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Best Practice & Research. Clinical... Mar 2022People with obesity may require induction of labour (IoL) due to a higher incidence of pre-existing comorbidities and pregnancy complications, as well as to prevent... (Review)
Review
People with obesity may require induction of labour (IoL) due to a higher incidence of pre-existing comorbidities and pregnancy complications, as well as to prevent post-term pregnancies and late-term stillbirths. IoL at 39-40 weeks is associated with fewer caesarean births and lower morbidity for the pregnant person and neonate when compared with expectant management. Ensuring the success and safety of IoL in people with obesity requires adherence to evidence-based protocols for the management of labour induction and augmentation. Cervical ripening as well as the latent and active phases of labour in people with obesity may be considerably prolonged, requiring higher cumulative doses of oxytocin. This should be guided by intrauterine pressure catheters and early provision of neuraxial analgesia, where possible. There is insufficient evidence to recommend one method of IoL over another. The need for higher doses of prostaglandins and concurrent agents for cervical ripening should be studied in prospective studies.
Topics: Cervical Ripening; Female; Humans; Infant, Newborn; Labor, Induced; Obesity; Oxytocics; Pregnancy; Prospective Studies
PubMed: 35031244
DOI: 10.1016/j.bpobgyn.2021.12.004 -
American Journal of Obstetrics and... Mar 2024Oxytocin is a reproductive hormone implicated in the process of parturition and widely used during labor. Oxytocin is produced within the supraoptic nucleus and... (Review)
Review
Oxytocin is a reproductive hormone implicated in the process of parturition and widely used during labor. Oxytocin is produced within the supraoptic nucleus and paraventricular nucleus of the hypothalamus and released from the posterior pituitary lobe into the circulation. Oxytocin is released in pulses with increasing frequency and amplitude in the first and second stages of labor, with a few pulses released in the third stage of labor. During labor, the fetus exerts pressure on the cervix of the uterus, which activates a feedforward reflex-the Ferguson reflex-which releases oxytocin. When myometrial contractions activate sympathetic nerves, it decreases oxytocin release. When oxytocin binds to specific myometrial oxytocin receptors, it induces myometrial contractions. High levels of circulating estrogen at term make the receptors more sensitive. In addition, oxytocin stimulates prostaglandin synthesis and release in the decidua and chorioamniotic membranes by activating a specific type of oxytocin receptor. Prostaglandins contribute to cervical ripening and uterine contractility in labor. The oxytocin system in the brain has been implicated in decreasing maternal levels of fear, pain, and stress, and oxytocin release and function during labor are stimulated by a social support. Moreover, studies suggest, but have not yet proven, that labor may be associated with long-term, behavioral and physiological adaptations in the mother and infant, possibly involving epigenetic modulation of oxytocin production and release and the oxytocin receptor. In addition, infusions of synthetic oxytocin are used to induce and augment labor. Oxytocin may be administered according to different dose regimens at increasing rates from 1 to 3 mIU/min to a maximal rate of 36 mIU/min at 15- to 40-minute intervals. The total amount of synthetic oxytocin given during labor can be 5 to 10 IU, but lower and higher amounts of oxytocin may also be given. High-dose infusions of oxytocin may shorten the duration of labor by up to 2 hours compared with no infusion of oxytocin; however, it does not lower the frequency of cesarean delivery. When synthetic oxytocin is administered, the plasma concentration of oxytocin increases in a dose-dependent way: at infusion rates of 20 to 30 mIU/min, plasma oxytocin concentration increases approximately 2- to 3-fold above the basal level. Synthetic oxytocin administered at recommended dose levels is not likely to cross the placenta or maternal blood-brain barrier. Synthetic oxytocin should be administered with caution as high levels may induce tachystole and uterine overstimulation, with potentially negative consequences for the fetus and possibly the mother. Of note, 5 to 10 IU of synthetic oxytocin is often routinely given as an intravenous or intramuscular bolus administration after delivery to induce uterine contractility, which, in turn, induces uterine separation of the placenta and prevents postpartum hemorrhage. Furthermore, it promotes the expulsion of the placenta.
Topics: Pregnancy; Female; Humans; Oxytocin; Receptors, Oxytocin; Peripartum Period; Labor, Obstetric; Oxytocics; Labor, Induced
PubMed: 38462255
DOI: 10.1016/j.ajog.2023.04.011 -
International Journal of Obstetric... Nov 2021Postpartum hemorrhage is a leading cause of maternal morbidity and mortality, and uterine atony is the leading cause of postpartum hemorrhage. Risk factors for uterine... (Review)
Review
Postpartum hemorrhage is a leading cause of maternal morbidity and mortality, and uterine atony is the leading cause of postpartum hemorrhage. Risk factors for uterine atony include induced or augmented labor, preeclampsia, chorio-amnionitis, obesity, multiple gestation, polyhydramnios, and prolonged second stage of labor. Although a risk assessment is recommended for all parturients, many women with uterine atony do not have risk factors, making uterine atony difficult to predict. Oxytocin is the first-line drug for prevention and treatment of uterine atony. It is a routine component of the active management of the third stage of labor. An oxytocin bolus dose as low as 1 IU is sufficient to produce satisfactory uterine tone in almost all women undergoing elective cesarean delivery. However, a higher bolus dose (3 IU) or infusion rate is recommended for women undergoing intrapartum cesarean delivery. Carbetocin, available in many countries, is a synthetic oxytocin analog with a longer duration than oxytocin that allows bolus administration without an infusion. Second line uterotonic agents include ergot alkaloids (ergometrine and methylergonovine) and the prostaglandins, carboprost and misoprostol. These drugs work by a different mechanism to oxytocin and should be administered early for uterine atony refractory to oxytocin. Rigorous studies are lacking, but methylergonovine and carboprost are likely superior to misoprostol. Currently, the choice of second-line agent should be based on their adverse effect profile and patient comorbidities. Surgical and radiologic management of uterine atony includes uterine tamponade using balloon catheters and compression sutures, and percutaneous transcatheter arterial embolization.
Topics: Carboprost; Female; Humans; Misoprostol; Oxytocics; Oxytocin; Postpartum Hemorrhage; Pregnancy; Uterine Inertia
PubMed: 34391025
DOI: 10.1016/j.ijoa.2021.103207 -
The Journal of Maternal-fetal &... Aug 2022Induction of labor is a common obstetric intervention. For women requiring cervical ripening, the current standard practice of inpatient labor induction can be long and...
INTRODUCTION
Induction of labor is a common obstetric intervention. For women requiring cervical ripening, the current standard practice of inpatient labor induction can be long and challenging. Outpatient cervical ripening may be a safe and beneficial option for a select subset of low-risk pregnant women.
METHODS
Electronic databases were searched with specific criteria to select articles for review. The review covered literature on the safety, efficacy and acceptability of outpatient cervical ripening in the low-risk population.
DISCUSSION
Pharmacological and mechanical cervical ripening agents have been trialed in the outpatient setting. Mechanical ripening is safer than pharmacological priming, and there appears to be no disadvantage to offering outpatient catheter balloon cervical ripening to appropriately screened women who require this intervention prior to labor induction. Maternal and midwifery acceptability of outpatient care further support outpatient cervical ripening for women with low-risk pregnancies.
CONCLUSION
The balloon catheter appears to be the optimal method for outpatient cervical ripening, but further prospective studies are required to ensure safety and benefit before it can be routinely offered to low-risk women.
Topics: Cervical Ripening; Delivery, Obstetric; Female; Humans; Labor, Induced; Outpatients; Oxytocics; Pregnancy; Urinary Catheters
PubMed: 32847436
DOI: 10.1080/14767058.2020.1811665 -
Current Opinion in Obstetrics &... Apr 2020Recent evidence supports elective induction of labor after 39 weeks; however, labor induction in patients with an unfavorable cervix, a Bishop score less than 6, may... (Review)
Review
PURPOSE OF REVIEW
Recent evidence supports elective induction of labor after 39 weeks; however, labor induction in patients with an unfavorable cervix, a Bishop score less than 6, may take several days. In this review, we focus on the efficacy and safety of methods of labor induction for the unfavorable cervix.
RECENT FINDINGS
Recent evidence on the use of mechanical cervical preparation with transcervical balloons suggests balloons are the most effective option for decreasing time to delivery in the nulliparous patient. Single and double balloons are equally effective, with a volume of more 30 ml being more effective. The addition of misoprostol or oxytocin concurrently with a balloon further expedites time to delivery.
SUMMARY
Mechanical dilation should be considered when available and technically possible for labor induction in patients with an unfavorable cervix. Misoprostol is an effective adjunct to trans-cervical balloons, further decreasing time to delivery as compared with balloon alone. When misoprostol is contraindicated, oxytocin is a safe, effective, alternative adjunct to trans-cervical balloons. More research is needed to evaluate safe outpatient options, induction methods in the setting of prior cesarean with an unfavorable cervix, and to directly compare misoprostol with oxytocin as adjuncts to transcervical balloons.
Topics: Catheterization; Cervical Ripening; Female; Humans; Labor, Induced; Oxytocics; Pregnancy; Prostaglandins; Randomized Controlled Trials as Topic; Time Factors
PubMed: 32004172
DOI: 10.1097/GCO.0000000000000608 -
Best Practice & Research. Clinical... Nov 2021The mean duration of human pregnancy is 280 days but the range is wide, and "term" has been defined to range from 37 to 42 weeks. In the 18th and 19th centuries, labour... (Review)
Review
The mean duration of human pregnancy is 280 days but the range is wide, and "term" has been defined to range from 37 to 42 weeks. In the 18th and 19th centuries, labour induction was used mainly in cases of pelvic deformity, before the foetus grew too large to be delivered. Induction methods were unreliable until the 20th century, when pituitary extract, and then synthetic oxytocin and prostaglandins, became available. "Disproportion" was the leading indication for induction until the 1950s, when it became clear that prolonged pregnancy was associated with increased perinatal mortality. Pregnancy dating was improved by ultrasound, which also showed that foetal growth slows at term. Induction rates rose during the 1970s, causing public concern about obstetric intervention. In the 21st century, large-scale randomised trials showed that perinatal mortality is lowest at 39-40 weeks, and that induction at that time does not increase the rate of operative delivery.
Topics: Female; Humans; Labor, Induced; Oxytocics; Oxytocin; Perinatal Death; Pregnancy; Pregnancy, Prolonged
PubMed: 34330639
DOI: 10.1016/j.bpobgyn.2021.07.004 -
Lancet (London, England) Dec 2023Oxytocin is effective in reducing labour duration but can be associated with fetal and maternal complications that could potentially be reduced by discontinuing the... (Randomized Controlled Trial)
Randomized Controlled Trial
BACKGROUND
Oxytocin is effective in reducing labour duration but can be associated with fetal and maternal complications that could potentially be reduced by discontinuing the treatment during labour. We aimed to assess the impact of discontinuing oxytocin during active labour on neonatal morbidity.
METHODS
STOPOXY was a multicentre, randomised, open-label, controlled, superiority trial conducted in 21 maternity units in France. Participants who received oxytocin before 4 cm dilation were randomly assigned 1:1 to either discontinuous oxytocin (oxytocin infusion stopped beyond a cervical dilation equal to or greater than 6 cm) or continuous oxytocin (administration of oxytocin continued until delivery). Randomisation was stratified by centre and parity. The primary outcome, neonatal morbidity, was assessed at birth using a composite variable defined by an umbilical arterial pH at birth less than 7·10, a base excess greater than 10 mmol/L, umbilical arterial lactates greater than 7 mmol/L, a 5-min Apgar score less than 7, or admission to the neonatal intensive care unit. Efficacy and safety was assessed in participants who were randomly assigned (excluding those who withdrew consent or were deemed ineligible after randomisation) and had reached a cervical dilation of at least 6 cm. This trial is registered with ClinicalTrials.gov, NCT03991091.
FINDINGS
Of 2459 participants randomly assigned between Jan 13, 2020, and Jan 24, 2022, 2170 were eligible to receive the intervention and were included in the final modified intention-to-treat analysis. The primary outcome occurred for 102 (9·6%) of 1067 participants (95% CI 7·9 to 11·5) in the discontinuous oxytocin group and for 101 (9·2%) of 1103 participants (7·6 to 11·0) in the continuous oxytocin group; absolute difference 0·4% (95% CI -2·1 to 2·9); relative risk 1·0 (95% CI 0·8 to 1·4). There were no clinically significant differences in adverse events between the two groups of the safety population.
INTERPRETATION
Among participants receiving oxytocin in early labour, discontinuing oxytocin when the active phase is reached does not clinically or statistically significantly reduce neonatal morbidity compared with continuous oxytocin.
FUNDING
French Ministry of Health and the Département de la Recherche Clinique et du Développement de l'Assistance Publique-Hôpitaux de Paris.
Topics: Infant, Newborn; Pregnancy; Female; Humans; Oxytocin; Oxytocics; Labor, Induced; Labor, Obstetric; Morbidity
PubMed: 37952548
DOI: 10.1016/S0140-6736(23)01803-2 -
Obstetrics and Gynecology Jun 2021
Topics: Clinical Protocols; Female; Humans; Labor, Induced; Oxytocics; Oxytocin; Perineum; Pregnancy
PubMed: 33957646
DOI: 10.1097/AOG.0000000000004425 -
Best Practice & Research. Clinical... Nov 2021Induction of labour is a two-step process involving cervical ripening and the initiation of uterine contractions, with the goal of achieving vaginal birth. To optimize... (Review)
Review
Induction of labour is a two-step process involving cervical ripening and the initiation of uterine contractions, with the goal of achieving vaginal birth. To optimize the chance of a safe and timely vaginal birth, the process of induction of labour should be evidence based and individualized to the given person and situation. In this study, we lay out a framework for how this should be done, emphasizing on careful clinical assessment and planning, flexibility in the strategy of induction, patience during the ripening and latent phases of labour, and thoughtful consideration regarding changing the strategy if active labour is not initially achieved. The goal of this review is to present the current evidence on this topic in the form of a user-friendly protocol that can be easily adapted to institutional practice.
Topics: Cervical Ripening; Female; Humans; Labor, Induced; Misoprostol; Oxytocics; Pregnancy; Uterine Contraction
PubMed: 34497038
DOI: 10.1016/j.bpobgyn.2021.08.006 -
Revista Brasileira de Ginecologia E... Jun 2023
Topics: Humans; Pregnancy; Female; Misoprostol; Obstetrics; Oxytocics; Gynecology
PubMed: 37494579
DOI: 10.1055/s-0043-1770931