Relationship between prolonged gestation and nifedipine pharmacokinetics in long-term tocolysis.

In this study, we examined the pharmacokinetics of nifedipine and investigated the maternal and foetal background factors that prolong pregnancy in pregnant women undergoing long-term tocolysis. This prospective observational study included 38 pregnant women hospitalised for threatened preterm labour and treated with nifedipine extended-release tablets in combination with an intravenous ritodrine infusion. Maternal plasma nifedipine concentrations were determined using high-performance liquid chromatography. All patients were administered 20 or 40 mg/dose of nifedipine every 6 h at the time of blood sampling. The plasma trough concentration (Ctrough ) was 22.6 ± 17.3 ng/mL, the maximum plasma concentration (Cmax ) was 30.9 ± 15.3 ng/mL and the time to maximum concentration (Tmax ) was 1.70 ± 1.10 h, as determined using noncompartmental analysis (NCA). The area under the curve for drug concentration (AUCtau ) was 152.3 ± 91.8 mg/L・h, and oral clearance (CL/F) was 0.17 ± 0.08 L/h. Using logistic regression analyses, we identified the factors that predicted term delivery from 37 weeks to <42 weeks of gestation. Gestational age at admission and the AUCtau of nifedipine can predict term delivery. The AUCtau of nifedipine is a valuable regulatory predictor of term delivery in pregnant women undergoing long-term tocolysis.

Carvacrol-Loaded Nanoemulsion Promotes Tocolytic and Anti-Dysmenorrhea Effects in Rodents.

INTRODUCTION: Carvacrol is a phenolic constituent of essential oils that has antinociceptive, anti-inflammatory, and antioxidant activities. METHOD: This study aimed to evaluate the in vitro spasmolytic and in vivo anti-dysmenorrhea potential of a nanoemulsion-containing carvacrol (nanoCARV). RESULTS: In isolated rat uterus, nanoCARV reduced spontaneous contractions (pEC50 = 3.91 ± 0.25) and relaxed preparations pre-contracted with oxytocin (pEC50 = 3.78 ± 0.2), carbachol (pEC50 = 4.15 ± 0.4), prostaglandin F2α (pEC50 = 3.00 ± 0.36), and KCl (pEC50 = 3.98 ± 0.32). The investigation of the mechanism of action revealed significant differences (p < 0.05) between the pEC50 values of nanoCARV in the absence or presence of aminophylline or tetraethylammonium. In a primary dysmenorrhea model, treatment with nanoCARV reduced the number of oxytocin-induced abdominal writhes. CONCLUSIONS: These data indicate that the anti-dysmenorrhea effect of nanoCARV may be related to the relaxation of uterine smooth muscle, with participation of the cAMP signaling pathway and potassium channels.

Ritodrine-induced rhabdomyolysis and psychiatric symptoms: a case report and literature review.

BACKGROUND: Ritodrine hydrochloride, a ß2-adrenergic agonist, has been widely used in Asia and Europe to treat preterm labor in pregnant women. It has some typical side effects, such as palpitations, pulmonary edema, and hypokalemia. Here, we report a case of rhabdomyolysis and psychiatric symptoms might be associated with intravenous ritodrine. CASE PRESENTATION: A 32-year-old Chinese primigravida woman who was pregnant with twins by in vitro fertilization-embryo transfer was diagnosed with placenta previa and threatened abortion at 21 gestational weeks (GW). The patient was then treated with ritodrine hydrochloride. The initial dose of ritodrine was 150 µg/min, gradually increasing to 360 µg/min at 235/7 GW and 400 µg/min at 271/7 GW. Magnesium sulfate was added to the ritodrine regimen at 215/7 GW in dosage of 1-2 g/h. Psychiatric symptoms appeared at 245/7, 265/7, and 273/7 GW, manifesting as depression, anxiety, and suicidal tendencies. Severe muscle pain in her limbs and general weakness appeared after six weeks of ritodrine administration, which might have been a sign of rhabdomyolysis resulting from ritodrine administration. After ceasing the administration of ritodrine, the muscle pain and relevant data from laboratory tests on the patient were significantly improved, and her mood was stable. It is worth noting that this is the first time to report psychiatric symptoms may associated with the administration of ritodrine. In addition, we reviewed and analyzed six reported cases of rhabdomyolysis caused by ritodrine. CONCLUSION: Our results suggest that we should pay more attention to the risk of rhabdomyolysis and psychiatric symptoms induced by intravenous ritodrine hydrochloride, especially in patients with a history of neuromuscular disorder, or concomitant use of magnesium sulfate.

Tocolytics for delaying preterm birth: a network meta-analysis (0924).

BACKGROUND: Preterm birth is the leading cause of death in newborns and children. Tocolytic drugs aim to delay preterm birth by suppressing uterine contractions to allow time for administration of corticosteroids for fetal lung maturation, magnesium sulphate for neuroprotection, and transport to a facility with appropriate neonatal care facilities. However, there is still uncertainty about their effectiveness and safety. OBJECTIVES: To estimate relative effectiveness and safety profiles for different classes of tocolytic drugs for delaying preterm birth, and provide rankings of the available drugs. SEARCH METHODS: We searched Cochrane Pregnancy and Childbirth's Trials Register, ClinicalTrials.gov (21 April 2021) and reference lists of retrieved studies. SELECTION CRITERIA: We included all randomised controlled trials assessing effectiveness or adverse effects of tocolytic drugs for delaying preterm birth. We excluded quasi- and non-randomised trials. We evaluated all studies against predefined criteria to judge their trustworthiness. DATA COLLECTION AND ANALYSIS: At least two review authors independently assessed the trials for inclusion and risk of bias, and extracted data. We performed pairwise and network meta-analyses, to determine the relative effects and rankings of all available tocolytics. We used GRADE to rate the certainty of the network meta-analysis effect estimates for each tocolytic versus placebo or no treatment. MAIN RESULTS: This network meta-analysis includes 122 trials (13,697 women) involving six tocolytic classes, combinations of tocolytics, and placebo or no treatment. Most trials included women with threatened preterm birth, singleton pregnancy, from 24 to 34 weeks of gestation. We judged 25 (20%) studies to be at low risk of bias. Overall, certainty in the evidence varied. Relative effects from network meta-analysis suggested that all tocolytics are probably effective in delaying preterm birth compared with placebo or no tocolytic treatment. Betamimetics are possibly effective in delaying preterm birth by 48 hours (risk ratio (RR) 1.12, 95% confidence interval (CI) 1.05 to 1.20; low-certainty evidence), and 7 days (RR 1.14, 95% CI 1.03 to 1.25; low-certainty evidence). COX inhibitors are possibly effective in delaying preterm birth by 48 hours (RR 1.11, 95% CI 1.01 to 1.23; low-certainty evidence). Calcium channel blockers are possibly effective in delaying preterm birth by 48 hours (RR 1.16, 95% CI 1.07 to 1.24; low-certainty evidence), probably effective in delaying preterm birth by 7 days (RR 1.15, 95% CI 1.04 to 1.27; moderate-certainty evidence), and prolong pregnancy by 5 days (0.1 more to 9.2 more; high-certainty evidence). Magnesium sulphate is probably effective in delaying preterm birth by 48 hours (RR 1.12, 95% CI 1.02 to 1.23; moderate-certainty evidence). Oxytocin receptor antagonists are probably effective in delaying preterm birth by 48 hours (RR 1.13, 95% CI 1.05 to 1.22; moderate-certainty evidence), are effective in delaying preterm birth by 7 days (RR 1.18, 95% CI 1.07 to 1.30; high-certainty evidence), and possibly prolong pregnancy by 10 days (95% CI 2.3 more to 16.7 more). Nitric oxide donors are probably effective in delaying preterm birth by 48 hours (RR 1.17, 95% CI 1.05 to 1.31; moderate-certainty evidence), and 7 days (RR 1.18, 95% CI 1.02 to 1.37; moderate-certainty evidence). Combinations of tocolytics are probably effective in delaying preterm birth by 48 hours (RR 1.17, 95% CI 1.07 to 1.27; moderate-certainty evidence), and 7 days (RR 1.19, 95% CI 1.05 to 1.34; moderate-certainty evidence). Nitric oxide donors ranked highest for delaying preterm birth by 48 hours and 7 days, and delay in birth (continuous outcome), followed by calcium channel blockers, oxytocin receptor antagonists and combinations of tocolytics. Betamimetics (RR 14.4, 95% CI 6.11 to 34.1; moderate-certainty evidence), calcium channel blockers (RR 2.96, 95% CI 1.23 to 7.11; moderate-certainty evidence), magnesium sulphate (RR 3.90, 95% CI 1.09 to 13.93; moderate-certainty evidence) and combinations of tocolytics (RR 6.87, 95% CI 2.08 to 22.7; low-certainty evidence) are probably more likely to result in cessation of treatment. Calcium channel blockers possibly reduce the risk of neurodevelopmental morbidity (RR 0.51, 95% CI 0.30 to 0.85; low-certainty evidence), and respiratory morbidity (RR 0.68, 95% CI 0.53 to 0.88; low-certainty evidence), and result in fewer neonates with birthweight less than 2000 g (RR 0.49, 95% CI 0.28 to 0.87; low-certainty evidence). Nitric oxide donors possibly result in neonates with higher birthweight (mean difference (MD) 425.53 g more, 95% CI 224.32 more to 626.74 more; low-certainty evidence), fewer neonates with birthweight less than 2500 g (RR 0.40, 95% CI 0.24 to 0.69; low-certainty evidence), and more advanced gestational age (MD 1.35 weeks more, 95% CI 0.37 more to 2.32 more; low-certainty evidence). Combinations of tocolytics possibly result in fewer neonates with birthweight less than 2500 g (RR 0.74, 95% CI 0.59 to 0.93; low-certainty evidence). In terms of maternal adverse effects, betamimetics probably cause dyspnoea (RR 12.09, 95% CI 4.66 to 31.39; moderate-certainty evidence), palpitations (RR 7.39, 95% CI 3.83 to 14.24; moderate-certainty evidence), vomiting (RR 1.91, 95% CI 1.25 to 2.91; moderate-certainty evidence), possibly headache (RR 1.91, 95% CI 1.07 to 3.42; low-certainty evidence) and tachycardia (RR 3.01, 95% CI 1.17 to 7.71; low-certainty evidence) compared with placebo or no treatment. COX inhibitors possibly cause vomiting (RR 2.54, 95% CI 1.18 to 5.48; low-certainty evidence). Calcium channel blockers (RR 2.59, 95% CI 1.39 to 4.83; low-certainty evidence), and nitric oxide donors probably cause headache (RR 4.20, 95% CI 2.13 to 8.25; moderate-certainty evidence). AUTHORS' CONCLUSIONS: Compared with placebo or no tocolytic treatment, all tocolytic drug classes that we assessed (betamimetics, calcium channel blockers, magnesium sulphate, oxytocin receptor antagonists, nitric oxide donors) and their combinations were probably or possibly effective in delaying preterm birth for 48 hours, and 7 days. Tocolytic drugs were associated with a range of adverse effects (from minor to potentially severe) compared with placebo or no tocolytic treatment, although betamimetics and combination tocolytics were more likely to result in cessation of treatment. The effects of tocolytic use on neonatal outcomes such as neonatal and perinatal mortality, and on safety outcomes such as maternal and neonatal infection were uncertain.

Betamethasone use and risk factors for pulmonary edema during the perinatal period: a single-center retrospective cohort study in Japan.

BACKGROUND: A few studies have reported that maternal administration of antenatal corticosteroids increased the risk of pulmonary edema (PE). However, despite the increasing usage rate of betamethasone as antenatal corticosteroid, maternal administration of betamethasone as a risk factor for PE has not been well studied. This study aimed to evaluate how maternal backgrounds and complications, tocolytic agents, and betamethasone affect the incidence of PE during the perinatal period and determine the risk factor for PE. METHODS: This was a single-center retrospective cohort study in Kurashiki, Japan. The study subjects were patients who had been admitted to our hospital for perinatal management including pregnancy, delivery and puerperium between 2017 and 2020. The primary outcome measure was defined as the incidence of PE during hospitalization. First, in all study subjects, Cox proportional hazards model was used to determine the risk factor for PE during the perinatal period. Next, using propensity score matching, we divided the patients into the betamethasone and betamethasone-free groups and examined the association between betamethasone use and the incidence of PE with Cox proportional hazards model. RESULTS: During the study period, 4919 cases were hospitalized, and there were 16 PE cases (0.3%). In all analyzed subjects, the occurrence of PE was significantly associated with preeclampsia (hazard ratio 16.8, 95% confidence intervals (CI) 5.39-52.7, P < 0.001) and the combined use of the tocolytic agents such as ritodrine hydrochloride and magnesium sulfate, and betamethasone (hazard ratio 11.3, 95% CI 2.66-48.1, P = 0.001). In contrast, after propensity score matching, no statistically significant difference was found between the betamethasone and betamethasone-free groups in the incidence of PE (hazard ratio 3.19, 95% CI 0.67-15.3, P = 0.145). CONCLUSIONS: A combined use of tocolytic agents and antenatal corticosteroids such as betamethasone may be an independent risk factor for PE during the perinatal period. On the other hand, betamethasone use alone may not be associated with the incidence of PE. When tocolytic agents and betamethasone are administrated to pregnant women, it is important to pay attention to the appearance of maternal respiratory symptoms.

Four kinds of tocolytic therapy for preterm delivery: Systematic review and network meta-analysis.

WHAT IS KNOWN AND OBJECTIVE: Premature birth affects more than 15 million infants, as well as mothers and families around the world. With the relaxation of the two-child policy, the problem of premature birth has become relatively prominent in China. According to statistics, China had a birth population of 15.23 million in 2018, with a considerably large number of premature births. This study aims to evaluate the efficacy and safety of tocolysis in the treatment of preterm delivery, provide clinical evidence for medical staff and promote the self-management of patients with premature births. METHODS: Four English databases (PubMed, Embase, Cochrane Library and Web of Science) were retrieved by computer, the retrieval time was from the establishment of each database to November 2021, and the randomized controlled trials for the treatment of preterm delivery were screened according to the pre-set natriuretic exclusion criteria. After literature screening, data selection and risk of bias evaluation were independently conducted by two researchers. R 4.1.1 and Stata 17.0 software were used for statistical analysis. RESULTS AND DISCUSSION: A total of 44 RCTs were included, including 6939 patients. The results of network meta-analysis reveal that in terms of effectiveness, indomethacin was the most effective intervention measure, followed by nifedipine, and the difference was statistically significant; regarding safety, nifedipine was the safest intervention measure, followed by indomethacin, and the difference was statistically significant; and in respect of adverse reactions, ritodrine had the highest probability, and the difference was statistically significant. WHAT IS NEW AND CONCLUSION: Nifedipine may be better for delayed delivery and less likely to produce adverse pregnancy outcomes, followed by indomethacin. Limited by the number and quality of recipient studies, the aforementioned conclusions need to be verified through more high-quality studies. At the same time, the focus should be on patients with twin pregnancy and patients with clinical manifestations of extreme preterm delivery.

The use of calcium channel blockers as tocolytics may adversely affect pregnancy outcomes: a randomized clinical trial.

OBJECTIVES: To investigate the effect of calcium channel blockers in tocolytic therapy on obstetric outcomes. MATERIAL AND METHODS: For our study, as a retrospective case control study, data were obtained from hospital records. During 2018, there were 65 patients hospitalized with a diagnosis of preterm labor and were treated with calcium channel blockers used as tocolytics (nifedipine, nicardipine) and these patients constituted the study group. Pregnant women with systemic disease were excluded from the total of 1552 patients who were followed and who gave birth in 2018. After exclusion to equalize the samples, we chose 65 healthy pregnant women from the remaining 646 healthy pregnancies using a simple random number table and these patients formed the control group. The obstetric and neonatal results of both groups were compared. RESULTS: There was no difference between the groups in terms of birth week, preterm labor rate, low birth weight, and delivery type. While birth weights were significantly lower, the need for neonatal intensive care and the number of infants weighing 2500-3000 g were higher in the study group (p < 0.05). When the results of pregnancies that gave birth at term weeks and were not administered steroids were compared, the birth weight was lower and the number of infants weighing 2500-3000 g was higher in the study group. CONCLUSION: The use of calcium channel blockers in pregnancy may adversely affect birth weight gain and the need for intensive care.

Effects of acute tocolysis using ritodrine hydrochloride on foetal heart rate patterns in intrauterine foetal resuscitation: a retrospective, single-centre observational study.

No consistent recommendations concerning the preferred tocolytic agents for intrauterine foetal resuscitation are available. We evaluated the effects of acute tocolysis (AT) using ritodrine hydrochloride on foetal heart rate (FHR) patterns and neonatal outcomes. We retrospectively analysed the data of patients undergoing emergency caesarean section because of non-reassuring foetal status indicated by foetal scalp electrodes. Patients were classified into AT (ritodrine hydrochloride approximately 500 µg/min) and control groups with 15 and 12 participants, respectively. FHR patterns, Apgar scores, umbilical arterial analysis, and neonatal admission were compared. All participants had FHR category II; decelerations disappeared in all foetuses in the AT group, with no significant difference in neonatal outcomes. The AT group had a higher baseline FHR and lower short-term FHR variability than the control group, indicating foetal autonomic responses. Further studies are needed to clarify the effects of AT on FHR patterns, neonatal outcomes, and foetal and neonatal autonomic responses.Impact statementWhat is already known on this subject? The usefulness of acute tocolysis using ritodrine hydrochloride has been well-documented in several studies; however, such an application often induces side effects, such as maternal tachycardia, palpitations, and tremors.What the results of this study add? The short-term administration of ritodrine hydrochloride eliminated decelerations, with no significant difference in neonatal outcomes in pregnant women with foetal heart rate category II. Meanwhile, there were higher foetal heart rate and lower short-term foetal heart rate variability in pregnant women administered with ritodrine hydrochloride, indicating foetal autonomic responses.What the implications are of these findings for clinical practice and/or further research? Ritodrine hydrochloride administration, even for short-term, appears to be associated with foetal autonomic responses. Further studies with stratification of patient groups based on the severity and aetiology of non-reassuring foetal status, including pregnant women with foetal category III, would elucidate the risk and benefit of acute tocolysis using ritodrine hydrochloride, based on foetal heart rate patterns, neonatal outcomes, and foetal and neonatal autonomic responses.

The Effect of a Short Course of Tocolytic Indomethacin on Urinary Biomarkers in Premature Infants.

OBJECTIVE: The aim of this study was to determine the effects of a 2-day prenatal course of indomethacin on the premature kidney as reflected by serum creatinine and urinary biomarkers. STUDY DESIGN: Urine of infants ≤32 weeks was collected for the first 14 days and analyzed for cystatin C, neutrophil gelatinase-associated lipocalin, osteopontin, ß2 microglobulin, epidermal growth factor, uromodulin, and microalbumin. Bivariate analysis compared serum creatinine and biomarkers of exposed (INDO) and unexposed (CONT) subjects. RESULTS: Fifty-seven infants (35 CONT and 22 INDO) were studied. The cohorts were similar in gestational age, birthweight, race, gender, nephrotoxic medication exposure, and Apgar's scores. CONT had more dopamine exposure and included more pre-eclamptic mothers (p = 0.005). No difference in creatinine-based acute kidney injury or the log transformed mean, maximum, and minimum values of urinary biomarkers was detected. CONCLUSION: Our findings suggest that a short course of tocolytic indomethacin does not result in neonatal acute kidney injury. KEY POINTS: · A short prenatal course of indomethacin does not result in neonatal acute kidney injury (AKI).. · Urinary EGF might have a promising role as a more sensitive biomarker for early detection of AKI in premature infants..

Association between the prolonged use of magnesium sulfate for tocolysis and fracture risk among infants.

ABSTRACT: In 2013, the U.S. Food and Drug Administration issued a safety warning that cautioned against using magnesium sulfate (MgSO4) injections for more than 5 to 7 days to stop preterm delivery due to the bone problems subsequently observed in infants. However, the warning was mainly based on case reports, and further investigation is necessary to determine whether prolonged MgSO4 use increased infant fractures.To evaluate whether prolonged MgSO4 use for tocolysis increased the risk of subsequent fractures among infants.A retrospective population-based cohort study was conducted with a new-user study design using the National Health Insurance Database in Taiwan. We included pregnant women aged between 12 and 55 years old who delivered a live-born singleton. The enrollment period was from January 1, 2012 to December 31, 2014. The exposure group was defined as pregnant women who received MgSO4 injection for >5 days during pregnancy, while those not receiving any tocolytics were the reference group. The outcome was any bone fracture among the infants during the 2-year follow-up period. Propensity score matching and Cox proportional hazards regression models were used to estimate the hazard of fractures. We further studied the effect of MgSO4 treatment with varied dosages and durations of treatment in the sensitivity analyses.Among the 4092 pregnant women in the database, 693 (16.9%) of them were included in the exposure group. The hazard ratio of infant fractures among prolonged MgSO4 users was not significantly different from that of tocolytic nonusers in adjusted models (adjusted hazard ratio (aHR) = 1.48; 95% confidence interval (CI) = 0.59-3.71). A similar lack of significance was found in the sensitivity analyses (aHR = 1.45; 95% CI = 0.40-5.28 for larger treatment dosage; aHR = 2.52; 95% CI = 0.49-12.98 for longer treatment duration).Prolonged MgSO4 tocolysis use did not increase the risk of infant fractures. Our findings reconfirmed the safety of MgSO4 as a tocolytic treatment.

Neonatal rebound hyperkalemia associated with ritodrine alone: a case report.

BACKGROUND: Betamimetics have been used for tocolysis extensively in the past, and one of them, ritodrine is widely used in Japan. Various adverse events have been reported for this agent, including newborn hypoglycemia and hypokalemia, as well as maternal hypokalemia and rebound hyperkalemia; however, cases of neonatal rebound hyperkalemia are not described in the literature. CASE PRESENTATION: A male infant born at 36 weeks of gestation by cesarean section at a local maternity clinic suddenly entered cardiopulmonary arrest with ventricular tachycardia and fibrillation due to hyperkalemia (K+, 8.7 mmol/L). No monitoring, examination of blood electrolyte levels, or infusions had been performed prior to this event. Maternal infusion of ritodrine (maximum dose, 170 µg/min) had been performed for 7 weeks prior to cesarean section. After resuscitation combined with calcium gluconate, the infant died at 4 months old due to serious respiratory failure accompanied by acute lung injury following shock. No cause of hyperkalemia other than rebound hyperkalemia associated with ritodrine was identified. CONCLUSIONS: This case report serves as a warning regarding the potential risk of neonatal rebound hyperkalemia in association with maternal long-term ritodrine administration.

Short-Term Outcomes of Atosiban in the Treatment of Preterm Labour at the Sultan Qaboos University Hospital, Muscat, Oman: A tertiary care experience.

OBJECTIVES: This study aimed to generate baseline evidence regarding the effectiveness of atosiban in delaying delivery by ≥48 hours among pregnant women presenting with threatened preterm labour (TPL). The secondary objective was to assess the relationship between atosiban success and various perinatal factors and neonatal outcomes. METHODS: This retrospective study was conducted between June 2008 and May 2018 at the Sultan Qaboos University Hospital, Muscat, Oman. The medical records of all pregnant women who received atosiban between 24-34 gestational weeks for TPL during this period were reviewed. RESULTS: A total of 159 women were included in the study. Atosiban was successful in delaying delivery by ≥48 hours in 130 cases (81.8%). Approximately half of the women (50.9%) achieved uterine quiescence in <12 hours. Failure to delay delivery by ≥48 hours was significantly lower among women with normal versus abnormal cervical findings (11.1% versus 25.6%; P = 0.023). Only 9.4% of women experienced minor side-effects. Mean birth weight (2,724.55 versus 1,707.59 g; P <0.001) and Apgar scores at 5 minutes (9.66 versus 8.28; P <0.001) were significantly higher among neonates delivered at ≥48 versus <48 hours post-atosiban, whereas the rate of neonatal respiratory distress syndrome was significantly lower (18.4% versus 81.6%; P <0.001). CONCLUSION: Atosiban was highly effective in delaying delivery by ≥48 hours and resulted in few adverse maternal side-effects and neonatal outcomes. To the best of the authors' knowledge, this is the first study conducted in Oman to evaluate the effectiveness of atosiban in preventing preterm labour.

Novel oxytocin receptor antagonists for tocolysis: a systematic review and meta-analysis of the available data on the efficacy, safety, and tolerability of retosiban.

OBJECTIVE: To assess the efficacy, safety, and tolerability of retosiban-a novel tocolytic unavailable in the US-in the management of preterm labor. METHODS: We searched ClinicalTrials.Gov, MEDLINE, PubMed, SCOPUS, Web of Science, and the Cochrane Library for relevant clinical trials using the terms "retosiban" and "preterm labor" through 09/2020. We included all published randomized clinical trials (three) that compared retosiban to placebo for preterm labor, excluding conferences, books, reviews, posters, case reports, and animal studies. We analyzed homogeneous data under the fixed-effects model and heterogeneous data under the random-effects model. RESULTS: We included all randomized clinical trials addressing this topic, which ultimately resulted in three trials with a total of 116 patients. There were no significant differences between retosiban and placebo in births at term (RR = 0.41, p = .02), births ≤7 days from the first study treatment (RR = 0.59, p = .23), or administration of rescue tocolytic (RR = 0.36, p = .07); the maternal adverse events of headache, anemia, constipation, or urinary tract infection (p > .05); or neonatal outcomes of Apgar score at 1 min (p = .88) or 5 min (p = .69), weight (p = .23), head circumference (p = .55), malnutrition (p = .27), hyperbilirubinemia (RR = 0.56, p = .21), jaundice (RR = 1.21, p = .84), respiratory distress (RR = 0.53, p = .49), or tachypnea (RR = 0.40, p = .42). CONCLUSION: With the limited high quality evidence available, retosiban demonstrates no clear benefit over placebo in the management of preterm labor. Nevertheless, its favorable safety profile, oral bioavailability, and novel mechanism of action and the limited number of studies available for review warrant further analysis.

Acute Pulmonary Edema Induced by a Low Dose of Ritodrine Hydrochloride: A Case Report.

OBJECTIVE: Acute pulmonary edema associated with ritodrine hydrochloride is a rare, life-threatening complication, and dose and duration of ritodrine use are closely associated with this pathology. We report a case of acute pulmonary edema associated with short-duration infusion of ritodrine hydrochloride in a patient with pectus excavatum as an underlying factor. CASE REPORT: A 30-year-old healthy pregnant woman was treated with oral ritodrine for tocolysis between 31 and 35 weeks of pregnancy. At 36 weeks of gestation, she went into preterm labor, with premature rupture of the membrane and breech presentation, and received an infusion of ritodrine hydrochloride for a few hours. Although she was normotensive until labor onset, mild hypertension and proteinuria were recognized. Intraoperatively, a funnel-chest deformity was observed, and she developed postoperative pulmonary edema associated with dyspnea and wet cough and confirmed on chest radiography and arterial gas analysis, and recovered with supportive care. CONCLUSION: Small-dose infusion of ritodrine hydrochloride might cause pulmonary edema in patients with underlying medical problems, including pectus excavatum.

Atosiban Combined with Ritodrine for Late Threatened Abortion or Threatened Premature Labor Patients with No Response to Ritodrine: A Clinical Trial.

BACKGROUND Premature labor is an important cause of infant death and long-term disability. This study aimed to explore the safety and effectiveness of combining the tocolytic agents atosiban and ritodrine to extend gestation. MATERIAL AND METHODS The study included 52 patients with late threatened abortion and threatened premature labor between 20°â¸7 and 336⸍7 weeks' gestation who were administrated continuous tocolytic agents for 48 h. Patients were divided into a research group receiving ritodrine combined with atosiban, owing to having no response to ritodrine alone (n=30), and a control group receiving ritodrine alone (n=22). The mean infusion rate and duration of tocolytic administration, gestation extension, pregnancy outcomes, and adverse effects were recorded. Routine blood tests, including C-reactive protein, and cultures for leukorrhea, candida, and mycoplasma were performed before and 1 week after treatment. RESULTS Patients receiving ritodrine with atosiban had a mean gestation extension of 42.53±31.70 days. The extension of gestation of the research group was statistically shorter than that of the control group (P<0.05). The fetal loss rate, newborn birth weight, and Apgar score at 1 min were similar between the 2 groups (all, P>0.05). The research group had a lower incidence of palpitations than the control group (P<0.05). CONCLUSIONS For patients with late threatened abortion or threatened premature labor not controlled with ritodrine alone, ritodrine combined with atosiban extends gestation and improves pregnancy outcomes. For patients with abnormal uterine contractions, routine testing for reproductive tract infection should be performed. When infection is present, anti-infective therapy should be administered.

Noninvasive positive-pressure ventilation in pregnancy to treat acute pulmonary edema induced by tocolytic agents: a case report.

BACKGROUND: We report a case of pulmonary edema induced by tocolytic agents that was successfully managed with noninvasive positive-pressure ventilation (NPPV) and resulted in extended gestation. CASE PRESENTATION: A 36-year-old Japanese pregnant woman received tocolytic therapy with ritodrine hydrochloride, magnesium sulfate, nifedipine, and betamethasone from 28 weeks of gestation. She developed respiratory failure. and her chest X-ray showed enlarged pulmonary vascular shadows. At 29 weeks and 1 day of gestation, she was diagnosed with pulmonary edema induced by tocolytic agents. Because respiratory failure worsened 2 days after ritodrine hydrochloride and magnesium sulfate were stopped, NPPV was initiated. Her respiratory status improved and she was weaned off of NPPV after 3 days. She underwent cesarean section because of breech presentation at 30 weeks and 0 days of gestation due to initiation of labor pains. CONCLUSIONS: NPPV can be safely administered in cases of tocolytic agent-induced pulmonary edema during pregnancy.

A comparative study of transdermal nitroglycerine patch and oral nifedipine in preterm labor.

Background: Currently, the main goal for the use of tocolytic therapy is to delay the birth so as to allow the use of corticosteroids for accelerating fetal lung maturity and maternal transfer to a tertiary care center and thereby reducing neonatal morbidity and mortality. Aims and Objectives: The aims amd objectives were to compare the safety and efficacy of transdermal nitroglycerine patch with oral nifedipine as a tocolytic agent to arrest preterm labor and prevent preterm birth. Materials and Methods: Based on the selection criteria, 50 patients were selected randomly in Group A and Group B. Group A women were given transdermal nitroglycerin patch, which delivered 10 mg Nitroglycerin (NTG) over 24 h and it was applied to the woman's abdomen followed by another patch of 10 mg after 1 h if contractions persisted. After 24 h, it was replaced by a fresh patch. Group B women were given an oral loading dose of nifedipine 20 mg followed by a similar dose if contractions persisted after 1 h. A maintenance dose of 10 mg thrice daily was given if contractions were suppressed. Patients were monitored from the time of admission to the time of discharge. Results: The mean duration of prolongation of pregnancy in Group B (3.68 ± 1.91 days) was significantly more than Group A (2.78 ± 1.39 days). Headache was seen significantly more in Group A (42%) than group B (6%). Tachycardia, hypotension, and palpitation showed no statistically significant difference between them. There was no statistically significant difference in the birth weight of the babies in both the groups. Conclusion: Nifedipine is a safe and effective drug in prolonging preterm labor and has minimal maternal and neonatal side effects.

RésuméContexte: Actuellement, le principal objectif de l'utilisation de la thérapie tocolytique est de retarder la naissance afin de permettre l'utilisation de corticostéroïdes pour accélérer la maturité pulmonaire fœtale et le transfert maternel vers un centre de soins tertiaires et ainsi réduire la morbidité et la mortalité néonatales. Buts et objectifs: Les buts et objectifs étaient de comparer l'innocuité et l'efficacité du timbre transdermique de nitroglycérine avec la nifédipine par voie orale comme agent tocolytique pour arrêter le travail prématuré et prévenir l'accouchement prématuré. Matériel et méthodes: Sur la base des critères de sélection, 50 patientes ont été sélectionnées au hasard dans les groupes A et B.Les femmes du groupe A ont reçu un patch transdermique de nitroglycérine, qui a administré 10 mg de NTG en 24 h et appliqué sur l'abdomen de la femme suivi d'un autre patch de 10 mg après 1 h si les contractions ont persisté. Après 24 h, il a été remplacé par un nouveau patch. Les femmes du groupe B ont reçu une dose de charge orale de 20 mg de nifédipine suivie d'une dose similaire si les contractions persistaient après 1 h. Une dose d'entretien de 10 mg trois fois par jour était administrée si les contractions étaient supprimées. Les patients ont été suivis du moment de l'admission au moment de la sortie. Résultats: La durée moyenne de prolongation de la grossesse dans le groupe B (3,68 ± 1,91 jours) était significativement plus élevée que dans le groupe A (2,78 ± 1,39 jours). Les céphalées étaient significativement plus observées dans le groupe A (42%) que dans le groupe B (6%). La tachycardie, l'hypotension et les palpitations n'ont montré aucune différence statistiquement significative entre elles. Il n'y avait pas de différence statistiquement significative du poids à la naissance des bébés dans les deux groupes. Conclusion: La nifédipine est un médicament sûr et efficace pour prolonger le travail prématuré et a des effets secondaires maternels et néonatals minimes.

The safety of ritodrine hydrochloride: Adverse effects on fetuses and newborns.

Prematurely born infants face unique risks, and the treatment of imminent preterm birth is thus an important part of perinatal care. Ritodrine hydrochloride (Rito) is widely used as a therapeutic agent to treat imminent preterm birth in Japan. Following assessment of the risks and benefits of short-acting ß-agonists, including Rito, in Europe, however, the use of Rito has begun to be questioned. Thus, in this study we investigated the safety of Rito in the treatment of imminent preterm birth, with a particular focus on the adverse effects (AEs) on fetuses and newborn infants. Using the Pharmaceuticals and Medical Devices Agency of Japan's Japanese Adverse Drug Event Report (JADER) database, the AEs on fetuses and newborns caused by oral and injected Rito were extracted and analyzed. The reported odds ratios for oral Rito were significantly higher for fetal tachycardia, fetal bradycardia, neonatal hypoglycemia, and neonatal heart failure than for other drugs. The reported odds ratios for Rito injection were significantly higher for fetal tachycardia and neonatal hypoglycemia than for other drugs. Oral drugs had more adverse effect reports than injectable drugs.

In utero exposure to ritodrine during pregnancy and risk of autism in their offspring until 8 years of age.

Beta-2 adrenergic receptor (B2AR) agonists, used as asthma treatments and tocolytics during pregnancy, have recently been reported to be associated with autism in their offspring. However, the particular link between autism and ritodrine, a common type of B2AR agonist used solely as tocolytics, has never been substantiated with any nationwide database. Thus, we aimed to examine the association between in utero exposure of ritodrine and the risk of autism in their offspring using a national database. This population-based cohort study was conducted by merging the Korea National Health Insurance claims database and National Health Screening Program for Infants and Children database. These databases included all women who had delivered singleton between January 2007 and December 2008 in Korea. Out of the total 770,016 mothers, 30,959 (4.02%) were exposed to ritodrine during pregnancy, and 5583 (0.73%) of their children were identified as having autism, defined until 8 years of age. According to our analysis, the overall cumulative incidence of autism up to 8 years was 1.37% in ritodrine exposure group and 0.70% in ritodrine non-exposure group (p < 0.05, log-rank test). By Cox proportional hazard analysis, use of ritodrine in preterm birth was associated with significantly higher hazard of autism [adjusted hazard ratio: 1.23, 95% CI 1.04-1.47], after adjusting for confounding variables including maternal age, parity, cesarean section, preterm labor, steroid use, birth weight, gender, and preeclampsia. Thus, in utero exposure to ritodrine was associated with an increased risk of autism in their offspring.

Antenatal magnesium sulfate and intestinal morbidities in preterm infants with extremely low gestational age.

BACKGROUND: Antenatal magnesium sulfate is widely used as a tocolytic, for maternal seizures, and for seizure prophylaxis in preeclampsia. Recent studies have suggested that antenatal magnesium sulfate use is associated with favorable neurodevelopmental outcomes in preterm infants. However, there are concerns regarding the effects of antenatal magnesium sulfate on neonates, especially regarding gastrointestinal morbidities. This study aims to explore the effects of antenatal magnesium sulfate on intestinal morbidities requiring surgery in preterm infants. METHODS: This was a retrospective cohort study of 181 preterm infants who were born at less than 28 weeks of gestational age. Subjects were categorized as infants exposed to antenatal magnesium sulfate and those not exposed to antenatal magnesium sulfate. RESULTS: Antenatal magnesium sulfate was associated with a decreased risk of surgical conditions of the intestine (OR 0.393, 95% CI 0.170-0.905). The multivariate analysis showed that the duration of antenatal magnesium sulfate use was associated with surgical conditions of the intestine (adjusted OR 0.766, 95% CI 0.589-0.997). In the <26 weeks of gestational age subgroup, the use of antenatal magnesium sulfate was significantly associated with decreased intestinal morbidities requiring surgery (adjusted OR 0.234, 95% CI 0.060-0.922). CONCLUSION: Antenatal magnesium sulfate use appears to have a protective effect on intestinal morbidities requiring surgery in preterm infants in a duration-dependent manner. Association of antenatal magnesium sulfate use and decreased intestinal morbidities requiring surgery was more distinct in preterm infants <26 weeks of gestational age.