Results of a large randomized clinical trial indicate that in low-risk nulliparas, elective induction of labor (IOL) at 39 weeks lowers rates of cesarean delivery (CD) without significantly increasing adverse perinatal outcomes. Plus, more coverage from The Pregnancy Meeting.
Results of a large randomized clinical trial presented at The Pregnancy Meeting indicate that in low-risk nulliparas, elective induction of labor (IOL) at 39 weeks lowers rates of cesarean delivery (CD) without significantly increasing adverse perinatal outcomes. The findings represent experience at 41 hospitals in the Eunice Kennedy Shriver National Institute of Child Health and Human Development Maternal-Fetal Medicine Units Network.
In the ARRIVE study, 61,06 low-risk nulliparas were randomized to either IOL or expectant management (EM) at 39 /07 to 39 4/7 weeks. A sample size of 6,000 was necessary to detect ≥ 40% difference in the primary perinatal outcome, assuming 85% power. Outcomes for the study were composite adverse perinatal events (primary) and CD (secondary). The perinatal events analyzed included perinatal death, respiratory support, Apgar score, hypoxic ischemic encephalopathy, and seizures. Besides CD, maternal outcomes studies included preeclampsia/gestational hypertension, chorioamnionitis, and third- and fourth-degree laceration.
At randomization, reliably determined gestational age ranged from 38 0/7 and 38 6/7 weeks. All the women underwent cervical examination to determine modified Bishop score from 72 hours before to 24 hours after randomization. The women in the EM group were expected to forgo elective delivery before 40 5/7 weeks and to be delivered no later than 42 2/7 weeks. Of the women in the study, 94% in the IOL group and 95% in the EM group adhered to the study protocol.
Delivery in the IOL group was significantly earlier than in the EM group (39.3 weeks [IQR 39.1 to 39.6] vs 40.0 weeks [IQR 39.3 to 40.7]; P < .001). Preeclampsia and gestational hypertension occurred in 9% of the IOL group versus 14% of the EM group. Among newborns, 3% in the IOL group needed respiratory support versus 4% in the EM group. The primary (adverse) perinatal outcome occurred in 4.4% of the IOL group versus 5.4% of the EM group (RR 0.81, 95% CI 0.64 to 1.01; P = .06). Frequency of CD also was significantly lower in the IOL group (18.6% vs 22.2%; RR 0.84, 95% CI 0.76 to 0.93).
The authors said that the findings for the primary and secondary outcome or CD were no different in subgroup analysis based on race/ethnicity, maternal age > 34 years, body mass index > 30 kg/m2 or modified Bishop score < 5. They concluded that in low-risk nulliparas, IOL at 39 weeks reduces frequency of CD without statistically significantly changing frequency of a composite of adverse perinatal outcomes.
Reflecting on the study, Editorial Board member Sarah J. Kilpatrick, MD, PhD, said that “the results suggest that induction at 39 weeks in nulliparas may be beneficial, but these data are not yet published.” She noted that “important questions were raised at the meeting, including about the unusually low cesarean delivery rate and the lack of data on cost and length of stay.” Dr. Kilpatrick also cautioned that this report is based on data from an abstract data and not a final publication, which warrants caution before changing clinical management.
Study: O2 supplementation not superior to RA in improving UA lactate
According to research presented at the 2018 Annual meeting of the Society for Maternal-Fetal Medicine, room air (RA) is not inferior to O2 for improving umbilical artery (UA) lactate in patients with Category II fetal heart tracings (FHT) during active labor. According to the authors, approximately two-thirds of women in labor receive O2 to reverse perceived fetal hypoxemia and to prevent acidosis.
In a randomized controlled non-inferiority trial conducted from June 2016 to June 2017, the researchers looked at 114 singleton pregnancies ³ 37 weeks with Category II FHT that required intrauterine resuscitation in active labor (³ 6 cm). The participants were randomized to receive either RA or 10L/min O2 by facemask until delivery. The primary outcome was UA lactate measured by umbilical cord gases collected at delivery. Secondary outcomes were other UA gas components, cesarean delivery for nonreassuring fetal status, and operative vaginal delivery. Noninferiority was declared if the mean difference in lactate between RA and O2 was < 1.0 mmol/L and analysis was by intention-to-treat.
Of the 114 patients included in the study, 99 with paired cord gases were included in the intention-to-treat analysis. There were 48 patients who received O2 and 51 patients who received RA. The researchers found no difference in mean UA lactate between the randomized 02 and RA groups (mean [95% CI], O2 = 3.4 [3.0,3.8] vs RA = 3.5 [3.1, 4.0], P = 0.69). For UA lactate, the mean difference was 0.1 mmol/L (95% CI -0.5, 0.7). The researchers found no differences in other UA gas components, vaginal delivery or nonreassuring fetal status between the groups.
Does intrapartum O2 administration affect Category II EFM patterns?
A study presented at the 2018 Annual meeting for the Society for Maternal-Fetal Medicine found that intrapartum maternal oxygen supplementation has no impact on Category II electronic fetal monitoring (EFM) patterns.
The researchers performed a secondary analysis of a randomized trial conducted from 2016-2017, in which 114 patients in active labor with Category II EFM were assigned to 10L/min O2 by face mask or room air (RA) until delivery. The primary outcome of this analysis was resolution of recurrent decelerations (late and/or variable) within 60 minutes of randomization. Secondary outcomes were presence of recurrent variables, recurrent late decelerations, tachycardia, or minimal variability. Outcomes in the two groups were compared using univariable statistics and time-to-event analysis was used to compare time to resolution between the groups.
There was no difference in resolution of recurrent decelerations within 60 minutes between the two groups of patients (O2 75.4% vs RA 86.0%, P = 0.15). Both the RA and O2 groups had similar time to resolution of recurrent deceleration. They also had similar rates of recurrent variables, recurrent late decelerations, tachycardia and minimal variability 30 and 60 minutes after randomization. Given the similarity of the findings in both groups, the researchers concluded that O2 administration has no impact on Category II EFM patterns.
Valnoctamide holds promise for CMV-induced deafness
A drug used for mood stabilization may have potential for treating congenital cytomegalovirus (CMV)-related deafness, according to results of a mouse study presented at The Pregnancy Meeting. CMV is the leading infectious cause of non-hereditary sensorineural hearing loss in newborns and children and there are no treatments for infected fetuses and substantial safety concerns about postnatal therapy.
For the study, researchers from Yale University and the University of Milan-Bicocca used CMV infection in the auditory system of newborn mice to test the potential benefits of valnoctamide on long-term hearing. Brain development in such mice, the authors said, parallels that in an early second-trimester fetus.
On the day of birth, the mice were inoculated with 750 PFU of CMV and they received 1.4 mg of valnoctamide or vehicle daily from Days 1 to 21 of life. Controls were uninfected animals. The authors used qPCR and histochemistry at multiple time points post-infection to assess CMV load and distribution in the cochlea and central auditory regions. Hearing was investigated blindly using Auditory Brainstem Responses in 7-week-old mice.
The researchers detected CMV-infected cells in the mice in several areas of the inner ear, including the stria vascularis, temporal bone, and cochlea. The cells were also present in central components of the auditory system. Increased hearing thresholds were identified in the infected mice at multiple frequency tone stimuli.
Treatment with valnoctamide substantially reduced CMV load in the cochlea (P < 0.001 for treatment vs vehicle in infected mice) and the brain. It also ameliorated hearing development with restoration of normal auditory responses (P < 0.05 for treatment vs vehicle in infected mice).
The authors concluded that treatment with valnoctamide blocks CMV infection in the developing auditory system and rescues virally induced hearing impairment. Because of this potential and its lack of teratogenic activity, they said it “merits consideration as a novel approach in treatment CMV-mediated deafness during development.”