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Release of results from the ARRIVE trial has provided answers to some concerns about 39-week induction while leading to some questions about the participants and the implication of the findings for clinical practice. PLUS: CDC updates on Zika virus. Also: FDA warns about tests for rupture of membranes
Release of results from the ARRIVE trial has provided answers to some concerns about 39-week induction while leading to some questions about the participants and the implication of the findings for clinical practice. The data and an accompanying editorial were published in The New England Journal of Medicine.
Led by investigators from the Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD), the trial was conducted at 41 US obstetrical centers. The objective was to assess the impact of induction at 39 weeks versus expectant management in low-risk nulliparas. The primary outcome was a composite of perinatal death or severe neonatal complications; the principal secondary outcome was cesarean delivery.
For the study, 3062 women were randomized to labor induction at 39 weeks 0 days to 39 weeks 4 days and 3044 were randomized to expectant management. All of the participants were low-risk nulliparas who at the time of randomization were at 38 weeks 0 days to 38 weeks 6 days’ gestation. Of the participants, 63% had a modified Bishop score < 5 at randomization. Both groups were similar but fewer women in the induction group had a previous pregnancy loss (22.8% vs 25.6%; P= 0.001).
Cesarean delivery was significantly less likely in the induction group than in the expectant management group (18.6% vs 22.2%; relative risk [RR], 0.84; 95% CI, 0.76 to 0.93; P< 0.001) and it was not materially affected by adjustment for a history of pregnancy loss. Hypertensive disorders also were significantly less likely in women randomized to induction (9.1% vs. 14.1%; RR, 0.64; 95% CI, 0.56 to 0.74; P< 0.001). Less pain on a 10-point Likert scale and more perceived control during childbirth were reported by the women in the induction arm, and while they had shorter postpartum hospital stays, they spent less time on labor and delivery.
The primary perinatal come occurred in 4.3% of neonates in the induction group and in 5.4% in the expectant management group (RR, 0.80; 95% CI 0.64 to 1.00; P= 0.049). “Labor induction,” the authors said, “is probably not associated with a higher risk of adverse perinatal outcomes than expectant management and it may be associated with as much as a 36% lower risk than expectant management.”
Subgroup analyses showed that the maternal and perinatal results were not significantly affected by race, ethnic group, maternal age, body mass index, or modified Bishop score nor by type of admitting provider. (In 94% of cases, the provider was a physician and in 6%, it was a midwife.)
The authors said their data suggest that “1 cesarean delivery may be avoided for every 28 deliveries among low-risk nulliparous women who plan to undergo elective induction of labor at 39 weeks.” Given the size of the ARRIVE trial, they said it had the ability to detect differences that may not have been discerned in previous trials. However, most of the individual perinatal outcomes are infrequently seen and the trial was not powered to detect differences in them. It is also not clear whether the results are broadly generalizable. The researchers noted that more studies are needed to determine whether labor induction at 39 weeks in low-risk nulliparas is cost-effective.
In an accompanying editorial, Dr. Michael Greene said that other unanswered questions include why more than 16,000 women eligible for the trial declined to participate and how obstetrical centers across the country would accommodate longer lengths of stay on labor and delivery if the idea of induction at 39 weeks has a wide appeal to women. He said, however, that the results “should reassure women that elective induction of labor at 39 weeks is a reasonable choice that is very unlikely to result in poorer obstetrical outcomes.”
CDC updates on Zika virus
The Centers for Disease Control and Prevention (CDC) has issued new guidance about Zika virus for couples planning a pregnancy. Also updated are the CDC’s statistics on the impact of the virus on babies in US territories.
In Interim Guidance, CDC advised that men who may have been exposed to Zika virus and are planning to conceive with a partner wait at least 3 months after symptom onset or their last possible Zika virus exposure before engaging in unprotected sex. That timeframe also applies to prevention of sexual transmission of Zika. In its previous guidance, CDC recommended a 6-month waiting period for men before trying to conceive with a partner.
For couples who are not trying to conceive, the CDC said men can consider using condoms or abstaining from sex for at least 3 months after onset of Zika symptoms (if symptomatic) or their last possible exposure to the virus (if asymptomatic) to minimize risk of sexual transmission of the virus.
The guidance is based on a review of evidence, including the largest published cohort study of Zika virus to date. It involved 184 men with confirmed symptomatic Zika infection from whom a baseline specimen and serial semen specimens were collected at 2-week intervals. In that study, Zika virus RNA shedding in semen declined during the 3 months after symptom onset. At more than 90 days after illness onset, semen from 7% or fewer of the participants had detectable Zika virus RNA. Estimated mean time to clearance of Zika virus RNA from semen was 54 days.
Provisional data from the CDC show that there were 5,716 symptomatic Zika virus disease cases reported in the United States between January 1 2015 and August 1, 2018. Of those cases, 5,430 were in travelers returning from affected areas, in 231 mosquito-borne transmission was presume to have occurred locally, in 52 cases the route of transmission was sexual, two cases were attributed to laboratory transmission, and one cases was ascribed to person-to-person transmission through an unknown route.
In its latest Vital Signs publication, CDC reported that more than 4,800 pregnancies in US territories had a lab result showing confirmed or possible Zika from 2016 to 2018. Some 1,450 babies from those pregnancies were at least 1 year old at the time of the report and had some follow-up care. Of them, CDC said, 14% had one or more health problems that may have been caused by Zika and only about 36% had a recommended eye exam.
FDA warns about tests for rupture of membranes
False-negative results are possible with rupture of membrane (ROM) tests and clinicians shouldn’t use them independently to diagnose the condition in a pregnant woman, according to the US Food and Drug Administration (FDA). The guidance is part of a new alert from the agency to healthcare providers about the tests, one of which is being voluntarily recalled.
ROM tests are approved for marketing by the FDA for use by healthcare providers in conjunction with other clinical assessments to make critical management decisions about ROM. The tests are not intended to be used independently, yet the agency said it has received information about healthcare providers doing so, contrary to labeling.
FDA expressed concern that misuse of the tests could result in increased risk of fetal harm or death. The agency is aware of adverse events related to use of ROM tests, including 15 fetal deaths and multiple health complications in pregnant women.
One ROM test-Amnisure ROM Test Strips-is under voluntary recall. Approximately 40,500 of those strips distributed between October 2017 and March 2018 were found to have a device malfunction. They do not exhibit a control line, which makes it difficult for the test results to be interpreted.
“Our review of the risks associated with improper use of these ROM tests is ongoing, but we want to be transparent with providers and patients about the information that we have indicating an issue, and provide recommendations to minimize the risks,” said Courtney Lias, PhD, director, Division of Chemistry and Toxicology Devices in the FDA’s Center for Devices and Radiological Health in the alert. The agency also urged patients to talk to their healthcare providers about the signs and symptoms of ROM and contact them right away if they are concerned that their amniotic membranes may have ruptured too early.