Labor, Induced, Pregnancy
Conditions
Keywords
Ultrasound, Induced labor, Cervical length, Engagement of fetal head, Occiput posterior, Outcome of labor
Brief summary
The aim of the study was to evaluate any possible associations between engagement and position of the fetal head and the outcome of labor in women with induced labor, and to compare the value of ultrasound measurements in predicting the time from induction to delivery and operative deliveries.
Detailed description
Fetal head engagement measured by ultrasound as a predictive factor of labor outcome in women with induced labor T. EGGEBØ, L. K. GJESSING, I. ØKLAND, C. HEIEN, P. ROMUNDSTAD\*, K. Å. SALVESEN\*\* Department of Obstetrics and Gynaecology, Stavanger University Hospital, Norway \* Department of Public Health, NTNU, Norway, St Olavs Hospital, Trondheim University Hospital \*\* National Center for Fetal Medicine, Department of Obstetrics and Gynaecology, Trondheim University Hospital (St. Olav's Hospital) and Department of Laboratory Medicine, Children's and Women's Health, Norwegian University of Science and Technology KEYWORDS: Ultrasound, induced labor, cervical length, engagement of fetal head, occiput posterior, Bishop score, outcome of labor Objective The aim of the study is to evaluate any possible associations between engagement of the fetal head, the cervical status or occiput posterior position and the outcome of labor in women with induced labor, and to compare the value of ultrasound measurements with Bishop score in predicting operative deliveries. Methods The ultrasound examinations will be carried out in 275 women immediately before induction of labor. A transabdominal scan will be performed to determine the position of the fetal occiput, a transperineal scan with transverse view to determine the degree of engagement and a transvaginal examination to evaluate the cervical length and the cervical angle.. The Bishop score will be performed by another examinator who is blinded to the results of the ultrasound examinations. The time from induction to delivery will be tested in a Cox regression analysis with fetal head engagement, cervical length and parity as possible predictive factors and maternal age, BMI, gestational age, birth weight and head circumference as possible confounders. Inclusion and exclusion criteria: Women were eligible for the study if they had a live singleton pregnancy with cephalic presentation and a gestational age of more than 37 completed pregnancy weeks according to a mid-trimester scan. Statistical analysis Appropriate statistical tests for comparisons, such as Mann Whitney U test, chi-square test, Fisher's exact test, Pearson correlation, Kaplan Meier survival analysis and Cox regression analysis will be used. For receiver-operating characteristics (ROC) curves, the area under the curve will be used as discriminator. P-values \< 0.05 will be considered significant.
Interventions
None listed
Sponsors
Norwegian University of Science and Technology
St. Olavs Hospital
Helse Stavanger HF
Study design
Observational model
CASE_ONLY
Time perspective
PROSPECTIVE
Eligibility
Sex/Gender
FEMALE
Healthy volunteers
No
Inclusion criteria
* Pregnancy * Indication of induced labor
Exclusion criteria
* More than one fetus * Less than 37 weeks of pregnancy * Previous cesarean section * Breach position * Dead fetus
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Vaginal Delivery in Induced Labors | Time from induction of labor to delivery | The association between Bishop score, ultrasound assessed fetal station, ultrasound assessed cervical length, cervical posterior angle and a vaginal delivery was investigated using area under the ROC curves. Fetal station was assessed by ultrasound as the fetal head-perineum distance (HPD); which was measured by transperineal ultrasound imaging as the shortest distance from the outer bony limit of the fetal skull to the skin surface of the perineum. |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Delivery Within 24 Hours | Time from induction to delivery | Association between parity, HPD, cervical length, cervical angle, occiput posterior position, parity, BMI and the Hazard ratio of delivering within 24 hours was investigated using Cox regression analysis. |
Countries
Norway
Participant flow
Participants by arm
| Arm | Count |
|---|---|
| Time From Induction to Delivery Variables associated to time from induction to delivery were investigated. | 275 |
| Total | 275 |
Baseline characteristics
| Characteristic | Time From Induction to Delivery |
|---|---|
| Age, Categorical <=18 years | 3 Participants |
| Age, Categorical >=65 years | 0 Participants |
| Age, Categorical Between 18 and 65 years | 272 Participants |
| Age, Continuous | 30 years |
| Region of Enrollment Norway | 275 participants |
| Sex: Female, Male Female | 275 Participants |
| Sex: Female, Male Male | 0 Participants |
Adverse events
| Event type | EG000 affected / at risk |
|---|---|
| deaths Total, all-cause mortality | — / — |
| other Total, other adverse events | 0 / 275 |
| serious Total, serious adverse events | 1 / 275 |
Outcome results
Primary
Vaginal Delivery in Induced Labors
The association between Bishop score, ultrasound assessed fetal station, ultrasound assessed cervical length, cervical posterior angle and a vaginal delivery was investigated using area under the ROC curves. Fetal station was assessed by ultrasound as the fetal head-perineum distance (HPD); which was measured by transperineal ultrasound imaging as the shortest distance from the outer bony limit of the fetal skull to the skin surface of the perineum.
Time frame: Time from induction of labor to delivery
| Arm | Measure | Group | Value (NUMBER) |
|---|---|---|---|
| Successful Vaginal Delivery | Vaginal Delivery in Induced Labors | Area under the ROC curve associated to HPD | 62 percentage of area under the ROC curve |
| Successful Vaginal Delivery | Vaginal Delivery in Induced Labors | Area under the curve associated to cervical length | 61 percentage of area under the ROC curve |
| Successful Vaginal Delivery | Vaginal Delivery in Induced Labors | Area under the curve associated to cervical angle | 63 percentage of area under the ROC curve |
| Successful Vaginal Delivery | Vaginal Delivery in Induced Labors | Area under the curve associated to Bishop score | 60 percentage of area under the ROC curve |
Secondary
Delivery Within 24 Hours
Association between parity, HPD, cervical length, cervical angle, occiput posterior position, parity, BMI and the Hazard ratio of delivering within 24 hours was investigated using Cox regression analysis.
Time frame: Time from induction to delivery
Population: Hazard ratio was reported.
| Arm | Measure | Group | Value (NUMBER) |
|---|---|---|---|
| Successful Vaginal Delivery | Delivery Within 24 Hours | HPD ≤ 40 mm | 1.67 Hazard ratio |
| Successful Vaginal Delivery | Delivery Within 24 Hours | Cervical length ≤ 25 mm | 2.35 Hazard ratio |
| Successful Vaginal Delivery | Delivery Within 24 Hours | Cervical posterior > 90 degrees | 1.92 Hazard ratio |
| Successful Vaginal Delivery | Delivery Within 24 Hours | Occiput posterior position | 1.27 Hazard ratio |
| Successful Vaginal Delivery | Delivery Within 24 Hours | Multiparous woman | 3.25 Hazard ratio |
| Successful Vaginal Delivery | Delivery Within 24 Hours | BMI < 30 | 1.14 Hazard ratio |