cervical score was 3.0 +/- 0.3 (mean +/- SEM) in the dilator group and 2.8 +/- 0.4 in the PGE2 group (P = .7). The mean length of time from amniotomy to delivery was similar in both groups (10.1 +/- 1.0 and 10.3 +/- 1.3 hours, respectively) (P = .9). The proportions of patients in each arm of the study undergoing cesarean section were similar. Eight cesarean sections (21.0%) were performed in the PGE2 group; seven (19.4%) were performed in the dilator group (P = .9). Maternal morbidity, five-minute Apgar scores and admissions to the neonatal intensive care unit were similar in the two groups. Because patients were required to stay in the labor-and-delivery unit for four to six hours of fetal monitoring after PGE2 application, the costs were higher in that group. The dilators and PGE2 gel appear comparable in efficacy as preinduction cervical ripening agents. The need to monitor patients receiving PGE2 gel, however, appears to favor the choice of the dilators from a cost and convenience perspective.

The medical and legal risks of the electronic fetal monitor.

Electronic fetal heart monitoring (EFM) is the most widely used method of monitoring the fetal heartbeat for possible signs of distress during delivery. Soon after its development in the 1960s, EFM replaced intermittent auscultation as the standard of care in the obstetrical community. However, Margaret Lent argues that the widespread use of EFM is both medically and legally unsound. Lent points to a series of clinical trials that demonstrate that EFM does not reduce fetal mortality, morbidity, or cerebral palsy rates. These studies suggest that EFM has a very high false positive rate, and that EFM usage correlates strongly with a rise in cesarean section rates. Similarly, EFM provides no protection in the courtroom. Though obstetricians believe that they should use EFM because its status as the standard of care will protect them from liability, Lent argues that it may in fact expose them to liability given its failings. Instead, she argues that auscultation is equally, if not more, safe and effective, and is more likely to protect physicians from liability. Lent concludes that obstetricians have an obligation to their patients and to themselves to adopt auscultation as the new standard of care.

Fetal monitor for non-stress-test screening at home.

A fetal monitoring device developed for non-stress-test (NST) screening at home works on battery power, and is so small and lightweight (152 x 120 x 64 mm, 600 g) that a pregnant woman can monitor fetal Doppler ultra-sound and record fetal heart rate (FHR) and uterine contraction (UC) data on an attached memory IC card at any time and in any place away from a hospital. The physician can evaluate these data, transmitted via public telephone lines, using a built-in modem in the monitor. The combination of the memory IC card as a temporary storage device with the intermittent data transmission to the host provides endless data storage. The input-output relationship of the device was quantitatively evaluated using a Doppler ultrasound heart rate simulator. Forty pregnant women participated in an evaluation of this system. The total number of NST data transmissions was 648, and the total amount of data received was more than 6.7 Mbytes. Of the 648 transmissions, 475 were adequate for clinical interpretation. Of the 101 failed NST data transmissions, 85 resulted from patient handling errors. However, 82.4% of these errors resulted in reexamination and transfer of new data by the patients, who were aware of the insufficiency of the original data. The main cause of the noise in the data was zero-count data; this noise rate accounted for 4.1% of the data abnormalities. A questionnaire survey found that 96% of the participants wanted to use the monitor again in their next pregnancies, and 83% would recommend its use to pregnant friends. The system was easily used and accepted by pregnant women, and the NST data obtained were sufficient for clinical interpretation.

[Problems in fetal monitoring characteristic of risks for malpractice suits].

Medical malpractice suits in obstetrics comprise about 10% of all claims against medical institutions in Israel. A significant proportion are due to failures relating to fetal monitoring. We studied the characteristics of 102 of 4125 obstetrical cases reported to the Medical Risk Management Co. as being at risk for a malpractice suit. The cases were divided into those with medical management failures (misinterpretation of fetal monitor tracing, failure to respond promptly to fetal monitoring indicating distress, etc.) and technical failures (loss of monitor tracings, interruption in the tracing at a critical time, unreadable tracings, etc.). The monetary quantum in fetal monitoring failures exceeded $30,000,000. The majority of these failures could have been avoided by using central electronic fetal monitoring systems with alerting and archival capabilities.

Medicaid coverage and medical interventions during pregnancy.

This paper extends prior research on the effect of Medicaid coverage on medical interventions during pregnancy (prenatal ultrasound) and birth (ultrasound during delivery, cesarean delivery, inducement, and fetal monitor). The data are from two sources: the New York State Vital Statistics (VS) matched infant birth-death file and the Statewide Planning and Research Cooperative System (SPARCS) file for 1993--1996. Medicaid coverage increases the likelihood of teens and adults receiving prenatal care relative to being uninsured. Overall, the effect of insurance type varies depending on whether the procedure is part of standard care (ultrasound and fetal monitor) or more likely to be elective (inducement and cesarean delivery). Insurance type has a greater effect for elective procedures than for procedures that are part of standard care.

Critics attack electronic fetal monitoring use.

Electronic fetal monitoring has rapidly spread into use in clinical obstetrics since its development in the 1960s--without scientific evidence as to its benefit versus its risks and costs, critics say.