Timing of Labor Induction Significantly Impacts Duration, Study Finds
New research from Michigan state University reveals a strong link between the time of day labor is induced and its duration, potentially offering a pathway to improved maternal and infant outcomes. The study,published in Molecular Metabolism,combined laboratory investigations using mice and human cells with a retrospective analysis of over 2,300 pregnancies.
Researchers discovered that labors induced in the early morning,between 8 a.m. and noon, were significantly shorter than those initiated around midnight. This difference was particularly pronounced in patients with gestational diabetes, with induction timing impacting labor length by as much as seven hours.
The findings center on BMAL1, a crucial gene regulating the body’s circadian rhythm - the internal 24-hour clock. Experiments with mice demonstrated that BMAL1 plays a key role in controlling the oxytocin receptor in the uterus, the same receptor targeted by synthetic oxytocin to stimulate contractions. Suppressing or disabling the BMAL1 gene, either genetically or through a gestational diabetes model, significantly reduced the effectiveness of oxytocin in inducing contractions.
“We were able to show that BMAL1 directly controls the oxytocin receptor, which helps explain why time of day changes the drug’s effectiveness,” explained Hanne Hoffmann, associate professor of animal science at Michigan State University and lead author of the study. “This is the first study to make that molecular connection in the uterus.”
Human cell experiments corroborated these findings, demonstrating a circadian rhythm in the uterus’s response to oxytocin, confirming previous hypotheses.
Analysis of labor and delivery records from Sparrow Health System in Lansing, Michigan, supported the laboratory results.The records, encompassing over 2,300 patients at least 39 weeks pregnant, showed the shortest labors consistently occurred with inductions between 8 a.m. and noon, while the longest occurred between midnight and 4 a.m. The effect was most noticeable in women with gestational diabetes,indicating reduced oxytocin sensitivity during nighttime hours.
Hoffmann emphasized that the research isn’t about convenience, but about optimizing patient care. “If we can better align medical interventions with a patient’s internal clock, we may improve safety for both mother and baby, while potentially being able to reduce the amount of a drug a woman receives.”
the research team is currently expanding their study to a larger cohort to refine optimal induction timing. Ongoing work suggests that factors like prior births and a woman’s Body Mass Index (BMI) may also influence oxytocin effectiveness. Future research will involve a prospective study in collaboration with labor and delivery units to develop practical guidelines for obstetricians. The ultimate goal is to personalize labor induction, potentially leading to improved delivery outcomes, reduced rates of cesarean sections and NICU admissions, and enhanced recovery for both mothers and newborns.
Source: Michigan State University.
