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Inducing labor at 41 weeks’ gestation for women with low-risk pregnancies was associated with a 1.4% lower risk of adverse perinatal outcomes, compared with expectant management until 42 weeks, according to results from a randomized, controlled noninferiority trial.
“As with every intervention in the natural birth process, the decision to induce labour must be made with caution, as the expected benefits should outweigh possible adverse effects for both mother and child,” wrote Judit K.J. Keulen, of the department of obstetrics and gynecology at Amsterdam University Medical Center, and her colleagues. “The results of our study should be used to inform women approaching a gestational age of 41 weeks, so they can weigh the respective outcomes and decide whether to be induced at 41 weeks or to continue pregnancy until 42 weeks.”
Ms. Keulen and her colleagues randomized 1,801 women from 123 primary care midwifery practices and 45 hospitals across the Netherlands to receive induction (n = 900) at 41 weeks or expectant management (n = 901) at 42 weeks between 2012 and 2016. The investigators used a composite of perinatal mortality measures, which included Apgar score less than 7 at 5 minutes, arterial pH less than 7.05, meconium aspiration syndrome, neonatal ICU admission, intracranial hemorrhage, and/or brachial plexus injury.
Overall, there were 15 adverse perinatal outcomes in the induction group (1.7%) and 28 adverse outcomes in the expectant management group (3.1%; absolute risk difference, −1.4%). A lower number of infants (n = 11; 1.2%) in the induction group had an Apgar score less than 7 at 5 minutes, compared with infants (n = 23; 2.6%) in the expectant management group (relative risk, 0.48), and there were zero infants and 3 infants (RR, 0.3%) in the induction and expectant management groups, respectively, who had an Apgar score less than 4 at 5 minutes.
Three (0.3%) infants in the induction group and 8 (0.9%) infants in the expectant management group were admitted to the NICU (RR, 0.38). There was one (0.1%) case of fetal death in the induction group and two (0.2%) cases in the expectant management group, but there were no neonatal deaths in either group. With regard to composite adverse maternal outcomes, there were no significant differences between the induction group (n = 122; 14%) and the expectant management group (n = 102; 11%) and both groups had the same number of cesarean sections (n = 97; 11%).
The investigators noted several limitations, such as the noninferiority study design, use of composite adverse perinatal outcome, and lack of stratification by parity that led to an imbalance between the induction and expectant management groups.
“If the composite outcome is interpreted straightforwardly, there is a small benefit of induction at 41 weeks that could justify standard induction at 41 weeks,” Ms. Keulen and colleagues wrote.
“It could be argued, however, that a change of policy to earlier induction, concerning roughly one-fifth of all women with a singleton pregnancy, is too rigorous in light of the relatively low incidence of perinatal mortality, gestational age associated NICU admission, and Apgar score less than 4 at 5 minutes as indicator for encephalopathy,” they added. “This could justify expectant management if women want to avoid induction.”
This study was supported by a grant from the Netherlands Organisation for Health Research and Development ZonMw. Dr. Ben Willem Mol reported a practitioner fellowship with the National Health and Medical Research Council and is a consultant for ObsEva, Merck, and Guerbet. The other authors reported no relevant conflicts of interest.
SOURCE: Keulen JKJ et al. BMJ. 2019 Feb 20. doi: 10.1136/bmj.l344.
In the United States, the current guidelines state that you should consider induction of labor between 41 0/7 and 41 6/7 weeks of gestation and recommend induction between 42 0/7 and 42 6/7 weeks. This study demonstrates that there is a high rate of spontaneous labor among women who are managed with expectant management. Of the women randomized to the expectant management group, only 19% had not gone into labor by 42 weeks and thus, ultimately required induction.
In addition, there is only a 2-day difference in the gestational age of delivery between the induction and expectant management groups. The difference of 2 days does not change the rate of cesarean section or meconium aspiration system. There was a decrease in the rate of the composite neonatal outcome with induction which was mainly related to Apgar less than 7 at 5 minutes. Other significant neonatal outcomes were very rare in the study population (3 vs. 8 neonatal ICU admissions and 0 vs. 2 meconium aspiration).
However, arterial pH, a common marker of adverse neonatal outcomes, was not collected in 70% of the individuals enrolled this study. The rare rate of neonatal complications may reflect the relatively homogenous (about 86% white) and healthy population (about 11% of body mass index greater than or equal to 30).
Further, the lack of difference must be looked at with some caution as the rate of cesarean sections in the study population (11%) is much lower than the cesarean section rate in the United States of 32%. The absolute number of neonates with meconium aspiration system is very low in the study (0.2% for expectant management and none with induction). Previous studies on this subject have demonstrated rates 10-fold higher than in this current study.
In a related editorial, Kenyon et al. are correct in noting that by excluding Apgar scores, the composite adverse neonatal outcome loses its statistical significance (BMJ 2019 Feb 20. doi: 10.1136/bmj.l681). But, the study did not routinely collect arterial pH, which could be an objective measure of neonatal acidemia; thus, Apgar less than 7 at 5 minutes has to remain, as it is associated with neonatal acidemia. Induction should be part of the decision making for patients who are approaching post term. While an induction may alter a birth experience, some individuals opt for this method as evident by 616 individuals who refused enrollment because they desired induction at 41 weeks or the 87 individuals in the expectant management group who desired induction prior to 42 weeks. Thus, this study allows the clinician to provide counseling about the patient’s desires for management of their pregnancy with more information about neonatal outcomes with both expectant management and induction.
This trial, as well as the ARRIVE trial, have studied the effects of induction on a composite neonatal outcome. Both studies note statistical significance with the composite outcome but secondary to rare outcomes, statistical significance is not demonstrated when you look at each individual outcome. The study by Keulen et al. may help guide clinicians in counseling patients about the timing of their induction at late term. In the low-risk patient, these findings may help guide in the timing of induction.
Sarah D. Crimmins, DO, is an assistant professor of obstetrics, gynecology, and reproductive sciences at the University of Maryland, Baltimore, and specializes in maternal-fetal medicine. She was asked to comment on the article by Keulen et al. Dr. Crimmins reported having no conflicts of interest.
In the United States, the current guidelines state that you should consider induction of labor between 41 0/7 and 41 6/7 weeks of gestation and recommend induction between 42 0/7 and 42 6/7 weeks. This study demonstrates that there is a high rate of spontaneous labor among women who are managed with expectant management. Of the women randomized to the expectant management group, only 19% had not gone into labor by 42 weeks and thus, ultimately required induction.
In addition, there is only a 2-day difference in the gestational age of delivery between the induction and expectant management groups. The difference of 2 days does not change the rate of cesarean section or meconium aspiration system. There was a decrease in the rate of the composite neonatal outcome with induction which was mainly related to Apgar less than 7 at 5 minutes. Other significant neonatal outcomes were very rare in the study population (3 vs. 8 neonatal ICU admissions and 0 vs. 2 meconium aspiration).
However, arterial pH, a common marker of adverse neonatal outcomes, was not collected in 70% of the individuals enrolled this study. The rare rate of neonatal complications may reflect the relatively homogenous (about 86% white) and healthy population (about 11% of body mass index greater than or equal to 30).
Further, the lack of difference must be looked at with some caution as the rate of cesarean sections in the study population (11%) is much lower than the cesarean section rate in the United States of 32%. The absolute number of neonates with meconium aspiration system is very low in the study (0.2% for expectant management and none with induction). Previous studies on this subject have demonstrated rates 10-fold higher than in this current study.
In a related editorial, Kenyon et al. are correct in noting that by excluding Apgar scores, the composite adverse neonatal outcome loses its statistical significance (BMJ 2019 Feb 20. doi: 10.1136/bmj.l681). But, the study did not routinely collect arterial pH, which could be an objective measure of neonatal acidemia; thus, Apgar less than 7 at 5 minutes has to remain, as it is associated with neonatal acidemia. Induction should be part of the decision making for patients who are approaching post term. While an induction may alter a birth experience, some individuals opt for this method as evident by 616 individuals who refused enrollment because they desired induction at 41 weeks or the 87 individuals in the expectant management group who desired induction prior to 42 weeks. Thus, this study allows the clinician to provide counseling about the patient’s desires for management of their pregnancy with more information about neonatal outcomes with both expectant management and induction.
This trial, as well as the ARRIVE trial, have studied the effects of induction on a composite neonatal outcome. Both studies note statistical significance with the composite outcome but secondary to rare outcomes, statistical significance is not demonstrated when you look at each individual outcome. The study by Keulen et al. may help guide clinicians in counseling patients about the timing of their induction at late term. In the low-risk patient, these findings may help guide in the timing of induction.
Sarah D. Crimmins, DO, is an assistant professor of obstetrics, gynecology, and reproductive sciences at the University of Maryland, Baltimore, and specializes in maternal-fetal medicine. She was asked to comment on the article by Keulen et al. Dr. Crimmins reported having no conflicts of interest.
In the United States, the current guidelines state that you should consider induction of labor between 41 0/7 and 41 6/7 weeks of gestation and recommend induction between 42 0/7 and 42 6/7 weeks. This study demonstrates that there is a high rate of spontaneous labor among women who are managed with expectant management. Of the women randomized to the expectant management group, only 19% had not gone into labor by 42 weeks and thus, ultimately required induction.
In addition, there is only a 2-day difference in the gestational age of delivery between the induction and expectant management groups. The difference of 2 days does not change the rate of cesarean section or meconium aspiration system. There was a decrease in the rate of the composite neonatal outcome with induction which was mainly related to Apgar less than 7 at 5 minutes. Other significant neonatal outcomes were very rare in the study population (3 vs. 8 neonatal ICU admissions and 0 vs. 2 meconium aspiration).
However, arterial pH, a common marker of adverse neonatal outcomes, was not collected in 70% of the individuals enrolled this study. The rare rate of neonatal complications may reflect the relatively homogenous (about 86% white) and healthy population (about 11% of body mass index greater than or equal to 30).
Further, the lack of difference must be looked at with some caution as the rate of cesarean sections in the study population (11%) is much lower than the cesarean section rate in the United States of 32%. The absolute number of neonates with meconium aspiration system is very low in the study (0.2% for expectant management and none with induction). Previous studies on this subject have demonstrated rates 10-fold higher than in this current study.
In a related editorial, Kenyon et al. are correct in noting that by excluding Apgar scores, the composite adverse neonatal outcome loses its statistical significance (BMJ 2019 Feb 20. doi: 10.1136/bmj.l681). But, the study did not routinely collect arterial pH, which could be an objective measure of neonatal acidemia; thus, Apgar less than 7 at 5 minutes has to remain, as it is associated with neonatal acidemia. Induction should be part of the decision making for patients who are approaching post term. While an induction may alter a birth experience, some individuals opt for this method as evident by 616 individuals who refused enrollment because they desired induction at 41 weeks or the 87 individuals in the expectant management group who desired induction prior to 42 weeks. Thus, this study allows the clinician to provide counseling about the patient’s desires for management of their pregnancy with more information about neonatal outcomes with both expectant management and induction.
This trial, as well as the ARRIVE trial, have studied the effects of induction on a composite neonatal outcome. Both studies note statistical significance with the composite outcome but secondary to rare outcomes, statistical significance is not demonstrated when you look at each individual outcome. The study by Keulen et al. may help guide clinicians in counseling patients about the timing of their induction at late term. In the low-risk patient, these findings may help guide in the timing of induction.
Sarah D. Crimmins, DO, is an assistant professor of obstetrics, gynecology, and reproductive sciences at the University of Maryland, Baltimore, and specializes in maternal-fetal medicine. She was asked to comment on the article by Keulen et al. Dr. Crimmins reported having no conflicts of interest.
Inducing labor at 41 weeks’ gestation for women with low-risk pregnancies was associated with a 1.4% lower risk of adverse perinatal outcomes, compared with expectant management until 42 weeks, according to results from a randomized, controlled noninferiority trial.
“As with every intervention in the natural birth process, the decision to induce labour must be made with caution, as the expected benefits should outweigh possible adverse effects for both mother and child,” wrote Judit K.J. Keulen, of the department of obstetrics and gynecology at Amsterdam University Medical Center, and her colleagues. “The results of our study should be used to inform women approaching a gestational age of 41 weeks, so they can weigh the respective outcomes and decide whether to be induced at 41 weeks or to continue pregnancy until 42 weeks.”
Ms. Keulen and her colleagues randomized 1,801 women from 123 primary care midwifery practices and 45 hospitals across the Netherlands to receive induction (n = 900) at 41 weeks or expectant management (n = 901) at 42 weeks between 2012 and 2016. The investigators used a composite of perinatal mortality measures, which included Apgar score less than 7 at 5 minutes, arterial pH less than 7.05, meconium aspiration syndrome, neonatal ICU admission, intracranial hemorrhage, and/or brachial plexus injury.
Overall, there were 15 adverse perinatal outcomes in the induction group (1.7%) and 28 adverse outcomes in the expectant management group (3.1%; absolute risk difference, −1.4%). A lower number of infants (n = 11; 1.2%) in the induction group had an Apgar score less than 7 at 5 minutes, compared with infants (n = 23; 2.6%) in the expectant management group (relative risk, 0.48), and there were zero infants and 3 infants (RR, 0.3%) in the induction and expectant management groups, respectively, who had an Apgar score less than 4 at 5 minutes.
Three (0.3%) infants in the induction group and 8 (0.9%) infants in the expectant management group were admitted to the NICU (RR, 0.38). There was one (0.1%) case of fetal death in the induction group and two (0.2%) cases in the expectant management group, but there were no neonatal deaths in either group. With regard to composite adverse maternal outcomes, there were no significant differences between the induction group (n = 122; 14%) and the expectant management group (n = 102; 11%) and both groups had the same number of cesarean sections (n = 97; 11%).
The investigators noted several limitations, such as the noninferiority study design, use of composite adverse perinatal outcome, and lack of stratification by parity that led to an imbalance between the induction and expectant management groups.
“If the composite outcome is interpreted straightforwardly, there is a small benefit of induction at 41 weeks that could justify standard induction at 41 weeks,” Ms. Keulen and colleagues wrote.
“It could be argued, however, that a change of policy to earlier induction, concerning roughly one-fifth of all women with a singleton pregnancy, is too rigorous in light of the relatively low incidence of perinatal mortality, gestational age associated NICU admission, and Apgar score less than 4 at 5 minutes as indicator for encephalopathy,” they added. “This could justify expectant management if women want to avoid induction.”
This study was supported by a grant from the Netherlands Organisation for Health Research and Development ZonMw. Dr. Ben Willem Mol reported a practitioner fellowship with the National Health and Medical Research Council and is a consultant for ObsEva, Merck, and Guerbet. The other authors reported no relevant conflicts of interest.
SOURCE: Keulen JKJ et al. BMJ. 2019 Feb 20. doi: 10.1136/bmj.l344.
Inducing labor at 41 weeks’ gestation for women with low-risk pregnancies was associated with a 1.4% lower risk of adverse perinatal outcomes, compared with expectant management until 42 weeks, according to results from a randomized, controlled noninferiority trial.
“As with every intervention in the natural birth process, the decision to induce labour must be made with caution, as the expected benefits should outweigh possible adverse effects for both mother and child,” wrote Judit K.J. Keulen, of the department of obstetrics and gynecology at Amsterdam University Medical Center, and her colleagues. “The results of our study should be used to inform women approaching a gestational age of 41 weeks, so they can weigh the respective outcomes and decide whether to be induced at 41 weeks or to continue pregnancy until 42 weeks.”
Ms. Keulen and her colleagues randomized 1,801 women from 123 primary care midwifery practices and 45 hospitals across the Netherlands to receive induction (n = 900) at 41 weeks or expectant management (n = 901) at 42 weeks between 2012 and 2016. The investigators used a composite of perinatal mortality measures, which included Apgar score less than 7 at 5 minutes, arterial pH less than 7.05, meconium aspiration syndrome, neonatal ICU admission, intracranial hemorrhage, and/or brachial plexus injury.
Overall, there were 15 adverse perinatal outcomes in the induction group (1.7%) and 28 adverse outcomes in the expectant management group (3.1%; absolute risk difference, −1.4%). A lower number of infants (n = 11; 1.2%) in the induction group had an Apgar score less than 7 at 5 minutes, compared with infants (n = 23; 2.6%) in the expectant management group (relative risk, 0.48), and there were zero infants and 3 infants (RR, 0.3%) in the induction and expectant management groups, respectively, who had an Apgar score less than 4 at 5 minutes.
Three (0.3%) infants in the induction group and 8 (0.9%) infants in the expectant management group were admitted to the NICU (RR, 0.38). There was one (0.1%) case of fetal death in the induction group and two (0.2%) cases in the expectant management group, but there were no neonatal deaths in either group. With regard to composite adverse maternal outcomes, there were no significant differences between the induction group (n = 122; 14%) and the expectant management group (n = 102; 11%) and both groups had the same number of cesarean sections (n = 97; 11%).
The investigators noted several limitations, such as the noninferiority study design, use of composite adverse perinatal outcome, and lack of stratification by parity that led to an imbalance between the induction and expectant management groups.
“If the composite outcome is interpreted straightforwardly, there is a small benefit of induction at 41 weeks that could justify standard induction at 41 weeks,” Ms. Keulen and colleagues wrote.
“It could be argued, however, that a change of policy to earlier induction, concerning roughly one-fifth of all women with a singleton pregnancy, is too rigorous in light of the relatively low incidence of perinatal mortality, gestational age associated NICU admission, and Apgar score less than 4 at 5 minutes as indicator for encephalopathy,” they added. “This could justify expectant management if women want to avoid induction.”
This study was supported by a grant from the Netherlands Organisation for Health Research and Development ZonMw. Dr. Ben Willem Mol reported a practitioner fellowship with the National Health and Medical Research Council and is a consultant for ObsEva, Merck, and Guerbet. The other authors reported no relevant conflicts of interest.
SOURCE: Keulen JKJ et al. BMJ. 2019 Feb 20. doi: 10.1136/bmj.l344.
FROM BMJ
