A comparative analysis of methods of preinduction cervical ripening and induction of labor in Poland and in Germany (Part II): maternal and neonatal outcomes

Abstract

The benefits and risks of delivery should always be considered before initiating preinduction cervical ripening and labor induction. Understanding the benefits and potential complications is crucial for healthcare professionals to make informed decisions and provide optimal care. The research was conducted retrospectively between January 2019 and July 2022. It involved the analysis of the medical records of 154 pregnant women staying in the Clinic of Obstetrics and Gynecology in the city of Szczecin and 150 pregnant women hospitalized in the Clinic of Obstetrics and Gynecology in the town of Schwedt/Oder in Germany. Inclusion criteria were consent to participate and the implementation of internal written protocols in line with national guidelines for labor induction. The research concerned a group of pregnant women with postdate pregnancy, calculated according to the Naegele’s rule and confirmed by the USG examination conducted in the first trimester of the pregnancy, as well as an unfavorable cervix that received less than 6 points in the Bishop score. Moreover, the pregnant patients with a low biophysical profile and an abnormal record of CTG or comorbidities were also included, as these factors determined the classification of the group above. The study did not include patients who had undergone cesarean section. The average change in evaluation of the cervix marked on the Bishop Score was higher in Germany, and it was 2.7 points, whereas in Poland, it was 1.6 points. The largest percentage of the scores on the Apgar Scale in the first, third and fifth minutes after birth was in the norm and indicated a good health condition of infants. They reached 8 to 10 points in both countries. Significantly more infants in Germany received pH from the umbilical cord within the limits of the norm. And it marks the welfare of neonates (7.20–7.45). The duration of hospitalization in Poland was shorter than in Germany. It was 3.8 days in the case when the median equalled 3. The number of days of preinduction cervical ripening and induction was similar in both countries. The levels of haemoglobin were comparable in both countries. The most common postpartum complications in Poland and Germany were first-degree perineal tears, episiotomies and anemia. Among the postpartum complications, cervical tears, revision of the uterine cavity, and episiotomy were significantly more common in Poland. First- and second-degree perineal tears were more frequent in Germany.

Introduction

The preinduction and induction of labor have become significant interventions in modern obstetrics [1–21]. They are aimed at facilitating delivery and reducing potential complications for both the mother and infant [1, 5, 8, 14, 22–24]. Preinduction involves preparing the cervix before induction. It plays a crucial role in determining the success and safety of the procedure [10, 16, 23, 25–28]. Induction of labor is a pivotal practice in contemporary obstetrics. It is designed to initiate childbirth artificially before spontaneous onset [10, 17, 24, 28–31]. Understanding the benefits and potential complications is vital for healthcare professionals [30]. It allows them to make the right decisions and provide optimal care [1, 5, 6, 12–15, 20, 24, 31–37].

Induction and preinduction of labor can prevent complications associated with post-term pregnancies [9, 16, 23, 38]. The procedures reduce the risks of prolonged gestation, such as hypoxia, macrosomia, perinatal mortality, cerebral palsy, perinatal trauma, shoulder dystocia, severe respiratory failure and meconium aspiration syndrome [8, 9, 12, 15, 16, 20, 22, 39, 40]. By inducing labor, the risk of intrauterine infection and stillbirth is decreased [8, 22, 41, 42]. Conditions such as hypertension, preeclampsia, diabetes, FGR, premature rupture of membranes, intrahepatic cholestasis of pregnancy, or gestational diabetes can be better managed with planned induction [10, 22, 43, 44]. Scheduled inductions can provide predictability for the health care team and the parents [24]. It allows to prepare better and manage resources in the best possible way [2, 10].

While this medical intervention can offer significant benefits, it also presents certain risks [10, 14, 17, 24, 31, 33]. Induced labor may not always progress as expected. It may lead to obstetric complications such as postpartum hemorrhage, maternal tachycardia and bradycardia, prolonged labor, the need to perform an episiotomy, the necessity of a caesarean section, or perinatal trauma [6, 10, 12–14, 17, 30, 45–47]. In some cases, despite preinduction efforts, the cervix may not adequately dilate. As a consequence, there is a necessity of a cesarean Sects. [10, 14, 22]. The use of medications to induce labor can sometimes cause uterine tachysystole and then immediate intervention is required [2, 10, 12, 13, 17, 30, 36, 41, 46, 48]. Especially, if the amniotic sac is ruptured for an extended period, an increased risk of chorioamnionitis may appear. It can lead to inflammation of the endometrium, placenta, umbilical cord and the development of intrauterine infection in the fetus, including sepsis [15, 22].

To improve the quality of perinatal care, increase comfort and reduce patients’ anxiety, preinduction cervical ripening and induction should be implemented only when clearly indicated [12, 21, 24, 26, 30, 49, 50]. Like any medical intervention, it involves the risk of complications. Therefore, in medical treatment, the benefits and risks must be weighed [21]. Recommendations regarding labor induction in Poland are presented in the Recommendations of the Polish Society of Gynecologists and Obstetricians, and in Germany in the Recommendations of the German Society of Gynecologists and Obstetricians [21, 50]. Indications for preinduction cervical ripening and induction of labor in Poland and Germany are postterm pregnancy, premature rupture of membranes, macrosomia, FGR or maternal diseases complicating the course of pregnancy. These diseases include hypertension, diabetes or cholestasis [21, 43, 50]. Prior to the implementation of preinduction cervical ripening or induction, the following conditions should be excluded: placenta praevia, invasive cervical cancer, active genital herpes infection, abnormal fetal position and intrapartum uterine muscle rupture. These factors are absolute contraindications to start the labor induction. To reduce the number of abnormal preinductions and labor inductions, it is necessary to collect reliable medical records. It is essential to properly assess the gestational age and the degree of maturity of the cervix on the Bishop scale. It is also crucial to reliably estimate the date of delivery [17, 21, 33, 43, 50].

Due to the increasing use of preinduction cervical ripening and labor induction methods, research has been conducted for many years to verify these methods [6, 13, 14, 33]. Medics around the world make every effort to make the implemented methods safer and more effective. Finding the balance between these benefits and risks is the key in the decision-making process for both healthcare providers and patients [1, 5, 10, 13, 14, 17, 23, 26, 31–37, 51].

Materials and methods

The research was conducted retrospectively between January 2019 and July 2022, and involved the analysis of medical records of 154 pregnant women staying in the Clinic of Obstetrics and Gynecology in the city of Szczecin in Poland and 150 pregnant women hospitalized in the Clinic of Obstetrics and Gynecology in the town of Schwedt/Oder in Germany.

Inclusion criteria were consent to participate and the implementation of internal written protocols in line with national guidelines for labor induction. The research concerned the group of pregnant women with them postdate pregnancy, calculated according to the Naegele’s rule and confirmed by the USG examination conducted in the first trimester of the pregnancy, as well as the unfavorable cervix, which received less than 6 points in the Bishop score. Moreover, the pregnant patients with a low biophysical profile and an abnormal record of CTG or comorbidities were also included, as these factors determined the classification of the group above. The study did not include patients who had undergone cesarean section.

The analysis presented below was carried out in two stages. The first stage involved collecting data from the medical records of those women who were classified as part the group on the grounds of an auctorial data form. Data were collected on maternal age, parity, gestational age, coexisting diseases, indication(s) for induction or augmentation of labor, mode of preinduction or induction of labor, way of delivery, the time from induction to an onset of an active labor, the duration of labor and its individual phases, indications for cesarean delivery, maternal hemoglobin level after birth, the time of preinduction and induction of labor, change of Bishop Score from induction to an onset of an active labor, the time of hospitalization, postpartum complications such as: first- and second-degree perineal tear and neonatal outcomes such as: Apgar score, pH and cBase. The assessment of the effectiveness of preinduction cervical ripening and induction of labor was examined using the results of cervical scores on the Bishop scale before and after the use of preinduction cervical ripening or induction of labor.

The second stage of the research was done by means of the statistical studies in the view of the conducted research. The Bishop score decided about the readiness of the cervix. The neonatal results were elaborated not only by means of the Apgar Score System but also on the grounds of pH value, cBase in the gasometric test and acid-base balance of the cord blood. The levels of hemoglobin of women were indicated in the venous blood test during the first day after labor.

The obtained research results were subjected to statistical analysis. The values of the analysed measurable parameters are presented using the mean value, median, minimum and maximum values, and standard deviation, and for non-measurable ones using counts and percentages. For qualitative features, the Chi² test was used to detect the existence of relationship between the analysed variables. Checking the normality of the distribution of variables in the study groups was performed using the Shapiro-Wolf test. To examine the differences between the two groups, the Student’s t-test was used, and if the conditions for its use were not met, the Mann-Whitney U test. The differences between the three groups were assessed using the Kruskal-Wallis test. The analysis also used ROC curves to assess the correctness of the classifier for which the last cervical measurement was taken when determining the type of delivery. A significance level of p < 0.05 was assumed, indicating the existence of statistically significant differences or dependencies. The database and statistical research were based on Statistica 9.1 computer software (StatSoft, Poland).

This study was approved by the Institutional Ethics Committee of Pomerian Medical University in Szczecin and the State Medical Council of Brandenburg, and Informed Consent was obtained by all the participants in the study.

Results

The study included a total of 304 women who had indications for preinduction cervical ripening or induction of labor. In the Republic of Poland and the Federal Republic of Germany, 154 and 150 women were examined, respectively. The average age of patients who underwent preinduction cervical ripening or induction of labor in both Poland and Germany was 28. The average gestational age in Poland was 277 days (39 weeks + 4 days), and in Germany, it was 278 days (39 weeks + 5 days). In Poland, the highest percentage concerned women (63.64%) in their first pregnancy. In Germany, in the third pregnancy or more, there were 38.00% of women. Whereas, 62.67% (p < 0.001) of women gave birth at least once or more. The most common complication among the examined patients was gestational diabetes (18.18% in Poland and 14.67% in Germany). Significantly more Polish women (p = 0.033) had a history of struggling with hypertension 9.09% and hypothyroidism 17.53% than from Germany (p < 0.001) – Table 1.

Table 1.

Demographic parameters

Parameter	PL (n = 154)	DE (n = 150)	p value*
Maternal age, (years) (M ± SD)	28 ± 5.1	28 ± 5.4	0.611
Gestational age, (days) (M ± SD)	277 ± 8.6	278 ± 9.0	0.088
Gravidity:
1	98 (63.64%)	53 (35.33%)	< 0.001*
2	36 (23.38%)	40 (26.67%)
< 3	20 (12.98%)	57 (38.00%)
Parity:
0	98 (63.64%)	56 (37.33%)	< 0.001*
< 1	56 (36.36%)	94 (62.67%)
Coexisting diseases:
Gestational hypertension	14 (9.09%)	4 (2.67%)	0.033
Gestational diabetes	28 (18.18%)	22 (14.67%)	0.408
Cholestasis of pregancy	7 (4.55%)	3 (2.00%)	0.356
Hypothyroidism	27 (17.53%)	0 (0.00%)	< 0.001*

M – median, SD - standard deviation, n – count, *Bold p values indicate a statistical significance < 0.05, p value: Pearson chi-squared test

The efficacy results are presented in Table 2. There were no statistically significant differences (p = 0.089) between postpartum hemoglobin values in both Polish and German patients, they were similar. The number of days of preinduction cervical ripening and induction of labor was similar in Poland and Germany. The median, mean and minimum represent the same values. The maximum number of days on which patients in Poland underwent pre-induction and labor induction was 5 days, while in Germany it was 6 days. The average change on the Bishop scale in Poland was significantly lower (p = 0.001) and amounted to 1.6 ± 2.6 points, whereas in Germany it was 2.7 ± 2.5 points. In Poland, the duration of hospitalization was shorter than in Germany and averaged 3.8 ± 1.9 days.

Table 2.

Efficacy outcomes

Outcome parameter	PL (n = 154)	DE (n = 150)	p value*
Maternal hemoglobin level after birth, (mmol/L) (M ± SD)	6.6 ± 0.8	6.8 ± 0.7	0.089
Time of preinduction and induction of labor, (minutes) (M ± SD)	1.5 ± 0.9	1.5 ± 0.7	0.999
Change of Bishop Score from induction to an onset of an active labor, (M ± SD)	1.6 ± 2.6	2.7 ± 2.5	0.001*
Time of hospitalization, (days) (M ± SD)	3.8 ± 1.9	4.1 ± 1.3	0.001*

M – median, SD - standard deviation, n – count, *Bold p values indicate a statistical significance < 0.05, p value: Pearson chi-squared test

The most common postpartum complications in our study were first-degree perineal tear, episiotomy) and postpartum anemia. Significantly more often first- (p = 0.045) and second-degree (p < 0.001) perineal tears occurred in Germany, while in Poland cervical tears were documented more often (p = 0.001), revisions of the uterine cavity (p < 0.001) and episiotomy (p < 0.001) were also performed – Table 3.

Table 3.

Maternal outcomes / postpartum complications

Complications:	PL (n = 154)	DE (n = 150)	p value*
First-degree perineal tear	30 (19.48%)	44 (29.33%)	0.045*
Second-degree perineal tear	0 (0.00%)	22 (14.67%)	< 0.001*
Labia tear	6 (3.90%)	4 (2.67%)	0.780
Revision of uterine	12 (7.79%)	1 (0.67%)	< 0.001*
Uterine atony	1 (0.65%)	0 (0.00%)	0.989
Vaginal tear	5 (3.25%)	7 (4.67%)	0.733
Fiber	0 (0.00%)	3 (2.00%)	0.236
Postpartum hemorrhage	1(0.65%)	0 (0.00%)	0.989
Episiotomy	49 (31.82%)	16 (10.67%)	< 0.001*
Cervical tear	11 (7.14%)	1 (0.67%)	0.001*
Umbilical cord entanglement	1(0.65%)	3 (2.00%)	0.596
Postpartum anemia	58 (37.66%)	45 (37.66%)	0.158

n – count, *Bold p values indicate a statistical significance < 0.05, p value: Pearson chi-squared test

The neonatological results are presented in Table 4. The mean Apgar score in the 1st minute of a newborn’s life was 9.1 ± 1.2 in Poland and 8.8 ± 0.8 points in Germany. The average Apgar score in the 3rd minute of life was 9.5 ± 0.9 in Poland and 9.7 ± 0.6 points in Germany, while in the 5th minute of life the mean score in Poland was 9.7 ± 0.6, and in Germany 9.9 ± 0.7 points. The highest percentage of Apgar scores both in the 1st, 3rd and 5th minute of newborn’s life, in both compared countries was within the normal range, corresponding to the good condition of the newborn after delivery (8–10 points). The highest percentage of pH values from umbilical cord blood after childbirth both in Poland and Germany was within the normal range (7.20–7.45). Significantly more newborns in Germany had umbilical cord blood pH within the normal range (7.20–7.45). The average pH of umbilical cord blood in Poland (7.28) was significantly lower than in Germany (7.31). Remarkably, more 96.67% newborns in Germany than in Poland (81.17%) obtained the cBase result from umbilical cord blood in the blood gas test within the normal range.

Table 4.

Neonatal outcomes

Parameter	PL (n = 154)	DE (n = 150)	p value*
Apgar score at the 1’ minute, (M ± SD)	9.1 ± 1.2	8.8 ± 0.8	0.001*
0–3	1 (0.65%)	0 (0.00%)	0.572
4–7	13 (8.44%)	11 (7.33%)
8–10	140 (90.91%)	139 (92.67%)
Apgar score at the 3’ minute, (M ± SD)	9.5 ± 0.9	9.7 ± 0.6	0.042*
0–3	1 (0.65%)	0 (0.00%)	0.253
4–7	4 (2.60%)	1 (0.67%)
8–10	149 (96.75%)	149(99.33%)
Apgar score at the 5’ minute, (M ± SD)	9.7 ± 0.6	9.9 ± 0.7	0.001*
0–3	0 (0.00%)	1 (0.67%)	0.368
4–7	1 (0.65%)	0 (0.00%)
8–10	153 (99.35%)	149 (99.33%)
pH, (M ± SD)	7.28 ± 0.1	7.31 ± 0.1	0.001*
< 7,20	37 (24.03%)	7 (4.67%)	< 0.001*
7,20–7,45	110 (71.43%)	140 (93.33%)
> 7,45	7 (4.55%)	3 (2.00%)
cBase
< -10	(7.79%)	(2.67%)	0.001*
-10 - +2	(81.17%)	(96.67%)
+ 2	(11.04%)	(0.67%)

M – median, SD - standard deviation, n – count, *Bold p values indicate a statistical significance < 0.05, p value: Pearson chi-squared test

Multivariate linear regression analysis showed that the use of a Foley catheter in Poland (OR 2.292, 95%CI: 1.639–2.945, p = < 0.001) and oxytocin in Germany (OR= -2.727, 95%CI: -3.921-(-1.532), p < 0.001) are predictors influencing an increase in change in the Bishop cervical scoring during preinduction cervical ripening and induction of labor – Table 5.

Table 5.

Linear regression model to use change of bishop score from induction to an onset of an active labor in Poland and in Germany

Country	Predictors	OR	-95% CI	+ 95% CI	p value*
Poland	Parity	-0.331	-0.956	0.295	0.297
	Mode of preinduction or induction of labor	2.292	1.639	2.945	< 0.001*
Germany	Parity	-0.168	0.674	-0.395	0.693
	Mode of preinduction or induction of labor	-2.727	-1.532	-4.517	< 0.001*

OR – odds ratio, CI - confidence interval, *Bold p values indicate a statistical significance < 0.05, p value: Pearson chi-squared test

Multivariate linear regression analysis showed that the use of Foley catheter in Poland (OR = 1.147, 95%CI: 0.385–0.385, p = 0.004) and in Germany multiparity (OR= -0.570, 95%CI: -1.016-(-0.125), p = 0.013), use of oxytocin versus misoprostol (OR -1.172, 95%CI-1.754-(-0.590), p < 0.001), and type of delivery (OR = 1.186, 95%CI:0.517–1.855, p < 0.001) are factors affecting the hospitalization period of postpartum patients – Table 6.

Table 6.

Linear regression model time of hospitalization in Poland and in Germany

Country	Predictors	OR	-95% CI	+ 95% CI	p value*
Poland	Parity	0.046	-0.802	0.895	0.914
	Mode of preinduction or induction of labor	1.147	0.385	1.910	0.004*
	Way of delivery	0.127	-0.887	1.142	0.804
Germany	Parity	-0.570	-1.016	-0.125	0.013*
	Mode of preinduction or induction of labor	-1.172	-1.754	-0.590	< 0.001*
	Way of delivery	1.186	0.517	1.855	< 0.001*

OR – odds ratio, CI - confidence interval, *Bold p values indicate a statistical significance < 0.05, p value: Pearson chi-squared test

Multivariate logistic regression analysis showed that parity (OR = 0.119, 95%CI: 0.040–0.356, p < 0.001) and type of delivery (OR = 1.005, 95%CI:1.000–1.010, p = 0.047) in Poland are factors influencing to postpartum complications – Table 7.

Table 7.

Logistic regression model of postpartum complications after delivery in Poland and in Germany

Country	Predictors	OR	95% CI	p value*
Poland	Parity	0.119	0.040–0.356	< 0.001*
	Mode of preinduction or induction of labor	0.616	0.185–2.051	0.430
	Way of delivery	1.005	1.000–1.010	0.047*
Germany	Parity	0.949	0.388–2.325	0.909
	Mode of preinduction or induction of labor	2.557	0.837–7.811	0.099
	Way of delivery	1.000	0.997–1.003	0.926

OR – odds ratio, CI - confidence interval, *Bold p values indicate a statistical significance < 0.05, p value: Pearson chi-squared test

The last measurement of the cervix on the Bishop scale in patients pre-induced or induced with the most common therapy in Poland and Germany is a variable that can be used to determine what type of delivery will occur: vaginal delivery or caesarean section. The statistical significance of the DeLong test p = 0.016 Table 8, Fig. 1.

Table 8.

Analysis of the ROC curve for the variable of the last measurement of the cervix on the Bishop scale for the differentiation of the type of delivery for the whole group of women who received the most common pre-induction or labor induction therapy in Poland and Germany

Parameter	AUC	p value*
Change of Bishop Score from induction to an onset of an active labor to way of delivery	0.620	0.016*

AUC – area under curve, *Bold p values indicate a statistical significance < 0.05, p value: Pearson chi-squared test

Fig. 1.

ROC curve for the last measurement of the cervix on the Bishop scale for the differentiation of the type of delivery for the whole group of women who received the most common pre-induction or induction therapy in Poland and Germany

The last measurement of the cervix on the Bishop scale in patients pre-induced or induced with the most common therapy in Germany is a variable that can be used to determine what type of delivery will occur: vaginal delivery or caesarean section. The statistical significance of the DeLong test p = 0.005 - Table 9; Fig. 2.

Table 9.

Analysis of the ROC curve for the variable of the last measurement of the cervix on the Bishop scale for the differentiation of the type of delivery for the group of women, who received the most common pre-induction or labor induction therapy in Germany

Parameter	AUC	p value*
Change of Bishop Score from induction to an onset of an active labor to way of delivery	0.712	0.005*

AUC-area under curve, *Bold p values indicate a statistical significance < 0.05, p value: Pearson chi-squared test

Fig. 2.

ROC curve for the last measurement of the cervix on the Bishop scale for the differentiation of the type of delivery for a group of German women who received the most common pre-induction or induction therapy

The last measurement of the cervix on the Bishop scale in patients pre-induced or induced with the most common therapy in Poland is a variable that cannot be used to determine what type of delivery will occur: vaginal delivery or caesarean section. The statistical significance of the DeLong test p = 0.975 - Table 10; Fig. 3.

Table 10.

Analysis of the ROC curve for the variable of the last measurement of the cervix on the Bishop scale for the differentiation of the type of delivery for the group of women, who received the most common pre-induction or labor induction therapy in Polen

Parameter	AUC	p value*
Change of Bishop Score from induction to an onset of an active labor to way of delivery	0.497	0.975

AUC – area under curve, *Bold p values indicate a statistical significance < 0.05, p value: Pearson chi-squared test

Fig. 3.

ROC curve for the last measurement of the cervix on the Bishop scale for the differentiation of the type of delivery for a group of women in Poland who received the most common pre-induction or labor induction therapy

Discussion

In the studies by Baczyńska et al. [52] comparing pre-induction with Foley catheter and with PGE₂ gel, no differences in the incidence of anemia were observed between the groups of patients. Similar blood loss at birth was found between the groups in the above studies.

In the studies by Jenkins et al. [53] the score of the cervix assessed with the Bishop scale before the use of preinduction cervical ripening of labor in the group of women who were to receive the Foley catheter was 2.34 ± 0.63, misoprostol 2.67 ± 0.82 and PGE₂ gel 2.24 ± 0.74 points. 57.14% of pregnant women after the use of Foley catheter, 66.66% of misoprostol and 75.75% of PGE₂ gel had a change on the Bishop scale more than 5 points. According to the study by Alam and Ahmed [54] the change in the score of the cervix assessed with the Bishop scale in women who were pre-induced with the Foley catheter was 5.10 ± 1.55, and in the group of women in whom the preparation with PGE₂ was used 5.14 ± 1.60.

In studies by Morris et al. [55] postpartum complications such as retained placenta and postpartum hemorrhage were documented in 10% of women induced with misoprostol. One patient diagnosed with preeclampsia died after birth as a result of excessive blood loss due to postpartum hemorrhage. According to the study by Nair et al. [28] 9.04% of women experienced postpartum hemorrhage and 12.67% had sepsis in the puerperium. The most common postpartum complications in the study by Hokkila et al. [56] were episiotomy and postpartum hemorrhage. Studies by Bernitz et al. [13] shows that use of oxytocin in high doses, as oxytocin doses of 20 mU/min or more were associated with PPH, regardless of the length of augmentation for vaginally delivered women.

Similar results were obtained by Baczyńska et al. [52], who analyzed the Apgar scores of infants of mothers who had previously undergone pre-induction with Foley catheter and then induction with oxytocin. The majority of neonates, 94.8% in the 3rd minute of life and 100% in the 5th minute of life, had Apgar scores above 7. The average neonatal score, assessed on the Apgar scale, was 9.48 points in the 3rd minute of life and 9.6 points in the 5th minute of life. The same result concerns the group of women pre-induced with misoprostol and then induced with oxytocin. Baczyńska et al. [52] also observed that, regardless of the chosen method, the majority of newborns assessed using the Apgar scale scored more than 8 points. It concerned 93.5% of infants when Foley catheter was applied to the mothers and 92.6% after using PGE₂ gel. Also, the gasometric test results of the umbilical cord blood pH and acid-base balance were comparable and were above 7.20. In the studies by Fareed et al. [57] comparing Foley catheter with the PGE₂ preparation, they obtained an Apgar score 7.8 + 0.5 and 7.8 + 0.6 in the 1st minute of the newborn’s life for both groups, respectively, and 9.7 + 0.6 and 9.8 + 0.5 in the 5th minute respectively. No statistically significant differences on the Apgar scores and umbilical cord blood pH values were observed in the above studies when comparing the two groups of patients.

On the other hand, studies by Jenkins et al. [53] show that significantly more newborns of mothers who were administered misoprostol vaginally scored 7 points on the Apgar scale in the 1st minute of life, less in relation to newborns of mothers who were pre-induced with Foley catheter and PGE₂ gel. In the above studies, no differences in the newborn’s Apgar score in the 5th minute of life were noted. The vast majority of newborns, 98%, 96% and 98%, respectively, of mothers receiving Foley catheter, misoprostol or PGE₂ gel, had an Apgar score higher than 7 in the 5th minute of life. The obtained results are consistent with the results of studies conducted by Agarwal et al. [58], and no statistically significant differences were observed between the scores of newborns in the 1st and 5th minute of life of mothers who underwent pre-induction and induction with Foley catheter or misoprostol. Most of the newborns in the above-mentioned studies scored 8–10 points in the 1st minute of life, and 10 points on the Apgar scale in the 5th minute of life. In the study by Jasim et al. [59], no statistically significant differences were observed between the scores of newborns in the 1st and 5th minute of life of mothers who were induced with misoprostol or oxytocin. The mean Apgar score in the above studies was 6.6 points in the 1st minute of life in newborns of mothers receiving misoprostol and 8.1 points in the 5th minute of life. Newborns of mothers induced with oxytocin received 6.4 points in the 1st minute of life, and 8.1 points in the 5th minute of life. According to the study by Abdel-Al et al. [60], the average Apgar score was 8.3 and 8.4 points, respectively, in newborns of mothers induced with oxytocin and misoprostol. In the studies of Acharya et al. [61], the average score in the group of newborns of mothers induced with misoprostol in the 1st minute of life was 5.7, and in the 5th minute of life 7.5. In the case of oxytocin, the score in the 1st minute was 5.3, and in the 5th minute of life it was 7.3. The results of the study by Sharada et al. [62] show that newborns of mothers induced with oxytocin, in the 1st minute of life received 4.7 points, and in the 5th minute of life 7.9 points, and of those induced with misoprostol received 5.2 points in the 1st minute of life, and in the 5th minute of life 8.2 points. The mean neonatal Apgar score in the study by Pourali et al. [63] was higher after the use of misoprostol 9.8 points than after the use of oxytocin 9.3 points. According to our own research and studies conducted by Kashanian et al. [64], the highest percentage of Apgar scores, both in the 1st and 5th minute, respectively 62.5% and 77.5%, was within the normal range, corresponding to the good condition of the newborn after delivery (9–10 points) in the case of induction with oxytocin and misoprostol.

In contrast, in the studies of Sajjad et al. [65], the highest percentage of newborns of mothers induced with misoprostol 86.8% and oxytocin 83%, scored more than 6 points on the Apgar scale in the 1st minute of life. Also, the largest number of newborns, regardless of the method of induction, received more than 7 points on the Apgar scale in the 5th minute of life. In these studies, no differences were observed between misoprostol induction and oxytocins induction in terms of neonatal Apgar scores. Results of the study by Fareed et al. [66] indicate that newborns of mothers induced with misoprostol 92% and oxytocin 90% obtained more than 7 points on the Apgar scale in the 5th minute of life. On the other hand, Tayab et al. [67] in their study on the comparison of labor induction with misoprostol or oxytocin, noted that the average neonatal Apgar score in the 1st minute of life was 8.4 points after using misoprostol and 8.5 after using oxytocin. A similar result of the average Apgar score in the above-mentioned studies was recorded in the 5th minute of life, with misoprostol 9.1 and oxytocin 9.2. In the studies by Hokkila et al. [56], comparing the effects of vaginal and oral misoprostol, no differences in neonatal outcomes were observed. Infants of mothers receiving intravaginal 3.1% or oral misoprostol 1.5% had a cord blood pH value below 7.05. The majority of newborns, both in the 1st and 5th minute of life, received more than 7 points on the Apgar scale. In their research, Schmidt et al. [68] observed that more often newborns of primiparous women 14.8% had pH value lower than 7.15 compared to newborns of multiparous women (6.9%). In their studies, Wallstrom et al. [69] noted that more newborns of mothers induced with amniotomy had umbilical cord blood pH below 7.10 than after using other methods: misoprostol, oxytocin, preparations with PGE₂ and Foley catheter. The majority of newborns (100%) of mothers induced with oxytocin and the preparation with PGE₂ - Propess received more than 7 points on the Apgar scale in the 5th minute of life. In the studies of Litorp at al. [30] noted that the augmentation of labor with oxytocin may lead to an increased risk of adverse perinatal outcomes such as low Apgar score, and neonatal death.

Conclusions

The objective of this research was to compare the methods of preinduction and induction of labor in Poland and in Germany. We found that the health condition after birth estimated on the Apgar Scale did not depict substantial differences. And it was irrespective of the preinduction cervical ripening or induction methods. However, the methods in Germany were safer for the infants in terms of the results the acid base balance. Complications such as cervical tears, revision of the uterus, episiotomies appeared significantly more frequently in Poland. Whereas in Germany, first- and second-degree perineal tears occurred more often. The levels of hemoglobin did not indicate any specific differences between the two countries. The period of hospitalization was shorter in Poland. The duration of preinduction and induction in both countries did not reveal significant discrepancies. Nevertheless, the methods used in Germany were more effective, as the change in scoring on the Bishop Scale was more considerable in Germany. To conclude, the methods of preinduction and induction of labor used in Germany should be implemented in Poland due to their high effectiveness and safety of use.

Abbreviations

FGR

Fetal growth restriction

RDS

Respiratory distress syndrome

WHO

World Health Organization

USG

Ultrasonography

CTG

Cardiotocography

cBase

Base excess

PGE₂

Prostaglandin E₂

Author contributions

Dr. Agnieszka Kleszcz conceived the study, analyzed the data, and drafted the manuscript. Dr. Dorota Ćwiek and Prof. O. Sipak -Szmigiel analyzed the data. All authors have approved the manuscript and agree with its submission to the journal. All authors approved the final version of the manuscript and agree to be accountable for all aspects of this work.

Funding

Not appicable. The author(s) received no specific funding for this work.

Data availability

The datasets used and/or analysed during the current study are available from the corresponding author on reasonable request.

Declarations

Ethics approval and consent to participate

Informed consent was obtained from all the participants. The need for study approval was waived by the Ethics Committee of Pomeranian Medical University in Szczecin, Poland (No. KB-0012/370/11/17) and the Ethics Committee of State Chamber of Physicians of Brandenburg, Germany (No. AS 93(a)/2017). They confirmed that official ethical approval was not required. The consent of the Hospital Director was obtained for access to medical data.

Consent for publication

Not applicable.

Competing interests

The authors declare no competing interests.