Original Article
Predictor variables in the success of slow-release dinoprostone used for cervical ripening in intrauterine growth restriction pregnancies

https://doi.org/10.1016/j.jogoh.2020.101739Get rights and content

Abstract

Objective

This study aims to evaluate the consequences of a trigger by vaginal Dinoprotone on outcome of pregnancies with Intrauterine growth restriction (IUGR).

Materials and methods

This retrospective study included 161 induced IUGR fetuses (35–39 weeks). Consecutive patients who were evaluated formed the basis of the clinical outcomes. The penalized maximum likelihood estimation (PMLE) method was used instead of traditional logistic regression in order to reduce the risk of overfitting.

Results

Of the 25,678 deliveries that occurred during the study period, 161 (0.6%) women underwent IUGR delivery; of these, 117 (73%) succeeded and 44 (27%) failed to achieve cervical ripening using the dinoprostone slow-release vaginal insert. Two predictors were associated with dinoprostone vaginal delivery success: Parity (OR:1.4([0.89–2.3]), and Bishop score (OR:1.54[1.23–1.94]). The PMLE model correctly classified 78% participants (c-index: 0.78).

Conclusion

Basic parameters such as parity and Bishop score can be used to predict successful vaginal birth following dinoprostone slow-release vaginal insert administration.

Introduction

Intrauterine growth restriction (IUGR), is the failure of the fetus to achieve its genetically determined growth potential or target. It affects 5–10 % of pregnancies. It is a significant clinical problem due to high prenatal mortality and morbidity. IUGR is present in 50 % of fetuses with intrauterine asphyxia findings. It is the second most common cause of perinatal mortality [1].

A wide variety of factors are involved in the pathogenesis of IUGR. IUGR etiology includes environmental (drugs, toxins, infections), fetal (aneuploidy, genetic-structural anomalies, syndromes), maternal (preeclampsia, AFAS, thrombophilia, diabetes mellitus), placental (abnormal placentation, chronic decolman) causes but in more than 20 % of cases, etiology may not be detected in [1].

The most common method used for diagnosis of IUGR is to measure the estimated fetal weight (EFW) and show that it is below the 10th centile. Other than this, the most successful method is the measurement of the abdominal circumference (AC) [2]. The 10th centile limit may cause confusion between IUGR pregnancies and small for gestational age (SGA) pregnancies. Therefore in recent studies, EFW < 10th centile fetuses with Doppler flow abnormalities and EFW < 3th centile fetuses are considered IUGR [3].

Induction of labor is the iatrogenic stimulation of uterine contractions before labor contractions begin spontaneously [4]. The continuation of pregnancy poses a risk of mortality or morbidity for the mother or fetus, leading to the suggestion of labor induction [5]. In the case of ending of pregnancy, it is substantial to deliberate advantages and handicaps of primary cesarean section versus attempting vaginal delivery through the labor induction. Although it is possible to induce labor in the early weeks of pregnancy, it becomes an option when the pregnancy close to term or at term. The DIGITAT trial showed that inducing labor for Iugr is possible without increasing the rate of surgical deliveries and without short-term adverse neonatal outcomes [6]. The level of cervical ripening must be taken into consideration when initiating labor. In this way, the success of labor induction can be predicted, and the weather to use cervical ripening agents or not will be decided. Bishop score is used most frequently for this purpose. Bishop scores less than six indicates that insufficient cervical ripening [4].

In the case where cervical ripening is insufficient, both the duration of labor induction is prolonged, and the rates of operative vaginal delivery and cesarean section increase. Oxytocin, one of the most commonly used pharmacological agents in labor induction, has minimum effect on cervical ripening. Prostaglandin analogs are used both for induction of labor and also for cervical ripening [7,8]. Prostaglandin E2 (PgE2) (Dinoprostone) preparations are used as a vaginal insert system, providing continuous and low-dose PgE2 release. In Turkey, there is a slow release form of ovules containing 10 mg dinoprostone. Since these preparations can be readily withdrawn, they can be removed at the end of the administration period (12−24 hours) or when the cervical ripening is achieved.

This study aims to evaluate the consequences of a trigger by vaginal Dinoprotone on outcome of pregnancies with IUGR.

Section snippets

Patient characteristics

This retrospective study included 161 induced IUGR fetuses (35–39 weeks) who was referred to the Department of Gynecology and Obstetrics of Diyarbakir Gazi Yaşargil Training and Research Hospital of Health Sciences University between September 2017 and August 2018. The study was approved by the local institutional review board (02.02.2018/21). Patient data were extracted from the hospital information system in the form of Demographic data of patients included maternal age, parity, and

Results

Of the 25,678 deliveries that occurred during the study period, 161 (0.6 %) of these deliveries were IUGR pregnancies treated with dinoprostone vaginal insert system (Fig. 1). These patients were divided into two groups: 117 (73 %) succeeded (vaginal delivery group) and 44 (27 %) failed (cesarean section group) to achieve cervical ripening using the dinoprostone slow-release vaginal insert. There was no significant difference between the two groups in terms of age. The median gravida was 2 in

Discussion

This study was designed retrospectively to determine predictor variables that play a role in the success of slow release Dinoprostone used for cervical ripening in the induction of labor in IUGR pregnancies. The principal findings are as follows:

  • 1

    The vaginal delivery success rate after dinoprostone application was approximately 73 %.

  • 2

    The predictors that associated with cervical ripening and dinoprostone vaginal delivery success included parity and Bishop score.

Many complications may occur as a

Conclusion

Ripening success with vaginal dinoprostone slow-release insert can be estimated by specific factors including high parity and high Bishop score. Inclusion of these factors in the management protocol for induction of labor with cervical ripening may improve the quality of care and should be considered.

Declaration of Competing Interest

None.

We have no conflict of interest.

There is no funding to report for this submisson.

References (26)

  • S.M. Yount et al.

    The pharmacology of prostaglandins for induction of labor

    J Midwifery Womens Health

    (2013)
  • J. Stirnemann et al.

    International estimated fetal weight standards of the INTERGROWTH-21st Project

    Ultrasound Obstet Gynecol

    (2017)
  • F.E. Harrell

    Regression modeling strategies with applications to linear models, logistic and ordinal regression, and survival analysis

    (2015)
  • View full text