Cervical Sliding Sign to Predict Outcome of Induction of Labor

Induction of labor is a common practice in modern obstetrics. It is the use of mechanical or pharmacological -or both ways- to stimulate uterine contractions before spontaneous labor to induce cervical dilatation and delivery. Induction of labor at term have many advantages. It can reduce to risk of still birth. It also reduces the risk of macrosomia and its adverse outcomes such as maternal trauma, shoulder dystocia or the need for instrumental delivery (Kim, et al., 2019). However, induction of labor can also have adverse outcomes, the most common is failure and increasing the risk of cesarean section. Induction of labor may not be tolerated by some patients because of the potential increase in the duration of labor or a prolonged latent phase. Increased cost compared to spontaneous delivery course and possible neonatal morbidity if the gestational age is less than 39 weeks of gestation are other drawbacks. (Kim, et al., 2019) Since the success of induction of labor is related to the condition of the cervix, investigators have proposed the importance of having a reliable system for determining the cervical maturity. A number of studies considered the use of sonographic measurement of cervical length to predict the success of labor induction. The sonographic marker for assessing the cervical softening called the cervical sliding sign (CSS) which was introduced by (Volpe, et al., 2019), demonstrated its correlation with the occurrence of impending delivery in women with preterm uterine contractions. The performance of the CSS in predicting the success of IOL was conducted in two academic centers by (Volpe, et al., 2022). However, its generalizability to community hospitals cannot be certain and needs further testing. The presence of CSS was defined as the sliding of the anterior cervical lip on the posterior one under gentle pressure of the transvaginal probe. (Volpe, et al., 2022)

Aim/ Objectives. Assess the role of the cervical sliding sign (CSS) as a marker in the prediction of the outcome of induction of labor (IOL) at term gestation.

Research Hypothesis:

The presence of Cervical Sliding sign in pregnant women at term gestation planned for Induction of labor predicts a higher chance of vaginal delivery within 24 hours.

Research Question:

Is CSS a successful marker for prediction of outcome of induction of labor in pregnant women at term gestation? Methodology

Type of Study: Prospective observational cohort study Study Setting: Ain Shams University Maternity Hospital (labor ward). Study period: 6 months Study Population: The study will be conducted on term pregnant women with Singleton living fetus attending Ain Shams University Maternity Hospital for induction of labor with the following criteria:

Inclusion criteria:

1. women age: from 18 to 35 years old.
2. Single living term fetus with gestational age ≥ 37 weeks. 3- Eligible for IOL. 4- Bishop score <6 5- Estimated fetal weight < 4Kg.

Exclusion criteria:

1. previous caesarean section. (increases risk of rupture uterus)
2. Multiple pregnancy, IUFD, preterm or macrosomic fetus (defined as fetus >4.5kg or fetus of diabetic mother >4Kg) (increases risk of shoulder dystocia)
3. Women with major uterine anomalies. (appendix A: ESHRE/ESGE classification for Female genital tract anomalies (Grimbizis GF, et al,. 2013) (increases risk of CS)
4. Vasa previa, placenta previa (increases risk of antepartum hemorrhage)
5. previous myomectomy reaching the endometrial cavity. (Increases risk of rupture uterus)

7- patient refuse to participate or inability to consent. (patient's right to refuse).

Sample Size and sample Size Justification:

Using the PASS 15 program for sample size calculation, reviewing results from a previous study (Volpe et al.2022) showed that the cervical sliding sign (CSS) was found in 48% of the study group (non-consecutive series of uncomplicated singleton term pregnancies, planned for IOL, with a fetus in cephalic presentation patients), based on this frequency and after 20% adjustment for dropout rate, a sample size of at least 130 participants produces a two-sided 95% confidence interval with a width equal to 0.199 when the sample proportion is 0.480.

Ethical Consideration:

This study will be done after approval of the ethical committee of the department of obstetrics and gynecology, faculty of medicine, Ain Shams University. Informed consent will be taken from all participants before recruitment in the study, and after explaining the purpose and procedures of the study. The investigator will obtain the written, signed informed consent of each subject prior to performing any study specific procedures on the subject. The investigator will retain the original signed informed consent form. All laboratory specimens, evaluation forms, reports, video recordings and other records that leave the site will not include unique personal to maintain subject confidentiality. The study will be based on the investigator self-funding.

Study procedures and interventions:

Women fitting into our inclusion criteria will be subjected to:

1. history taking (personal, obstetric, medical and surgical)
2. Transvaginal ultrasound to assess the presence of CSS with a semi-filled bladder using a 10 MHz endo-vaginal probe EC3-10T of Alpinion E-CUBE 5 ultrasound machine (ALPINION MEDICAL SYSTEMS Co., Ltd. Guro-gu, Seoul, 08393, Republic of Korea) will be done by the most senior resident. "The CSS will be evaluated as follows:

1- acquisition of a sagittal view of the cervix, on which the internal and external os and the endocervical canal could be identified. 2- Gentle pressure with the transvaginal probe on the cervix until maximum compression of the cervix is achieved. 3- Visualization of the anterior cervical lip "sliding" on the posterior one is defined as the presence of CSS." (Volpe, et al., 2022) 3- Induction and management of labor will be conducted following the hospital's protocol (APPENDEX B: FIGO MISOPROSTOL-ONLY RECOMMENDED REGIMENS 2017(Morris JL, et al., 2017)) 4- record the mode of delivery for each participant either vaginal delivery or cesarean deliveries. 5- Measurement of induction-to-active-labor1 time (active labor time defined as ≥ 6cm dilated cervix), active-labor-to-delivery time, total length of labor.

Outcomes:

• 1ry outcome: successful vaginal delivery.
• 2ry outcomes:
• induction-to-active-labor time interval.
• Active -labor-to-delivery time interval.
• Mode of Delivery (vaginal/ Instrumental/ Cesarean)
• Reason for CS (Fetal distress/ failure of induction/ failure of progress).

Statistical analysis:

• All data will be collected, tabulated, and statistically analyzed by software package program