Outcome of prolapsed chorioamniotic membrane: relationship between the degree of herniation, infection, and pregnancy prolongation

Our objective was to determine the outcome predictor of conservative bed rest therapy for prolapsed chorioamniotic membrane. We could perform tocolysis for 61 women, 41 of visible membrane (group A) and 20 of protruding membrane (group B). The duration of pregnancy prolongation and gestational age (in weeks) at delivery in group A were significantly larger than in group B ( p < 0.05). Outcome of neonates was also significantly different between two groups ( p < 0.05). In 37 women of group A (90%) and 10 of group B (50%; group D), signs of infection were negative throughout the admission to delivery with conservative therapy (white blood cell counts </= 13000/microL and CRP values </= 1.0 mg/dL). In group D, pregnancy was prolonged 23.9 days, which was significantly longer than in group B ( p < 0.05). This study suggests that pregnancy prolongation for prolapsed membrane with conservative therapy depends on the success of prophylactic treatment for infection.

Perinatales Management und Ausgang von Drillingsschwangerschaften zwischen 1997 und 2001

BACKGROUND

Because of the trend for premature birth, multifetal pregnancies are at high risk for neonatal morbidity and mortality. This study presents our perinatal management scheme and the outcome of triplet pregnancies.

PATIENTS AND METHODS

From 1997 to 2001 we studied 31 triplet pregnancies. Their management consisted of cervical measurement at 20 weeks, admission from 25 weeks onwards, regular ultrasound examinations, intravenous tocolysis with preterm contractions or cervical shortening, promotion of fetal lung maturation, antibiotic therapy with evidence of vaginal infection, delivery by caesarean section ideally at 33 weeks.

RESULTS

In the studied group 4 triplet pregnancies were monochorionic, 6 dichorionic, and 21 (68 %) trichorionic. 2/31 triplet pregnancies finalized in late abortions. Furthermore, a single and a double intrauterine death occured in two triplet pregnancies. 6 (21 %) of triplet pregnancies were delivered before the 30th week and 23 (79 %) after the 30th week of gestation (median gestational age 31.5 weeks, median birth weight 1545g). Neonates of trichorionic pregnancies in comparison to those of mono- and dichorionic pregnancies were delivered two to three weeks later and presented with significantly higher birth weights (1660 g vs. 1245 g vs. 1240 g; p = 0.001 and 0.0009, respectively). 13/84 (15.5 %) of the neonates showed growth retardation. In 4/84 (4.1 %) children brochopulmonary dysplasia or cerebral haemorrhage was observed. Only one child developed enterocolitis. 19 % (16/84) of neonates showed evidence of retinopathy. No intrauterine death occured after 28 weeks and no child died after delivery.

CONCLUSION/DISCUSSION

With our well defined management of triplet pregnancies from 20 weeks onwards we reach similar gestational ages at delivery but remarkably lower neonatal complication rates compared to previous studies.

Beta-2 mimetics and magnesium: true or false friends?

Physiological beta stimulation may be involved in the regulation of magnesium status namely by homeostatic increase of magnesemia during magnesium deficiency. But conversely excessive beta stimulation namely by use of pharmacological high doses of beta mimetics may induce a decrease of magnesemia. Two different types of magnesium therapy ought to be distinguished. Nutritional magnesium therapy which may physiologically palliate a magnesium deficiency due to an insufficient magnesium intake. It is devoid of any toxicity. Pharmacological magnesium therapy, whatever the magnesium status, causes a iatrogenic magnesium load. It may induce magnesium toxicity. Tocolysis is the one common obstetrical indication for beta mimetics and magnesium. Beta-2 mimetics are the reference tocolytic drugs in most countries. But high doses of beta-2 mimetics for suppression of premature labor are associated to a high incidence of maternal, fetal and neonatal side effects. Tocolysis must then be discontinued or limited to shorter treatments with the lowest possible doses. Nutritional magnesium therapy which palliates gestational magnesium deficiency is efficient and atoxic. Conversely, high doses of intravenous MgSO4 for tocolysis are less efficient and unsafe. Because of its maternal and above all pediatric side effects, this maternal pharmacological magnesium therapy should be abandoned for tocolysis. Investigation of the therapeutic ratio of various magnesium salts before their clinical use could help to determine if other anions different from sulfate could decrease the toxicity. Beta-2 agonists are first line asthma therapy, but their safety is debated. Asthma and Chronic Obstructive Pulmonary Disease (COPD) per se may induce magnesium depletion related to a dysregulation of the control mechanisms of magnesium status. It requires a correction of its causal regulation, but nutritional magnesium supplementation is ineffective. When chronic primary magnesium deficiency coexists with obstructive bronchial disorders, it constitutes a decompensatory factor. Atoxic nutritional magnesium therapy may palliate this coexistent magnesium deficiency. Pharmacological magnesium treatment for obstructive pulmonary diseases is not very efficient with low safety. Combination of palliating nutritional magnesium therapy and of beta-2 mimetics for tocolysis or pulmonary obstructive indications may be beneficial and remain atoxic. Conversely combination of intravenous tocolytic high doses of magnesium and of beta-2 mimetics is contra-indicated because of its dubious efficiency and its possible toxicity. The possible role of SO4- as regards toxicity must be discussed. Contra-indications of lower intravenous or inhaled Mg doses for pulmonary bronchial obstruction are less imperative than for tocolysis. The selection of a particular magnesium salt among others should take into account reliable plasmacological and toxicological data. It seems necessary to determine the therapeutic ratio (LD50/ED50) of the various available magnesium salts before pharmacological use.

Rebound hyperkalemia after cessation of intravenous tocolytic therapy with terbutaline in the treatment of preterm labor: anesthetic implications

Beta-adrenergic agents have been widely used in obstetrics to attenuate premature labor (termed tocolytic therapy), delay delivery, allow fetal maturation, and thereby reduce neonatal morbidity and mortality. Hypokalemia is a common side effect during beta-adrenergic tocolytic therapy for the treatment of preterm labor. Although rebound hyperkalemia after cessation of tocolytic therapy with ritodrine has been reported, there have been no reports of hyperkalemia occurring after the cessation of beta-adrenergic tocolytic therapy with terbutaline for preterm labor; we report such a case.

Preterm premature rupture of membranes and neonatal outcome prior to 34 weeks of gestation

OBJECTIVES

To investigate the impact of preterm premature rupture of membranes on neonatal outcome.

METHODS

A retrospective study was conducted among singleton pregnancies with or without intact amniochorional membranes. The impact of maternal age, gestational age at birth, 1- and 5-min Apgar scores, birthweight, presence of meconium, use of tocolytics, corticosteroids and antibiotics, mode of delivery, umbilical artery pH, histologic presence of chorioamnionitis, and state of the membranes were analyzed in relation to neonatal outcome. Neonatal outcomes were categorized into: none, presence of respiratory distress syndrome, early neonatal sepsis, neonatal death, and days at neonatal intensive care unit.

RESULTS

A total of 180 preterm deliveries with ruptured (n=80) and intact membranes (n=100) constituted the study group (group 1) and the control group (group 2), respectively. Compared with group 2, there were more cases in group 1 of maternal antibiotic use (P<0.001), short-term tocolysis (P=0.03), and histologic chorioamnionitis (P<0.001). Multiple logistic regression analysis showed that gestational age at delivery (P=0.009), 1-min Apgar score (P=0.013), and umbilical artery pH (P=0.05) were the independent factors affecting neonatal outcome.

CONCLUSIONS

Neonatal outcome was mainly affected by prematurity rather than by preterm premature rupture of membranes.

Delayed delivery of second twin: a multicentre study of 35 cases

OBJECTIVE

The aim of this study was to conduct a statistical analysis to determine the outcome of conservative treatment after delivery of a first fetus in multiple pregnancy and thus define new prognostic factors.

STUDY DESIGN

Multicentre retrospective study involving 12 centers over a 10-year period.

RESULTS

Twenty-eight twin pregnancies and seven triplet pregnancies which were managed conservatively. In twin pregnancies, 79% of the delayed-delivery fetuses survived; only 7% of the first delivered fetuses survived. The mean interval between deliveries was 47 days. No statistical difference was found concerning cerclage, antibiotic therapy, tocolysis and hospitalization. Earlier delivery of the first twin and premature rupture of membranes for the second twin were significantly related to a longer interval between deliveries.

CONCLUSION

Delayed delivery in multifetal pregnancies can be successful if there are no contraindications and these pregnancies are managed in a tertiary perinatal center. Publications limited to successful cases have undoubtedly introduced some bias in assessment.

[Investigation of a fetal heart-rate pattern that shows a reduced oscillation amplitude]

A fetal heart-rate pattern that has a reduced oscillation amplitude may indicate a physiological fetal dormant period but could also be an indication of fetal hypoxemia. In some rare cases such a fetal heart rate-pattern can be an indicator of cerebral or cardial fetal malformation or of an intoxication caused by sedative drugs. Our patient is a 32-year-old Para III in the phase of 29 weeks and 3 days gestation. Upon admission to the clinic, the fetal heart-rate pattern showed a reduced oscillation amplitude, and there were no signs of fetal movement. The ultrasound examination gave us no reason to suspect fetal malformation, and the results of the Doppler ultrasonography were also normal. However, although the patient had denied taking any medication at all, the results of an toxicological blood test confirmed our suspicion of benzodiazepine intoxication. Throughout the night the fetal heart-rate pattern was continuously measured, and in the early hours of the morning, after breaking down of the oxazepam medication, a normalization of the fetal heart-rate pattern was observed. This case report definitively demonstrates that Doppler ultrasonography is a valuable method for assessing any uncertainty regarding a fetal heart-rate pattern.

Tocolysis does not improve neonatal outcome in patients with preterm rupture of membranes

To investigate the effects of magnesium sulfate therapy in premature preterm rupture of membranes (PPROM), this retrospective cohort study of deliveries after PPROM over a 3-year period was performed. Gestational age-matched patients, who received magnesium sulfate therapy after PPROM, were compared with those who did not receive tocolysis. Deliveries within 48 hours (47 versus 22%) and a week (92 versus 44%) of PPROM occurred more frequently in those who received tocolysis. Cervical dilation and frequency of contractions were not different between the two groups. There was no difference at 24 hours in the delivery rates (36 versus 22%). Population demographics and neonatal/obstetrical outcomes were similar between the two groups except for a shorter latency in patients who received tocolysis (60 [1-245] versus 127 [1-1848] hours, median [range]). Magnesium sulfate therapy does not appear to improve maternal or neonatal outcome in PPROM and may in fact shorten the latency period.

[Cervical incompetence in multifetal gestation: diagnosis and prophylaxis]

OBJECTIVE

Preterm birth following cervical incompetence threatens infants of multiple gestation. The questions at hand are whether we can validate a sonographic early detection system and if prophylactically intended strategies, such as cervical cerclage, potentially influence pregnancy management and/or perinatal outcome.

METHODS

Multifetal pregnancies surveyed with three-dimensional ultrasound and pregnancies treated with cervical cerclage were compared to controls.

RESULTS

Volumetry of the cervix was possible in all 34 examinations performed. In contrast, two-dimensional cervical length assessment could not be obtained in 6% because the presenting fetal part obstructed the sonographic plane. Mean cervical length was 28.7 mm (SD 7.7). Mean cervical volume was 30.0 cm3 (SD 16.0). A significant correlation was found between mean two-dimensional cervical length and mean cervical volume as both parameters decreased with gestational age (p = 0.01). Prophylactic cervical cerclage was used in 17% of triplet pregnancies studied at a mean gestational age of 16 + 2 weeks (98-138 days). In 50% of the quadruplet/quintuplet pregnancies studied, the cerclage was performed at a mean gestational age of 15 + 2 weeks of gestation (78-152 days). The time interval from operation to delivery was 106 days (62-119) for triplets and 96 days (57-142) for quadruplets/quintuplets. Prophylactic cervical cerclage did not prolong pregnancies compared to controls. With respect to the need for hospitalization or intravenous tocolysis or perinatal outcome parameters, no benefit was achieved.

CONCLUSIONS

The results disclaim a positive impact of prophylactic cervical cerclage on the course of a multifetal pregnancy and/or perinatal outcome. On the other hand, early non-invasive diagnosis of cervical incompetence enables a risk-adapted conservative pregnancy management.

Clostridium botulinum toxin inhibits myometrial activity in vitro: possible application on the prevention of preterm labor after fetal surgery

BACKGROUND/PURPOSE

The current study aimed to analyze the effects of Clostridium botulinum toxin (Botox) on pregnant myometrium activity in vitro.

METHODS

Strips of myometrium were obtained from pregnant Wistar rats on gestational day 13 through 15 and placed under controlled conditions within tissue baths containing DeJalon solution. Muscular activity, including amplitude and frequency of contractions, was recorded by a force transducer connected to a polygraph. After stable baseline values were recorded, different concentrations of Botox were added to the tissue baths. Myometrial activity data points for each drug concentration were entered as mean percentual variations of the baseline. A total of 26 uterine samples from 13 animals were studied. Statistical analysis was by single-factor analysis of variance (ANOVA) with P <.05 considered significant.

RESULTS

Except for a narrow concentration range, when the effects were nonmonotonic, both amplitude and frequency of myometrial contractions were significantly depressed (P <.05) and eventually totally abolished at most concentrations studied, albeit in a potentially biphasic pattern. Those effects could be reversed by a complete washout of the tissue bath.

CONCLUSIONS

Within appropriate concentrations, Botox consistently inhibits or completely arrests myometrial activity in potentially reversible fashion. This agent may prove valuable in premature labor prevention after fetal surgery.

Therapies administered to mothers at risk for preterm birth and neurodevelopmental outcome in their infants

A decrease in the rate of preterm births and the prevention of prematurity-associated neurodevelopmental morbidity are critical for the reduction of neurodevelopmental disability. Efforts to reduce the overall preterm delivery rate have been unsuccessful. Although progress has been achieved in the prevention of short-term neonatal morbidity over the past several decades, the majority of the improvements have resulted from improved neonatal care. Whether obstetric interventions can improve neurodevelopmental outcome is unknown. The ability to adequately assess obstetric interventions is hampered by the limited number of interventional studies that included long-term outcome assessment. Thus, it is incumbent upon ongoing and future interventional studies to consider long-term outcome assessment as a critical component of the overall evaluation of efficacy of obstetric therapies.

[Tocolysis and its place in premature labor]

Premature labour ranges from 6 to 8 per cents from all of the deliveries but it causes 75 80 per cents of the perinatal infant mortality. The purposes of the present research are: to prove the benefit of the tocolytic therapy in case of progressing premature labour (cervical dilatation 3 and more cm and distinguishable uterine contractions--at least 2 in 10 min for more that 1 hour); to compare the efficiency of the medicines used in tocolysis, as well as their influence on the maternal and infant morbidity and mortality; A successful tocolysis is considered to be the one, which delays the delivery for at least 48 hours. The authors concluded, that there is not any significant statistic difference in the tocolysis success with beta-adrenomymethics and the use aquatic solution of Magnesium sulfate. Better results were achieved in the cases when Indomethacin was added to the basic tocolytic medicine. No significant harms were observed in the maternal and infant organisms in result of the tocolytics application. It has been found that after the tocolytic therapy application the newborns were with greater birth body weight and the percentage of the respiratory distress was lower, compared to the group with expectant behaviour at hospitalization.

Central neuraxial blockade promotes external cephalic version success after a failed attempt

External cephalic version (ECV) has been successfully used to decrease the fetal and maternal morbidity and costs of cesarean delivery. As there are limited data regarding the use of central neuraxial blockade in the setting of previously failed ECV attempts, we sought to evaluate the efficacy and safety of spinal and epidural anesthesia in this setting. A retrospective review of all ECV attempts performed by a single experienced obstetrician between 1995 and 1999 was conducted. Standardized tocolytic and anesthetic regimens were used. A total of 77 patients underwent ECV attempts; of these, 37 (48%) were unsuccessful, 15 of which consented to further attempts with anesthesia. Neuraxial anesthesia was associated with frequent ECV success in both multiparous 4/4 (100%) and nulliparous 9/11 (82%) parturients. Overall 5/6 (83%) and 8/9 (89%) (P = NS) ECV attempts were successful with spinal and epidural anesthesia, respectively, with 2/5 (40%) and 6/8 (75%) (P = NS) resulting in vaginal deliveries. One successful ECV in the epidural group had an urgent cesarean delivery for persistent fetal bradycardia with good neonatal and maternal outcomes. We conclude central neuraxial anesthesia promotes successful ECV after previously failed ECV attempts.

IMPLICATIONS

Our retrospective analysis of central neuraxial techniques, both epidural and spinal anesthesia, noted a significant success rate in the setting of previously failed external cephalic version attempts.

Extremely preterm vaginal breech delivery en caul

OBJECTIVE

To describe an alternative method of vaginal birth to the conventional assisted delivery for extremely preterm breech infants within intact amnions, and to compare the immediate neonatal outcomes with those delivered by cesarean.

METHODS

Retrospective review of singleton breech deliveries under 26 weeks' gestation after spontaneous labor with intact membranes. Nine "en caul" vaginal births after tocolysis and six cesarean deliveries performed for the sole indication of preterm labor were identified between 1996 and 2001.

RESULTS

The vaginal group's mean gestation and cervical dilatation on admission were 23(+6) weeks and 3.2 cm, respectively, and 24(+6) weeks and 2.8 cm in the cesarean group. Vaginal delivery occurred an average of 4 days after admission and 1 day for cesarean delivery. Mean time interval between the first corticosteroid injection and delivery was greater in the vaginal group (90 versus 22 hours). Failure to start or complete a steroid course was more likely in the operative group (67% versus 11%). Mean birth weights were comparable. Five-minute Apgar scores and cord pHs were 6 and 7.41, respectively, for vaginal births, and 5.5 and 7.32 after cesarean deliveries. Fifty-five percent of vaginally delivered infants had a 5-minute Apgar score less than 7, with 22% of the whole group dying during the first week of life. This compared with 66% and 50%, respectively, for cesarean infants. Of the survivors, average age at discharge was 121 days for both groups.

CONCLUSION

Vaginal birth can be effected in extremely preterm breech pregnancies with intact membranes by adopting the "en caul" delivery method.

Treatment of preterm labor

The ultimate goal of treating preterm labor is to prolong the pregnancy long enough to decrease the incidence of neonatal mortality and morbidity associated with prematurity, while minimizing maternal and fetal risks. There are many controversies in treating preterm labor. Much of this controversy stems from the difficulty in establishing efficacy and safety of interventions and uncertainty of the diagnosis of preterm labor. This article outlines conventional measures and tocolytic therapy directed at prolonging the pregnancy. A review of the effect of tocolytic agents, administration, side effects, and nursing interventions is included. Key words: preterm labor treatment,

Short-term maternal outcomes that are associated with the EXIT procedure, as compared with cesarean delivery

OBJECTIVE

The ex utero intrapartum treatment procedure was developed to treat iatrogenic tracheal obstruction that resulted from in utero fetal therapy for congenital diaphragmatic hernia. The ex utero intrapartum treatment procedure allows for controlled intubation while the neonate is maintained on placental circulation, prolonging operative time. This study evaluates whether there is increased maternal morbidity associated with this procedure compared with routine cesarean deliveries.

STUDY DESIGN

Maternal outcomes on 34 patients who underwent the ex utero intrapartum treatment procedure were evaluated. Infection rate, estimated blood loss, need for transfusion, and length of postoperative hospital stay were compared to maternal outcomes from 52 non-laboring patients who underwent non-emergent primary cesarean delivery of singleton fetuses during the same time interval.

RESULTS

The rate of chorioamnionitis was similar between groups (26% vs 21%; P =.57). Postpartum wound complications were more common in patients who underwent ex utero intrapartum treatment (15% vs 2%; P =.03), although the rate of endometritis was similar (15% vs 10%; P =.50). Estimated blood loss was higher in the patients who underwent ex utero intrapartum treatment (1104 mL vs 883 mL; P <.001), but there was no difference between groups in hematocrit level change or postpartum hospital stay.

CONCLUSION

Women who undergo the ex utero intrapartum treatment procedure experience more wound complications but no difference in postoperative hematocrit level change or postpartum length of stay.

Risk factors for early death among extremely low-birth-weight infants

OBJECTIVE

The purposes of this study were to compare the clinical characteristics of extremely low birth-weight infants (501-1000 g birth weight) who die early (<12 hours of age) with those of infants who die >12 hours after birth and infants who survive to neonatal intensive care unit discharge and to develop a model of risk for early death.

STUDY DESIGN

Perinatal data were prospectively collected on 5986 infants in the 12 participating centers of the National Institute of Child Health and Human Development Neonatal Research Network from March 1993 through December 1997. Maternal and neonatal characteristics of infants who died early were compared with infants who survived and infants who died beyond 12 hours of age. A model for risk for early death was developed by logistic regression analysis, with results expressed as odds ratio with 95% CI.

RESULTS

Mothers of infants who died early were more likely to be delivered in an inborn setting and experience labor and were less likely to have hypertension or preeclampsia, to receive antenatal corticosteroids, or to be delivered by cesarean birth than mothers of infants who died >12 hours after birth or infants who survived. Infants who died early were more likely to have lower Apgar scores and lower gestational age/birth weight and were less likely to be intubated at birth and to receive mechanical ventilation and surfactant therapy than infants who died >12 hours after birth or infants who survived. Greater risk for early death versus survival to neonatal intensive care unit discharge was associated with the lack of surfactant administration (odds ratio, 8.6; 95% CI, 6.3-11.9), lack of delivery room intubation (odds ratio, 5.3; 95% CI, 3.5-8.1), lack of antenatal corticosteroid use (odds ratio, 2.3; 95% CI, 1.6-3.2), lower 1-minute Apgar score (odds ratio, 2.0; 95% CI, 1.8-2.2), male sex (odds ratio, 1.7; 95% CI, 1.3-2.3), multiple gestation (odds ratio, 1.7; 95% CI, 1.2-2.5), no tocolytics (odds ratio, 1.7; 95% CI, 1.2-2.3), lower gestational age per week (odds ratio, 1.4; 95% CI, 1.3-1.6), and lower birth weight per 50 g (95% CI, 1.2-1.4).

CONCLUSION

Early death (<12 hours of age) among extremely low-birth-weight infants may reflect an assessment of non-viability by obstetricians and neonatologists.

Interventions to help external cephalic version for breech presentation at term

BACKGROUND

Breech presentation places a fetus at increased risk. The outcome for the baby is improved by planned caesarean section compared with planned vaginal delivery. External cephalic version attempt reduces the chance of breech presentation at birth, but is not always successful. Tocolytic drugs to relax the uterus as well as other methods have been also used in an attempt to facilitate external cephalic version at term.

OBJECTIVES

The objective of this review is to assess the effects of routine tocolysis, fetal acoustic stimulation, epidural or spinal analgesia and transabdominal amnioinfusion for external cephalic version at term on successful version and measures of pregnancy outcome.

SEARCH STRATEGY

The Cochrane Pregnancy and Childbirth Group Trials Register (searched December 2001) and the Cochrane Controlled Trials Register (The Cochrane Library, Issue 4, 2001) were searched.

SELECTION CRITERIA

Randomised and quasi-randomised trials comparing routine versus selective or no tocolysis; fetal acoustic stimulation in midline fetal spine positions versus dummy or no stimulation; epidural or spinal analgesia versus no regional analgesia; or transabdominal amnioinfusion versus no amnioinfusion for external cephalic version at term.

DATA COLLECTION AND ANALYSIS

Eligibility and trial quality were assessed by the reviewer.

MAIN RESULTS

In six trials, routine tocolysis was associated with fewer failures of external cephalic version (relative risk 0.74, 95% confidence interval 0.64 to 0.87). The reduction in non-cephalic presentations at birth was not statistically significant. Caesarean sections were reduced (relative risk 0.85, 95% confidence interval 0.72 to 0.99). Fetal acoustic stimulation in midline fetal spine positions was associated with fewer failures of external cephalic version at term (relative risk 0.17, 95% confidence interval 0.05 to 0.60). With epidural or spinal analgesia, external cephalic version failure, non-cephalic births and caesarean sections were reduced in two trials but not the other. The overall differences were not statistically significant. No randomised trials of transabdominal amnioinfusion for external cephalic version at term were located.

REVIEWER'S CONCLUSIONS

Routine tocolysis appears to reduce the failure rate of external cephalic version at term. Although promising, there is not enough evidence to evaluate the use of fetal acoustic stimulation in midline fetal spine positions, nor of epidural or spinal analgesia. Large volume intravenous preloading may have contributed to the effectiveness demonstrated in two of the latter trials. No randomised trials of transabdominal amnioinfusion for external cephalic version at term were found.

In utero indomethacin alters O2 delivery to the fetal ductus arteriosus: implications for postnatal patency

Indomethacin produces constriction and hypoxia of the fetal ductus arteriosus. This is associated with death of smooth muscle cells in the ductus wall and an increased incidence of patent ductus arteriosus in the newborn period. We used fetal sheep to determine which factors are responsible for indomethacin-induced hypoxic cell death. Cell death in the ductus wall is directly related to the degree of indomethacin-induced ductus constriction and is present at both moderate and marked degrees of constriction. Both moderate and marked degrees of ductus constriction reduce vasa vasorum flow to the ductus (moderate = 69 +/- 25%; marked = 30 +/- 16% of preinfusion values) and increase the thickness of the ductus wall. In contrast, ductus luminal blood flow is not affected by moderate degrees of constriction and is reduced only after marked constriction. Although indomethacin increases ductus tone, it has no effect on ductus oxygen consumption. These findings suggest that the hypoxic cell death that occurs during the early stages of indomethacin-induced constriction is primarily due to changes in vasa vasorum blood flow and muscle media thickness.

Endoscopic techniques in fetal surgery

Fetal endoscopic surgery (FETENDO) involves many techniques that allow surgical procedures to be performed inside the uterus without an hysterotomy. The impetus for developing these minimal access techniques for fetal surgery is the unusual occurrence with an open hysterotomy of preterm labor, premature rupture of membranes, and maternal complications resulting from tocolytic therapy. The unique requirements of this approach necessitated a modification of existing endoscopic techniques, the development of novel fetoscopic instruments, and the inclusion of a wide variety of specialists. Technical expertise in the field and a natural evolution of techniques have given rise to innovative repairs previously not envisioned. Severe congenital diaphragmatic hernia, diseases of monochorionic twins, and obstructive uropathy have already been successfully treated using fetoscopic surgical techniques. Fetoscopic correction of many other non-life threatening anomalies continues to evolve. The future of fetoscopic surgical intervention depends on the continual evolution of novel approaches to disease, the elucidation of the pathophysiology and treatment of other fetal disorders, and a better understanding of treatment of complications of such intervention.

The diagnosis and management of preterm labor

Accurate diagnosis of preterm labor remains a problematic issue. New techniques such as transvaginal cervical sonography and fetal fibronectin are increasingly important in diagnosis and intervention planning. Neither test can, at present, be recommended for screening of the general population since there is no effective intervention for a positive test. Future directions in research include development of new tocolytic agents such as COX-2 inhibitors and clarification of the best use of adjunctive therapies such as betamethasone for lung maturity.