Effects on the neonate of propranolol administered during pregnancy

The Risk for Neonatal Hypoglycemia and Bradycardia after Beta-Blocker Use during Pregnancy or Lactation: A Systematic Review and Meta-Analysis

Beta-blockers are often used during pregnancy to treat cardiovascular diseases. The described neonatal side effects of maternal beta-blocker use are hypoglycemia and bradycardia, but the evidence base for these is yet to be evaluated comprehensively. Hence, this systematic review and meta-analysis was performed to evaluate the potential increased risk for hypoglycemia and bradycardia in neonates exposed to beta-blockers in utero or during lactation. A systematic search of English-language human studies was conducted until 21 April 2021. Both observational studies and randomized controlled trials investigating hypoglycemia and/or bradycardia in neonates following beta-blocker exposure during pregnancy and lactation were included. All articles were screened by two authors independently and eligible studies were included. Pair-wise and proportion-based meta-analysis was conducted and the certainty of evidence (CoE) was performed by standard methodologies. Of the 1.043 screened articles, 55 were included in this systematic review. Our meta-analysis showed a probable risk of hypoglycemia (CoE—Moderate) and possible risk of bradycardia (CoE—Low) in neonates upon fetal beta-blocker exposure. Therefore, we suggest the monitoring of glucose levels in exposed neonates until 24 h after birth. Due to the limited clinical implication, monitoring of the heart rate could be considered for 24 h. We call for future studies to substantiate our findings.

Emergency therapy of maternal and fetal arrhythmias during pregnancy

Atrial premature beats are frequently diagnosed during pregnancy (PR); supraventricular tachycardia (SVT) (atrial tachycardia, AV-nodal reentrant tachycardia, circus movement tachycardia) is less frequently diagnosed. For acute therapy, electrical cardioversion with 50–100 J is indicated in all unstable patients (pts). In stable SVT, the initial therapy includes vagal maneuvers to terminate tachycardias. For short-term management, when vagal maneuvers fail, intravenous adenosine is the first choice drug and may safely terminate the arrhythmia. Ventricular premature beats are also frequently present during PR and benign in most of the pts; however, malignant ventricular tachyarrhythmias (sustained ventricular tachycardia [VT], ventricular flutter [VFlut] or ventricular fibrillation [VF]) may occur. Electrical cardioversion is necessary in all pts who are in hemodynamically unstable situation with life-threatening ventricular tachyarrhythmias. In hemodynamically stable pts, initial therapy with ajmaline, procainamide or lidocaine is indicated. In pts with syncopal VT, VF, VFlut or aborted sudden death, an implantable cardioverter-defibrillator is indicated. In pts with symptomatic bradycardia, a pacemaker can be implanted using echocardiography at any stage of PR. The treatment of the pregnant patient with cardiac arrhythmias requires important modifications of the standard practice of arrhythmia management. The goal of therapy is to protect the patient and fetus through delivery, after which chronic or definitive therapy can be administered.

The autonomic nervous system and perinatal metabolism

The development of the autonomic nervous system in relation to perinatal metabolism is reviewed with particular attention given to the adipocyte, hepatocyte and the A and B cells of the islets of Langerhans. Adrenergic receptors develop in the B cell independently of normal innervation and by the time of birth, in most species studied, the pancreas, liver and adipose tissue respond appropriately to autonomic signals. Birth is associated with a huge surge in circulating catecholamines which is probably responsible for the early postnatal rise in free fatty acids and glucagon concentrations in plasma. beta-Blocking drugs such as propranolol have an adverse effect on fetal growth and neonatal metabolism, being responsible for hypoglycemia and for impairing the thermogenic response to cold exposure. beta-Mimetic drugs are commonly used to prevent premature labour and may help the fetus in other ways, for example, by improving the placental blood supply and the delivery of nutrients by increasing maternal fat and carbohydrate mobilization.

Acute therapy of maternal and fetal arrhythmias during pregnancy

Atrial premature beats are frequently diagnosed during pregnancy. Supraventricular tachycardia (atrial tachycardia, atrioventricular nodal reentrant tachycardia, circus movement tachycardia) is diagnosed less frequently. For acute therapy, electrical cardioversion with 50 to 100 J is indicated in all unstable patients. In stable supraventricular tachycardia, the initial therapy includes vagal maneuvers to terminate tachycardias. For short-term management, when vagal maneuvers fail, intravenous adenosine is the first choice drug and may safely terminate the arrhythmia. Ventricular premature beats are also frequently present during pregnancy and are benign in most patients; however, malignant ventricular tachyarrhythmias (sustained ventricular tachycardia, ventricular flutter, or ventricular fibrillation) may occur. Electrical cardioversion is necessary in all patients who are hemodynamically unstable with life-threatening ventricular tachyarrhythmias. In hemodynamically stable patients, initial therapy with ajmaline, procainamide, or lidocaine is indicated. In patients with syncopal ventricular tachycardia, ventricular fibrillation, ventricular flutter, or aborted sudden death, an implantable cardioverter-defibrillator is indicated. In patients with symptomatic bradycardia, a pacemaker can be implanted using echocardiography at any stage of pregnancy. The treatment of the pregnant patient with cardiac arrhythmias requires important modifications of the standard practice of arrhythmia management. The goal of therapy is to protect the patient and fetus through delivery, after which chronic or definitive therapy can be administered.

A double blind, randomized trial on augmentation of labour with a combination of intravenous propranolol and oxytocin versus oxytocin only

OBJECTIVE

To compare the combination of intravenous propranolol and oxytocin with oxytocin only in augmentation of labour.

STUDY DESIGN

A prospective randomized double-blind study in an obstetric department of a large university hospital in Finland. A total of 107 parturients with arrested first stage of labour owing to inadequate uterine contractility were randomized to receive intravenously once or twice a 2 mg dose of propranolol or placebo combined with oxytocin infusion. The main outcome measure was the effect of intravenous propranolol on the frequency of Caesarean section among parturients with arrested labour. The secondary outcome measures were the duration of labour, the required dosage of oxytocin, CTG readings, neonatal outcome and maternal and cord plasma levels of beta-adrenoceptor-binding component of propranolol. Categorial variables between the groups were compared using Chi square and Fisher's exact tests. Continuous variables were compared using the Mann-Whitney U-test and Student's t-test.

RESULTS

No reduction in Caesarean section rate was found in the propranolol group. Seventy-three percent of the parturients in the propranolol group and 85% in the placebo group had spontaneous vaginal delivery, RR=0.86 (95% CI 0.70-1.05). The percentage proportion of the augmented part of labour was significantly shorter in the propranolol group than in the placebo group. No differences in the required oxytocin dosage or CTG pathology were found between the groups. Propranolol was found to be safe for the neonates. The concentrations of its beta-adrenoceptor-binding component after a 2mg intravenous dose were quite similar in parturients and neonates at the time of delivery. The active drug component crossed placental barriers with an average neonate umbilical artery/parturient venous plasma ratio of 0.7. After a 4 mg dose the active drug concentrations in parturients were rather similar to those measured after 2 mg dose, whereas in neonates there were signs of drug accumulation. No picture could be obtained from the kinetics of the beta-adrenoceptor-binding component of propranolol from the data.

CONCLUSIONS

Propranolol (2 or 4 mg i.v.) combined with oxytocin, as treatment for arrested labour did not affect the Caesarean section rate compared with placebo plus oxytocin. The percentage proportion of the augmented part of labour was significantly shorter after propranolol. Propranolol was safe for the neonates and can be used as an additional medication among parturients with arrested labour.

Pregnancy complicated with pulmonary edema due to hyperthyroidism

Hyperthyroidism is one of the most common causes of cardiac failure. Blood volume expands greatly during pregnancy, especially after the last part of the second trimester. Such expansion exacerbates the symptoms of heart failure and accelerates the development of pulmonary edema when abnormal thyroid function is not well controlled. Two cases of pregnancy complicated with congestive heart failure and pulmonary edema due to hyperthyroidism are reported here. Both patients did not receive treatment for hyperthyroidism during pregnancy, and both sought clinical help during the third trimester. The clinical problems were resolved by medical management before delivery.

Exposition aux bêtabloquants en fin de grossesse

OBJECTIVES

To analyse neonatal effects after in utero betablockers exposure and the pertinence of recommendations delivered by our team.

POPULATION AND METHODS

We report 44 pregnancies exposed to betablockers during the late pregnancy including the period of delivery about which the Regional Pharmacovigilance Center of Tours (CRPV) was questionned.

RESULTS

Among the 39 children for whom we know the follow up, 22 had neonatal adverse effects of which 19 could be explained by in utero exposure to betablockers i.e. an hypoglycaemia (11 times), a bradycardia (six times), a bradycardia and hypoglycemia (one time) and an hypotension (one time). A drug-related effect was retained for eleven newborns (27%) and another etiology could be evoked in the eight others. The risk of neonatal adverse effects seems to increase in newborns exposed to labetalol (5/11), to betaxolol (1/2) or to propranolol (2/6) or when the dose is high. The eight newborns who had intrauterine growth retardation were generally more often exposed to atenolol than eutrophic newborns. Four babies had malformations.

CONCLUSIONS

Our recommendation was an hospitalization 44 times (100%) to monitor heart rate, blood pressure and glycemia. When the follow-up is known, hospitalization was performed in 88% of the cases. Glycemia, heart rate and blood pressure were monitored in all the hospitalized children and in three of the five not hospitalized children. Our recommendation seems particularly justified with regard to hypoglycemia which is often asymptomatic but whose consequences can be severe. Atenolol often provider of intrauterine growth retardation and labetalol more often at the origin of neonatal adverse effects are probably to avoid during pregnancy.

Effects of antihypertensive drugs on the unborn child: what is known, and how should this influence prescribing?

This review discusses the use of antihypertensive drugs in acute and long term treatment of hypertensive disorders of pregnancy, including their placental transfer and adverse effects on the fetus. All antihypertensive agents cross the placental barrier and are present in varying concentrations in the fetal circulation, with varying resultant effects on fetal metabolism. Antihypertensive drugs that are lipid soluble will pass through the placental barrier with ease whereas the most polar will not. Placental transfer diminishes under conditions that decrease the surface area or increase the thickness of the placenta. Highly protein-bound drugs form complexes which impair placental transfer while unbound drugs cross the placenta easily. The ionised drug form is highly charged and cannot cross lipid membranes while the un-ionised form can easily cross the placenta. A decrease in placental blood flow can slow down the transfer of lipid soluble drugs to the fetus. Close monitoring of the fetal and maternal condition is necessary for the rest of the pregnancy after antihypertensive therapy is commenced. Methyldopa is the initial drug of choice for long term oral antihypertensive therapy in pregnancy. Neither short term nor long term use of methyldopa is associated with adverse effects. In the short term (<6 weeks) beta-receptor antagonists are effective and well tolerated provided there are no signs of intrauterine growth impairment. ACE (angiotensin converting enzyme) inhibitors are contraindicated in the second and third trimesters of pregnancy because they are teratogenic. Intravenous dihydralazine is widely used for rapid reductions of severely elevated blood pressure. The use of nifedipine concurrently with MgSO4 must be approached with caution because the combination is associated with severe hypotension, neuromuscular blockade and cardiac depression. In the last decade, knowledge of antihypertensive drugs used in pregnancy has improved and new drugs, e.g. calcium antagonists, which have been shown to have great potential for use in pregnancy, have been introduced. Safety for the fetus with newer drugs has not yet been adequately evaluated. Currently, well established and cost effective drugs such as methyldopa (long term use) and intravenous dihydralazine (rapid reduction) are the agents of choice to treat hypertensive disorders of pregnancy.

Mitral stenosis in pregnancy: a four-year experience at King Edward VIII Hospital, Durban, South Africa

OBJECTIVE

To evaluate prospectively mitral stenosis in pregnancy with emphasis on women with persistent symptoms.

SETTING

King Edward VIII Hospital, a tertiary referral obstetric unit.

PARTICIPANTS

One hundred and twenty-eight consecutive women with mitral stenosis.

DEMOGRAPHICS

The mean age was 27 years and 38 women (30%) were primigravidae. Seventy-eight (61%) women had their first cardiac evaluation in the third trimester. Fifty-four women (42%) of these women had mitral stenosis diagnosed for the first time in the index pregnancy. Twenty-nine (23%) had a previous mitral valvulotomy. Nineteen women (15%) developed hypertension during pregnancy, 10 of whom had pre-eclampsia. Sixty-three women (49%) had a mitral valve area of < or = 1.2 cm2 with 11 having critical mitral stenosis (mitral valve area < or = 0.8 cm2). Atrial fibrillation was present in 12 women. Most women (87%) required medical therapy to control the heart rate. OUTCOME IN PERSISTENT SYMPTOMATIC WOMEN: Intervention was considered in 37 women (29%) who remained symptomatic, 11 (9%) of whom had a calcified mitral valve. The remaining 26 women were scheduled for balloon mitral valvulotomy during pregnancy, 20 of whom had balloon mitral valvulotomy with good effect (16 antepartum; 4 postpartum). In seven women, scheduled balloon mitral valvulotomy was not performed because of advanced preterm labour (n = 5), fetal distress (n = 1) and preterm labour with fetal distress (n = 1). These seven, together with the 11 with calcific mitral stenosis, were managed conservatively with good outcome. MATERNAL COMPLICATIONS: Fifty-one percent had maternal complications, the majority occurring at their initial admission to hospital. Pulmonary oedema was the most frequent. Multiple logistic regression analysis showed that the severity of stenosis assessed by measurement of the mitral valve area by echo-Doppler was the most powerful predictor of maternal pulmonary oedema. The other factors were late antenatal presentation, presence of symptoms prior to the index pregnancy and diagnosis of cardiac disease for the first time in the index pregnancy.

CONCLUSION

Despite serious disease, women with persistent symptoms treated either by balloon mitral valvulotomy where feasible, or conservatively with close noninvasive monitoring, had a satisfactory fetal and maternal outcome.

Neonatal hepatic propranolol elimination: studies in the isolated perfused neonatal sheep liver

Using the isolated perfused neonatal sheep liver model, we examined the disposition of propranolol (n = 8, age 0.25-10 days) and compared our findings with our previous study from the perfused near-term fetal sheep liver (Ring JA, et al. 1995. Drug Metab Dispos 23:190-196). Within 45 min of dosage, perfusate propranolol levels had fallen by three orders of magnitude to be less than the limit of detection. Perfusate disappearance curves were monoexponential in six experiments and biexponential in two experiments. The mean shunt-corrected hepatic extraction ratio was 0.92 +/- 0.09, much greater than that seen in the fetal sheep liver (0.26 +/- 0.13, P < 0.0001) but still less than values in the adult sheep (0.97). At the conclusion of the perfusion, 4-hydroxypropranolol was the major metabolite present and 5-hydroxypropranolol and N-desisopropylpropranolol were minor metabolites. We conclude that the isolated perfused neonatal sheep liver is a useful model with which to study the maturation of neonatal hepatic drug oxidation. Our study shows that propranolol is rapidly eliminated by the neonatal liver to form several metabolites at rates far greater than in the fetal liver, but rates of elimination have not yet reached that reported in the adult sheep liver.

Antiarrhythmic drug therapy in pregnancy and lactation

Antiarrhythmic agents commonly used in clinical practice are reviewed with respect to their potential for teratogenic or other adverse fetal effects. Although most experience with antiarrhythmic drug therapy during pregnancy has accrued with digoxin, quinidine, and propranolol, other antiarrhythmic agents may also be used in the pregnant patient if indicated. The choice of antiarrhythmic drug depends on the specific arrhythmia being treated, the cardiac condition of the patient or fetus, and the known or anticipated actions of the antiarrhythmic drug being considered. The management of specific arrhythmias encountered in pregnant women are also discussed. For benign arrhythmias, a conservative approach starting first with preventive measures is appropriate. For more severe or symptomatic arrhythmias, pharmacologic therapy should be instituted using drugs with proven safety to the fetus, if possible. Electrical cardioversion of the patient may be performed with relative safety in more emergent situations.

Influence of pregnancy on the risk for cardiac events in patients with hereditary long QT syndrome. LQTS Investigators

BACKGROUND

The effects of pregnancy on women with the hereditary long QT syndrome are currently unknown. The appropriate medical management of pregnant patients with the long QT syndrome has not been established.

METHODS AND RESULTS

The study was a retrospective analysis of the 422 women (111 probands affected with the long QT syndrome and 311 first-degree relatives) enrolled in the long QT syndrome registry who had one or more pregnancies. The first-degree relatives were classified as affected (QTc >0.47), borderline (QTc=0.45 to 0.47), and unaffected (QTc <0.45). Cardiac events were defined as the combined incidence of long QT syndrome-related death, aborted cardiac arrest, and syncope. The incidence of cardiac events was compared during equal prepregnancy, pregnancy, and postpartum intervals (40 weeks each). Multivariate logistic regression analysis was performed by use of a mixed-effects model to identify independent predictors of cardiac events among probands. The pregnancy and postpartum intervals were not associated with cardiac events among first-degree relatives. The postpartum interval was independently associated with cardiac events among probands (odds ratio [OR], 40.8; 95% confidence interval [CI], 3.1 to 540; P=.01); the pregnancy interval was not associated with cardiac events. Treatment with beta-adrenergic blockers was independently associated with a decrease in the risk for cardiac events among probands (OR, 0.023; 95% CI, 0.001 to 0.44; P=.01).

CONCLUSIONS

The postpartum interval is associated with a significant increase in risk for cardiac events among probands with the long QT syndrome but not among first-degree relatives. Prophylactic treatment with beta-adrenergic blockers should be continued during the pregnancy and postpartum intervals in probands with the long QT syndrome.

Thyroid disease in women

Thyroid diseases occur more commonly in women than men, in part because of the autoimmune nature of many thyroid disorders. Hypothyroidism, and thyroid nodules occur frequently in both pre- and postmenopausal women. Pregnancy is also associated with changes in thyroid function. The goal of this article is to review the current information on the pathophysiology and treatment of thyroid disorders which are common in women.

Drug management of hypertensive disorders of pregnancy

Drugs used in the acute and long-term management of hypertension in pregnancy and the preeclampsia-eclampsia syndrome have been reviewed and their therapeutic effects and maternal and fetal adverse effects have been considered. The review also focuses on recent developments in the areas of prevention and management of pre-eclampsia-eclampsia syndrome. Although a number of new drugs have emerged, as potentially useful in the management of hypertension in pregnancy and pre-eclampsia-eclampsia syndrome, some remain at the cornerstone of therapy; for example, methyldopa for long-term treatment of chronic hypertension, hydralazine or nifedipine for rapid reduction of severely elevated blood pressure, and magnesium sulphate for eclampsia. Some of these agents, especially the calcium antagonists, show promise in that their use is associated with fewer side effects. Safety for the fetus, however, has not been adequately evaluated yet. Neither aspirin nor calcium supplements appear to improve the outcome in pregnancy. Currently, the dilemma whether to treat hypertension in pregnancy and pre-eclampsia-eclampsia syndrome with old, established, cost-effective drugs or the promising newer drugs provides an interesting academic challenge.

Increased alpha 2-adrenoceptor mediated regulation of adult rat brain noradrenaline overflow after chronic neonatal exposure to propranolol; a microdialysis study

Direct and persistent effects of chronic neonatal administration of the beta-adrenoceptor antagonist propranolol on brain noradrenergic activity were investigated by measuring tissue concentrations of noradrenaline and its metabolites and in vivo overflow of noradrenaline during adulthood. Rat pups were chronically treated with propranolol from postnatal day 1 to day 10. Determination of monoamine metabolism after the last injection showed an increase in noradrenaline metabolism in frontal cortex, limbic system and hippocampus of propranolol-exposed rats, but 47 days after this last injection it was apparent that these effects were not long-lasting. Moreover, basal noradrenaline overflow in vivo in the hippocampus of 40-55 day-old propranolol-exposed rats did not differ from that in controls. However, the regulation of noradrenaline release seemed to have been altered, since a pharmacological challenge with the alpha 2-adrenoceptor antagonist idazoxan induced an enhanced increase in the in vivo noradrenaline overflow in propranolol-exposed rats compared to controls. It is suggested that the neonatal beta-blockade induced a supersensitivity of the presynaptic alpha 2-adrenoceptor. The precise mechanism underlying this effect has to be elucidated.

Perinatal factors associated with retinopathy of prematurity

The etiology of retinopathy of prematurity appears to be multifactorial. Introduction of new treatments in neonatal care may add new risk factors. We have analyzed the relationship between 42 perinatal factors and the development of retinopathy of prematurity in 78 infants with a birth weight < 1501 g and/or gestational age < 33 weeks. We have also applied a chronological analysis of the maximum and minimum pO2 and pCO2 values. Retinopathy of prematurity was seen in 37 of 78 infants (47.4%). Nineteen factors were found to be related to the development of retinopathy of prematurity. However, when step-wise logistic regression analysis was used, only birth weight, number of days of oxygen therapy and use of beta-blocking agents by the mother before birth were found to be associated with the development of retinopathy of prematurity. The results suggest that medication with beta blockers immediately before birth should be used cautiously.

Drug therapy of the fetus

The fetus has become an intended object of drug therapy administered through the mother with the successful prevention of hyaline membrane disease with glucocorticoids. Maternal drug treatment has now been undertaken for a variety of fetal problems, including arrhythmias, congestive heart failure, infections, and inborn errors of adrenal metabolism. Interestingly, this planned maternal drug exposure during pregnancy coincided with increasing concerns during the last two decades about inadvertent transplacental exposure of the fetus to licit and illicit drugs. Efforts to direct drug therapy to the fetus have pointed out important gaps in knowledge of the pharmacology of the maternal-placental-fetal-unit (MPFU), whereas other observations illustrated recognized principles of the pharmacology of the MPFU. Many of these principles fit the basic framework of pharmacokinetics: absorption, distribution, metabolism and excretion. Rapid changes in maternal-placental physiology and fetal development during gestation, however, lead to dramatic variations in these processes throughout pregnancy.

New-onset ventricular tachycardia during pregnancy

During evaluation for palpitations, presyncope, or syncope, seven pregnant women had documented ventricular tachycardia. Before pregnancy none had a history of significant cardiac disease or symptomatic arrhythmia. The tachycardia rate ranged from 117 to 250 beats/min and lasted up to 65 seconds. Arrhythmia evaluation in five of the patients suggested catecholamine-sensitive ventricular tachycardia. This diagnosis was supported by either a positive relation to exercise or isoproterenol infusion, suppression of arrhythmia by beta-blockade or sleep, and lack of induction of arrhythmia by programmed electrical stimulation of the heart. The arrhythmias resolved in one patient soon after evaluation and in one other patient after 2 months of controlling therapy. Five other patients continued to receive therapy throughout pregnancy. Delivery was accomplished in all patients without significant maternal or neonatal complications.

Mechanism of growth retardation following chronic administration of beta-adrenoceptor antagonists to developing rats

A total of 112 3-week old Wistar rats were separated into eight groups: control groups I-IV (n = 62) and propranolol-treated groups V-VIII (n = 50). Propranolol hydrochloride (100 mg/kg) was present in the rats' drinking water until 26 weeks of age and growth rates of all groups were monitored daily until 53 days of age and thereafter every third day throughout the study. Chronic oral propranolol administration produced growth retardation (P less than 0.05) in both sexes that was reversible when treatment was discontinued. Organ weights were generally smaller in propranolol-treated rats; on the other hand, the ratio of most organ weights per 100 g of body weight was greater in propranolol-treated rats (especially females). The radio-immunological determination of plasma growth hormone showed increased concentrations of growth hormone in propranolol-treated rats (P less than 0.05), whereas hypothalamic somatostatin content was not significantly changed. The results showed that the retarded growth rate following chronic oral propranolol administration to growing rats was independent of changes in plasma growth hormone and hypothalamic somatostatin concentrations, and that retardation was entirely reversible when the beta-adrenoceptor antagonist was discontinued.

Chronic propranolol treatment in developing rats: acute and lasting effects on monoamines and beta-adrenergic receptors in the rat brain

During early postnatal development rat pups were treated twice daily with the beta-adrenergic antagonist propranolol (15 mg/kg) in order to study the acute and long-lasting effects of early blockade of noradrenergic beta-mediated neurotransmission. Treatments from postnatal days 1-10 or days 11-20 did not induce alterations in the number of beta-adrenergic receptors as measured three days after the last injection, nor could lasting effects be shown at 60 days of age. The day 1-10 treatment, however, had a significant effect on the regional brain levels of noradrenaline (NA) and its metabolite 3-methoxy-4-hydroxyphenylglycol (MHPG), measured 90 min after the last injection. The metabolite had increased by 40% in all brain regions examined. On day 60, the MHPG concentrations were still increased when compared to postnatally saline-treated animals. Propranolol treatment from day 11-20 only marginally increased MHPG on day 20 and induced no lasting differences. These results suggest that propranolol treatment during the first ten days of life produces a long-lasting increase in NA metabolism, possibly reflecting an increased neuronal NA turnover.

Behavioral and biochemical studies in rats following prenatal treatment with beta-adrenoceptor antagonists

Increased motor activity and poor performance in the active avoidance test were observed in the offspring of rats treated with dl-propranolol or sotalol during pregnancy, but not with atenolol and d-propranolol. All substances were administered in drinking water from days 8-22 of gestation. A significant increase in the density of muscarinic acetylcholine receptors in the hippocampus was found for dl-propranolol and sotalol, at 35 and 20 days of age, respectively. Twenty-day-old pups born to dl-propranolol-treated rats exhibited a non-significant decrease in the number of beta-adrenoceptors in the frontal cortex. Assuming that all the beta-adrenoceptor antagonists tested had access to the developing fetal brain, the effect of dl-propranolol and sotalol on behavior could stem from central beta 2-adrenoceptor blockade. In view of the lack of behavioral changes after atenolol, a beta 1-selective adrenoceptor antagonist, it is suggested that the clinical use of beta 1-selective adrenoceptor antagonists during pregnancy might be safer for the fetus than beta 2-adrenoceptor antagonists.

Response to beta-blockers in maternal and fetal rat hearts in vitro

The effects of beta-blockers on maternal and fetal heart rates have been assessed by comparing isoprenaline concentration-heart rate relationships of hearts isolated from pregnant rats. The normal and maximal heart rates obtained for the maternal and fetal hearts were similar to published data. A slightly but significantly higher concentration of isoprenaline was required to produce 50% of the maximal response of fetal hearts than maternal hearts, suggesting that fetal hearts were less sensitive to isoprenaline than the maternal hearts. The beta-blockers used (propranolol, labetalol, metoprolol and atenolol) all showed a lower affinity to the beta-receptors of fetal hearts than those of maternal hearts, as indicated by significant differences in the pA2 values. Given the similar effects of the beta-blockers in the maternal and fetal hearts it is concluded that pharmacokinetic considerations and beta-blocker selectivity should be used as the basis of choice when treating maternal hypertension during pregnancy.

The cardiac, obstetric, and anesthetic management of pregnancy complicated by acute myocardial infarction

Myocardial infarction (MI) occurring during pregnancy is a rare but potentially lethal event for both mother and fetus, particularly when it occurs in the third trimester or peripartum period. The authors report two cases of MI occurring in the third trimester of pregnancy and review the literature. Management of the acute infarct and the medical, obstetric, and anesthetic considerations in such patients during labor and delivery are discussed. Successful use of percutaneous transluminal coronary angioplasty is described in a patient with evolving MI and ongoing pain. The preferred method of delivery in the pregnant MI patient is addressed, with emphasis on the need for individualization of care and coordination between the cardiac, obstetric, and anesthetic teams. Finally, the authors review the risks of subsequent pregnancy in this patient population.

Half-life of maternal labetalol in a premature infant

Intra-uterine heart arrhythmia, postpartal respiratory insufficiency, bradycardia and hypoglycaemia were observed in a premature infant (37 weeks gestational age) delivered by a caesarian section. The mother had been treated with adequate doses of labetalol because of pregnancy-induced hypertension and her plasma concentration was found to be 89 micrograms/l one day after delivery. The half-life of labetalol in the plasma of the infant was found to be approximately 24 h, i.e. substantially longer than in normal adults. The half-life of labetalol in newborn premature infants may be prolonged as compared to normal adults. More studies are required regarding the pharmacokinetics of this agent in premature infants and newborn babies.

Transplacental and mammary passage of radioactivity in rats treated vaginally and orally with [14C]propranolol

The milk transfer, maternal-fetal distribution, and disposition of the antihypertensive/spermicidal agent propranolol were studied in pregnant and lactating rats. Single doses (10 mg/kg) of an aqueous solution of [14C]propranolol were administered either orally (po) or intravaginally (ivg) on gestational d 15, or on postpartum d 7-10. Upon ivg administration, [14C]propranolol was quickly transferred to systemic circulation and the mean blood [14C] concentrations were significantly greater during the first 0.25-2 h than in po dosed counterparts. About 98% of the ivg applied dose was absorbed after 6 h in gravid rats, and the combined 6-h excretions of radioactivity in the urine (ivg = 24.6%; po = 22.9%) and feces (ivg = 16.8%; po = 14.6%) were equivalent in both groups. At the end of 6 h, the levels of [14C] in the urinary bladder, adrenal, uterus, ovary, spleen, skeletal muscle, brain, heart, lung and fat were significantly higher in ivg treated rats than po dosed animals. Compared with the maternal plasma (ivg = 0.76; po = 0.88 microgram/ml), the mean concentrations of [14C] in the placentas were similar in both groups, while the amounts of [14C] were three to five times lower in the amniotic fluids and the fetuses of both po and ivg treated dams. In lactating rats, over 99% of the administered radioactivity was absorbed from the vagina within 6 h. The blood concentrations of [14C] were significantly elevated at 0.5 and 1 h in the per vaginam treated animals, and afterward the disappearance rate of [14C] followed a similar course in both groups. Following ivg application, the milk radioactivity peaked at 0.5 h and declined rapidly. However, the appearance of [14C] in milk was rather slow after oral dosing: the milk [14C] peaked between 2 and 3 h posttreatment and remained steady thereafter. The milk to blood (M/B) [14C] concentration ratios were markedly greater during 0.5 to 1 h in the ivg group than in their po dosed counterparts. At 6 h, the [14C] levels in the whole blood, plasma, milk, and mammary gland were virtually equivalent in the ivg and po treated females. Comparison of the areas under the milk [14C] concentration-time curves (AUCs) indicated that the milk availability of [14C] was about 31% more in dams dosed vaginally. These data suggest that route of administration alters the disposition and milk excretion of [14C]propranolol-derived radioactivity in pregnant and lactating rats.

Coronary angioplasty in pregnancy

Myocardial infarction is rare in pregnancy. A 30 year old white primigravida had an anterior infarct at 20 weeks' gestation, which was followed by troublesome angina. Coronary angiography showed a tight stenosis of the left anterior descending coronary artery. This was treated successfully by percutaneous transluminal coronary angioplasty.

Use of magnesium sulphate in the anaesthetic management of phaeochromocytoma in pregnancy

The anaesthetic management of two patients with phaeochromocytoma complicating pregnancy is presented. In one patient, the operative delivery was followed by elective tumour resection at a later stage. Magnesium sulphate was used as an adjunct to all three anaesthetics, with notable success on two occasion. In one of the operative deliveries, it proved impossible to achieve adequate blood levels of magnesium, due to severe pre-existing magnesium deficiency. Hypomagnesaemia is likely to be present in such cases and must be corrected preoperatively. Magnesium sulphate is a useful adjunct to the anaesthetic management of the pregnant patient with a phaeochromocytoma provided that adequate serum levels of magnesium can be established.

Early postnatal treatment with propranolol affects development of brain amines and behavior

The present study examined the effects of early postnatal treatment with a beta-adrenoceptor antagonist propranolol (5 mg/kg IP daily) on concomitant and subsequent behavior and central aminergic transmission in rats. During propranolol exposure from the 7th to the 20th postnatal days sleep-wake recordings, carried out with the static charge sensitive bed (SCSB) method, showed a decrease in the percentage of active sleep and an increase in waking. When the animals were 1-3 months of age, the open field behavior was changed, immobility time in the Porsolt's swim test was lengthened, and voluntary alcohol consumption was increased in the propranolol-treated rats. Neither motor reactivity to auditory stimuli nor spontaneous alternation behavior was affected. At the age of 4 months concentrations of brain amines and their metabolites were measured from several brain regions. In the propranolol-treated rats the noradrenaline levels were increased in the limbic forebrain and cerebellum. The results suggest that in rats the exposure to propranolol during the rapid growth period of cerebral catecholamine systems, and the concomitant alterations in sleep are related to later changes in behavior and to increased noradrenaline content in the limbic forebrain and cerebellum.

Nonobstetric surgery in pregnancy

Diagnostic and judgmental uncertainty that results in operative delay, leading to a more severe degree of illness and more complex surgery, is the major factor effecting both maternal and fetal morbidity and mortality in pregnant surgical patients. The acute abdomen is responsible for most errors in diagnosis and therapy. An understanding of anatomic, physiologic, and laboratory changes occurring in pregnancy and a timely interdisciplinary approach will expedite management and optimize outcome.

Intrauterine treatment of fetal tachycardia

The presence of sustained tachycardia in a fetus can result in congestive heart failure, hydrops, and eventual fetal death. With the increased use of advanced technology in routine obstetric practice, fetal tachycardias are being diagnosed with greater frequency. Recently, administration of antiarrhythmic medications to the mother has been successful in slowing the fetal heart rate and preventing or reversing potentially lethal complications in the fetus. The medications that have been used to treat fetal tachycardia and their potential effects on the mother are discussed. A case study and nursing protocol are presented.

Carbohydrate metabolism in the fetus and neonate and altered neonatal glucoregulation

Altered glucose homeostasis in the neonate often results from antecedent events during fetal life. This article describes the normal and altered development of glucoregulatory capabilities during perinatal life and relates it to problems of hypo- and hyperglycemia in the neonate.

First year of life after the use of atenolol in pregnancy associated hypertension

We describe the results of a prospective study in which 120 women who developed hypertension in the last trimester of pregnancy were randomly allocated in double blind manner to atenolol or placebo. The mean duration of treatment was five weeks. The only difference between groups during the neonatal period was in respiratory distress syndrome, mainly related to spontaneous premature labour, which occurred in six placebo group babies but in none from the atenolol group. Fifty five children from each group have been followed to 1 year of age. All in the atenolol group are developing normally but one child from the placebo group is brain damaged. These findings do not suggest any short or medium term paediatric complications after the use of beta blockers in pregnancy.

Successful treatment of fetal supraventricular tachycardia with maternal digoxin therapy

In a fetus with supraventricular tachycardia (SVT) and cardiac failure, normal sinus rhythm (NSR) was restored with maternal digoxin therapy at 26 weeks' gestation. The diagnosis of cardiac failure was based on ultrasound evidence of ascites and scalp edema. Cardiac failure was attributed to the persistent SVT. The infant remained in NSR and was delivered at 36 weeks' gestation because of persistent ascites. Intracardiac anatomy was normal. This case confirms the usefulness of prenatal ultrasound examinations in the diagnosis of fetal SVT and cardiac failure and illustrates the effectiveness and safety of transplacental digoxin therapy in the management of fetal SVT.

Fetal drug exposure-behavioral teratogenesis

This paper reviews the neurobehavioral and developmental effects of fetal drug exposure. The drugs most commonly associated with adverse developmental outcome include alcohol, anticonvulsants (particularly phenytoin and trimethadione), narcotics, and some environmental toxins. Major limitations of studies examining the consequences of prenatal drug exposure on development include inadequate control of other confounding factors, uncertain accuracy of drug histories, and outcome criteria that provide insufficient delineation of subtle developmental delays.

Treatment of intrauterine supraventricular tachycardia with digoxin and verapamil

Intrauterine fetal supraventricular tachycardia (ISVT) is a rare condition which is connected with organic heart disease in only 4-10 per cent. However, neonatally these children develop heart failure in a high frequency (62 per cent). Intrauterine digitalization has been suggested as treatment, especially if the fetus is preterm. Fetal therapeutic concentrations might demand doses inconvenient to the mother. We hereby report one case of intrauterine SVT in the 26th gestational week treated with a standard dose of digoxin resulting in subtherapeutic umbilical digoxin levels. When no consistent influence on fetal heart rate could be seen, verapamil (80 mg x 3) was added to the treatment. A reversion of the tachycardia and the fetal ECG changes was achieved within two days. The verapamil treatment could be withdrawn after ten days, while the digoxin treatment was continued. An initial discrete heart enlargement also was reversed by the treatment. The delivery in gestational week 38 was uneventful and the child did well. A neonatal ECG showed a sinus rythm interfoliated with supraventricular extrasystoles. No signs of organic heart disease have appeared. When last seen at nine months of age, the ECG was normal and digoxin had been discontinued without recurrence of tachycardia.

Propranolol in pregnancy three year prospective study

We compared propranolol with methyldopa in a randomized prospective study of 28 women with pregnancy associated hypertension. Both drugs were equally effective in controlling maternal hypertension. There was no significant difference in the birthweights of the babies in each group. However one infant born to a mother receiving propranolol had symptomatic hypoglycaemia. The mean peak levels of propranolol, propranolol glucuronide, 4-hydroxypropranolol, and 4-hydroxypropranolol glucuronide were not significantly different in the first, second, third trimesters and at least 3 months post partum. The mean peak plasma level of naphthoxylactic acid however was significantly less in the third trimester compared with post partum levels. Propranolol and its metabolites were found to cross into breast milk with the maximum dose likely to be ingested by the infant as either propranolol or propranolol glucuronide being 7 micrograms of propranolol per 100 g of breast milk, being approximately 0.1% of the maternal dose.