Is Unfavourable Cervix prior to Labor Induction Risk for Adverse Obstetrical Outcome in Time of Universal Ripening Agents Usage? Single Center Retrospective Observational Study

Abstract

Cervical assessment on the Bishop scale prior to induction of labor (IOL) is one of the strongest prognostic criteria in relation to the success of the procedure. The commonly used preinduction methods are mainly aimed at reducing the percentage of cesarean sections. Our study has analyzed obstetric results of patients who had unripe cervix (Bishop score <7) before IOL and used preinduction (Foley catheter or misoprostol vaginal insert releasing 7 mcg of misoprostol per hour for 24 hours) with obstetric results of patients in whom, due to favourable cervix, only a low-dose infusion of oxytocin was used. We reviewed the medical records of 1010 single pregnancies in whom IOL was performed. We divided the patients into two groups: group A (where preinduction was used) and group B (Bishop score ≥7 points) where preinduction was not used. Patients in group A were more likely to complete the delivery by caesarean section (OR=4.58, 95% CI 3.22-6.51), and more likely to have events that were indications for operative delivery: unreassuring fetal heart rate trace (OR=3.29, 95% CI 2.07-5.23) and arrested labor or failed induction (OR=3.4, 95% CI 2.06-5.62). The groups did not differ in the percentage of vacuum extraction, postpartum haemorrhage, and meconium stained amniotic fluid. In group B, more infants were born with umbilical cord blood pH <7.1 (1.38% vs. 0%), both groups included no deliveries of newborns with Apgar score ≤3 points, the groups did not differ in terms of the percentage of newborns with Apgar score between 4 and 7 at birth (OR=0.66, 95% CI 0.29-1.49). The immature cervix and the need to use labor preinduction is a risk factor for caesarean section. The necessity of preinduction does not impair neonatological results.

Misoprostol vs dinoprostone vaginal insert in labour induction: comparison of obstetrical outcome

“…Physiologically, the cervix undergoes a ripening before delivery, which is associated with shortening, softening, changing the utero-cervical angle and opening the cervix. The Bishop score (BS) is commonly used in clinical examination to assess the cervix before delivery, which allows us to evaluate the chance of successful induction of labour 3 , 4 . Higher BS score before starting the IOL has strong negative correlation with the duration of the induction procedure (r = − 0.59 p < 0.01) 5 which may increase the patient's satisfaction with the IOL 6 .…”

Misoprostol vaginal insert and Foley catheter in labour induction — single center retrospective observational study of obstetrical outcome

“…However, in the study cited above [12], the proportion of plurigravidas to the primagravidas in the studied group (31/69 = 0.45) was higher, and in our studies it was lower (24/111 = 0.21), (p = 0.018). Numerous studies show that vaginal childbirth in the history is one of the strongest predictive factors of induction efficiency and occurs in most of the predictive models published in the literature [14,15]. In our opinion, this proportion is crucial if we want to compare the percentage of caesarean sections between individual studies.…”

Factors of Non-Compliance with a Protocol for Oral Administration of Misoprostol (Angusta®) 25 Micrograms to Induce Labor: An Observational Study

“…In our first analysis, we found that patients with a higher initial Bishop score had a better response to the protocol, but after our multivariable analysis we did not find this variable to be a factor of good response, which seems surprising because every IOL is more effective on a ripe cervix [ 22 ].…”