Effect of alcohol on threatened premature labor

A historical narrative review through the field of tocolysis in threatened preterm birth

Preterm birth presents a significant challenge in clinical obstetrics, requiring effective strategies to reduce associated mortality and morbidity risks. Tocolytic drugs, aimed at inhibiting uterine contractions, are a key aspect of addressing this challenge. Despite extensive research over many years, determining the most effective tocolytic agents remains a complex task, prompting better understanding of the underlying mechanisms of spontaneous preterm birth and recording meaningful outcome measures. This paper provides a comprehensive review of various obsolete and current tocolytic drug regimens that were instituted over the past century, examining both historical contexts and contemporary challenges in their development and adoption. The examination of historical debates and advancements highlights the complexity of introducing new therapies. While the search for effective tocolytics continues, questions arise regarding their actual benefits in obstetric care and the necessity for ongoing exploration. The presence of methodological limitations in current research emphasizes the importance of well-designed randomized controlled trials with robust endpoints and extended follow-up periods.In response to these complexities, the consideration of shifting towards prevention strategies aimed at addressing the root causes of preterm labor becomes more and more evident. This potential shift may offer a more effective approach than relying solely on tocolytics to delay labor initiation.Ultimately, effectively managing threatened preterm birth necessitates ongoing investigation, innovation, and a willingness to reassess strategies in pursuit of optimal outcomes for mothers, neonates, and long-term child health.

Effects of Solvents, Emulsions, Cosolvents, and Complexions on Ex Vivo Mouse Myometrial Contractility

A great need exists to develop tocolytic and uterotonic drugs that combat poor, labor-related maternal and fetal outcomes. A widely utilized method to assess novel compounds for their tocolytic and uterotonic efficacy is the isometric organ bath contractility assay. Unfortunately, water-insoluble compounds can be difficult to test using the physiological, buffer-based, organ bath assay. Common methods for overcoming solubility issues include solvent variation, cosolvency, surfactant or complexion use, and emulsification. However, these options for drug delivery or formulation can impact tissue function. Therefore, the goal of this study was to evaluate the ability of common solvents, surfactants, cosolvents, and emulsions to adequately solubilize compounds in the organ bath assay without affecting mouse myometrial contractility. We found that acetone, acetonitrile, and ethanol had the least effect, while dimethylacetamide, ethyl acetate, and isopropanol displayed the greatest inhibition of myometrial contractility based on area under the contractile curve analyses. The minimum concentration of surfactants, cosolvents, and human serum albumin required to solubilize nifedipine, a current tocolytic drug, resulted in extensive bubbling in the organ bath assay, precluding their use. Finally, we report that an oil-in-water base emulsion containing no drug has no statistical effect beyond the control (water), while the drug emulsion yielded the same potency and efficacy as the freely solubilized drug.

Ignored Papers, Invented Quotations: A History of Fetal Alcohol Syndrome

Given the high rate of alcoholism throughout history, its effects on the fetus may have existed for millennia. But, the claim that Greeks and Romans were aware of fetal alcohol syndrome rests on incorrect citations. From 1725, maternal alcohol consumption was associated with retarded fetal growth and neurological anomalies. From 1809, scientists followed Lamarck's theory that the disorders parents acquire during their lifetime are passed on to their offspring. Fetal effects were thought to be inherited mainly from the father. During the 19th century, parental alcoholism became associated with malformations. In 1915, Ballantyne distinguished genetic influence via germ cells from toxin's effect on the embryo. Fetal alcohol syndrome was characterized by Rouquette [Influence de la toxicomanie alcoolique parentale sur le développement physique et psychique des jeunes enfants] in 1957 and Lemoine et al. [Ouest Medical. 1968;21:476-482] in 1968 as consisting of 4 features: (A) facial anomalies (narrow forehead, retracted upper lip, and cupped ears), (B) severe growth retardation (prenatal and postnatal), (C) malformations (limbs, cardiac, and visceral), and (D) central nervous system anomalies (hyperexcitability and mental retardation). But, their studies, written in French, remained disregarded. In 1973, Jones et al. [Lancet. 1973;302:999-1001] reported "the first association between maternal alcoholism and aberrant morphogenesis in the offspring." The history of fetal alcohol syndrome reveals shortcomings in citation practice. Alleged quotations remained unverified, non-English publications neglected, and short quotations taken out of context. Prejudiced by religious and abstinence groups, reports on alcohol damage to the unborn were fraught with emotions, moralizing, social implications, and presentism, the interpretation of past events with present knowledge.

Advances in Management for Preterm Fetuses at Risk of Delivery

Preterm birth accounts for only 11% of live births but contributes to up to 75% of neonatal mortality and more than half of long-term morbidity. Targeted interventions to reduce the most common causes of perinatal morbidity and mortality include intrapartum group B Streptococcus prophylaxis, magnesium sulfate for fetal neuroprotection, antenatal corticosteroids for fetal lung maturity, latency antibiotics for preterm premature rupture of membranes, and tocolysis to allow corticosteroid administration and transfer to a tertiary care center. This article reviews the evidence for interventions to improve outcomes for fetuses at risk for preterm delivery at different gestational ages.

The contributions of Dr. Kathleen K. Sulik to fetal alcohol spectrum disorders research and prevention

Dr. Kathleen Sulik (Kathy) has spent 35 years studying fetal alcohol syndrome (FAS) and fetal alcohol spectrum disorders (FASD). Beginning with her landmark 1981 Science paper describing the early gestational window when alcohol can cause the craniofacial malformations characteristic of FAS, Kathy has contributed a vast amount of research furthering our knowledge of FASD. After her seminal work that definitively demonstrated that alcohol is the causative factor in FAS, she and her lab went on to explore and define the stage-dependent effects of early gestational alcohol exposure on the face and brain in numerous different ways throughout her career. She explored and discovered numerous mechanisms of alcohol's effects on the embryo, as well as describing several genetic factors that can modify susceptibility to developmental alcohol exposure. She did not restrict her research to the face and brain; her lab described in intricate detail the effects of developmental alcohol exposure on many different organs, including the heart, ears, kidneys, and limbs. In addition to her research, and in conjunction with NIAAA and the National Organization on Fetal Alcohol Syndrome (NOFAS), Kathy developed several FASD prevention curricula that are still in use today. Finally, as part of her drive to eradicate FAS and FASD, Kathy labored tirelessly with public policy makers to change how FASD is viewed by the public, how FASD is identified in affected individuals, and how FASD is studied by researchers. While no article could fully cover Kathy's contributions to FASD research and prevention, or her other contributions to embryology and teratology, this review will attempt to illustrate some of the highlights of Kathy's remarkable career.

Impact of intranasal oxytocin on interoceptive accuracy in alcohol users: an attentional mechanism?

Interoception, i.e. the perception and appraisal of internal bodily signals, is related to the phenomenon of craving, and is reportedly disrupted in alcohol use disorders. The hormone oxytocin influences afferent transmission of bodily signals and, through its potential modulation of craving, is proposed as a possible treatment for alcohol use disorders. However, oxytocin's impact on interoception in alcohol users remains unknown. Healthy alcohol users (n = 32) attended two laboratory sessions to perform tests of interoceptive ability (heartbeat tracking: attending to internal signals and, heartbeat discrimination: integrating internal and external signals) after intranasal administration of oxytocin or placebo. Effects of interoceptive accuracy, oxytocin administration and alcohol intake, were tested using mixed-effects models. On the tracking task, oxytocin reduced interoceptive accuracy, but did not interact with alcohol consumption. On the discrimination task, we found an interaction between oxytocin administration and alcohol intake: Oxytocin, compared with placebo, increased interoceptive accuracy in heavy drinkers, but not in light social drinkers. Our study does not suggest a pure interoceptive impairment in alcohol users but instead potentially highlights reduced flexibility of internal and external attentional resource allocation. Importantly, this impairment seems to be mitigated by oxytocin. This attentional hypothesis needs to be explicitly tested in future research.

Advances in the Determination of Alcohol and Other Drug Consumption during Pregnancy: A Study of 900 Births in Montevideo, Uruguay

A study was performed in Uruguay to estimate the prevalence of drug consumption during pregnancy. The study consisted of a survey and biological samples to validate the responses and investigate information concerning risks involved in drug consumption during pregnancy. The survey consisted of 900 face-to-face interviews performed within 48 hours after birth. Perinatal registries were taken from hospital archives. Nine hundred meconium samples were tested for alcohol, tobacco, illegal drugs, and tranquilizers. The results of the survey indicated consumption during pregnancy of the following: 41.3% tobacco, 36.8% alcohol, 16.3% tranquilizers, 68% caffeine (more than 400 mg/day), and 1.4% illegal drugs. In addition, 8.9% of the pregnancies were unplanned. Among the planned pregnancies, some physicians warned their patients about risks associated with tobacco (34%), alcohol (27%) and illegal drugs (7%). Meconium analysis revealed tobacco (cotinine), 51.8%; alcohol (fatty acid ethyl esters, or FAEES), 43.5%; and cocaine (base paste), 2.5%. Newborns whose mothers smoked tobacco presented statistically lower birth weights: 11% of all newborns at low birth weight, with health problems reported for 14.8%.

A Review of the History of Attitudes Toward Drinking in Pregnancy

BACKGROUND

It is now well accepted in pediatrics and obstetrics that prenatal alcohol is a teratogenic agent and the primary causative factor underlying fetal alcohol spectrum disorders (FASDs), although for the majority of the 20th century that knowledge was either unknown or ignored. At least 2 factors contributed to the delay in recognizing alcohol's role in teratogenicity: the rejection of earlier evidence pertaining to alcohol and pregnancy following the repeal of Prohibition in the United States, Canada, and several European countries; and misinterpretation of earlier research findings in a eugenic rather than toxicological context. The pervasive belief held well into the 1970s that there was no risk to either mother or fetus from prenatal alcohol posed a major challenge to changing physician and public attitudes on alcohol and pregnancy. This review provides insight on key events that occurred in changing physician and public understanding of the risks posed by prenatal alcohol use in pregnancy.

METHODS

Historical review of events primarily in the U.S. federal government, found in referenced documents.

RESULTS

The transition in physician and public understanding of the risks posed by prenatal alcohol use was aided by the existence of National Institute on Alcohol Abuse and Alcoholism (NIAAA) which was created in 1971. This government agency was able to support research on alcohol and pregnancy immediately following the 1973 published clinical reports calling attention to a proposed fetal alcohol syndrome (FAS). These early research studies provided the foundation for the first government health advisory on alcohol and pregnancy, issued by NIAAA in 1977. Subsequently, the U.S. Food and Drug Administration (FDA) used this new knowledge on FAS in their effort to add alcoholic beverages to the range of products with ingredient and consumer information labeling. The ensuing hearings and actions resulted in a new health advisory under the auspices of the Surgeon General, encouraging avoidance of alcohol consumption in pregnancy. In subsequent years, Congressional attention to the FAS issue resulted in the Alcoholic Beverage Labeling Law.

CONCLUSIONS

The pace at which understanding of the risks of prenatal alcohol moved forward from a total misunderstanding to acceptance was aided by both the efforts of the NIAAA in its support of research, and the FDA in its efforts to improve consumer information. Today, many women in the United States as well as other countries continue to ignore advisories on avoiding alcohol consumption in pregnancy, emphasizing the need for persistence in education on these health risks.

Ethanol for preventing preterm birth in threatened preterm labor

BACKGROUND

Preterm birth is the leading cause of death and disability in newborns worldwide. A wide variety of tocolytic agents have been utilized to delay birth for women in preterm labor. One of the earliest tocolytics utilized for this purpose was ethanol infusion, although this is not generally used in current practice due to safety concerns for both the mother and her baby.

OBJECTIVES

To determine the efficacy of ethanol in stopping preterm labor, preventing preterm birth, and the impact of ethanol on neonatal outcomes.

SEARCH METHODS

We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (31 May 2015) and reference lists of retrieved studies.

SELECTION CRITERIA

We included randomized and quasi-randomized studies. Cluster-randomized trials and cross-over design trials were not eligible for inclusion. We only included studies published in abstract form if there was enough information on methods and relevant outcomes. Trials were included if they compared ethanol infusion to stop preterm labor versus placebo/control or versus other tocolytic drugs.

DATA COLLECTION AND ANALYSIS

At least two review authors independently assessed studies for inclusion and risk of bias. At least two review authors independently extracted data. Data were checked for accuracy.

MAIN RESULTS

Twelve trials involving 1586 women met inclusion criteria for this review. One trial did not report on the outcomes of interest in this review.Risk of bias of included studies: The included studies generally were of low quality based on inadequate reporting of methodology. Only three trials had low risk of bias for random sequence generation and one had low risk of bias for allocation concealment and participant blinding. Most studies were either high risk of bias or uncertain in these key areas. Comparison 1: Ethanol versus placebo/control (two trials, 77 women) Compared to controls receiving pain medications and dextrose solution, ethanol did not improve any of the primary outcomes: birth < 48 hours after trial entry (one trial, 35 women; risk ratio (RR) 0.93, 95% confidence interval (CI) 0.43 to 2.00), or neonatal mortality (one trial, 35 women; RR 1.06, 95% CI 0.31 to 3.58). Serious maternal adverse events and perinatal mortality were not reported by either of the two trials in this comparison. Maternal adverse events (overall) were not reported but one trial (42 women) reported that there were no maternal adverse events that required stopping or changing drug) in either group. One trial did report delay until delivery but this outcome was reported as a median with no mention of the standard deviation (median 19 days in ethanol group versus "less than 1" day in the glucose/water group). There were no differences in any secondary outcomes reported: preterm birth < 34 weeks or < 37 weeks; serious infant outcome; fetal alcohol syndrome/fetal alcohol spectrum disorder; or small-for-gestational age. Comparison 2: Ethanol versus other tocolytic (betamimetics) (nine trials, 1438 women) Compared to betamimetics (the only tocolytic used as a comparator in these studies), ethanol was associated with no clear difference in the rate of birth < 48 hours after trial entry (two trials, 130 women; average RR 1.12, 95% CI 0.53 to 2.37, Tau² = 0.19, I² = 59%), similar rates of perinatal mortality (six trials, 698 women; RR1.20, 95% CI 0.78 to 1.84), higher rates of neonatal mortality (eight trials, 1238 women; RR 1.43, 95% CI 1.02 to 2.02), higher rates of preterm birth < 34 weeks (two trials, 599 women; RR 1.56, 95% CI 1.11 to 2.19), higher rates of neonatal respiratory distress syndrome (three trials, 823 women; RR 1.76, 95% CI 1.33 to 2.33), and higher rates of low birthweight babies < 2500 g (five trials, 834 women; RR 1.30, 95% CI 1.09 to 1.54). These outcomes are likely all related to the lower incidence of preterm birth seen with other tocolytics, which for all these comparisons were betamimetics. Serious maternal adverse events were not reported in any of the nine trial reports. However, ethanol had a trend towards a lower rate of maternal adverse events requiring stopping or changing the drug (three trials, 214 women; RR 0.25, 95% CI 0.06 to 0.97). There were no differences in other secondary outcomes of preterm birth < 37 weeks, number of days delivery was delayed, or overall maternal adverse events.Planned sensitivity analysis, excluding quasi-randomized trials did not substantially change the results of the primary outcome analyses with the exception of neonatal mortality which no longer showed a clear difference between the ethanol and other tocolytic groups (3 trials, 330 women; RR 1.49, 95% CI 0.82 to 2.72).

AUTHORS' CONCLUSIONS

This review is based on evidence from twelve studies which were mostly low quality. There is no evidence that to suggest that ethanol is an effective tocolytic compared to placebo. There is some evidence that ethanol may be better tolerated than other tocolytics (in this case betamimetics), but this result is based on few studies and small sample size and therefore should be interpreted with caution. Ethanol appears to be inferior to betamimetics for preventing preterm birth in threatened preterm labor.Ethanol is generally no longer used in current practice due to safety concerns for the mother and her baby. There is no need for new studies to evaluate the use of ethanol for preventing preterm birth in threatened preterm labour. However, it would be useful for long-term follow-up studies on the babies born to mothers from the existing studies in order to assess the risk of long-term neurodevelopmental status.

Prenatal alcohol exposure and prenatal stress differentially alter glucocorticoid signaling in the placenta and fetal brain

Adverse intrauterine environments increase vulnerability to chronic diseases across the lifespan. The hypothalamic-pituitary-adrenal (HPA) axis, which integrates multiple neuronal signals and ultimately controls the response to stressors, may provide a final common pathway linking early adversity and adult diseases. Both prenatal alcohol exposure (PAE) and prenatal stress (PS) induce a hyperresponsive HPA phenotype in adulthood. As glucocorticoids are pivotal for the normal development of many fetal tissues including the brain, we used animal models of PAE and PS to investigate possible mechanisms underlying fetal programing of glucocorticoid signaling in the placenta and fetal brain at gestation day (GD) 21. We found that both PAE and PS dams had higher corticosterone (CORT) levels than control dams. However, 11β-hydroxysteroid dehydrogenase type 2 (11β-HSD2) enzyme levels were increased in PAE and unchanged in PS placentae, although there were no differences in 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1) levels. Moreover, only PAE fetuses showed decreased body weight and increased placental weight, and hence a lower fetal/placental weight ratio, a marker of placenta efficiency, compared to all other prenatal groups. Importantly, PAE and PS differentially altered corticosteroid receptor levels in placentae and brains. In the PS condition, maternal CORT was negatively correlated with both 11β-HSD1 and mineralocorticoid receptor (MR) protein levels in male and female placentae, whereas in the PAE condition, there were trends for a positive correlation between maternal CORT and 11β-HSD1, regardless of sex, and a negative correlation between maternal alcohol intake and MR in male placentae. In fetal brains, sexually dimorphic changes in MR and glucocorticoid receptor (GR) levels, and the MR/GR ratio seen in C fetuses were absent in PAE and PS fetuses. In addition, PS but not PAE female fetuses had higher MR and lower GR expression levels in certain limbic areas compared to C female fetuses. Thus the similar adult HPA hyperresponsive phenotype in PAE and PS animals likely occurs through differential effects on glucocorticoid signaling in the placenta and fetal brain.

Species extrapolation of life-stage physiologically-based pharmacokinetic (PBPK) models to investigate the developmental toxicology of ethanol using in vitro to in vivo (IVIVE) methods

To provide useful alternatives to in vivo animal studies, in vitro assays for dose-response assessments of xenobiotic chemicals must use concentrations in media and target tissues that are within biologically-plausible limits. Determining these concentrations is a complex matter, which can be facilitated by applying physiologically-based pharmacokinetic (PBPK) models in an in vitro to in vivo extrapolation (IVIVE) paradigm. We used ethanol (EtOH), a ubiquitous chemical with defined metrics for in vivo and in vitro embryotoxicity, as a model chemical to evaluate this paradigm. A published series of life-stage PBPK models for rats was extended to mice, yielding simulations that adequately predicted in vivo blood EtOH concentrations (BECs) from oral, intraperitoneal, and intravenous routes in nonpregnant and pregnant adult mice. The models were then extrapolated to nonpregnant and pregnant humans, replicating BEC data within a factor of two. The rodent models were then used to conduct IVIVEs for rodent and whole-embryo culture embryotoxicity data (neural tube closure defects, morphological changes). A second IVIVE was conducted for exposure scenarios in pregnant women during critical windows of susceptibility for developmental toxicity, such as the first 6-to-8 weeks (prerecognition period) or mid-to-late pregnancy period, when EtOH consumption is associated with fetal alcohol spectrum disorders. Incorporation of data from human embryonic stem cell studies led to a model-supported linkage of in vitro concentrations with plausible exposure ranges for pregnant women. This effort demonstrates benefits and challenges associated with use of multispecies PBPK models to estimate in vivo tissue concentrations associated with in vitro embryotoxicity studies.

Preterm birth and small for gestational age in relation to alcohol consumption during pregnancy: stronger associations among vulnerable women? Results from two large Western-European studies

BACKGROUND

Inconsistent data on the association between prenatal alcohol exposure and a range of pregnancy outcomes, such as preterm birth (PTB) and small for gestational age (SGA) raise new questions. This study aimed to assess whether the association between low-moderate prenatal alcohol exposure and PTB and SGA differs according to maternal education, maternal mental distress or maternal smoking.

METHODS

The Amsterdam Born Children and their Development (ABCD) Study (N = 5,238) and the German Health Interview and Examination Survey for Children and Adolescents (KiGGS) (N = 16,301) are both large studies. Women provide information on alcohol intake in early pregnancy, 3 months postpartum and up to 17 years retrospectively. Multivariate logistic regression analyses and stratified regression analyses were performed to examine the association between prenatal alcohol exposure and PTB and SGA, respectively.

RESULTS

No association was found between any level of prenatal alcohol exposure (non-daily, daily, non-abstaining) and SGA. The offspring of daily drinkers and non-abstainers had a lower risk of PTB [ABCD: odds ratio (OR) 0.31, 95% confidence interval (CI) 0.13, 0.77; KiGGS: OR 0.75, 95% CI 0.57, 0.99]. Interactions with maternal education, maternal distress or maternal smoking were not significant.

CONCLUSIONS

Although these results should be interpreted with caution, both studies showed no adverse effects of low-moderate prenatal alcohol exposure on PTB and SGA, not even in the offspring of women who were disadvantaged in terms of low education, high levels of distress, or smoking during pregnancy.

Vaginal progesterone vs. cervical cerclage for the prevention of preterm birth in women with a sonographic short cervix, previous preterm birth, and singleton gestation: a systematic review and indirect comparison metaanalysis

OBJECTIVE

No randomized controlled trial has compared vaginal progesterone and cervical cerclage directly for the prevention of preterm birth in women with a sonographic short cervix in the mid trimester, singleton gestation, and previous spontaneous preterm birth. We performed an indirect comparison of vaginal progesterone vs cerclage using placebo/no cerclage as the common comparator.

STUDY DESIGN

Adjusted indirect metaanalysis of randomized controlled trials.

RESULTS

Four studies that evaluated vaginal progesterone vs placebo (158 patients) and 5 studies that evaluated cerclage vs no cerclage (504 patients) were included. Both interventions were associated with a statistically significant reduction in the risk of preterm birth at <32 weeks of gestation and composite perinatal morbidity and mortality compared with placebo/no cerclage. Adjusted indirect metaanalyses did not show statistically significant differences between vaginal progesterone and cerclage in the reduction of preterm birth or adverse perinatal outcomes.

CONCLUSION

Based on state-of-the-art methods for indirect comparisons, either vaginal progesterone or cerclage are equally efficacious in the prevention of preterm birth in women with a sonographic short cervix in the mid trimester, singleton gestation, and previous preterm birth. Selection of the optimal treatment needs to consider adverse events, cost and patient/clinician preferences.

Prenatal alcohol exposure, blood alcohol concentrations and alcohol elimination rates for the mother, fetus and newborn

Fetal alcohol spectrum disorders (FASDs) are a common cause of intellectual impairment and birth defects. More recently, prenatal alcohol exposure (PAE) has been found to be a risk factor for fetal mortality, stillbirth and infant and child mortality. This has led to increased concern about detection and management of PAE. One to 2 h after maternal ingestion, fetal blood alcohol concentrations (BACs) reach levels nearly equivalent to maternal levels. Ethanol elimination by the fetus is impaired because of reduced metabolic capacity. Fetal exposure time is prolonged owing to the reuptake of amniotic-fluid containing ethanol by the fetus. Alcohol elimination from the fetus relies on the mother's metabolic capacity. Metabolic capacity among pregnant women varies eightfold (from 0.0025 to 0.02 g dl(-1)  h(-1)), which may help explain how similar amounts of ethanol consumption during pregnancy results in widely varying phenotypic presentations of FASD. At birth physiological changes alter the neonate's metabolic capacity and it rapidly rises to a mean value of 83.5% of the mother's capacity. FASDs are highly recurrent and younger siblings have increased risk. Detection of prenatal alcohol use offers an important opportunity for office-based interventions to decrease exposure for the remainder of pregnancy and identification of women who need substance abuse treatment. Mothers of children with FAS have been found to drink faster, get drunk quicker and to have higher BACs. A modest increase in the prevalence of a polymorphism of alcohol dehydrogenase, which increases susceptibility to adverse outcomes from PAE has been reported. Lastly, detection of alcohol use and appropriate management would decrease risk from PAE for subsequent pregnancies.

Efficacy of aggressive tocolysis for preterm labor with advanced cervical dilatation

OBJECTIVE

Study the effectiveness of tocolysis for preterm labor with advanced cervical dilatation ( > or = 3 cm) to achieve sufficient latency for the effect of steroids to occur, and delivery of more mature neonates.

STUDY DESIGN

We studied 249 singleton pregnancies, 23-36 weeks gestation in preterm labor, stratified by weeks of gestation and degree of cervical dilatation (Group A: 117, < 3 cm; Group B: 132, 3 cm) who were given tocolysis and compared for the length of latency and neonatal outcome.

RESULTS

Maternal characteristics were similar between groups except African-American women were admitted with more advanced cervical dilatation. Latency 72 hours was achieved in Group A: > 75% at all gestational ages, and Group B: > 50%. Latency > or = 72 hours, according to the degree of cervical dilatation, was for Group A: 90%, for Group B: 50-75% from > 3-5 cm dilatation, and 40% at 5.1-6 cm dilatation. Neonatal morbidity was mild with a decreased risk of long-term disability.

CONCLUSIONS

Aggressive tocolytic therapy for preterm labor with advanced cervical dilatation is efficacious, allows for steroid therapy, and allows delivery of more mature neonates.

The extracorporeal perfusion of the swine uterus as an experimental model: The effect of tocolytic drugs

OBJECTIVE

Comparison of the effect of tocolytic drugs on isolated swine uterus preparations.

STUDY DESIGN

Forty swine uteri were perfused with the aim to preserve a viable organ, which should be responsive to oxytocic hormones and tocolytic pharmaca. An intrauterine catheter recorded the pressure changes. After initiation of rhythmical uterine contractions we administered known tocolytic drugs (fenoterol, ritodrine, terbutaline, propofol, acetylsalicylic acid, alcohol, atosiban, verapamil, and glyceryl trinitrate) in various concentrations.

RESULTS

Perfusate pH and lactate, partial oxygen and carbon dioxide tensions, and oxygen saturation in the perfusate showed good preservation of the organ for up to 8h. All substances showed a tocolytic effect on the swine uterus. The effect varied substantially with regard to the length of the contraction free intervals, which was our main effect parameter. Fenoterol, acetylsalicylic acid, and alcohol showed the most and glyceryl trinitrate the least powerful effect.

CONCLUSIONS

A direct comparison of various tocolytic substances in the same experimental model showed the best effect for fenoterol. Furthermore, we could demonstrate that the swine uterus perfusion system is a suitable model to study the influence of various conditions like the administration of drugs or the induction of oxidative stress on the uterus function.

Acute management of preterm labor

We are continually reminded that the preterm birth rate has failed to improve; in fact, it has increased over the last 20 years. Much of this increase is related to the tremendous strides made by neonatologists and the resulting increased willingness of obstetricians to deliver preterm babies from hostile intrauterine environments. However, there is still much to learn concerning the pathogenesis, accurate early detection, treatment, and prevention of spontaneous preterm labor. This article concentrates on the clinical diagnosis and acute management of this enigmatic clinical problem.

Development and clinical experience with the new evidence-based tocolytic atosiban

The incidence of preterm birth has remained unchanged for the last few decades. This is due, in part, to the complex etiology of preterm labor, and the limited ability of tocolytic agents to prolong pregnancy as a result of limited efficacy and poor safety profiles. The recent introduction of the oxytocin antagonist, atosiban, represents a new generation of uterine-specific tocolytics, which are associated with more favorable safety profiles. This paper discusses the rationale behind the development of the oxytocin antagonists and provides a review of the phase II and III trials that have investigated atosiban. Also included is a retrospective analysis of 83 women assessed in the Vienna Medical School, providing an insight into the benefits associated with atosiban in the everyday clinical setting. The introduction of a safer tocolytic agent offers the potential to change the current approach to the management of preterm labor. This includes a prolonged period of treatment at earlier or later gestational ages and possibly an extended use to women with contraindications who would normally have been excluded from treatment, e.g. preterm premature rupture of the membranes.

Secretion of oxytocin in pregnant and parturient cows: corpus luteum may contribute to plasma oxytocin at term

Plasma oxytocin (OT) concentrations were determined in 14 late-pregnant and parturient Angus-Hereford cows. Jugular and utero-ovarian veins were cannulated for simultaneous withdrawal of blood samples. Samples were collected at 10-min intervals for 6 h once weekly beginning 60-14 days before the date of expected delivery (group 1), or daily 3-7 days before the due date (group 2). In a third group, samples were collected at 15-min intervals every other day for 12 h beginning 1 wk before calving. Basal levels of OT were low, the overall mean for both veins was 0.46 +/- 0.03 microU/ml until a week before parturition, and then increased to 0.77 +/- 0.1 microU/ml (P < 0.02). Spurts of OT occurred intermittently on all days. Interpeak intervals averaged 71.0 +/- 10.7 min until Day -14, and from Day -14 to Day -1 the intervals were 44.0 +/- 5.3 min (P < 0.05). From Day -60 to Day -25 the amplitudes of OT peaks were low and similar in both veins (mean 1.37 +/- 0.1 microU/ml). From Day -14 to Day -1 the peak amplitudes were 3.6 +/- 0.4 microU/ml on average (P < 0.02). During the last 2 wk the utero-ovarian peak of OT was frequently higher than the peripheral peak. In addition, a number of spurts were observed in the utero-ovarian vein only (solo peaks). On the day of parturition during the first stage of labor, peak amplitudes had increased to 7.3 +/- 2.0 microU/ml, and the interpeak intervals had become shorter than before labor (mean 25.1 +/- 2.6 min). A large surge of OT initiated the expulsive stage of labor. Basal levels rose to 43.1 +/- 16 microU/ml and 38.7 +/- 12.6 microU/ml, and peak levels to 77.4 +/- 19.1 microU/ml and 91.6 +/- 21 microU/ml in the jugular and utero-ovarian veins, respectively. Interpeak intervals had decreased to 17.2 +/- 3.3 min (P < 0.05). Oxytocin levels remained high after delivery of the calf until the placenta was expelled. The posterior pituitary was the source of circulating OT during most of gestation and labor, but the solo peaks observed during late gestation in the utero-ovarian vein were probably of luteal origin or possibly of caruncular origin, because near term, both tissues express OT mRNA. Fetal posterior pituitary is another possible source for these peaks. Our conclusions are that during bovine pregnancy, low amplitude spurts of OT are secreted intermittently; near term, both the frequency and peak amplitude of the spurts increase; and during labor, a dramatic increase in plasma OT precedes the expulsion of the calf. The main source of OT is the posterior pituitary, but near term, a utero-ovarian source secretes additional OT into the systemic circulation.

Diagnosing moral disorder: the discovery and evolution of fetal alcohol syndrome

The diagnosis of fetal alcohol syndrome (FAS) was invented in 1973. This paper investigates the process by which a cluster of birth defects associated with exposure to alcohol in utero came to be a distinct medical diagnosis, focusing on the first ten years of the medical literature on FAS. Fetal alcohol syndrome was "discovered" by a group of American dysmorphologists who published the first case reports and coined the term FAS. However, the nature of the diagnosis and its salient symptoms were determined collectively over time by the medical profession as a whole. The paper traces the natural history of the diagnosis in the U.S. through five stages: introduction, confirmation and corroboration, dissent, expansion, and diffusion. FAS serves as an example of the social construction of clinical diagnosis; moral entrepreneurship plays a key role and the medical literature on FAS is infused with moral rhetoric, including passages from classical mythology, philosophy, and the Bible. FAS is a moral as well as a medical diagnosis, reflecting the broader cultural concerns of the era in which it was discovered, including a greater awareness of environmental threats to health, the development of fetal medicine, an emphasis on "the perfect child," and a growing paradigm of maternal-fetal conflict.

Ethanol and parturition: a role for prostaglandins

A common pattern of birth defects was reported in children born to alcoholic women over 20 years ago. Shortly thereafter the constellation of defects became known as the Fetal Alcohol Syndrome, and reports from around the world served to acknowledge the pervasiveness of the disorder. Simultaneously with the clinical reports, animal models were developed to characterize the full spectrum of the teratogenic effects of ethanol. Not only did these animal models serve to define the actions of ethanol on fetal growth and development at the molecular pharmacological, neuroanatomical, and behavioral level, but unintentionally, they have resulted in renewed scientific interest in the effects of ethanol on pregnancy and parturition itself. The purpose of this review is twofold. First we will consolidate and summarize data from both clinical and basic research that pertains to ethanol and parturition. These data will demonstrate that ethanol consumption during pregnancy results in both delayed as well as premature delivery depending upon the pattern of consumption and timing of exposure. With these data as a background, the second objective will be to present a theoretical case for prostaglandins as possible mediators of ethanol-induced effects on the onset of parturition.

Cardioteratogenic dose of ethanol in the chick embryo results in albumin ethanol concentrations comparable to human blood alcohol levels

Three-day-old chick embryos (Hamburger-Hamilton stages 18-19) were exposed to a dose of ethyl alcohol (0.32 ml of 50% ethanol) that causes cardiac malformations in 96.6% of the animals. Ethanol was administered into the air sac after 72-80 h of incubation. Samples of albumin at the opposite pole of the egg were drawn 0-50 h after treatment and quantitated for ethanol concentration with capillary gas-liquid chromatography. Ethanol concentrations in the albumin increased significantly (P < 0.05) at 2, 5 and 15 h after injection of ethanol, reached a maximum mean ethanol concentration at 20 h (217.3 +/- 23.5 mg dl-1), decreased significantly at 30 h to 175.4 +/- 27.5 mg dl-1, then increased again and stabilized at 40-50 h. Individual sample concentrations ranged from 0 mg dl-1 (at 0.5-2 h) to 286.5 mg dl-1 at 40 h. Ethanol concentrations in the albumin were comparable to human blood alcohol levels during intoxication (> 150 mg dl-1). Our results suggest that a potent cardioteratogenic dose of ethanol in the chick embryo is reasonable in terms of potential human embryo exposure.

Effect of chronic ethanol consumption on the spontaneous contractions, prostaglandin production, triglycerides and glucose metabolism of uterine strips isolated from pregnant rats and in embryos

The constancy of spontaneous isometric developed tension (IDT) and the metabolism of triglycerides (TGs), U-14C-Glucose and 14C-arachidonic acid (14C-AA) in uterine strips isolated from controls and from chronic ethanol (ETOH) fed pregnant rats were explored. The studies were performed on isolated uterine strips suspended in glucose-containing as well as a glucose-free medium. The spontaneous decrement of IDT as time progressed after tissue isolation and mounting was significantly higher in tissue preparations obtained from pregnant rats drinking 20% ETOH, than the controls. This situation was evident in uterine strips isolated from rats at 10 and at 16 days of pregnancy, both in solutions containing glucose or in glucose-free conditions. On the other hand, uterine strips isolated from control rats at 7, 10 and 16 days of pregnancy exhibited almost no decrement of IDT after 60 min of activity in a solution containing glucose or in a glucose-free medium. The absolute values of TGs in uteri obtained from rats drinking ETOH were significantly greater (p < 0.001) than in non-drinking controls. TG levels did not differ at 0 min (initial or postisolation) to those at 60 min in control uterine preparations obtained from pregnant rats at 7, 10 or 16 days of pregnancy and incubated either in a medium with or without glucose. On the contrary, in strips from ETOH-fed animals isolated on the same day of pregnancy, TG levels determined at 60 min following isolation and mounting were significantly lower, when glucose was present or absent from the suspending solution.(ABSTRACT TRUNCATED AT 250 WORDS)

Acute effects of a single ethanol injection on in vitro rat uterine spontaneous motility, on uteri prostaglandin production and on tissue metabolism of triglycerides

The acute effects of ethanol (ETOH), injected at 3 g.kg-1i.p. on spontaneous contractions, on prostaglandin (PG) production and on the metabolism of triglycerides (TGs), have been studied in uterine strips obtained from rats at diestrus and suspended in glucose-containing or glucose-free solution. The absolute values of isometric developed tension (IDT: expressed in mg) recorded at 0 time (initial or post isolation determinations) and the frequency of contraction (FC), expressed as the number of contraction cycles during 20 min, were similar for uterine strips from controls and from ETOH treated rats. The uterine IDT and the FC expressed as percent changes from internal controls (0 time values) were explored during 180 min in uteri suspended in glucose medium. The magnitude of IDT decreased, as time progressed, both in controls as well as in ETOH-treated rats. Afterwards, uterine strips from controls exhibited a partial recovery of their contractile activity. This pattern of recovery was not observed in uterine strips from ETOH-treated rats. The uterine IDT, in the ETOH-injected animals after 180 min of activity, were significantly smaller than those of controls. On the other hand, the FC decreased progressively up to the end of the experimental period both in controls as well as in ETOH-treated rats. In glucose-free medium, the IDT of uterine strips from ETOH-injected animals diminished significantly more than controls from 100-180 min following isolation and mounting. In addition, the FC of uterine strips from the ETOH group of rats were significantly smaller than in controls suspended in glucose-free solution.(ABSTRACT TRUNCATED AT 250 WORDS)

Effect of chronic alcohol consumption on rat uterine spontaneous motility, prostaglandin production and triglyceride metabolism

The spontaneous isometric developed tension (IDT), the synthesis and release of prostaglandins (PGs) into the incubating medium and the metabolism of triglycerides (TGs) in uterine strips isolated from controls and chronic ethanol fed rats, were studied. In order to observe how the uterus of rats fed alcohol reacts during a situation of metabolic emergency, the above mentioned studies were done in the presence or in the absence of glucose in the incubating medium. The decrement of IDT as time progressed was significantly greater in strips obtained from rats which had been drinking 20% ETOH than in controls. Nevertheless, the absolute magnitude of the initial IDT was similar in both groups. On the other hand, the decline of the frequency of contractions (FC) of uterine strips isolated from controls and from ETOH-exposed rats, after 60 min of spontaneous activity was similar. When the uterine strips isolated from ETOH-exposed and from control rats were suspended in glucose-free solution they exhibited the same decrement of IDT and FC after 60 min of activity. The basal release of PGE1 and PGE2 was similar in control tissues incubated in medium containing glucose, but the output of PGE2 was significantly smaller than that of PGE1 in uterine strips isolated from ETOH-exposed rats. The production of PGE1 and PGE2 by uteri suspended in glucose-free medium was similar in control preparations. On the contrary the release of both PGs differs in uterine strips from ETOH-exposed rats, i.e. the output of PGE2 was significantly smaller than in controls and the release of PGE1 increased around 4-fold in comparison with controls.(ABSTRACT TRUNCATED AT 250 WORDS)

Inhibition of spontaneous uterine contractions during the last trimester in pregnant baboons by an oxytocin antagonist

The effect of a potent oxytocin antagonist, produced in our laboratories, on spontaneous uterine contractions in the pregnant baboon was examined. Three types of uterine contractions were studied: immediately after operation, during the nocturnal period, and near or at labor. Bolus intravenous injections of oxytocin antagonist were given and uterine activity was examined +/- 1 hour after the injection. The oxytocin antagonist caused a precipitate decrease (approximately 70%) in contractile force (mean amplitude x frequency) in the first 15 minutes after injection (p less than 0.05); this force diminished to approximately 90% at the end of 1 hour for both nocturnal and labor contractions. In contrast, uterine contractions immediately after operation were diminished by only 60% within 60 minutes after the oxytocin antagonist. These results indicate that the oxytocin antagonist is a potent inhibitor and suggest that oxytocin is a primary regulator of spontaneous nocturnal and labor uterine contractions in the pregnant baboon.

Cardioteratogenic dose of ethanol in the chick embryo results in egg white concentrations comparable to human blood alcohol levels

Three-day-old chick embryos were exposed to a dose of ethyl alcohol (0.32 ml of 50% ethanol) that we previously demonstrated produces cardiac malformations in 96.6% of the animals. Ethanol was administered into the air sac at 72-80 h of incubation. Samples of egg white were drawn at 2, 6 and 24 h after treatment and analyzed by capillary gas-liquid chromatography. Ethanol concentrations were significantly higher at 6 and 24 h after exposure than at 2 h (P less than 0.01), but there were no differences in mean concentrations between 6 and 24 h (P greater than 0.2). Furthermore, concentrations (43-303 mg dl-1) were comparable to human blood alcohol levels during intoxication. These results suggest that the cardioteratogenic doses of ethanol administered to chick embryos in a previous study are not excessive in terms of potential human embryo exposure.

Fetal alcohol syndrome: report of case

A report of a patient with fetal alcohol syndrome has been presented with a review of the syndrome and the literature. Although the patient was treated in the operating room, many patients with less severe medical involvement or less extensive dental needs can be treated as outpatients. Each case must be considered individually with the prime concern being the patient's safety. Such patients may have numerous emotional or physical problems that the dentist must recognize. These patients are at high risk for several types of heart defects, many of which will require consultation for bacterial endocarditis precautions. The major and minor anomalies associated with fetal alcohol syndrome have been outlined.

Prostaglandin F2 alpha and oxytocin interactions in ovarian and uterine function

The oxytocin-neurophysin gene is expressed in several nontraditional sites within the endocrine system. In the ovary its expression in the corpora lutea is initiated by ovulation. Ovarian oxytocin concentrations reach maximal levels around day 11 of luteal cycle and fall to a nadir at estrus. PGF2 alpha has the capacity to release oxytocin from the corpus luteum, and oxytocin in turn releases PGF2 alpha from the uterine endometrium or decidua. This positive feedback loop between the ovary and the uterus ensures the completion of luteolysis in species that depend on the presence of the uterus for the termination of luteal lifespan. Immunization against oxytocin has been shown to disrupt this loop, resulting in much-prolonged luteal cycles. In primates and other species in which luteal life span is independent of the uterus, an oxytocin PGF2 alpha interaction may take place within the ovary itself. At parturition a related interaction takes place which ensures the expulsion of the fetus and placenta in an orderly manner. Oxytocin of both pituitary and ovarian origin reaches the uterus via its blood supply and binds to two types of receptors: one on myometrial cells, the occupation of which initiates contractions, and the other on decidual cells, the occupation of which initiates prostaglandin generation. This prostaglandin diffuses into the adjacent myometrium and augments the oxytocin-induced contractions. In conjunction with a direct softening effect by prostaglandins on the cervix the augmented contractions achieve the force needed to dilate the cervix and expel the fetus. An additional source of oxytocin during labor may be the placenta, another non-traditional site for the occurrence of oxytocin.

The effect of ethanol on the production of lactate, triglycerides, phospholipids, and free fatty acids in the perfused human placenta

Eighteen fresh term placentas from normal deliveries were perfused to determine the biochemical response of the human placenta in the absence and presence of ethanol. The production rates were generally increased by ethanol administration; lactate, 22%; triglycerides, 49%; sphingomyelin, 362%; lecithin, 67%; lipid phosphorus, 780%; free fatty acids, 897%. Only the changes in lipid phosphorus and free fatty acids were significantly different (p less than 0.05). Glucose utilization rates were 600 and 551 mg per hour per placenta for eight control and 10 ethanol runs, respectively. The ethanol utilization rate was 442 mg per hour per placenta. Little difference in ultrastructural appearance between control and ethanol groups was observed at the level of ethanol administered. The general behavior of ethanol metabolism in human placenta seems qualitatively similar to that in the liver.

Comparative study of the effects of two tocolytic agents (magnesium sulfate and alcohol) on the ionic transfer through the isolated human amnion

The effects of two tocolytic agents (MgSO4 and ethanol) on ionic transfer through the isolated human amnion were observed and compared. The ionic transfer was estimated by conductance and ionic flux measurements. MgSO4 increased the ionic conductance (Gt) on the fetal side; it also increased the ionic fluxes from fetus to mother and from mother to fetus, but it decreased the flux ratio. Ethanol decreased Gt in both directions as well as the ionic fluxes; the flux ratio, however, remained constant. Thus, the two tocolytic agents (MgSO4 and ethanol) show a negative effect on ionic transfer through the human amnion.

Endocrinology of human parturition: a review

The existing data on the hormonal factors involved in human parturition indicate that the steroid hormones, progesterone and the oestrogens, play only a facilitatory role in the initiation of labour. A definite role for fetal adrenal steroids in this process has yet to be established, and they too may serve only a facilitating function. The stimulation of the uterine muscle during labour results from an interaction of oxytocin and prostaglandin (PG) F2 alpha. Recent evidence suggests that oxytocin is most important for the initial phase of labour, whereas increased synthesis of PGF2 alpha is essential for the progression of labour. The role of PGE2 remains unclear, but this PG may play an important role in the ripening of the cervix which in turn is essential for successful parturition. The finding of maximal oxytocin receptor concentrations in the myometrium in labour adds strong support to the notion that oxytocin is the trigger for uterine contractions. The factors which control oxytocin receptor formation are therefore important; this may be one of the processes where the steroids play a crucial role. Oxytocin is also one of the stimuli that increase uterine PG synthesis; the coupling of oxytocin receptor occupancy and PG synthetase activity in uterine tissues may be another crucial factor in the mechanism of labour. The formation of gap junctions between the myometrial cells also seems essential for the synchronization and progression of myometrial activity. We propose, therefore, that the co-ordinating of oxytocin receptor formation, PG synthesis and gap junction formation is a key to the initiation and maintenance of human labour. The fetus may fulfil such a co-ordinating role through its influence on placental oestrogen production, through mechanical distention of the uterus, and through its secretion of neuro-hypophysial hormones and other stimulators of PG synthesis.

Effect of ethyl alcohol infusions on glucose and hormone status in ovine pregnancy

Term pregnant ewes were given ethanol in dextrose water i.v. according to the usual 2-h loading dose recommended for premature labor. Glucose, insulin, cortisol, progestins, estrone and estradiol in maternal and fetal plasma were measured for 5 h. In both treated animals and controls (dextrose water only) there was reduction in maternal cortisol and a reduction followed by a rise in progesterone concentration. Mean concentration of insulin in maternal plasma across all sampling times was higher in ethanol treated animals.

Prevention of preterm delivery. The important role of early recognition

Perinatal deaths can be decreased most effectively by reducing the incidence of preterm delivery. Therapy with a tocolytic agent, such as ritodrine ( Yutopar ), can be of significant benefit if applied to patients in whom preterm labor is correctly diagnosed and has not advanced beyond the early stages. Identification of the patient at risk, intensive education and surveillance of such patients, and education of hospital and clinic staff can extend the application and success of labor-inhibiting therapy.

The use of ritodrine and magnesium sulfate in the arrest of premature labor

Sixty-seven cases of premature labor (48 with unruptured and 19 with ruptured membranes) were treated with ritodrine or magnesium sulfate infusion supplemented with oral ritodrine in case of initial success. Both treatment regimens were found effective irrespective of maternal age, parity, ethnic background and number of previous abortions. The study supports the clinical experience indicating that early administration of tocolytic agents is highly successful in arresting premature labor and preventing its dire consequences.

Magnesium sulfate as a tocolytic agent

Magnesium sulfate (MgSO4) has been successfully used to inhibit premature labor. A retrospective review was performed on the use of MgSO4 as a tocolytic agent at Memorial Hospital, Long Beach, California, during a 4-year period (1978-1982). Three hundred fifty-five patients with diagnoses of premature labor were treated with MgSO4 after transport from another hospital. Two hundred seventy-four patients (77%) had a singleton pregnancy with intact membranes, 38 (11%) had a singleton pregnancy with ruptured membranes, 35 (10%) had a multiple gestation with intact membranes, and eight (2%) had a multiple gestation with ruptured membranes. Delivery was successfully delayed in the majority of patients, and the incidence of unexplained failure of tocolysis was only 2%. Side effects occurred in 24 patients (7%) and necessitated stopping the drug in only seven (2%). Serum magnesium levels are reported and the use of MgSO4 in patients with significant vaginal bleeding is discussed. MgSO4 was found to be a successful, inexpensive, and relatively nontoxic tocolytic agent that had few side effects.

Effects of cigarette smoking, alcohol, coffee and tea consumption on preterm delivery

A case-control study of 175 mothers of singleton, preterm infants and 313 mothers of singleton, term infants was undertaken at Yale-New Haven Hospital during 1977 to explore possible risk factors of preterm delivery. Heavy alcohol consumption (an average of two or more drinks per day) during the pregnancy was associated with an approximately 3-fold risk of preterm delivery. Women who smoked 10 or more cigarettes per day were also at an increased risk of a preterm delivery, but the effect of cigarette smoking was less pronounced once confounding variables had been taken into account. No association was observed between coffee drinking and shortened gestations. Tea consumption, especially four or more cups of tea per day, was more frequent among women with a preterm as compared to a term infant, but no significant relation was evident between heavy tea consumption and preterm delivery after controlling for the effects of other risk factors.

Oxytocin receptors and human parturition: a dual role for oxytocin in the initiation of labor

The concentration of oxytocin receptors increased in the myometrium of pregnant women and reached maximum levels in early labor. Concentrations of oxytocin receptors were also high in the decidua and reached a maximum at parturition. In vitro, prostaglandin production by the decidua, but not by the myometrium, was increased by the addition of oxytocin. Oxytocin may therefore stimulate uterine contractions by acting both directly on the myometrium and indirectly on decidual prostaglandin production. Oxytocin receptors are probably crucial for the onset of human labor, and the stimulus for the increase in uterine prostaglandins may be oxytocin originating from the fetus.

Ethanol kinetics during pregnancy. Study in ewes and their fetuses

1. Kinetics of placental transfer and elimination of ethanol in maternal and fetal blood and amniotic fluid were studied after iv infusion of ethanol in 3 ewes in the third trimester of pregnancy. 2. Ethanol was transferred rapidly from the maternal to the fetal compartment, and more slowly from these to the amniotic fluid. 3. The kinetics of ethanol elimination from the maternal and fetal circulations were similar, indicating rapid bidirectional transfer between them and elimination from the former only. 4. There was significantly slower elimination of ethanol from the amniotic fluid, with increasing concentrations long after these had started to decline in the maternal and fetal blood. This suggests that the amniotic fluid can act as a reservoir for ethanol storage.

Prospective randomized study of corticosteroids in the management of premature rupture of the membranes and the premature gestation

A prospective randomized study involving patients with premature rupture of the membranes between the twenty-eighth week and the thirty-fourth week of pregnancy was conducted. Patients with chorioamnionitis, advanced labor, and fetal distress, as well as those with mature lecithin/sphingomyelin ratios and/or Gram stains positive for bacteria, were delivered immediately. The remaining patients were randomized. One group received betamethasone. Tocolytic agents were used in this group when necessary. After 48 hours all patients given corticosteroids (CS group) were delivered). The second group was managed expectantly (EM group) and were delivered only when spontaneous labor or infection occurred. A total of 160 patients were randomized, 80 in each group. Maternal outcome, including chorioamnionitis and cesarean section rates, was not different; however, the endometritis rate was significantly higher in the CS group (p less than 0.05). Neonatal outcome did not differ in mean birth weights, perinatal death rates, neonatal infections, or incidences of respiratory distress. The frequency of prolonged hospital stay (greater than 4 weeks) was higher in the neonates in the CS group (p less than 0.01). The conclusion is that corticosteroids and active management in patients with premature rupture of the membranes and premature gestations do not decrease the incidence of respiratory distress syndrome or perinatal mortality and may aggravate certain infectious complications.

A critical evaluation of the obstetric use of alcohol in preterm labor

The clinical use of alcohol to delay premature labor is critically reviewed. The evidence indicates that this procedure is no more effective in arresting preterm labor than placebo, i.e., bed rest. The rational for the clinical use of alcohol in obstetrics is also questionable. Furthermore, increasing evidence indicates that the blood alcohol levels associated with this method often causes nausea, vomiting, and headaches in mothers and can cause deleterious effects in the fetus, including death.