|Year : 2020 | Volume
| Issue : 4 | Page : 1264-1269
Predicting factors of success in induction of labor after 37 weeks
Ibrahim A Seif-Elnasr1, Thoraya A Omar1, Ahmed N Abd-Elhamid1, Dalia S Mohamed2
1 Department of Obstetrics and Gynecology, Faculty of Medicine, Menoufia University, Menoufia, Egypt
2 Department of Obstetrics and Gynecology, Shebin-Elkom Teaching Hospital, Ministry of Health, Menoufia, Egypt
|Date of Submission||12-Feb-2020|
|Date of Decision||02-Apr-2020|
|Date of Acceptance||12-Apr-2020|
|Date of Web Publication||24-Dec-2020|
Dalia S Mohamed
Source of Support: None, Conflict of Interest: None
To compare transvaginal measurement of cervical length and insulin-like growth factor-binding protein-1 (IGFBP-1) in the prediction of successful induction of labor.
The successful induction of labor aims to achieve vaginal delivery when the continuation of pregnancy presents a threat to the life or well-being of the mother and fetus. The process of induction should only be considered when vaginal delivery is felt to be the appropriate route of delivery.
Patients and methods
A total of 140 women, 37–42 weeks in pregnancy, underwent induction of labor. Before induction, detection of IGFBP-1 in cervical secretions by the Actim partus test was done, then a digital examination of the cervix was performed, and the Bishop score was noted. Cervical length was measured by transvaginal ultrasound.
The mean cervical length in patients delivered vaginally was 24.89 ± 5.48 mm whereas the mean cervical length in patients delivered by cesarean section was 26.79 ± 3.06 mm. IGFBP-1 is positive by Actim partus test in 94% in patients delivered vaginally, whereas IGFBP-1 is positive by Actim partus test in 39.5% in patients delivered by cesarean section.
There was a statistically significant positive correlation between detection of IGFBP-1 in cervical secretions and successful induction of labor.
Keywords: delivery, insulin-like growth factor-binding protein 1, labor induction, transvaginal ultrasound of cervical length
|How to cite this article:|
Seif-Elnasr IA, Omar TA, Abd-Elhamid AN, Mohamed DS. Predicting factors of success in induction of labor after 37 weeks. Menoufia Med J 2020;33:1264-9
|How to cite this URL:|
Seif-Elnasr IA, Omar TA, Abd-Elhamid AN, Mohamed DS. Predicting factors of success in induction of labor after 37 weeks. Menoufia Med J [serial online] 2020 [cited 2021 Apr 18];33:1264-9. Available from: http://www.mmj.eg.net/text.asp?2020/33/4/1264/304506
| Introduction|| |
Induction of labor is defined as an intervention designed to artificially initiate uterine contractions, leading to progressive dilatation and effacement of the cervix and birth of the baby. Induction of labor is indicated when benefits to the mother or the fetus outweigh those of continuing the pregnancy; indications for induction of labor include postdated pregnancy; premature rupture of the membranes, before the onset of labor; maternal diseases such as diabetes mellitus and gestational hypertension; or fetal growth restriction. Transvaginal ultrasonographic imaging measurement of the cervical length is a good method for cervical assessment, that is, if the cervical length is more than 30 mm and funneling (wedging) is more than 30 percent of total cervical length, this indicates an unripe cervix. Moreover, it might lead to a reduction in cesarean delivery and thereby its complications. Phosphorylated insulin-like growth factor-binding protein-1 (PhIGFBP-1) is a protein synthesized by the maternal decidua.It has been suggested that with cervical ripening and fetal membrane separation from the decidua, insulin-like growth factor-binding protein-1 (IGFBP-1) is released into cervical and vaginal secretions. The phosphorylated form is produced mainly by human decidual cells, and it presents between the chorion and decidua. As the cervix matures and the labor approaches, the chorion and decidua detach and PhIGFBP-1 gets into cervical secretion; thus, its presence reflects decidual activation and dilatation of the internal os. This study aimed to compare the preinduction ultrasonographic measurement of cervical length and detection of IGFBP-1 in cervical secretions by Actim partus test in prediction of successful induction of labor.
| Patients and Methods|| |
This comparative study was done on 140 women who met the inclusion criteria for induction and were admitted at either the Obstetrics Department of Menoufia University Hospital or at Shebin El Koom Teaching Hospital during the period between March 2019 and December 2019. The local ethics committee of Menoufia University approved the study protocol after taking written consent from the patients. Inclusion criteria were all patients from 18 to 35 years of age who met the diagnostic criteria for induction: primigravida, women with singleton pregnancies after 37 weeks, fetuses with cephalic presentation, and no history of previous cesarean section (CS) or myomectomy.
Indications of induction were postdate pregnancy (67 patients), gestational diabetes mellitus (33 patients), and gestational hypertension (40 patients).
Gestational age: after 37 weeks
Abdominal ultrasound was done by using abdominal probe 3.5 MHz of LOGIQ V5 machine (this machine made in China in 2018) for confirmation of fetal heart activity, presentation of the fetus, localization of the placenta, and amount of amniotic fluid. Fetal biometry was done to estimate gestational age and fetal weight. Exclusion criteria were multifetal pregnancy and apparent congenital anomalies.
Detection of IGFBP-1 in cervical secretions was done by Actim partus test (Actim Oy, Joensuu, Finland). Kit contents were one sterile polyester swab for specimen collection, one dipstick in a sealed aluminum foil pouch with desiccant, and one tube of specimen extraction solution (0.5 ml). This phosphate-buffered solution contains bovine serum albumin, protease inhibitors, and preservatives. Structure of dipstick, dip area, result area, test line, and control line.
Specimen collection was done as follows: the patient was placed in the lithotomy position. A sterile Cusco speculum was insert into the vagina. Sterilization of the cervix was done with antiseptic solution. A sterile polyester swab was inserted into the cervical os. The swab was left in the cervical os for 10–15 s to allow it to absorb the secretion specimen. The specimen extraction solution tube was opened and placed in a vertical position. The specimen was extracted immediately from the swab by swirling the swab vigorously in the extraction solution for 10–15 s. Swab was pressed against the wall of the specimen. Extraction solution tube was used to remove any remaining liquid from the swab. The swab was discarded after extraction. The yellow dip area was placed into the extraction sample and held until the liquid front entering the result area is seen. The dipstick from the solution is removed and placed in a horizontal position.
Interpretation of the results was as follows: the result was interpreted as positive as soon as two blue lines become visible in the result area. Negative result should be read at 5 min. If the test line and control line appear, the test result was positive. If one blue line, the control line, appears, the test result was negative. When control line did not appear, the test was invalid.
Vaginal examination was done to assess the Bishop score of the cervix, to exclude cephalopelvic disproportion; to confirm presentation, position, and detection of head station; and to exclude contraindications of vaginal delivery. Bishop scoring, digital examination, and scoring of the cervix using the modified Bishop score were done. Ultrasound evaluation of the cervix was done as follows: transvaginal ultrasound was used for cervical length measurement using 7.5 MHz frequency of LOGIQ V5 machine. The following steps were done: the patient was asked to empty her bladder. The transvaginal probe was inserted into the vagina and rocked in the anteroposterior direction to visualize the cervix. The line of the internal cervical canal was visualized.
The anterior and posterior lips of the cervix were checked to appear equal. The probe was slowly withdraw a little and slide back to make sure there is no compression artifact. The measurement was repeated three times, and we recorded the average. The cervical length was measured from internal to external os.
Any funneling was recorded and funneling percentage was calculated as follows: percentage of funneling = A/(A + B), where A is funnel length (length of imaginary line that connects the apex of the funnel to the cranial most edge of the base of the funnel), and B is residual or functional cervical length (cervical length distal to the funnel).
Labor induction was done according to the standard guidelines for induction of labor as follows: prostaglandin E1 (misoprostol) (75 patients) was started for unfavorable cervix, with a Bishop score above 5. Initial dose of 25 μg vaginal tablet (vagiprost R 25 μg manufactured by ADWIA CO. S.A.E, 6th of October Egypt) was given. Full reassessment was done 6 h after the initial dose unless clinical condition indicates earlier assessment. Second dose of 25 μg was given in cases with unfavorable cervix.
Reassessment was done every 6 h later, and redosing if cervix was still unfavorable.
If no cervical ripening occurred after four doses of misoprostol, the procedure was considered failure and the patient was delivered by CS.
If there is cervical ripening, we moved to the next step.
Oxytocin and/or amniotomy (65 patients)
Oxytocin infusion (Oxytocin manufactured by Novartis Pharma Stein Switzerland AG) was started by 5 U in 500 ml of normal saline or Ringer solution in 6 h following the last dose of misoprostol, starting with a rate of 12 drops/min.
Infusion rate was increased (by doubling drops/minute) at intervals of 30 min, until there are three good contractions in 10 min, each lasting 45–60 s.
Maximum allowed rate was 84 drops/min.
During the period of induction, the fetal heart rate was monitored continuously by means of electronic fetal heart rate monitoring (cardiotocography). Moreover, maternal monitoring was done including blood pressure measurements every 2 h and frequent clinical evaluation (according to the condition).
The fetal heart rate was considered reassuring if stable baseline rate was between 110 and 160 bpm with a short-term and long-term variability (>5 bpm) and No deceleration.
Accelerations are considered with more than 15 bpm for more than 15 s, with fetal movement and with contractions.
On the contrary, fetal heart rate patterns were considered as nonreassuring when there was decreased variability (<5 bpm for >40 min but <90 min), persistent mild to moderator variable deceleration, occasional severe variable decelerations, single prolonged deceleration up to 3 min, moderator to severe variable deceleration in the second stage of labor, fetal bradycardia (<110 bpm), or fetal tachycardia more than 160 bpm. The fetal heart rate was considered as abnormal FHR pattern when there is fetal heart rate less than 100 or more than 180 sinusoidal pattern for more than 10 min, beat to beat variability less than 5 bpm for more than 90 min, atypical variable deceleration, late deceleration, or single prolonged deceleration more than 3 min.
When a nonreassuring fetal heart rate was detected, closer monitoring of fetal heart rate was performed with simultaneous adequate conservative measures in the form of stopping or reducing uterotonic, avoiding supine position, and starting intravenous fluids. Administration of tocolytics was done if hyperstimulation persists despite previous measures. Delivery was expedited if hypoxia persists despite tocolysis.
If hypoxia was encountered in the second stage of labor, the mother was asked to stop pushing to allow the recovery of the fetal status. If no improvement is seen within 10 min, delivery was expedited. Once stable, pushing was recommend. If distress recurs, delivery was expedited. Uterine hyperstimulation is defined as either a series of single contraction lasting 2 min or more or a contraction frequency of five or more in 10 min. If the fetal heart rate pattern remains nonreassuring or maternal contractile abnormalities persist, prompt delivery was performed by CS. CS was done in the following situations: persistent nonreassuring or abnormal fetal heart pattern (10 patients), failed induction of labor (30 patients), and persistent contractile abnormalities (three patients).
The sample size was calculated to be 140, according to the formula, and sample size (n) has been calculated based on specifying = Z21-α/2 × SP×(1-SP) L2×(1-prevalence). All patients were subjected to full history taking, including personal, present, menstrual, and obstetrics history, and clinical examination, including general examination, abdominal examination, and vaginal examination to assess the Bishop score of the cervix, to exclude cephalopelvic disproportion, confirm presentation, position, and detection of head position and to exclude contraindication of vaginal delivery. Imaging included abdominal and transvaginal ultrasound (GE E8C Transvaginal Ultrasound, Guang Dong, China), Laboratory investigations included IGFBP-1 in cervical secretions.
Data were fed to the computer and analyzed by SPSS, version 22 (SPSS Inc., Chicago, Illinois, USA). An independent t-test was used for parametric data. Mann–Whitney test was used for nonparametric data. χ2 test was used for qualitative variables. P value less than 0.05 was considered significant. Binary logistic regression was used to identify factors associated with an increased likelihood of occurrence of disease. Qualitative data were described using numbers and percentages. Quantitative data were described using (minimum and maximum) mean, SD, and median.
| Results|| |
In our study, 140 women with the age ranged between 18 and 32 years, with mean age of 23.34 ± 4.09 years, were included. The BMI ranged between 23 and 37, with mean BMI of 29.12 ± 2.57. Gestational age ranged between 38 and 42 weeks, and the mean gestational age was 39.85 ± 1.41 weeks [Table 1]. The mean ultrasound measurement of cervical length for the patients who delivered vaginally was 24.89 ± 5.48 mm, and the mean of cervical length for the patients who delivered by cesarean delivery (CS) was 26.79 ± 3.06 mm. The Bishop score was more than or equal to 5 in 82 patients delivered vaginally. The Bishop score was more than or equal to 5 in 21 patients delivered by CS. The Bishop score was less than 5 in 15 patients delivered vaginally, and the Bishop score was less than 5 in 22 patients delivered by CS. IGFBP-1 by Actim partus test was positive in 97 women who were delivered vaginally, and IGFBP-1 by Actim partus test was positive in 17 women who were delivered by CS. IGFBP-1 by Actim partus test was negative in women who delivered vaginally, and IGFBP-1 by Actim partus test was negative in 26 women who were delivered by CS [Table 2].
|Table 2: Distribution of the ultrasound cervical length and insulin-like growth factor-binding protein-1 regarding the studied mode of delivery|
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| Discussion|| |
Induction of labor is performed in ~20% of all pregnancies, and successful induction is reported to be related to cervical characteristics, or 'ripeness'. Bishop score remains the standard method to predict the duration and outcome of induced labor. The preinduction 'favorability' of the cervix as assessed by the Bishop score is very subjective, and several studies have demonstrated a poor predictive value for the outcome of induction, especially in women with a low Bishop score. Transvaginal ultrasonographic measurement of cervical length can be used for assessing cervical status. A bedside test for phosphorylated isoforms of IGFBP-1 has been suggested to predict the success of labor induction. In this study, we compared the preinduction ultrasonographic measurement of cervical length and detection of IGFBP-1 in cervical secretions by Actim partus test in prediction of successful induction of labor. In this study, 140 pregnant women 37–42 weeks of gestational age underwent induction of labor owing to PIH, gestational diabetes, or passed date, with Bishop score less than 5 using 25 mg misoprostol vaginally. The dose was repeated at 6-h interval for 24 h, or amniotomy followed by oxytocin infusion when Bishop score was more than or equal to 5. In our study, 69.3% of our participants were delivered vaginally, and 30.7% women were delivered by CS. Bishop score, ultrasonographic measured cervical length, and detection of IGFBP-1 in cervical secretions provided independent contribution in the prediction of the likelihood of delivering vaginally within 48 h. In our study, IGFBP-1 was more sensitive than Bishop's score and cervical length, which was measured by transvaginal ultrasound. These results are in agreement with that of Dögl et al., who studied 391 women with singleton pregnancies, cephalic presentation, a living fetus, with postdate pregnancy. Bishop score was assessed by digital examination, transvaginal ultrasound measurement of cervical length was done, and detection of IGFBP-1 (Actim Partus test Medix Biochemical) in cervical secretions was done in the prediction of spontaneous onset of labor and successful induction. Similarly, a study of Riboni et al. studied 115 women and showed that the Bishop sore [odds ratio (OR 2.3)], IGFBP-1 test (Actim partus Medix Biochemical) (OR 11.2), and interleukin-8 (OR 6.6) predicted successful induction and concluded that PhIGFBP-1 test is a fast and easy test that can be used with the Bishop score and interleukin-8 in the prediction of the success of labor induction with prostaglandin. They used the beginning of the active phase of labor within 12 h as the marker of successful induction with prostaglandin. This is in disagreement with Cheung et al., who found a positive association between cervical IGFBP-1 and vaginal delivery after labor induction. After an assessment, they found that the combination of sonographic assessment of the cervix and maternal characteristic was superior to either Bishop score or transvaginal and transabdominal ultrasound (TVUS) cervical length alone in the prediction of the induction outcome. The inclusion of PhIGFBP-1 did not further improve prediction in their model. Their finding is in sharp contrast to ours, and the difference may result from a mixed population of nulliparous (61%) and parous (39%) women in their study. Moreover, 72% of their participants had their labor caused because of prolonged pregnancy. In contrast, our participants were exclusively nulliparous, and only 47.9% had labor induction for prolonged pregnancy.
These results are in agreement with that of Vallikkannu et al., who studied 193 term nulliparous women with intact membranes. Before labor induction, cervical fluid was obtained via a vaginal speculum and tested for IGFBP-1 (Actim Partus test Medix Biochemical), followed by TVUS and finally Bishop score. After each assessment, the procedure-related pain was scored from 0 to 10. Cut-off values for Bishop score and cervical length were obtained from the receiver operating characteristic curve. Multivariable logistic regression analysis was performed. Bedside IGFBP-1 testing was better tolerated than Bishop score, but is less well tolerated than TVUS [median (interquartile range) of pain score: 5 (4–5) vs. 6 (5–7) vs. 3 (2–3), respectively; P < 0.001), IGFBP-1 independently predict vaginal delivery [adjust odds ratio (AOR) 5.5; 95% confidence interval (95% CI) 2.3–12.9] and vaginal delivery within 24 h of induction (AOR 4.9; 95% CI 2.1–11.6). After controlling for Bishop score (24 or >5), cervical length (<29 or <27 mm), and other significant characteristic for which the Bishop score and TVUS were not predictive of vaginal delivery after adjustment. IGFBP-1 has 81% sensitivity, 59% specificity, 82 positive predictive value, and 58% negative predictive values, as well as positive and negative likelihood ratios of 2.0 and 0.3 for vaginal delivery, respectively. Our study is not consistent with Cheung et al., who studied 460 women at 37–41 weeks of gestations to determined cervical length, posterior cervical angle and the fetal occipital position. The Bishop score and the absence/presence of IGFBP-1 in cervical secretions. A total 340 (73.9%) women achieved a vaginal delivery following induction. Multivariate analysis indicated that significant independent predictors of vaginal delivery were cervical length (AOR 0.59; 95% CI 0.45–0.79), posterior cervical angle (AOR 1.89; 95% CI 1.09–3.28) and multiparae (AOR 10.02; 95% CI 5.10–19.69). For a specificity of 75%, the sensitivity for prediction of vaginal delivery using the Bishop score, the cervical length, and the multivariate model using the identified significant independent predictors were 37.1, 46.8, and 68%, respectively. After assessment, they found that the combination of TVUS measurement of the cervical length and maternal characteristic was superior to either Bishop score or TVUS cervical length alone in prediction of the induction outcome. The inclusion of IGFBP-1 did not further improve prediction in their model. Their findings are in sharp contrast to ours, and the difference may result from the mixed population of nulliparous (61%) and parous (39%) women in their study. Moreover, 72% of their participants had their labor induced because of prolonged pregnancy. In contrast, our participants were exclusively nulliparous, and only 47.9% had labor induction owing to prolonged pregnancy.
| Conclusion|| |
There was a statistically significant positive correlation between the detection of IGFBP-1 in cervical secretions and successful induction of labor.
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Conflicts of interest
There are no conflicts of interest.
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[Table 1], [Table 2]