Induction of Labor Resources

More than 22% of all gravid women undergo induction of labor in the United States, and the overall rate of induction of labor in the US has more than doubled since 1990 to 225 per 1,000 live births in 2006 (1). The goal of induction of labor is to achieve vaginal delivery by stimulating uterine contractions before the spontaneous onset of labor. Generally, induction of labor has merit as a therapeutic option when the benefits of expeditious delivery outweigh the risks of continuing the pregnancy. The benefits of labor induction must be weighed against the potential maternal and fetal risks associated with this procedure (2). The purpose of this document is to review current methods for cervical ripening and induction of labor and to summarize the effectiveness of these approaches based on appropriately conducted outcomes-based research. These practice guidelines classify the indications for and contraindications to induction of labor, describe the various agents used for cervical ripening, cite methods used to induce labor and outline the requirements for the safe clinical use of the various methods of inducing labor.

The goal of induction of labor is to achieve vaginal delivery by stimulating uterine contractions before the spontaneous onset of labor. According to the National Center for Health Statistics, the overall rate of induction of labor in the United States has increased from 90 per 1,000 births in 1989 to 184 per 1,000 live births in 1997. Generally, induction of labor has merit as a therapeutic option when the benefits of expeditious delivery outweigh the risks of continuing the pregnancy. The benefits of labor induction must be weighed against the potential maternal or fetal risks associated with this procedure. The purpose of this bulletin is to review current methods for cervical ripening and induction of labor and to summarize the effectiveness of these approaches based on appropriately conducted outcomes-based research. These practice guidelines classify the indications for and contraindications to induction of labor, describe the various agents used for cervical ripening, cite methods used to induce labor and outline the requirements for the safe clinical use of the various methods of inducing labor.

OBJECTIVE: The risk of neonatal morbidity with delivery  39 weeks (wks) is reduced by prior confirmation of fetal lung maturity (FLM). We assessed whether the risk is reduced to levels obtained with delivery at 39-40 wks. STUDY DESIGN: Retrospective cohort study of women delivered at 36-38 wks after positive FLM or at 39-40 wks at our center from ’99-’08.FLMwas positive if phosphatidyl glycerol was present or if L/S ratio
2 (non-diabetics) or
3.5 (diabetics). Multiples and conditions suggesting fetal compromise (major congenital anomalies, cord prolapse, non-reassuring antepartum testing, abruption and oligohydramnios) were excluded. The primary outcome was a composite of perinatal death and neonatal morbidities including those in the table. We also compared neonatal ICU (NICU) admission and hospital stay. RESULTS: 442 delivered at 36-38 wks after positive FLM and 12,881 delivered at 39-40 wks. Mean gestational age and birth weight were 37.2 vs. 39.8 wks and 3115 vs. 3360 g, respectively; both p0.001. Compared to births at 39-40 wks, morbidities, NICU admission and prolonged hospital stay increased with earlier birth after positive FLM and remained so after adjusting for differences in mode of delivery, diabetes, hypertension, age, parity, ethnicity and quality of dating (Table). Risks of bronchopulmonary dysplasia, persistent pulmonary hypertension, surfactant use, hyperbilirubinemia and feeding difficulties were also significantly higher with FLM and delivery39 wks. Risks of perinatal death and seizures were similar. CONCLUSION: Delivery before 39 wks after confirmed FLM is associated with increased neonatal morbidity compared to 39-40 wks, suggesting that purely elective delivery before 39 wks even after positive FLM should be avoided.

OBJECTIVE: No studies exist that have examined the effectiveness of different approaches to a reduction in elective early term deliveries or the effect of such policies on newborn intensive care admissions and stillbirth rates. STUDY DESIGN: We conducted a retrospective cohort study of prospectively collected data and examined outcomes in 27 hospitals before and after implementation of 1 of 3 strategies for the reduction of elective early term deliveries. RESULTS: Elective early term delivery was reduced from 9.6-4.3% of deliveries, and the rate of term neonatal intensive care admissions fell by 16%. We observed no increase in still births. The greatest improvement was seen when elective deliveries at
39 weeks were not allowed by hospital personnel. CONCLUSION: Physician education and the adoption of policies backed only by peer review are less effective than “hard stop” hospital policies to prevent this practice. A 5% rate of elective early term delivery would be reasonable as a national quality benchmark.

OBJECTIVE: The aim of this study was to determine gestational age specific, adjusted infant mortality rates for Ohio. STUDY DESIGN: Using a retrospective cohort design, all births and infant deaths from 2003–2005 were included in multivariable regression analyses. Variations in cause and timing of infant death were determined. RESULTS: Compared with births at 39 or 40 weeks, adjusted likelihood of infant death increased progressively between 38–32 weeks’ gestational age. At later gestational ages, death was more likely caused by sudden infant death syndrome or intentional injury compared with congenital malformations and asphyxia or cerebral palsy at earlier gestational ages. Less mature infants tended to die earlier. CONCLUSION: The current study confirms for Ohio and extends the findings of others that infant mortality risk is increased for births at late preterm and near-term gestational ages. Decisions to deliver before 39 weeks should consider increased likelihood of infant death that may be unrelated to fetal malformations or maternal illness.

OBJECTIVE: We sought to reduce scheduled births between 360/7-386/7 weeks that lack appropriate medical indication. STUDY DESIGN: Twenty Ohio maternity hospitals collected baseline data for 60 days and then selected locally appropriate Institute for Healthcare Improvement Breakthrough Series interventions to reduce the incidence of scheduled births. Deidentified birth data were analyzed centrally. Rates of scheduled births without a documented indication, birth certificate data, and implementation issues were shared regularly among sites. RESULTS: The rate of scheduled births between 360/7-386/7 weeks without a documented medical indication declined from 25% to
5% (P
.05) in participating hospitals. Birth certificate data showed inductions without an indication declined from a mean of 13% to 8% (P
.0027). Dating criteria were documented in 99% of charts. CONCLUSION: A statewide quality collaborative was associated with fewer scheduled births lacking a documented medical indication.

Term birth (37-41 weeks of gestation) has previously been considered a homogeneous group to which risks associated with preterm (less than 37 weeks of gestation) and post-term births (42 weeks of gestation and beyond) are compared. An examination of the history behind the definition of term birth reveals that it was determined somewhat arbitrarily. There is a growing body of evidence suggesting that significant differences exist in the outcomes of infants delivered within this 5-week interval. We focus attention on a subcategory of term births called "early term," from 37 0/7 to 38 6/7 weeks of gestation, because there are increasing data that these births have increased mortality and neonatal morbidity as compared with neonates born later at term. The designation "term" carries with it significant clinical implications with respect to the management of pregnancy complications as well as the timing of both elective and indicated delivery. Management of pregnancies should clearly be guided by data derived from gestational age-specific studies. We suggest adoption of this new subcategory of term births (early term births), and call on epidemiologists, clinicians, and researchers to collect data specific to the varying intervals of term birth to provide new insights and strategies for improving birth outcomes.

OBJECTIVE: To determine factors and outcomes associated with elective medical induction of labor as compared with spontaneous labor in low-risk women.
STUDY DESIGN: Using a birth certificate database including 11,849 low-risk, laboring women, univariate and multiple logistic regression was used to evaluate demographic and obstetric factors associated with elective labor induction. Low risk was defined as singleton, vertex, 37-41 weeks' gestation, no prior cesarean section, and no presenting medical/obstetric diagnoses considered indications for cesarean or induction. Adverse neonatal outcome was defined as 1- or 5-minute Apgar score < 7, neonatal intensive care unit admission or respiratory distress. Spontaneously laboring women (n = 10,608) were compared with women who underwent induced labor for no apparent medical/obstetric reason (n = 1,241). Interventions and outcomes during and after labor induction were adjusted for relevant associated variables.
RESULTS: Odds ratios for epidural anesthesia, cesarean delivery and diagnoses of nonreassuring fetal heart rate patterns were independently increased following elective induction; odds ratios for cephalopelvic disproportion, instrumental delivery and adverse neonatal outcome were not. Maternal length of stay was 0.34 days longer with induction than with spontaneous labor (p < 0.0001). Slightly more induced labors ended before midnight.
CONCLUSION: As compared with spontaneous labor, elective labor induction is independently associated with more intrapartum interventions, more cesarean deliveries and longer maternal length of stay. Neonatal outcome is unaffected.

BACKGROUND: Labor induction rates in the United States rose from 9.0 percent in 1989 to 20.5 percent in 2001, but reasons for the increase are poorly defined. A birth database from a region of upstate New York, including 31,352 deliveries from 1998 through 1999, was used to determine the degree of variation of labor induction rates among hospitals and practitioners.
METHODS: Total and elective labor induction rates were calculated for 16 hospitals and individual staff, and then evaluated using chi-square testing and regression.
RESULTS: Using all laboring women as the denominator, the regional labor induction rate was 20.8 percent; of these inductions, 25 percent had no apparent medical indication. Total induction rates and percent of elective inductions that were elective varied significantly among hospitals (10%-39% and 12%-55%, respectively, p<0.0001) and among practitioners within hospitals (7%-48% and 3%-76%, respectively, p<0.0001). Hospitals varied in size, risk status, and cesarean section rates, but these factors did not correlate with induction rates.
CONCLUSIONS: Labor induction rates are highly variable among and within hospitals. Delivery volume, population risk status, and differences in cesarean section rates did not explain this variation.

Abstract: The frequency of labor induction has increased significantly in recent years. Although medically indicated inductions comprise a portion of this increase, elective inductions have increased in frequency as well. Given that elective inductions, by definition, provide no benefit from a strictly medical standpoint, it is particularly important to evaluate whether women who undergo these inductions incur greater risks than those who labor spontaneously. This article will assess whether elective inductions are associated with changes in pregnancy outcomes, and evaluate how these associations are influenced by parity and cervical ripeness. Key words: elective labor induction, cesarean, pregnancy outcomes

OBJECTIVE: To investigate the cost-effectiveness of elective induction of labor at 41 weeks in nulliparous women. STUDY DESIGN: A decision analytic model comparing induction of labor at 41 weeks vs expectant management with antenatal testing until 42 weeks in nulliparas was designed. Baseline assumptions were derived from the literature as well as from analysis of the National Birth Cohort dataset and included an intrauterine fetal demise rate of 0.12% in the 41st week and a cesarean rate of 27% in women induced at 41 weeks. One-way and multiway sensitivity analyses were conducted to examine the robustness of the findings. RESULTS: Compared with expectant management, induction of labor is cost-effective with an incremental cost of $10,945 per quality-adjusted life year gained. Induction of labor at 41 weeks also resulted in a lower rate of adverse obstetric outcomes, including neonatal demise, shoulder dystocia, meconium aspiration syndrome, and severe perineal lacerations. CONCLUSION: Elective induction of labor at 41 weeks is cost-effective and improves outcomes.

Background: Previous studies have demonstrated an association between preterm delivery and increased risk of special educational need (SEN). The aim of our study was to examine the risk of SEN across the full range of gestation. Methods and Findings: We conducted a population-based, retrospective study by linking school census data on the 407,503 eligible school-aged children resident in 19 Scottish Local Authority areas (total population 3.8 million) to their routine birth data. SEN was recorded in 17,784 (4.9%) children; 1,565 (8.4%) of those born preterm and 16,219 (4.7%) of those born at term. The risk of SEN increased across the whole range of gestation from 40 to 24 wk: 37–39 wk adjusted odds ratio (OR) 1.16, 95% confidence interval (CI) 1.12–1.20; 33–36 wk adjusted OR 1.53, 95% CI 1.43–1.63; 28–32 wk adjusted OR 2.66, 95% CI 2.38–2.97; 24–27 wk adjusted OR 6.92, 95% CI 5.58–8.58. There was no interaction between elective versus spontaneous delivery. Overall, gestation at delivery accounted for 10% of the adjusted population attributable fraction of SEN. Because of their high frequency, early term deliveries (37–39 wk) accounted for 5.5% of cases of SEN compared with preterm deliveries (,37 wk), which accounted for only 3.6% of cases. Conclusions: Gestation at delivery had a strong, dose-dependent relationship with SEN that was apparent across the whole range of gestation. Because early term delivery is more common than preterm delivery, the former accounts for a higher percentage of SEN cases. Our findings have important implications for clinical practice in relation to the timing of elective delivery.

OBJECTIVE: The purpose of this investigation was to examine the economic impact of performing elective repeat cesarean during 37 or 38 weeks of gestation relative to the American College of Obstetricians and Gynecologists recommendation of a 39-week delivery. STUDY DESIGN: Decision analysis modeling was used to estimate economic outcomes for a hypothetical cohort of neonates using data from the Eunice Kennedy Shriver National Institute of Child Health and Human Development Maternal-Fetal Medicine Units Network study of “Timing of Elective Repeat Cesarean Delivery at Term and Neonatal Outcomes.” Costs and charges were estimated using the Florida Healthcare Cost and Utilization Project. RESULTS: A total of 82,541 deliveries occurring between 37-39 completed weeks of gestation were analyzed for the incidence of adverse outcomes and their hospital costs and charges. The model demonstrated increased costs through increasing adverse outcomes among elective repeat cesarean deliveries performed
39 weeks of gestation. CONCLUSION: Our findings suggest that there are benefits to waiting until 39 weeks of gestation to perform an elective repeat cesarean delivery.