Use of propranolol in dysfunctional labour

A pilot study to compare propranolol and misoprostol versus misoprostol and placebo for induction of labor in primigravidae; a randomized, single-blinded, placebo-controlled trial

BACKGROUND

The Induction of labor is the most common obstetric procedure in daily practice. Introducing propranolol as a new drug to augment the action of prostaglandins will help in the induction process and decrease CS rates. Several researchers have used propranolol in the augmentation of labor.

AIM

This pilot study compares propranolol and misoprostol versus misoprostol alone for labor induction in primigravids.

METHODS

This is a Randomized clinical trial, single-blinded, placebo-controlled trial at Ain Shams University Maternity hospital. This study included 128 pregnant full-term primigravid women candidates for labor induction, randomized into two groups. All candidates underwent labor induction with 25 µg of vaginal misoprostol. Group I received 20 mg of oral propranolol tablets, while group II received sugary pills as a placebo. Candidates who responded successfully to induction were assessed for possible augmentation of labor by amniotomy or oxytocin infusion. The Primary outcome was induction to delivery interval, while the secondary outcomes were the duration of the latent phase, mode of delivery, and APGAR score of the neonate.

RESULTS

The induction-delivery time was (11.8 ± 8.1 h. vs. 12.6 ± 8.9 h., P value = 0.027) and the duration of the latent phase of labor (7.9 ± 5.6 h. vs. 9.2 ± 6.03 h., P value = 0.017) were significantly shorter in the group of misoprostol and propranolol compared to the group of misoprostol and placebo. There was no statistically significant difference between both groups' mode of delivery, indications for cesarean section, misoprostol, and oxytocin doses, or neonatal outcome. (P value > 0.05).

CONCLUSION

Propranolol, when used with misoprostol for induction of labor, results in augmentation of action of misoprostol and a significantly shorter induction-delivery interval.

TRIAL REGISTRATION

We retrospectively registered this trial in clinicaltrial.gov on 01/09/2020 (NCT04533841). https://clinicaltrials.gov/ct2/show/NCT04533841.

Perinatal anxiety: approach to diagnosis and management in the obstetric setting

Anxiety is common in women during the perinatal period, manifests with various symptoms and severity, and is associated with significant maternal morbidity and adverse obstetric and neonatal outcomes. Given the intimate relationship and frequency of contact, the obstetric provider is positioned optimally to create a therapeutic alliance and to treat perinatal anxiety. Time constraints, absence of randomized controlled trials, mixed quality of data, and concern for potential adverse reproductive outcomes all limit the clinician's ability to initiate informed risk-benefit discussions. Clear understanding of the role of the obstetric provider in the identification, stabilization, and initiation of medication and/or referral to psychotherapy for women with perinatal anxiety disorders is critical to maternal and neonatal wellbeing. Informed by our clinical practice as perinatal psychiatric providers, we have provided a concise summary of current research on the approach to the treatment of perinatal anxiety disorders in the obstetric setting that includes psychotherapy and supportive interventions, primary and adjuvant psychiatric medication, and general prescribing pearls. Medications that we examined include antidepressants, benzodiazepines, sedative-hypnotics, antihistamines, quetiapine, buspirone, propranolol, and melatonin. Further research into management of perinatal anxiety, particularly psychopharmacologic management, is warranted.

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.

The tocolytic effect of catecholamines in the gravid rat uterus

Maternal catecholamines increase dramatically in labor because of pain and emotional stress. Because the uterus is richly endowed with both alpha- and beta-adrenergic receptors, catecholamines could alter uterine activity. We assessed the effect of clinically encountered concentrations of these catecholamines on uterine activity and modeled the effect of the abrupt reduction in circulating epinephrine that occurs during effective labor analgesia. Term pregnant rat uteri were excised, and cross-sectional rings were mounted for isometric force recording. Log concentration-response curves for epinephrine, norepinephrine, and their combination on uterine activity were constructed from 10(-12) to 10(-6) M. Catecholamine responses were repeated in the presence of phentolamine, an alpha-adrenergic blocker or propranolol, a beta-adrenergic blocker. The abilities of oxytocin and of washout of catecholamines to reverse catecholamine-induced changes in uterine activity were also assessed. Epinephrine caused dose-dependent reductions in uterine activity, blocked by propranolol. Epinephrine concentrations in the clinical range(10(-9) to 10(-8) M; 100-1000 pg/mL) decreased uterine activity to 49.6% +/- 6.6% (mean +/- SE) of control. Norepinephrine caused a dose-dependent increase in uterine activity, which was blocked by phentolamine. In the clinical range (10(-8) M), uterine activity was 139.2% +/- 13.40% of control. The combination of both catecholamines, however, was nearly as tocolytic as epinephrine alone. Oxytocin antagonized catecholamine-induced tocolysis, and washout of epinephrine or both catecholamines increased uterine activity. We conclude that mixed catecholamines are significantly tocolytic at concentrations encountered in laboring women. In this in vitro model, reduction in epinephrine concentration, comparable to that which occurs during effective analgesia, significantly increases uterine activity.

IMPLICATIONS

Maternal catecholamines increase in labor, but epinephrine decreases dramatically after regional analgesia. In this study, we found that norepinephrine and epinephrine together decrease uterine contractile activity and that decreased epinephrine causes significantly increased uterine activity.

Comparison of two extraction methods for determination of propranolol and furosemide in human plasma by mixed-mode chromatography

An isocratic high performance liquid chromatographic method is described for the determination of the beta-adrenergic blocking drug, propranolol, and the diuretic, furosemide, in human plasma. The two compounds and the internal standard were extracted from plasma using a two-step extraction technique. Propranolol and pindolol (internal standard) were first extracted from alkaline plasma into diethyl ether; this was followed by extraction of furosemide into acidified ether: hexane (65:35). The two extracts were then combined and evaporated under nitrogen, and the reconstituted residues were analysed on a C18/SCX reversed-phase/cation exchange column with a mobile phase of acetonitrile: 0.1 M sodium acetate pH 4 (33:67). The drugs and the internal standard were detected by UV absorption at 230 nm. The drugs were also extracted from plasma by a column-switching technique utilizing a ten-port valve. The drug compounds were retained on a C18 pre-column. A comparison of RSD for within-batch (intra-assay) and between-batch (inter-assay) runs for both methods was carried out, the liquid/liquid extraction method giving better recovery values. The calibration graphs were linear from 25-300 ng ml-1 for furosemide and 50-400 ng ml-1 for propranolol. Recovery values were > 90.0% by liquid/liquid extraction and > 76.0% by column switching.

The endocrinology of parturition in the human

Current evidence suggests that oestrogens, progesterone, relaxin, the prostaglandins, and oxytocin are all hormones concerned to a major degree with the onset and maintenance of parturition. Oestrogens, relaxin, and the prostaglandins are particularly involved with cervical ripening, while prostaglandins, progesterone and oxytocin are more involved in regulating myometrial contractility. Catecholamines may also have some regulatory function in relation to uterine contractions. Progesterone dominance during pregnancy is associated with a firm closed cervix, few myometrial gap junctions, low calcium levels in the cells, and a quiescent myometrium. At term, a change in the oestrogen/progesterone balance favours cervical ripening and increased uterine activity. Of particular importance at the level of the muscle cell are changes in the number of oxytocin receptors; a complex interaction between cAMP and phosphoinositide metabolism governs the intracellular level of calcium, thus regulating contractile activity.

Kinetic determination of propranolol in tablets by oxidation with ceric sulphate

A simple and accurate kinetic method for the determination of propranolol has been developed. Cerium(IV) sulphate (0.5 M) is used to oxidize propranolol in 2 M sulphuric acid at room temperature to the ketone form that absorbs light at a lambda max of 525 nm. The fixed-concentration method is used by recording the exact time, t(s), taken for the reaction to reach a fixed absorbance of 0.100. The unknown concentration, c(M), of propranolol is calculated from the equation: l/t = 0 0.000217 + 0.03 c. The method has been applied to the determination of propranolol in proprietary tablets and the results were compared with those obtained by the B.P. and other standard methods.

Direct, simultaneous determination of propranolol and its 4-hydroxy metabolite by liquid chromatography

Propranolol and its active 4-hydroxy metabolite are determined by direct injection of spiked plasma samples onto a protein-coated ODS liquid chromatographic column. The recovery of propranolol and the 4-hydroxy metabolite is essentially quantitative and the reproducibility is good. The reproducibility and simplicity may be superior to the conventional HPLC analyses which include pretreatment, i.e., solvent extraction or deproteinization.

Fetal catecholamines

Experimental data from fetal human and animal research suggest that the fetal sympathoadrenal system, composed of the adrenal medulla, sympathetic neurons, and extra-adrenal chromaffin tissue functions from early fetal life to maintain fetal homeostasis. The extra-adrenal chromaffin tissue undergoes maturation at 9 to 11 weeks of gestation, whereas the adrenal medulla and sympathetic nervous system mature later in fetal life. The fetal catecholamine response to hypoxia, mediated predominantly by norepinephrine, is an important component of the fetal cardiovascular response to hypoxia, i.e., through alpha-receptor stimulation, fetal cardiac output redistribution occurs. Fetal catecholamine secretion in response to substrate availability, through alpha- and beta-receptor stimulation, provide a mechanism by which the fetus can utilize its own substrate stores. Pulmonary beta-receptor stimulation by catecholamines has been demonstrated to increase lecithin synthesis, increase surfactant secretion, and decrease lung fluid production near term. beta-Receptor stimulation has also been demonstrated to have trophic effects on the development of thermogenic brown adipose tissue. Although the exact stimulus for the initiation of parturition in the primate is unknown, fetal catecholamines, through direct myometrial alpha-adrenergic or dopaminergic receptor stimulation and/or through the stimulation of prostaglandin production, have the potential of facilitating the onset of parturition.

Effect of propranolol on fetal tachycardia in diabetic pregnancy

Propranolol was administered during the last 20 days of pregnancy to a diabetic woman because of fetal tachycardia (heart rate approximately 200 beats/min). With a daily dose of 160 mg of propranolol, a fetal heart rat of 120 to 160 beats/min could be achieved. Blood concentration of propranolol was measured in the mother and infant after birth. The level in the neonatal blood was 20 percent of the maternal sample, which is definitely higher than expected from animal experiments. No undersirable effect of propranolol treatment was detected. Postpartum, the infant demonstrated paroxysmal supraventricular tachycardia, and propranolol was again essential in maintaining a normal rate.

Propranolol for the treatment of hypertension in pregnancy

Twenty-five women were treated with propranolol during 26 pregnancies complicated by hypertension. The fetal wastage, which had been 48 per cent before treatment with propranolol was reduced to 15.4 per cent, with one missed abortion and three stillbirths. Of the 22 liveborn infants 2 were small-for-dates but all 22 had Apgar scores of 9 or 10 at five minutes. There were no congenital anomalies in 25 viable infants and none of the 22 liveborn infants had clinical or laboratory evidence of hypoglycaemia. The blood pressure was controlled in 17 of 19 patients taking propranolol alone (40 to 160 mg/day) and in 6 of 7 taking propranolol with diuretics.

High-pressure liquid chromatographic method for the simultaneous quantitative analysis of propranolol and 4-hydroxypropranolol in plasma

A simple and rapid high-pressure liquid chromatographic procedure is reported for the simultaneous quantitative determination of propranolol and 4-hydroxypropranolol in plasma. Following an extraction the samples are chromatographed on a reversed-phase column and the components in the column effluent are detected by fluorescence monitoring. Using 1-ml plasma samples propranolol and 4-hydroxypropranolol concentrations at least as low as 1 ng/ml and 5 ng/ml, respectively, can be quantitated. The reproducibility of the method is satisfactory and no interference from endogenous plasma components or other drugs has been observed. A single plasma sample can be analyzed in approximately 20 min.

Wave-form analysis of intrauterine pressure curves with methods and models developed in cardiac research

With the Hill model of muscle dynamics and a modified cardiac model, a series of computer programs have been generated which permit the description of certain aspects of uterine contractility and uterine function in human parturition. Patterns of labor relating to delivery outcome, dysfunctional uterine activity, and use of drugs are discussed with reference to the parameters measured in the study. Central tendencies among 70 spontaneous and induced labors (6,302 contractions) are presented and discussed. (Am. J. Obstet. Gynecol.

Effect of propranolol infusion on the umbilical and uterine circulations of pregnant sheep

Propranolol was infused intravenously for 60 minutes to five ewes (4 mug per kilogram per minute) or five fetal sheep (10 mug per kilogram per minute). The umbilical blood flow was significantly decreased by 18 per cent from control at 60 minutes with either maternal or fetal propranolol infusion. Uterine blood flow and maternal and fetal mean arterial pressure did not significantly change. Maternal and fetal heart rates decreased 18 and 9 per cent from control, respectively, during maternal propranolol infusion. With propranolol to the fetus, fetal heart rate decreased 15 per cent and maternal heart rate did not change. During all infusion, maternal and fetal arterial pH, PCO2 and PO2 remained within normal physiologic limits.