Low-dose oral misoprostol for induction of labour

BACKGROUND

Misoprostol given orally is a commonly used labour induction method. Our Cochrane Review is restricted to studies with low-dose misoprostol (initially ≤ 50 µg), as higher doses pose unacceptably high risks of uterine hyperstimulation.

OBJECTIVES

To assess the efficacy and safety of low-dose oral misoprostol for labour induction in women with a viable fetus in the third trimester of pregnancy.

SEARCH METHODS

We searched Cochrane Pregnancy and Childbirth's Trials Register, ClinicalTrials.gov,  the WHO International Clinical Trials Registry Platform (14 February 2021) and reference lists of retrieved studies.

SELECTION CRITERIA

Randomised trials comparing low-dose oral misoprostol (initial dose ≤ 50 µg) versus placebo, vaginal dinoprostone, vaginal misoprostol, oxytocin, or mechanical methods; or comparing oral misoprostol protocols (one- to two-hourly versus four- to six-hourly; 20 µg to 25 µg versus 50 µg; or 20 µg hourly titrated versus 25 µg two-hourly static).

DATA COLLECTION AND ANALYSIS

Using Covidence, two review authors independently screened reports, extracted trial data, and performed quality assessments. Our primary outcomes were vaginal birth within 24 hours, caesarean section, and hyperstimulation with foetal heart changes.

MAIN RESULTS

We included 61 trials involving 20,026 women. GRADE assessments ranged from moderate- to very low-certainty evidence, with downgrading decisions based on imprecision, inconsistency, and study limitations. Oral misoprostol versus placebo/no treatment (four trials; 594 women) Oral misoprostol may make little to no difference in the rate of caesarean section (risk ratio (RR) 0.81, 95% confidence interval (CI) 0.59 to 1.11; 4 trials; 594 women; moderate-certainty evidence), while its effect on uterine hyperstimulation with foetal heart rate changes is uncertain (RR 5.15, 95% CI 0.25 to 105.31; 3 trials; 495 women; very low-certainty evidence). Vaginal births within 24 hours was not reported. In all trials, oxytocin could be commenced after 12 to 24 hours and all women had pre-labour ruptured membranes. Oral misoprostol versus vaginal dinoprostone (13 trials; 9676 women) Oral misoprostol probably results in fewer caesarean sections (RR 0.84, 95% CI 0.78 to 0.90; 13 trials, 9676 women; moderate-certainty evidence). Subgroup analysis indicated that 10 µg to 25 µg (RR 0.80, 95% CI 0.74 to 0.87; 9 trials; 8652 women) may differ from 50 µg (RR 1.10, 95% CI 0.91 to 1.34; 4 trials; 1024 women) for caesarean section. Oral misoprostol may decrease vaginal births within 24 hours (RR 0.93, 95% CI 0.87 to 1.00; 10 trials; 8983 women; low-certainty evidence) and hyperstimulation with foetal heart rate changes (RR 0.49, 95% CI 0.40 to 0.59; 11 trials; 9084 women; low-certainty evidence). Oral misoprostol versus vaginal misoprostol (33 trials; 6110 women) Oral use may result in fewer vaginal births within 24 hours (average RR 0.81, 95% CI 0.68 to 0.95; 16 trials, 3451 women; low-certainty evidence), and less hyperstimulation with foetal heart rate changes (RR 0.69, 95% CI 0.53 to 0.92, 25 trials, 4857 women, low-certainty evidence), with subgroup analysis suggesting that 10 µg to 25 µg orally (RR 0.28, 95% CI 0.14 to 0.57; 6 trials, 957 women) may be superior to 50 µg orally (RR 0.82, 95% CI 0.61 to 1.11; 19 trials; 3900 women). Oral misoprostol probably does not increase caesarean sections overall (average RR 1.00, 95% CI 0.86 to 1.16; 32 trials; 5914 women; low-certainty evidence) but likely results in fewer caesareans for foetal distress (RR 0.74, 95% CI 0.55 to 0.99; 24 trials, 4775 women). Oral misoprostol versus intravenous oxytocin (6 trials; 737 women, 200 with ruptured membranes) Misoprostol may make little or no difference to vaginal births within 24 hours (RR 1.12, 95% CI 0.95 to 1.33; 3 trials; 466 women; low-certainty evidence), but probably results in fewer caesarean sections (RR 0.67, 95% CI 0.50 to 0.90; 6 trials; 737 women; moderate-certainty evidence). The effect on hyperstimulation with foetal heart rate changes is uncertain (RR 0.66, 95% CI 0.19 to 2.26; 3 trials, 331 women; very low-certainty evidence). Oral misoprostol versus mechanical methods (6 trials; 2993 women) Six trials compared oral misoprostol to transcervical Foley catheter. Misoprostol may increase vaginal birth within 24 hours (RR 1.32, 95% CI 0.98 to 1.79; 4 trials; 1044 women; low-certainty evidence), and probably reduces the risk of caesarean section (RR 0.84, 95% CI 0.75 to 0.95; 6 trials; 2993 women; moderate-certainty evidence). There may be little or no difference in hyperstimulation with foetal heart rate changes (RR 1.31, 95% CI 0.78 to 2.21; 4 trials; 2828 women; low-certainty evidence). Oral misoprostol one- to two-hourly versus four- to six-hourly (1 trial; 64 women) The evidence on hourly titration was very uncertain due to the low numbers reported. Oral misoprostol 20 µg hourly titrated versus 25 µg two-hourly static (2 trials; 296 women) The difference in regimen may have little or no effect on the rate of vaginal births in 24 hours (RR 0.97, 95% CI 0.80 to 1.16; low-certainty evidence). The evidence is of very low certainty for all other reported outcomes.

AUTHORS' CONCLUSIONS

Low-dose oral misoprostol is probably associated with fewer caesarean sections (and therefore more vaginal births) than vaginal dinoprostone, and lower rates of hyperstimulation with foetal heart rate changes. However, time to birth may be increased, as seen by a reduced number of vaginal births within 24 hours. Compared to transcervical Foley catheter, low-dose oral misoprostol is associated with fewer caesarean sections, but equivalent rates of hyperstimulation. Low-dose misoprostol given orally rather than vaginally is probably associated with similar rates of vaginal birth, although rates may be lower within the first 24 hours. However, there is likely less hyperstimulation with foetal heart changes, and fewer caesarean sections performed due to foetal distress. The best available evidence suggests that low-dose oral misoprostol probably has many benefits over other methods for labour induction. This review supports the use of low-dose oral misoprostol for induction of labour, and demonstrates the lower risks of hyperstimulation than when misoprostol is given vaginally. More trials are needed to establish the optimum oral misoprostol regimen, but these findings suggest that a starting dose of 25 µg may offer a good balance of efficacy and safety.

Continued versus discontinued oxytocin stimulation in the active phase of labour (CONDISOX): double blind randomised controlled trial

OBJECTIVE

To determine whether discontinuing oxytocin stimulation in the active phase of induced labour is associated with lower caesarean section rates.

DESIGN

International multicentre, double blind, randomised controlled trial.

SETTING

Nine hospitals in Denmark and one in the Netherlands between 8 April 2016 and 30 June 2020.

PARTICIPANTS

1200 women stimulated with intravenous oxytocin infusion during the latent phase of induced labour.

INTERVENTION

Women were randomly assigned to have their oxytocin stimulation discontinued or continued in the active phase of labour.

MAIN OUTCOME MEASURE

Delivery by caesarean section.

RESULTS

A total of 607 women were assigned to discontinuation and 593 to continuation of the oxytocin infusion. The rates of caesarean section were 16.6% (n=101) in the discontinued group and 14.2% (n=84) in the continued group (relative risk 1.17, 95% confidence interval 0.90 to 1.53). In 94 parous women with no previous caesarean section, the caesarean section rate was 7.5% (11/147) in the discontinued group and 0.6% (1/155)in the continued group (relative risk 11.6, 1.15 to 88.7). Discontinuation was associated with longer duration of labour (median from randomisation to delivery 282 v 201 min; P<0.001), a reduced risk of hyperstimulation (20/546 (3.7%) v 70/541 (12.9%); P<0.001), and a reduced risk of fetal heart rate abnormalities (153/548 (27.9%) v 219/537 (40.8%); P<0.001) but rates of other adverse maternal and neonatal outcomes were similar between groups.

CONCLUSIONS

In a setting where monitoring of the fetal condition and the uterine contractions can be guaranteed, routine discontinuation of oxytocin stimulation may lead to a small increase in caesarean section rate but a significantly reduced risk of uterine hyperstimulation and abnormal fetal heart rate patterns.

TRIAL REGISTRATION

ClinicalTrials.gov NCT02553226.

Effect of β-blocker on maternal-fetal heart rates and coupling in pregnant mice and fetuses

The aim of this preliminary study is to look how maternal-fetal heart rates and their coupling patterns are influenced by injection of β blocker(propranolol) into pregnant mice. Total of 6 pregnant female mice were divided into two groups [control (N=3) and β blockade (N=3)]. On 17.5-day mean heart rate of mothers and fetuses (MHR and FHR) were simultaneously measured for 20 minutes (10 minutes under normal condition and 10 minutes with saline (to control group) and propranolol (to the β blockade group) solution by using an invasive maternal and fetal electrocardiogram techniques with needle electrodes. Results show that FHR decreased and maternal-fetal heart rate coupling (λ) patterns changed with propranolol infusion (no change with saline). Statistical test showed that changes (increase/decrease from pre to post values) in mean, rmssd and power spectral density (PSD) (2~4 Hz)) of MHR, short term variability of FHR, PSD (0.0~1.0 Hz) of FHR and λ were found to be significantly associated with treatment types (saline to propranolol). The presented results and protocol allow for assessment of β adrenergic control of maternal and fetal heart, which will further enhance the value of the mouse as a model of heritable human pregnancy and hypertension.

Maternal buprenorphine treatment and fetal neurobehavioral development

BACKGROUND

Gestational opioid use/misuse is escalating in the United States; however, little is understood about the fetal effects of medications used to treat maternal opioid use disorders.

OBJECTIVE

The purpose of this study was to determine the effect of maternal buprenorphine administration on longitudinal fetal neurobehavioral development.

STUDY DESIGN

Forty-nine buprenorphine-maintained women who attended a substance use disorder treatment facility with generally uncomplicated pregnancies underwent fetal monitoring for 60 minutes at times of trough and peak maternal buprenorphine levels. Data were collected at 24, 28, 32, and 36 weeks gestation. Fetal neurobehavioral indicators (ie, heart rate, motor activity, and their integration [fetal movement-fetal heart rate coupling]) were collected via an actocardiograph, digitized and quantified. Longitudinal data analysis relied on hierarchic linear modeling.

RESULTS

Fetal heart rate, heart rate variability, and heart rate accelerations were significantly reduced at peak vs trough maternal buprenorphine levels. Effects were significant either by or after 28 weeks gestation and tended to intensify with advancing gestation. Fetal motor activity and fetal movement-fetal heart rate coupling were depressed from peak to trough at 36 weeks gestation. Polysubstance exposure did not significantly affect fetal neurobehavioral parameters, with the exception that fetuses of heavier smokers moved significantly less than those of lighter smokers at 36 weeks gestation. By the end of gestation, higher maternal buprenorphine dose was related to depression of baseline fetal cardiac measures at trough.

CONCLUSION

Maternal buprenorphine administration has acute suppressive effects on fetal heart rate and movement, and the magnitude of these effects increases as gestation progresses. Higher dose (≥13 mg) appears to exert greater depressive effects on measures of fetal heart rate and variability. These findings should be balanced against comparisons to gestational methadone effects, relatively good outcomes of buprenorphine-exposed infants, and recognition of the benefits of medication-assisted treatment for pregnant women with opioid use disorders in optimizing pregnancy outcomes.

Mechanisms of Meconium Passage: Cholinergic Stimulation of Electromechanical Coordination in the Fetal Colon

OBJECTIVE

Fetal gastrointestinal function develops in utero, with evidence of enhanced motility near-term. Although colonic passage of meconium in utero may be associated with fetal maturation or stress, little is known of the mechanisms potentiating motility. We assessed the effect of bethanechol, a cholinergic prokinetic agent, on colonic muscle muscular contractile and electromyogram (EMG) activity in the near-term ovine fetus.

METHODS

Near-term (130 days, n = 8) singleton ovine fetuses were chronically prepared with vascular catheters and three sets of miniature strain gauges and bipolar EMGs on the serosal surface of the transverse colon, left colic flexure, and distal colon. Following a 60-minute control period, fetuses received intravenous bethanechol (60 microg/kg, Low-Beth; 120 microg/kg, High-Beth) at 60 and 180 minutes. Colonic activity was recorded digitally and analyzed for short-duration (2<SHORT<15 seconds) and long-duration (15<LONG<120 seconds) strain gauge and EMG contractions. Data were expressed as means +/- SEM and analyzed using one-way analysis of variance (ANOVA) and paired t test.

RESULTS

During the control period, there was significantly greater SHORT versus LONG strain gauge contractions in all segments (P <.05). As compared to control values, Low-Beth and High-Beth significantly increased SHORT strain gauge contractions in the transverse colon (160 +/- 13 to 201 +/- 36 and 307 +/- 74 spikes/30 min, respectively, P <.05), although not in left colic flexure or distal colon. Bethanecol did not affect LONG strain gauge contractions. SHORT-EMG and LONG-EMG spike bursts did not change in response to bethanecol (280 +/- 20, 59 +/- 2 spikes/30 min, respectively).

CONCLUSION

Cholinergic stimulation of fetal sheep colonic activity at 0.9 gestation occurs in the transverse colon, but not the more distal left colic flexure or distal colon. The increased strain gauge, but not EMG activity, suggests that cholinergic stimulation improves electromechanical coordination in the fetal colon. We speculate that cholinergic-induced delivery of gastrointestinal contents to the distal colon evokes local contractile/expulsive mechanisms resulting in meconium passage.

[Adverse effects and hemodynamic effects of nifedipine as a tocolytic]

OBJECTIVES

To describe maternal and fetal adverse effects, in particular cardiorespiratory, of nifedipine as tocolytic, as well as effects on hemodynamic parameters.

MATERIALS AND METHODS

A retrospective evaluative study describing the use of nifedipine as tocolytic at CHU Sainte-Justine in Montreal. Demographic data as well as maternal blood pressure and adverse effects, and maternal and fetal heart rate were collected from medical records of women treated with nifedipine following our tocolysis protocol between January 1st 2004 and March 1st 2007.

RESULTS

The medical records of 213 pregnant women were included in the study. Cardiorespiratory adverse effects were noted in 69 (32.4%); of these, 19 (8.9%) had serious cardiorespiratory adverse events, including 6 acute pulmonary edema or overload. Mean maternal systolic and diastolic blood pressures were significantly decreased and mean maternal and fetal heart rates were significantly increased after the bolus dose. Other adverse effects were reported for 100 (46.9%) women.

CONCLUSION

Nifedipine may cause cardiorespiratory adverse effects warranting a close monitoring.

Neutralizing anti-interleukin-1β antibodies modulate fetal blood-brain barrier function after ischemia

We have previously shown that increases in blood-brain barrier permeability represent an important component of ischemia-reperfusion related brain injury in the fetus. Pro-inflammatory cytokines could contribute to these abnormalities in blood-brain barrier function. We have generated pharmacological quantities of mouse anti-ovine interleukin-1β monoclonal antibody and shown that this antibody has very high sensitivity and specificity for interleukin-1β protein. This antibody also neutralizes the effects of interleukin-1β protein in vitro. In the current study, we hypothesized that the neutralizing anti-interleukin-1β monoclonal antibody attenuates ischemia-reperfusion related fetal blood-brain barrier dysfunction. Instrumented ovine fetuses at 127 days of gestation were studied after 30 min of carotid occlusion and 24h of reperfusion. Groups were sham operated placebo-control- (n=5), ischemia-placebo- (n=6), ischemia-anti-IL-1β antibody- (n=7), and sham-control antibody- (n=2) treated animals. Systemic infusions of placebo (0.154M NaCl) or anti-interleukin-1β monoclonal antibody (5.1±0.6 mg/kg) were given intravenously to the same sham or ischemic group of fetuses at 15 min and 4h after ischemia. Concentrations of interleukin-1β protein and anti-interleukin-1β monoclonal antibody were measured by ELISA in fetal plasma, cerebrospinal fluid, and parietal cerebral cortex. Blood-brain barrier permeability was quantified using the blood-to-brain transfer constant (Ki) with α-aminoisobutyric acid in multiple brain regions. Interleukin-1β protein was also measured in parietal cerebral cortices and tight junction proteins in multiple brain regions by Western immunoblot. Cerebral cortical interleukin-1β protein increased (P<0.001) after ischemia-reperfusion. After anti-interleukin-1β monoclonal antibody infusions, plasma anti-interleukin-1β monoclonal antibody was elevated (P<0.001), brain anti-interleukin-1β monoclonal antibody levels were higher (P<0.03), and interleukin-1β protein concentrations (P<0.03) and protein expressions (P<0.001) were lower in the monoclonal antibody-treated group than in placebo-treated-ischemia-reperfusion group. Monoclonal antibody infusions attenuated ischemia-reperfusion-related increases in Ki across the brain regions (P<0.04), and Ki showed an inverse linear correlation (r= -0.65, P<0.02) with anti-interleukin-1β monoclonal antibody concentrations in the parietal cortex, but had little effect on tight junction protein expression. We conclude that systemic anti-interleukin-1β monoclonal antibody infusions after ischemia result in brain anti-interleukin-1β antibody uptake, and attenuate ischemia-reperfusion-related interleukin-1β protein up-regulation and increases in blood-brain barrier permeability across brain regions in the fetus. The pro-inflammatory cytokine, interleukin-1β, contributes to impaired blood-brain barrier function after ischemia in the fetus.

Fetal heart rate and motor activity associations with maternal organochlorine levels: results of an exploratory study

Contemporaneous associations between circulating maternal organochlorines (OCs) and measures of fetal heart rate and motor activity were evaluated. A panel of 47 OCs, including pesticides and polychlorinated biphenyls (PCBs), was analyzed from serum of 50 pregnant women at 36 weeks gestation. Data were empirically reduced into four factors and six individual compounds. All participants had detectable concentrations of at least one-quarter of the assayed OCs and, in general, higher socioeconomic level was associated with higher OC concentrations. Fetal heart rate measures were not consistently associated with maternal OCs. In contrast, one or more indicators of greater fetal motor activity were significantly associated with higher levels of the DDT and low chlorinated OC factors and five of the six individual compounds (heptachlor epoxide, trans nonachlor, oxychlordane, and PCBs 18 and 52). This preliminary demonstration of associations between fetal motor activity and maternal concentrations of persistent and pervasive environmental contaminants suggests that fetal assessment may be useful in ascertaining the potential early effects of these compounds on development.

48-hours administration of fenoterol in spontaneous preterm labor - does it affect fetal preload?

OBJECTIVE

to investigate whether any changes in the preload index (PLI) occur within the first 48 hours of fenoterol intravenous tocolysis.

MATERIAL AND METHODS

Doppler evaluation of placental and fetal circulation was performed in 36 pregnant women prior to fenoterol administration and after 24/48 hours. Measurements were obtained from a longitudinal section of the inferior vena cava (IVC) and preload index was calculated. To determine changes over time, an all study variable analysis of variance (ANOVA) for repeated measurements, followed by Tukey-Kramer's multiple comparison test was used. The effects of additional clinical covariates were checked.

RESULTS

The maternal heart rate values were significantly increased after 24 hours and 48 hours in comparison to pre-treatment values. No significant changes in fetal heart rate were observed during treatment. The fetal IVC PLI values were significantly reduced after 24 hours and 48 hours of treatment. The increase in PLI values when comparing 24 and 48 hours results were not statistically significant. These observations were consistent with ANOVA post-hoc analysis.

CONCLUSIONS

48 hours intravenous administration of fenoterol appears not to alter inferior vena cava blood flow by itself. The reduction in PLI values may reflect lower fetal preload conditions during the course of successful tocolytic treatment. Therefore, Doppler IVC PLI measurement should be considered as a possible additional assessment method of effectiveness of treatment. However, other Doppler venous blood flow parameters should be assessed to confirm the results and clarify whether maternal corticosteroids administration may be interfering with the results.

48-hours administration of fenoterol in spontaneous preterm labor - Doppler blood flow assessment of placental and fetal circulation

OBJECTIVES

The aims were to investigate whether any changes in placental and fetal circulation were observed during fenoterol tocolysis within the first 48 hours of therapy.

MATERIAL AND METHODS

Doppler evaluation of placental and fetal circulation was performed prior to fenoterol administration and then after 24 and 48 hours. Maternal heart rate and pulsatility index (PI) in uterine arteries were assessed. FHR, RI and PI of umbilical artery and middle cerebral artery were measured. E/A ratio for A-V valves, the myocardial performance index (MPI) and shortening fraction (SF) were calculated for both ventricles independently. The blood flow pattern in DV was assessed using PI, S/a ratio and peak velocity index for the vein. To determine changes over time in all study variable analysis of variance (ANOVA) for repeated measurements followed by Tukey-Kramer's multiple comparison test was used. The effects of additional clinical covariates were checked.

RESULTS

Uterine and fetal arterial blood flow patterns were not altered significantly during 48 hours of tocolysis. No significant changes were observed in fetal cardiac function parameters as well. The evaluation of Doppler parameters in the DV revealed a significant increase in PVIV after 48 hours. Additionally after 48 hours of successful tocolysis S/a ratio values were significantly lower.

CONCLUSIONS

Short term intravenous administration of fenoterol seems not to alter uterine and fetal arterial blood flow pattern. Direct fetal cardiac function remained unaffected. However significant changes of selected Doppler parameters in DV may suggest further studies should be performed to assess more precisely fetal venous blood flow.

Doppler evaluation of blood flow in fetal inferior vena cava during 48-hours Atosiban administration in spontaneous preterm labor

OBJECTIVES

The aims were to evaluate whether any changes in blood flow in fetal inferior vena cava (IVC) are observed during Atosiban tocolysis within the first 48 hours of therapy.

METHODS

Detailed Doppler evaluation of blood flow in fetal IVC was performed prior to Atosiban administration and after 24 and 48 hours respectively. Maternal and fetal heart rate was assessed. IVC Doppler indices, such as, S/D (systole/diastole), PVIV (peak velocity index for the vein) and PLI (preload index) were calculated. To determine changes over time in all study variables, analysis of variance (ANOVA) for repeated measurements was used and followed by Tukey-Kramer's post hoc test. The effects of additional clinical covariates were checked.

RESULTS

Maternal heart rate was not altered significantly during Atosiban administration. No significant changes in FHR (fetal heart rate) as well as following IVC Doppler parameters (S/D, PVIV) were recorded after 24/48 hours of tocolytic treatment. The fetal IVC PLI values were significantly reduced after 24 hours and 48 hours of treatment. The changes in PLI values when comparing 24 and 48 hours results were not statistically significant.

CONCLUSIONS

As the questions about drug safety appeared after the animal study had been published about possible myocyte injury, detailed Doppler evaluation of IVC blood flow was performed. It revealed the changes in preload conditions which could be a reflection of successful Atosiban tocolytic treatment. No hemodynamic changes in IVC were noted, suggesting the presence of fetal acidemia due to possible heart damage was observed.

Preliminary report of 48-hours Atosiban administration in spontaneous preterm labor - Doppler blood flow assessment of placental and fetal circulation

OBJECTIVES

The aims were to investigate whether there are any changes in placental and fetal circulation during Atosiban tocolysis within the first 48 hours of therapy.

METHODS

Detailed Doppler evaluation of placental and fetal circulation was performed prior to Atosiban administration and thereafter at 24 and 48 hours. Maternal heart rate and the pulsatility index (PI) in both uterine arteries (R-UtA, L-UtA) were assessed. Fetal heart rate (FHR), the resistance (RI) and pulsatility index (PI) of umbilical (UA) and middle cerebral artery (MCA) were measured. Additionally cerebroplacental ratio was calculated. E-wave/A-wave ratio (E/A) for atrioventricular valves, the myocardial performance index (MPI) and shortening fraction (SF) for both ventricles were calculated for both ventricles independently. To determine changes over time in all study variables analysis of variance (ANOVA) for repeated measurements followed by Tukey-Kramer's post hoc test was used. The effects of additional clinical covariates were checked.

RESULTS

Maternal heart rate and blood flow in (R-UtA/L-UtA) were not altered significantly during Atosiban administration. No significant changes in FHR as well as Doppler parameters (RI, PI, PSV) in UA and MCA were recorded after 24/48 hours of tocolytic treatment. The mean values of cerebroplacental ratio (CPR) remained unaltered during treatment. Detailed evaluation of fetal cardiac function parameters (E/A, SF, MPI) calculated independently for both ventricles, revealed no significant changes over the time.

CONCLUSIONS

To our best knowledge this study has been first evaluation of placental and fetal circulation with assessment of cardiac hemodynamic function during 48-hours administration of Atosiban. This kind of tocolysis treatment seems not to alter uterine nor fetal arterial blood flow pattern seriously. Hemodynamic cardiac activity in fetuses has remained unaffected. We cannot conclude definitely that there are absolutely no changes in the fetal hemodynamic condition due to Atosiban. Further studies should be performed to verify its possible influence on fetal venous blood flow.

Defining uterine tachysystole: how much is too much?

OBJECTIVE

We sought to determine if uterine tachysystole, ≥ 6 contractions per 10 minutes, within the first 4 hours of labor induction, is associated with adverse infant outcomes.

STUDY DESIGN

This was a prospective cohort study of 584 women ≥ 37 weeks' gestation undergoing induction of labor with 100 μg of oral misoprostol. Fetal heart rate tracings were analyzed for contractions per 10 minutes during the initial 4 hours after misoprostol administration. Patients were analyzed based on the maximum number of contractions per 10 minutes. Infant condition at birth was assessed using the fetal vulnerability composite.

RESULTS

Adverse infant outcomes showed no association with increasing number of contractions per 10 minutes. Six or more contractions in 10 minutes were significantly associated with fetal heart rate decelerations (P ≤ .001). Analysis was performed using the maximum number of contractions per 30 minutes with similar results.

CONCLUSION

Uterine tachysystole, as currently defined, when occurring remote from delivery is not associated with adverse infant outcomes.

Maternal glucose administration for facilitating tests of fetal wellbeing

BACKGROUND

Antenatal maternal glucose administration has been suggested to improve the efficiency of antepartum fetal heart rate testing.

OBJECTIVES

The objective of this review was to assess the merits or adverse effects of antenatal maternal glucose administration in conjunction with tests of fetal wellbeing.

SEARCH METHODS

We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (6 July 2012).

SELECTION CRITERIA

All published and unpublished randomized controlled trials assessing the merits of antenatal maternal (oral or intravenous) glucose administration in conjunction with tests of fetal wellbeing.

DATA COLLECTION AND ANALYSIS

Both review authors independently extracted data and assessed trial quality. Authors of published and unpublished trials were contacted for further information.

MAIN RESULTS

A total of two trials, involving 708 participants, were included. Antenatal maternal glucose administration did not decrease the incidence of non-reactive antenatal cardiotocography tests.

AUTHORS' CONCLUSIONS

Antenatal maternal glucose administration has not been shown to reduce non-reactive cardiotocography. More trials are needed to further substantiate this and to determine not only the optimum dose, but also to evaluate the efficacy, predictive reliability, safety and perinatal outcome of glucose administration in conjunction with cardiotocography and also other tests of fetal wellbeing.

Foley catheter versus intra-vaginal misoprostol for induction of labor in post-term gestations

OBJECTIVE

To investigate whether a fluid filled intra-uterine extra-amniotic Foley catheter is an effective alternative to vaginal misoprostol in inducing labor in primigravid women with post-term gestations.

PATIENTS AND METHODS

A prospective quasi-randomized controlled trial was designed and 100 primigravid women with post-term gestations were enrolled and equally allocated into two groups. A fluid filled intra-uterine extra-amniotic Foley catheter was inserted in women of group I. Women in group II received 25 microgram misoprostol vaginally every 4 h. Artificial rupture of membranes was performed for all women when their cervices reached 3-4 cm dilatation followed by oxytocin infusion if needed. The main primary outcome parameter was the induction to delivery interval. Results were tabulated and statistically analyzed.

RESULTS

No significant difference was noted in any of the demographic data between both groups. The induction to delivery interval was shorter in the Foley group (897.36 ± 116.0 vs. 960.98 ± 94.18 min; P = 0.003). There were 34 cases which needed oxytocin augmentation in group I compared to 11 cases in group II (P < 0.01). Abnormal uterine activity occurred in three cases in the misoprostol group, but none in the Foley group. Ominous fetal heart rate was noted in one case in group I but three in group II.

CONCLUSION

Fluid filled Foley catheter seems to be superior to 25 μg vaginal misoprostol regimen, when used to induce labor in primigravidae with post-term gestations with the advantage of having a shorter induction delivery interval, but more need for oxytocin augmentation.

Timing of intravenous patient-controlled remifentanil bolus during early labour

BACKGROUND

Remifentanil labour analgesia is superior to nitrous oxide but less potent than epidural analgesia. The short onset and offset times of effect suggest that the timing of the bolus in the contraction cycle could have importance. We hypothesised that administering a remifentanil bolus during contraction pause would improve analgesia in early labour.

METHODS

With permission from the ethical committee and the National Authority of Medicines, 50 parturients with uncomplicated singleton pregnancies and informed consent participated in a double blind cross-over study. Intravenous doses of 0.4 μg/kg remifentanil with 1-min infusion times were used during two study periods lasting six to eight contractions. Remifentanil and saline syringes were attached to two patient-controlled devices, one of which administered the bolus immediately after a trigger and the other targeted to start 140 s before the next contraction. The parturients assessed contraction pain, pain relief, sedation and nausea. Oxygen saturation (SaO(2)) pulse and blood pressure were recorded. SaO(2)<95% was the indication for oxygen supplement.

RESULTS

Forty-one parturients were included in the analyses. Because of the period effect, pain and pain relief scores were analysed separately for each of the study periods. The mean pain and pain relief scores were similar during the two different dosing regimens. Side effects, the need for supplemental oxygen, SaO(2) and haemodynamics were similar. In a subgroup with long and regular contractions, however, delayed boluses were associated with lower pain scores.

CONCLUSIONS

Administering a remifentanil bolus during the uterine contraction pause does not improve pain relief.

Neuroactive steroids induce changes in fetal sheep behavior during normoxic and asphyxic states

Allopregnanolone and related steroids are potent γ-aminobutyric acid receptor-A receptor agonistic allosteric modulators that suppress central nervous system (CNS) activity; in some species, these neurosteroids regulate normal CNS activity before birth. The aims of this study were to determine the effect of suppressing allopregnanolone production on behavioral responses to transient asphyxia in late gestation fetal sheep using the 5α-reductase (R)-2 inhibitor, finasteride. Specificity of the effects of finasteride was assessed by co-infusion of alfaxalone, a synthetic analog of allopregnanolone. Fetal catheters and electrodes for measurement of the electrocorticogram (ECoG) and nuchal electromyogram were implanted at 125 days of gestation, and an inflatable occluder was placed to allow umbilical cord occlusion (UCO). At approximately 130 days of gestation, fetuses received carotid arterial infusion of vehicle (2-hydroxypropyl-β-cyclodextrin; 40% w/vol), finasteride (40 mg/kg/h), alfaxalone (5 mg/kg/h), or finasteride + alfaxalone. A further three groups of fetuses were subjected to 5 min UCO at 30 min after the start of each infusion regime. Finasteride treatment alone increased the incidence of arousal-like activity; this was reduced by co-infusion of alfaxalone. After UCO, finasteride treatment caused a prolongation of sub-low voltage (LV) ECoG activity and increase in aberrant ECoG spike activity when compared to vehicle-treated UCO fetuses. After UCO, alfaxalone treatment reduced the incidence of sub-LV, reduced the number of aberrant EEG spikes, and restored ECoG activity to the pattern observed after UCO in vehicle-treated fetuses. These results confirm that neurosteroids significantly modulate normal CNS activity in the late gestation fetus, modify, and limit the effects of asphyxia on the brain.

Effects of acute L-arginine infusion on non-stress test in hypertensive pregnant women

OBJECTIVE

The present report evaluates the effect of acute L-arginine administration on fetal heart variables by a computerized non-stress test (NST) analysis.

METHODS

Fifteen pregnant women at 30-34 weeks of gestational age affected by mild to moderate gestational hypertension were enrolled in the study. The study was performed in the second and third days of hospitalization. Each woman received both active (Arg) or placebo treatment (Placebo), in a double-blind, randomized, cross-over design. Women received saline infusion for 40 min, then they were infused with either placebo (saline infusion prepared by Damor Pharmaceutics and labeled as Arg-B) or Arg (L-Arg 20 g/500 ml labeled as Arg-A).

RESULTS

Multiple analysis of variance (MANOVA) indicated that both placebo and Arg infusion were unable to affect cardiac variables and fetal movements. As far as maternal blood pressure changes were concerned, MANOVA indicated that active treatment showed an acute hypotensive effect on both systolic (F=8.98, p<0.001) and diastolic values (F=15.78, p>0.001). Conversely, placebo infusion does not seems to have induced any change. Considering each time of infusion we observed that Arg treatment was able to lower systolic and diastolic blood pressure after the 40 min of infusion, with this effect persisting for 20 min.

CONCLUSIONS

These data indicate that the acute, intravenous administration of high-dose L-arginine does not induce significant changes in fetal heart rate (FHR), whereas it lowers maternal blood pressure. Such conclusions are reinforced by the observation that saline administration in the same pregnant women was neutral for both FHR and maternal blood pressure values. According to previous studies, it seems conceivable that maternal L-arginine treatment enters the fetal circulation by crossing the placenta. The lack of changes in FHR, however, suggests that no significant hemodynamic changes were induced by the treatment. Contrary to what happens in the mother, this may possibly be due to a low, if any, conversion of L-arginine to nitric oxide in the fetus.

Epidural analgesia with ropivacaine and sufentanil is associated with transient fetal heart rate changes

AIM

Fetal heart rate (FHR) changes have been reported after regional labor analgesia. In this prospective single-blinded study, we aimed to assess whether epidural analgesia with ropivacaine and sufentanil is associated with significant changes in fetal heart rate.

METHODS

Fetal heart rate traces from 120 women in active labor requesting epidural analgesia were recorded and analyzed by two reviewers 90 minutes before and after epidural analgesia for baseline fetal heart rate, accelerations, decelerations and long-term variability.

RESULTS

A significantly decreased number of fetal heart rate accelerations (ANOVA P=0.0001) and a higher percentage of segments with decelerations (P<0.05) were observed in the three segments after analgesia as compared to the three preceding segments. The minimum number of accelerations occurred during the 30 minutes immediately after analgesia was initiated. The reviewers were concordant in finding a significant change from the 60 minutes before to the 60 minutes after analgesia, a period in which there

CONCLUSION

Epidural analgesia with ropivacaine and sufentanil is associated with fetal heart rate changes. These modifications are transient and should be considered when evaluating fetal heart rate monitoring during labor to prevent inappropriate obstetric management decisions to proceed with operative labor.

Computerized analysis of heart rate in fetuses from mothers under levothyroxin treatment

OBJECTIVE

To investigate fetal heart rate (FHR) of fetuses whose mothers are under levothyroxin treatment for chronic hypothyroidism.

STUDY DESIGN

Sixty women under chronic therapy with levothyroxin and 180 controls at 37-39 weeks' gestation were studied by Sonycaid Sistem 8002(R) computerized cardiotocography (cCTG) for 30 min. cCTG parameters were expressed as mean and SD and the differences tested for statistics by Student t-test. Furthermore, cCTG parameters were related to levothyroxin dose by regression analysis. Significance was assessed at p < 0.05.

RESULTS

Computerized cardiotocographic tracings of fetuses from mothers under levothyroxin treatment revealed: significant reduction of baseline FHR (130.1 +/- 9.47 vs. 134.9 +/- 4.68 bpm); increased number of FHR decelerations greater than 20 bpm (0.2 +/- 0.41 vs. 0.05 +/- 0.22); reduction of body movements per hour (6.68 +/- 11.72 vs. 10.65 +/- 11.74); and increased uterine contraction peaks (5.15 +/- 4.69 vs. 2.7 +/- 2.57). Those fetuses also showed significantly reduced neonatal weight (2668.2 +/- 766.65 vs. 3215.44 + 523.88 g) and lower 1-min Apgar score (8.6 +/- 0.95 vs. 9.3 +/- 1.11). Regression analysis showed a significant correlation between levothyroxin dose and baseline FHR (r = 0.60; p < 0.0001) and fetal body movements per hour (r = 0.52; p < 0.0001), and an inverse relationship with uterine contraction peaks (r = -0.35; p < 0.006), whilst no correlation was found with the number of FHR decelerations greater than 20 bpm.

CONCLUSIONS

Maternal hypothyroidism and levothyroxin treatment influence FHR and cCTG is a sensible tool to reveal that influence.

Fetal dilated cardiomyopathy caused by persistent junctional reciprocating tachycardia

Ultrasound examination of a fetus at 32 weeks' gestation revealed dilated cardiomyopathy and a heart rate of 170 beats per minute. Prenatally, this mild tachycardia was not primarily suspected to be the cause of the myocardial changes. Postnatal electrocardiography revealed a persistent junctional reciprocating tachycardia (PJRT) and the diagnosis of tachycardia-induced cardiomyopathy (TICM) became apparent. After conversion to a sinus rhythm under digoxin and amiodarone, the cardiac changes regressed. PJRT is a rare form of supraventricular tachycardia. The prenatal findings in the condition have previously been described retrospectively, but it can only be diagnosed postnatally by its characteristic electrocardiographic properties. This case indicates that TICM can occur at lower heart rates than previously assumed. Even severe prenatal cardiomyopathy may be reversible once sinus rhythm has been restored.

Influence of carbon monoxide poisoning on the fetal heart monitor tracing: a report of 3 cases

BACKGROUND

The diagnosis of carbon monoxide poisoning in the third trimester of pregnancy requires an index of suspicion, and the appearance of the fetal heart monitor tracing may help in this regard.

CASES

Three cases of third-trimester acute carbon monoxide poisoning occurred. In each pregnancy, the fetal heart monitor tracing on admission was correlated with the maternal carboxyhemoglobin level, and how the pattern changed following the institution of therapy was analyzed.

CONCLUSION

In all 3 cases, the initial fetal heart rate pattern demonstrated decreased variability with an elevated baseline and an absence of accelerations and decelerations. Within 45-90 minutes of treatment onset, the baseline fetal heart rate dropped by 20-40 beats per minute, the variability became moderate, and accelerations occurred. Absent accelerations with minimal variability, if caused by uteroplacental insufficiency, are usually preceded by recurrent decelerations. Absent accelerations with minimal variability in the absence of recurrent decelerations may suggest another cause, of which carbon monoxide intoxication can be added to the differential, especially since this disorder often has nonspecific clinical symptoms.

Side-effect and vital sign profile of nifedipine as a tocolytic for preterm labour

OBJECTIVE

To examine the side-effect and vital sign profile of nifedipine used as a tocolytic.

DESIGN

Retrospective audit.

SETTING

Tertiary care university hospital, Hong Kong.

PATIENTS

Women presenting with preterm labour (before 34 weeks of gestation) between March 2001 and September 2004.

MAIN OUTCOME MEASURES

Maternal heart rate, blood pressure, and foetal heart rate were monitored regularly. A four-point Likert scale multiple-choice questionnaire was used to assess the perceived degree of flushing, headache, nausea, dizziness, and shortness of breath. All assessments were performed at predefined intervals from the onset of treatment. Repeated measures analysis of variance was performed to identify any time-dependent association with nifedipine treatment.

RESULTS

In all, 212 episodes of preterm labour were treated with nifedipine in 203 women. In 120 episodes, preterm labour was suppressed for more than 48 hours. Treatment was discontinued in three women because of profound hypotension (<90/60 mm Hg), and in one because of severe flushing. Only one patient developed maternal tachycardia (>or=140 beats per minute), and in two foetal tachycardia (>or=180 beats per minute) was encountered. Moderate headache was experienced in nine women, flushing in nine, dizziness in four, nausea in three, and shortness of breath in one. Repeated measures analysis of variance with time of measurement revealed a significant reduction in maternal blood pressure and increase in maternal heart rate that plateaued after 1 hour of therapy. The foetal heart rate returned to baseline values 3 hours after commencing therapy.

CONCLUSION

In general, use of nifedipine as the first-line tocolytic was safe. However, severe maternal hypotension can occur and close monitoring of vital signs is warranted.

The effects on maternal and fetal cardiovascular and acid–base variables after the administration of etomidate in the pregnant ewe

Etomidate is an intravenous (IV) hypnotic agent characterised by its cardiovascular stability. Although etomidate has been satisfactorily used in veterinary and human obstetrics, little is known about its effects on the fetus. This study determined the cardiovascular and acid-base effects of etomidate administration in the pregnant ewe and her fetus. The effects of etomidate were evaluated in two separate studies. In the first study, etomidate was administered as a 1mg/kg IV bolus; in the second, the drug was administered as a continuous infusion of 100 microg/kg/min for 1h, preceded by a 1mg/kg IV bolus. Etomidate administration did not depress cardiovascular function in the pregnant ewe or fetus. When administered as a continuous infusion, maternal heart rate and blood pressure increased during the second half of the infusion and the initial stages of recovery. Acid-base alterations led to transient but slight respiratory depression in both mother and fetus, probably reflecting the combined effects of etomidate on respiration and the positioning of the animal.

The kidney is resistant to chronic hypoglycaemia in late-gestation fetal sheep

We imposed a sustained reduction in glucose supply to late-gestation fetal sheep to see whether the reduction in glucose and insulin levels affected renal growth, renin expression and synthesis, and renal function. Maternal glucose concentrations were lowered to 1.7-1.9 mmol/L for 12-13 days by i.v. insulin infusion (n = 9, 121 days gestation, term = 150 days). Control ewes (n = 7) received vehicle. Maternal and fetal glucose concentrations were 40% and 31% lower than in controls (p < 0.001), respectively. Fetal plasma insulin levels fell 36% +/- 7% by day 7 (p < 0.05); IGF-I levels were unchanged. Arterial PO2 and pH increased and PCO2 fell (p < 0.05). Renal function was largely unaffected. Longitudinal growth was 28% slower and spleen weights were 36% smaller (p < 0.05); body and kidney weights were not affected. Renal renin levels and renin, angiotensinogen, and angiotensin receptor mRNA levels were similar to those of controls. Plasma renin levels increased from 2.1 +/- 0.6 to 7.6 +/- 2.8 ng angiotensin I.mL-1.h-1 (p = 0.01). Thus reductions in fetal glucose and insulin levels in late gestation that were sufficient to retard skeletal growth had no effect on kidney growth or function or the renal renin-angiotensin system, possibly because IGF-I levels were not reduced. There was, however, increased activity of the circulating renin-angiotensin system similar to that seen during insulin-induced hypoglycaemia.

Randomized comparison of intravenous terbutaline vs nitroglycerin for acute intrapartum fetal resuscitation

OBJECTIVE

The purpose of this study was to compare terbutaline and nitroglycerin for acute intrapartum fetal resuscitation.

STUDY DESIGN

Women between 32-, 42 weeks' gestation were assigned randomly to 250 microg of terbutaline or 400 microg nitroglycerin intravenously for nonreassuring fetal heart rate tracings in labor. The rate of successful acute intrapartum fetal resuscitation and the maternal hemodynamic changes were compared. Assuming a 50% failure rate in the terbutaline arm, we calculated that a total of 110 patients would be required to detect a 50% reduction in failure in the nitroglycerin group (50% to 25%), with an alpha value of .05, a beta value of .20, and a power of 80%.

RESULTS

One hundred ten women had nonreassuring fetal heart rate tracings in labor; 57 women received terbutaline, and 53 women received nitroglycerin. Successful acute resuscitation rates were similar (terbutaline 71.9% and nitroglycerin 64.2%; P = .38). Terbutaline resulted in lower median contraction frequency per 10 minutes (2.9 [25-75 percentile, 1.7- 3.3] vs 4 [25-75 percentile, 2.5- 5]; P < .002) and reduced tachysystole (1.8% vs 18.9%; P = .003). Maternal mean arterial pressures decreased with nitroglycerin (81-76 mm Hg; P = .02), but not terbutaline (82-81 mm Hg; P = .73).

CONCLUSION

Although terbutaline provided more effective tocolysis with less impact on maternal blood pressure, no difference was noted between nitroglycerin and terbutaline in successful acute intrapartum fetal resuscitation.

Thyroid hormone replacement normalizes renal renin and angiotensin receptor expression in thyroidectomized fetal sheep

Previous studies have suggested that thyroid hormone influences maturation of the renin-angiotensin system (RAS) and cardiovascular function in the late-gestation fetal sheep. To further examine the importance of thyroid hormone in this regard, we used the technique of thyroidectomy (TX) to remove endogenous thyroid hormone from the circulation and then replaced it with physiological amounts of exogenous thyroxine. We hypothesized that the previously observed changes in RAS activity and cardiovascular function associated with TX would be normalized. TX was performed at 120 days of gestational age (dGA), and control fetuses were sham operated. After 3 days of recovery, TX fetuses were continuously intravenously infused with thyroxine until delivery by cesarean section close to term (around 138 dGA). Immediately before necropsy, fetuses were infused with isoproterenol, and the hemodynamic responses were noted. Thyroid hormone replacement normalized not only plasma triiodothyronine (T3) and thyroxine (T4) levels but also the TX-induced decreases in renal renin mRNA and renal renin content. Renal ANG II subtype receptor expression levels were also normalized for both mRNA and protein. Decreased basal heat rate and systolic blood pressure associated with TX returned to normal following replacement; however, changes in mean blood pressure and isoproterenol-induced changes in mean blood pressure were not altered. These findings demonstrate that replacement of thyroid hormone in hypothyroid sheep fetuses can restore renal ANG II receptor and renin expression and secretion to normal.

Fetal atrial flutter: a case report and experience of sotalol treatment

OBJECTIVE

Fetal tachyarrhythmia may cause fetal hydrops and lead to fetal morbidity and mortality. Supraventricular tachycardia and atrial flutter have been the most diagnosed. We present a case of fetal atrial flutter diagnosed during the second trimester treated with digoxin and sotalol and delivered at term.

CASE REPORT

A 30-year-old primigravid woman was diagnosed with fetal atrial flutter at the gestational age of 25 weeks with atrial rates of 480-520 bpm and ventricular rates of 200-250 bpm. Initially, she was treated with digoxin then with a combination of digoxin and sotalol. The fetal heart beat slowed after sotalol treatment but did not return to sinus rhythm. The fetus was delivered vaginally. Neonatal echocardiography showed a small apical ventricular septal defect and small patent ductus arteriosus. Electrocardiography also revealed atrial flutter with occasional atrial fibrillation.

CONCLUSION

The efficacy of antiarrhythmic drug therapy for fetal atrial flutter has not been well established. In our case, we used sotalol combined with digoxin and the fetal heart beat slowed after therapy. Sotalol may be considered the drug of choice for fetal atrial flutter. If the fetal atrial flutter is resistant to these therapies, a combination of other congenital cardiac diseases or organic abnormalities should be considered.

Melatonin reduces inflammation and cell death in white matter in the mid-gestation fetal sheep following umbilical cord occlusion

The premature infant is at increased risk of cerebral white matter injury. Melatonin is neuroprotective in adult models of focal cerebral ischemia and attenuates ibotenate-induced white matter cysts in neonatal mice. Clinically, melatonin has been used to treat sleep disorders in children without major side effects. The aim of this study was to investigate the protective and anti-inflammatory effects of melatonin in the immature brain following intrauterine asphyxia. Fetal sheep at 90 d of gestation were subjected to umbilical cord occlusion. Melatonin (20 mg/kg, n = 9) or vehicle (n = 10) was administered IV to the fetus, starting 10 min after the start of reperfusion and continued for 6 h. Melatonin treatment resulted in a slower recovery of fetal blood pressure following umbilical cord occlusion, but without changes in fetal heart rate, acid base status or mortality. The production of 8-isoprostanes following umbilical cord occlusion was attenuated and there was a reduction in the number of activated microglia cells and TUNEL-positive cells in melatonin treated fetuses, suggesting a protective effect of melatonin. In conclusion, this study shows that melatonin attenuates cell death in the fetal brain in association with a reduced inflammatory response in the blood and the brain following intrauterine asphyxia in mid-gestation fetal sheep.

Intrathecal plainvs hyperbaric bupivacaine for labour analgesia: efficacy and side effects

PURPOSE

Baricity is an important determinant of block characteristics of the spinal component of a combined spinal epidural (CSE) for labour analgesia. This study compares the analgesic efficacy and side effects of intrathecally administered plain and hyperbaric bupivacaine (both with fentanyl) during active labour.

METHODS

Sixty-two women in active labour (cervical dilatation >or=5 cm and pain score > 5) were randomized in a prospective, single-blinded fashion to receive 2.5 mg of either hyperbaric or plain bupivacaine both combined with 15 microg of fentanyl as the spinal component of a CSE. The primary outcome was failure of satisfactory analgesia within ten minutes of the intrathecal injection as defined by a verbal pain score > 3. Secondary outcomes included need for rescue analgesia, hypotension, respiratory depression, nausea and vomiting, pruritus and sustained fetal bradycardia.

RESULTS

Sixty patients were analyzed. The failure rates were 20% in the hyperbaric group vs 0% in the plain group (P=0.024). The plain solution provided faster onset, higher sensory levels and less motor block at all times during the first 30 min. The incidence of both pruritus and sustained fetal bradycardia was 33% in the plain group and 10% in the hyperbaric group (P=0.03).

CONCLUSION

A plain rather than hyperbaric solution of bupivacaine 2.5 mg with fentanyl 15 microg provides a faster onset of analgesia, higher sensory levels and less motor block, while demonstrating an increased incidence of pruritus and sustained fetal bradycardia.

A randomized comparison between intravaginal misoprostol and prostaglandin E2 for labor induction

OBJECTIVE

The aim of this randomized study was to compare the effectiveness, safety, and side effects of 6 h vaginal misoprostol versus vaginal prostaglandin E(2) (PGE(2)) for labor induction.

STUDY DESIGN

Fifty microgram of misoprostol was given intravaginally in the misoprostol group (204 women), and 3 mg PGE(2) was given intravaginally in the PGE(2) group (211 women). In both groups, the dose was repeated every 6 h for a maximum of three doses, until active labor was achieved. Artificial rupture of membranes and oxytocin infusion was used during labor in both groups where it was indicated.

RESULTS

The mean interval from the institution of labor induction to delivery was 11.3 +/- 8.6 h for the misoprostol group, and 15.7 +/- 9.3 h for PGE(2 )group (P < 0.05). In the misoprostol group, oxytocin was used less frequently, but there was a higher prevalence of tachysystole. No statistically significant differences were observed between the two groups as regard abnormal patterns of fetal heart rate, the mode of delivery, and the need for neonatal intervention.

CONCLUSION

In conclusion, the intravaginal administration of 50 mug misoprostol at 6 h interval (maximum three doses) is comparable in safety, but more effective for induction of labor than 3 mg intravaginal PGE(2).

Endogenous alpha2-adrenergic receptor-mediated neuroprotection after severe hypoxia in preterm fetal sheep

Central alpha-adrenergic receptor activity is important for fetal adaptation to hypoxia before birth. It is unclear whether it is also important during recovery. We therefore tested the hypothesis that an infusion of the specific alpha(2)-adrenergic receptor antagonist idazoxan (1 mg/kg/h i.v.) from 15 min to 4 h after profound hypoxia induced by 25 min umbilical cord occlusion in fetal sheep at 70% of gestation (equivalent to the 28-32 weeks in humans) would increase neural injury. After 3 days' recovery, idazoxan infusion was associated with a significant increase in neuronal loss in the hippocampus (P<0.05), expression of cleaved caspase-3 (P<0.05), and numbers of activated microglia (P<0.05). There was no significant effect on other neuronal regions or on loss of O4-positive premyelinating oligodendrocytes in the subcortical white matter. Idazoxan was associated with an increase in evolving epileptiform electroencephalographic (EEG) transient activity after occlusion (difference at peak 2.5+/-1.0 vs. 11.7+/-4.7 counts/min, P<0.05) and significantly reduced average spectral edge frequency, but not EEG intensity, from 54 until 72 h after occlusion (P<0.05). Hippocampal neuronal loss was correlated with total numbers of epileptiform transients during idazoxan infusion (P<0.01; r(2)=0.7). In conclusion, endogenous inhibitory alpha(2)-adrenergic receptor activation after severe hypoxia appears to significantly limit evolving hippocampal damage in the immature brain.

Prenatal maternal stress is associated with delivery analgesia and unplanned cesareans

We tested the hypothesis that women with greater prenatal maternal stress (PNMS) would be more likely to receive intravenous opiates and epidural for delivery, and thereby increase the likelihood of unplanned cesarean delivery. PNMS was assessed during early, mid, and late pregnancy using psychometrically sound instruments in structured interviews with women receiving prenatal care at a public university clinic. Medical records were abstracted for analgesia during delivery, fetal heart tracing (FHT) abnormalities, and method of delivery. Only subjects attempting vaginal delivery (N = 298) were included. Using structural equation modeling, a PNMS variable was constructed from five indicators: pregnancy-specific distress, number of prenatal stressful life events, distress from life events, state anxiety, and perceived stress. After controlling for medical predictors of analgesia receipt and surgical delivery, women with higher PNMS were more likely to receive analgesia, and those who received analgesia were more likely to deliver surgically. Analgesia was also associated with FHT abnormalities, which in turn was associated with surgical delivery (all p's < 0.05). Women who received both an epidural and meperidine were most likely to have a cesarean delivery; 29% of this group delivered surgically. Results indicate that PNMS contributes to higher likelihood of unplanned cesarean delivery through its association with delivery analgesia.

[Assessment of fetus' hypoxia treatment with actovegin]

The condition of fetus dramatically impairs in the case of pregnancy pathologies, when uterine-placental blood circulation impairment reveals, as it happens during placental presentation followed by bleeding, chronic anemia, heart and lung diseases of mother and pneumonia. Fetus' hypoxia develops when blood circulation in the vessels of cord is impaired, placental blood circulation disorders reveal. Preventive measures of fetus intra-natal hypoxia lay in elimination of obstetric and extra-genital causes. For the treatment of fetus hypoxia the solution Actovegin 4.0+5% glucose 400.0+vitamin "C" 4.0 in dosage of 15-20 drops per minute was applied. Out of 36 pregnant patients treatment was effective in 24 cases. In 12 cases a Caesarean section was performed. In cases of fetus hypoxia Actovegin allows to transfer metabolic processes in the form of anaerobic glycolysis, thus protecting vital centers from oxygen deprivation.

Magnesium sulfate exposure increases fetal blood flow redistribution to the brain during acute non-acidemic hypoxemia in goats

BACKGROUND

It is still controversial that intrapartum exposure to magnesium may or may not reduce brain damage in premature infants in human and animal models.

AIMS

We investigated the effect of hypoxemia alone under magnesium exposure on fetal cardiovascular changes in chronically catheterized goat fetuses.

STUDY DESIGN

We performed a 3-day experimental protocol with control (10% glucose) on day 1, recovery on day 2, and magnesium on day 3. Magnesium sulfate was directly infused to fetuses in a bolus dose of 270 mg/kg followed by 80 mg/kg/h. Hypoxemia was induced by maternal inhalation of nitrogen gas on day 1 and on day 3. Cerebral blood flow was measured by colored microsphere techniques. Repeated measure ANOVA and Bonferroni's/Dunn's test were used for comparison.

SUBJECTS

Six Japanese Saanen goats at 0.85 gestation.

OUTCOME MEASURES

Fetal heart rate, blood pressure, and cerebral blood flow.

RESULTS

Ionized magnesium concentrations were significantly increased. Fetal PO2 decreased significantly from 30 mmHg to 14 mmHg without acidemia. Magnesium exposure significantly attenuated hypoxemia-induced bradycardia but did not affect blood pressure. Hypoxemia significantly increased fetal brain blood flow from the pre-hypoxic levels on day 1. Magnesium exposure further increased hypoxemia-induced brain blood flow on day 3, but statistical significance was limited to the cerebral cortex.

CONCLUSION

In near-term, initially healthy goat fetuses, brain blood flow during acute hypoxemia was significantly increased with magnesium sulfate exposure.

The effect of maternal methadone use on the fetal heart pattern: a computerised CTG analysis

Using a computerised analysis, the cardiotocograph (CTG) from women who use methadone (n= 25) when compared with women who do not use methadone (n= 25) showed a significant reduction in the fetal heart baseline rate, with a significant reduction in number of accelerations and episodes of high variation. The short-term variation, number of decelerations and episodes of low variation were not different between the two groups. The time taken to meet the standardised criteria was not different, and it is possible that a computer-assisted CTG analysis could be more accurate than a naked eye interpretation.

Effect of chronic maternal methadone therapy on intrapartum fetal heart rate patterns

OBJECTIVE

Treatment of maternal opioid dependence with methadone is associated with a delay in fetal heart rate (FHR) accelerations in nonstress tests. The objective of this investigation was to determine the effect of methadone maintenance therapy on intrapartum FHR patterns.

METHODS

This retrospective cohort study compared intrapartum FHR tracings from 56 methadone-treated patients > or =36 weeks gestation with a control group of nonsubstance using patients matched for maternal age, parity, gestational age, and ethnicity. Blinded FHR interpretation included the recording of baseline, variability, accelerations, and late or severe variable decelerations. The 8-point FHR scoring system was based on the National Institute of Child Health and Human Development Research Planning Workshop guidelines. We considered a 25% reduction in the score during the latent phase to be significant.

RESULTS

The median maintenance dose of methadone was 70 mg daily, with a range between 20 mg and 130 mg. Each patient tested negative for other substances on urine screening before admission. The significantly lower FHR score in the methadone group (mean difference, 1.4; 95% confidence interval, 1.1 to 1.7) was attributed to a lower baseline (P <.05), less moderate or marked variability (P <.01), and a lower proportion of accelerations during the first stage of labor (P <.01). A higher proportion of methadone-exposed fetuses had late or severe variable decelerations in the second stage (44.2% vs 22.9%; P <.03). Analgesic needs, operative vaginal or cesarean delivery rates, and Apgar scores less than 7 at 1 and 5 minutes were not significantly different between the two groups.

CONCLUSIONS

Chronic maternal methadone treatment affects intrapartum FHR patterns by reducing the variability, baseline, and proportion of accelerations during the first stage. These subtle drug-induced effects do not compromise intrapartum decision-making or immediate newborn adjustments.

[Short time variation of foetal heart rate: therapeutic management and effect on heart rate variation in the context of chronic hypotension in the 27th week of gestation]

The non-stress test is the most commonly used method in prepartal surveillance. Due to the high intra- and interobserver variability involved in subjective evaluation, the computer-assisted analysis is gaining in importance. Some studies have shown that low foetal STV may be associated with higher rates of acidosis and intrauterine mortality. Other factors influencing STV are largely not known. Low STV has been found as an effect of cortisone. In this case report, we illustrate the relevance of haemodilation therapy in the context of essential hypertension in the 27 (th) week of gestation and its effect on SVT. The treatment led to a prolongation of pregnancy to the 32 (nd) week. At the start of treatment STV increased to 4.5 ms and dropped back below this value concurrently with centralisation as documented by Doppler sonography. STV correlated clearly with the foetal condition. However, STV is dependent on numerous factors which should be investigated in further studies in order to determine appropriate reference values.

Pulmonary perfusion during lipopolysaccharide (LPS) induced fetal endotoxemia in the preterm fetal sheep

OBJECTIVE

To study endotoxin induced changes in pulmonary blood flow during normoxia and hypoxia and analyzed the role of nitric oxide (NO) and endothelin (ET) in this process.

STUDY DESIGN

Twenty-seven fetal sheep were chronically instrumented at 107+/-1 days (term is 147 days). Experiments were performed 3 days after surgery. Fetuses were randomized into four groups. Group 1: control group (n=5); Group 2: LPS group (n=6) with lipopolysaccharide (LPS) injection at t -60min; Group 3: L-NAME (n=6) with nitro-l-arginine methyl ester (l-NAME) treatment at t -75min; Group 4: l-NAME+LPS group (n=6) with nitro-l-arginine methyl ester (l-NAME) pre-treatment at t -75min and LPS administration at t -60min as described above; Group 5: BQ123+LPS group (n=4) with BQ123 pre-treatment at t -75min and LPS injection at t -60min as described above.

RESULTS

Unlike in control fetuses, there was a marked elevation in pulmonary perfusion in response to LPS induced endotoxemia during normoxia (+112%; p<0.01), which was even further increased during hypoxia (+434%; p<0.001). This increase was partially blocked by BQ123 (p<0.05) and completely abolished by pre-treatment with l-NAME (p<0.001).

CONCLUSION

During fetal endotoxemia, pulmonary perfusion is increased by LPS induced production of nitric oxide. This may have a significant impact in the fetal inflammatory response syndrome, particularly in the inflammation of the fetal lungs observed in response to intrauterine infection.

[Effect and risk analysis of misoprostol in stimulating cervical maturity for post-term pregnancy]

OBJECTIVE

To evaluate the effect and risk of misoprostol for stimulating cervical maturity in women with post-term pregnancy negative for insulin-like growth factor binding protein-1 (IGFBP-1) in cervical secretion with modified Bishop score less than 3.

METHODS

Seventy-one women with post-term pregnancy randomized into misoprostol group (n=37) and control group (n=34) received misoprostol placement at the posterior vaginal fornix and routine intravenous oxytocin infusion, respectively, to stimulate cervical maturity. Failure to respond to the treatment within the initial 24 h necessitated a repeated administration for no more than 3 times in all. Modified Bishop score was recorded and fetal heart monitored once every 24 h, and IGFBP-1 in the cervical secretion was detected at 24 and 48 h after drug administration.

RESULTS

The misoprostol group showed better effect of cervical maturity stimulation than the control group (P<0.001), and the positivity rates of IGFBP-1 24 and 48 h after drug administration were significantly higher than that of the control group (P<0.01 and 0.001). The number of cases with indication for cesarean section was significant higher in the control group (P<0.001). There were no significant differences in postpartum hemorrhage, excessive uterine contraction, incidence of fecal contamination of the amniotic fluid or Apgar score of the newborn between the two groups (P>0.05).

CONCLUSIONS

Misoprostol is safe and effective for stimulating cervical maturity in women with post-term pregnancy who have modified Bishop score lower than 3 and are negative for IGPBF-1 in cervical secretion. Oxytocin is not advised for use in such gravida for stimulating cervical maturity. IGFBP-1 in cervical secretion may serve as an important index for evaluating the cervical maturity.

Effects of cafedrine/theodrenaline, etilefrine and ephedrine on uterine blood flow during epidural-induced hypotension in pregnant sheep

INTRODUCTION

Maternal hypotension is a major concern in obstetric anesthesia, and concerns have been raised about standard vasopressor therapy with ephedrine. Therefore, we evaluated the maternal and fetal hemodynamic effects of two potential alternatives to ephedrine.

METHODS

Hypotension was induced by epidural administration of lidocaine in 6 chronically instrumented pregnant ewes (at 118-122 days of gestation, term 145 days). Three treatments were studied: 25 mg ephedrine, 5 mg etilefrine and 100 mg cafedrine/5 mg theodrenaline (C/T) intravenously. Mean fetal and maternal blood pressure and heart rate, uterine blood flow, as well as fetal and maternal arterial blood gases were recorded for 60 min.

RESULTS

All three vasopressors increased maternal blood pressure, accompanied by a significant increase in uterine blood flow. C/T caused marked maternal tachycardia, whereas ephedrine decreased maternal heart rate. Maternal and fetal blood gases did not change during any of the three treatment regimens.

CONCLUSION

All three vasopressors restored maternal blood pressure and uterine blood flow after epidurally induced maternal hypotension. However, restoration of uterine perfusion was delayed and less pronounced with C/T.

Beta1-adrenergic receptors maintain fetal heart rate and survival

Beta-adrenergic receptor (betaAR) activation has been shown to maintain heart rate during hypoxia and to rescue the fetus from the fetal lethality that occurs in the absence of norepinephrine. This study examines whether the same subtype of betaAR is responsible for survival and heart rate regulation. It also investigates which betaARs are located on the early fetal heart and whether they can be directly activated during hypoxia. Cultured E12.5 mouse fetuses were treated with subtype-specific betaAR antagonists to pharmacologically block betaARs during a hypoxic insult. Hypoxia alone reduced heart rate by 35-40% compared to prehypoxic levels. During hypoxia, heart rate was further reduced by 31% in the presence of a beta(1)AR antagonist, CGP20712A, at 100 nM, but not with a beta2 (ICI118551)- or a beta3 (SR59230A)-specific antagonist at 100 nM. Survival in utero was also mediated by beta1ARs. A beta1 partial agonist, xamoterol, rescued 74% of catecholamine-deficient (tyrosine-hydroxylase-null) pups to birth, a survival rate equivalent to that with a nonspecific betaAR agonist, isoproterenol (87%). Receptor autoradiography showed that beta1ARs were only found on the mouse heart at E12.5, while beta2ARs were localized to the liver and vasculature. To determine if the response to hypoxia was intrinsic to the heart, isolated fetal hearts were incubated under hypoxic conditions in the presence of a betaAR agonist. Heart rate was reduced to 25-30% by hypoxia alone, but was restored to 63% of prehypoxic levels with 100 nM isoproterenol. Restoration was completely prevented if beta1ARs were blocked with CGP20712A at 300 nM, a concentration that blocks beta1ARs, but not beta2- or beta3ARs. Our results demonstrate that beta1ARs are located on the heart of early fetal mice and that beta1AR stimulation maintains fetal heart rate during hypoxia and mediates survival in vivo.

Fetal response to maternal methadone administration

OBJECTIVE

The purpose of this study was to investigate the effect of methadone on fetal neurobehavioral functions and maternal physiologic indicators.

STUDY DESIGN

Forty women attending a substance abuse treatment facility with otherwise uncomplicated pregnancies were evaluated at peak and trough methadone levels. Fetal measures included heart rate, variability, periodic accelerations/decelerations, motor activity, and fetal movement-heart rate coupling. Maternal measures included maternal heart period, variability, electrodermal skin conductance, respiration, and respiratory sinus arrhythmia (RSA). Repeated measure analysis of variance was used to evaluate within-subject changes.

RESULTS

At peak methadone, fetal heart rate was slower, less variable, and displayed fewer accelerations. Fetuses displayed less motor activity, and the integration between heart rate and motor activity was attenuated. Maternal heart rate and skin conductance were unchanged, but methadone administration was associated with lower respiratory rate and RSA, an indicator of parasympathetic tone.

CONCLUSION

Maternal methadone administration has significant effects on fetal behavioral functions that are independent of maternal effects.