PARTICIPACIÓN ADOLESCENTE Y JUVENIL

A study proforma was used for data collection (Appendix III). It contained five subsections including socio-demographic characteristics, past obstetric history, pre-induction assessment, induction and neonatal outcomes. It was interviewer-administered and semi-structured with both open and close ended questions. The researcher and research assistants administered the

25 proforma. A pilot study was done on 13 consenting subjects (10% of the calculated sample size) to pretest the proforma and evaluate feasibility before conducting the actual research.

Necessary modifications were made. The result of the pilot study was not included in the final research.

The socio-demographic characteristics obtained included age, parity, booking status, patient’s occupation and educational status, husband’s occupation and educational status, gestational age as calculated from the LMP or early USS. Those who were unsure of date and did not have an early scan (in the first half of pregnancy) were excluded from the study. Clinical examination was carried out to validate some of the inclusion and exclusion criteria. The patient’s height and weight were measured and the Body Mass Index (BMI) calculated.

Obstetric examination was done to determine the fetal lie, presentation and viability. The transabdominal ultrasound scan done on admission was reviewed to confirm the number of fetuses, lie, presentation and viability, amniotic fluid index, estimated fetal weight, placental localization, estimate gestational age and rule out other exclusion criteria.

Measurement of Cervical Length

The measurement of cervical length was done by the researcher under the supervision of a Consultant Radiologist who is one of the supervisors of this project. The researcher has also undergone an online training on cervical assessment by The Fetal Medicine Foundation. She also had hands-on training on cervical length measurement by the Consultant Radiologist.

Results were validated by periodic re-evaluation of the researcher by the Consultant Radiologist. TVS was performed in the USS unit of the Obstetrics and Gynaecology Department. A transvaginal 5MHz transducer on Aloka SSD-1000 ultrasound machine designed by ALOKA GmbH, Meerbusch, Germany was used to measure the cervical length.

26 The measurement was done within the hour prior to commencement of the IOL process just before assessment of the Bishop score. For each subject the following steps were carried out.

After obtaining consent, the participant was asked to empty her bladder and was placed in the dorsal position on the couch. An improvised waist wedge using a pillow was placed underneath her waist and a draw sheet over her waist, thighs and legs to maintain some privacy. The examiner then donned latex gloves. The transvaginal probe was lubricated with sterile coupling gel and covered with a latex condom. The condom-covered probe was again lubricated. The lower edge of the draw sheet was lifted and the probe gently inserted into the anterior fornix of the vagina to obtain a sagittal view of the cervix with its centrally located endocervical mucosa. The endocervical mucosa is hypoechoic compared to the surrounding cervical stroma and there is usually a thin line of demarcation between it and the latter. The internal os was identified at the proximal end of the central endocervical mucosal stripe. The external os was identified as the point at which the anterior and posterior lips of the cervix come together within the relatively hypoechoic vagina. The picture was magnified so that the cervix occupied at least 50 - 75% of the image before measurement. The length of the canal was measured as the distance between the calipers placed on the internal and external os as seen in the picture below. Where there was funnelling, the calliper for the internal os was placed at the apex of the funnel. Three measurements were taken and the shortest measurement of the cervical length was recorded on the proforma 21, 66 – 69. After each examination, the used condom was discarded, the probe was wiped clean with tissue and used gloves were discarded. Handwashing was done in between scans and a fresh condom and fresh gloves were used for each patient.

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Following sonography, the patient was asked about her perception of pain on a pain numerical rating scale from 0 to 10. Point 0 represented no pain while point 10 represented unbearable pain (Appendix V) ⁷⁰. The pain score was noted on the data collection sheet.

Elective inductions with misoprostol are usually commenced at 6pm in our centre but may be earlier in emergency situations.

Assessment of Bishop Score

Immediately after the TVS, a digital vaginal examination was done to assess the favourability of the cervix using the Bishop score. This was performed by the researcher so as to minimize inter-observer error and improve validity. The patient was placed in the dorsal position and the vulva swabbed with antiseptic solution. The examiner donned sterile gloves and introduced the middle and index fingers of the right hand into the vagina. The cervix was identified and assessed for the 5 parameters that make up the Bishop score. These are cervical dilatation, length and position, consistency of the cervix and station of the presenting part.

Cervical dilatation, length and station of the presenting part were scored on a scale of 0 to 3 while cervical position and consistency of the cervix were on a scale of 0 to 2 as depicted in Appendix IV. The pain score was again determined as earlier described. The patient was asked what her choice would be if she had the opportunity of choosing between digital and

28 sonographic examinations and her reasons for choosing her answer. She was subsequently transferred to the antenatal ward.

Subsequent management of the patient was carried out by the obstetricians on duty according to the departmental protocol. The steps are outlined below.

Induction of Labour

Cervical ripening and induction of labour was carried out using 25ug misoprostol tablets placed in the posterior fornix of the vagina 4 hourly to a maximum of 6 doses. The patient was monitored hourly for uterine activity and fetal heart rate and four hourly for cervical changes. Misoprostol was discontinued when the patient was in active phase or when a maximum of 6 doses had been used. It was also discontinued in three patients when fetal heart rate abnormalities ensued. The patient was transferred to the labour ward in the active phase of labour. In this study, active phase of labour was defined as cervical dilatation of ≥ 4cm irrespective of parity. Those with an unripe cervix following the maximum number of doses of misoprostol were diagnosed as having failed IOL; further management was determined by the managing obstetrician.

Where required, labour was augmented with oxytocin infusion. It was administered intravenously using a fluid giving set. The initial base mixture concentration was 10mIU/ml with a starting dose of 5mIU/min; the dose was increased at intervals of 30 minutes.

Maximum oxytocin flow rate was 30 mIU/min. The oxytocin end point was 3 to 5 uterine contractions in 10 minutes lasting at least 40s. Oxytocin infusion was administered for a maximum of 12 hours.

Fetal heart rate was monitored using intermittent auscultation or electrocardiotocography during the induction process. The induction outcomes were recorded in the study proforma by

29 the researcher and research assistants. Neonates were followed up to the first seven days of life to determine perinatal outcomes.

Research Assistants

Four research assistants (Registrar I), one from each firm, were involved in the execution of the study. They were trained on the methodology of the study and took part in the pilot study which lasted 10 days. They were involved in patient recruitment, counseling and administering the questionnaire. They also took part in recording induction outcomes following delivery.

Successful Induction of Labour

Successful induction of labour was defined as vaginal delivery within 24 hours of onset of misoprostol administration⁴⁷.

Failed Induction of Labour

This was defined as failure to deliver vaginally within 24 hours of onset of induction or caesarean delivery^47.

Induction-Delivery Interval

The time interval between passage of the first dose of misoprostol and delivery of the fetus.