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ORIGINAL ARTICLE
Year : 2018  |  Volume : 21  |  Issue : 3  |  Page : 312-317

Is there A Relationship between route of delivery, perinatal characteristics, and neonatal outcome in preterm birth?


1 Department of Obstetrics and Gynecology, Trakya University Medicine Faculty, Edirne, Turkey
2 Department of Obstetrics and Gynecology, Pendik Research and Education Hospital, Marmara University, Istanbul, Turkey

Date of Acceptance13-Nov-2018
Date of Web Publication09-Mar-2018

Correspondence Address:
Dr. Z N Dolgun
Department of Obstetrics and Gynecology, Trakya University Medical Faculty, Edirne 22030
Turkey
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Source of Support: None, Conflict of Interest: None


DOI: 10.4103/njcp.njcp_333_16

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   Abstract 


Background: Preterm birth is one of the most challenging problems in obstetric care and it is closely related to perinatal mortality and morbidity. The aim of the current study was to document our experience with preterm births and to analyze the association between perinatal variables and clinical outcomes. Methodology: In this retrospective study, data were derived from the medical records of 785 singleton preterm births delivered in the obstetrics and gynecology department of our institution. Variables under investigation were maternal and gestational ages, fetal gender, route of delivery (vaginal vs. cesarean section [C/S]), causes of preterm birth, birth weight, placental weight, umbilical cord length, and Apgar scores at the 1st and 5th min. Results: Pregnant women with advanced age (≥35 years) were more likely to undergo C/S (P < 0.001). Apgar score at the 1st and 5th min was influenced significantly by gestational age (P < 0.001), newborn birth weight (P < 0.001), placental weight (P < 0.001), and umbilical cord length (P < 0.001). Infants delivered due to antepartum fetal distress indication had remarkably lower Apgar scores at the 1st min and the birth weight seemed to be positively correlated with Apgar scores at both 1st (P < 0.001) and 5th min (P < 0.001). Apgar scores both at the 1st and 5th min were positively correlated with placental weight (R: 0.239 and 0.231, respectively, and P < 0.001 for both) and length of umbilical cord (R:0.228 and 0.211, respectively, and P < 0.001 for both). Conclusion: Advanced age pregnancies have higher C/S rates, but Apgar scores are significantly correlated with infant characteristics. Umbilical cord length and placental weight might be the new add-on predictors of postpartum well-being in premature infants.

Keywords: Apgar score, morbidity, neonatal, outcome, pregnancy, preterm birth


How to cite this article:
Dolgun Z N, Inan C, Altintas A S, Okten S B, Karadag C, Sayin N C. Is there A Relationship between route of delivery, perinatal characteristics, and neonatal outcome in preterm birth?. Niger J Clin Pract 2018;21:312-7

How to cite this URL:
Dolgun Z N, Inan C, Altintas A S, Okten S B, Karadag C, Sayin N C. Is there A Relationship between route of delivery, perinatal characteristics, and neonatal outcome in preterm birth?. Niger J Clin Pract [serial online] 2018 [cited 2022 Dec 8];21:312-7. Available from: https://www.njcponline.com/text.asp?2018/21/3/312/226967




   Introduction Top


Preterm birth is one of the most serious problems encountered during the care of pregnant women, and it constitutes a substantial proportion of perinatal mortality and morbidity worldwide.[1],[2],[3]

It is linked with several maternal risk factors, a higher rate of complications in pregnancy, a higher cesarean section (C/S) rate, and low 1st and 5th min Apgar scores at birth.[4] However, there is a debate on the importance of Apgar scores, especially 5th-min Apgar score which defines the degree of birth asphyxia and reflects the quality of obstetric care.[4],[5] It is used to compare the neonatal outcome at different units worldwide and in spite of the development of novel indicators of birth asphyxia such as umbilical cord acid-base balance measurement; Apgar score has maintained its popularity. It is a reliable indicator for both full-term and preterm infants and low birth weight babies.[5] A low Apgar score <7 at 5th min has important implications in terms of neonatal mortality and morbidity including respiratory distress and neurological problems. Notably, the vast majority of these infants with low Apgar score <7 at the 5th min will be healthy both during the neonatal period and later on in life. Furthermore, the mode of delivery, intrauterine meconium release, and abnormalities in cardiotocography were associated with a low Apgar score.[4],[6],[7],[8]

The aim of the current study was to document our[7] experience with preterm births and to analyze the association between clinical outcomes and perinatal variables including gestational age (GA) at birth, fetal gender, route of delivery, causes of preterm birth, birth weight, placental weight, umbilical cord length, and Apgar scores at the 1st and 5th min.


   Methodology Top


This retrospective study was conducted in the obstetrics and gynecology department of our institution following the approval of local Institutional Review Board. Medical records of 785 singleton pregnancies who gave preterm birth (26–36 weeks of gestation) between January 2008 and December 2015 were studied. In this study, the average age of pregnant women was 27.2 ± 6.5 (range, 13–45) years. Basic descriptive, medical, and obstetrical histories were collected from the patients' medical records. According to our institution's protocol for the management of preterm labor, intravenous hydration and tocodynamometer monitorization were the first intervention. Transvaginal ultrasound was performed to evaluate cervical length (CL) when patients' bladder was empty. If a shortened CL (≤25 mm) was detected or the contractions caused progressive cervical shortening, tocolytic (oral nifedipine or beta-mimetics), and corticosteroid (intramuscular 12 mg of betamethasone, two doses, 24 h apart) administrations to promote fetal pulmonary maturation began. If premature rupture of membranes occurred after 34 weeks GA, spontaneous labor was accepted and monitored closely. Antibiotic administrations (1 g of intravenous ampicillin in every 6 h) began if the labor took longer than 24 h. Antibiotic administration was started immediately and tocolysis began if necessary for fetuses younger than 34 weeks of pregnancy in cases without findings of chorioamnionitis. In the event of chorioamnionitis suspicion, pregnancy was terminated immediately by the most appropriate route. Determination of GA was made with respect to the last menstrual date and ultrasonography during the first trimester. In case of discrepancy of more than 5 days between two diagnostic modes, ultrasonographic data were preferentially used. All the patients' first-trimester ultrasound measurements were available from their first-trimester screening test or prior examinations. Obstetric ultrasound examinations were performed through the same ultrasound machine Voluson Pro Expert 730 (General Electric, USA) every 2 weeks or when necessary. Fetal heart rate monitoring was made at least once a week before labor and continuously during labor.

Apgar score was utilized as a direct measure of perinatal morbidity and birth weight, head circumference, length of umbilical cord, and placental weight served as indirect indicators. Maternal age, gestational weeks, gender(s) of the infant(s), mode of delivery, indications for C/S, birth weight, head circumference, height, placental weight, Apgar scores at the 1st and 5th min, and length of umbilical cord were noted. Presumable causes of preterm birth were documented, and any association between Apgar scores and baseline descriptive and obstetric features was investigated. In this context, effort was spent to identify whether there was a relationship between the route of delivery, neonatal/maternal outcomes, and other clinical parameters.

Exclusion criteria included were intrauterine fetal death, major congenital malformations, multiple pregnancies, placental anomalies, pregnancy-induced hypertension disorders (preeclampsia, eclampsia, HELLP, etc.), fetal growth restriction (fetal abdominal circumference <10% and estimated fetal weight below the 10th percentile), and patients who had any missing data.

Analysis of data was made using the Statistical Package for Social Sciences (SPSS Inc; version 20.0, Chicago, IL, USA). Normal distribution of data was tested with Kolmogorov–Smirnov test. Parametric tests were used for variables with normal distribution while variables without normal distribution were evaluated with nonparametric tests. Multivariate analysis between quantitative variables was sought using Pearson correlation and Spearman's rho tests. Two independent groups were compared by means of independent-samples t-test and Mann–Whitney U-tests. More than two independent groups were compared by means of a parametric (one-way ANOVA) or a nonparametric (Kruskal–Wallis) test. Categorical variables were compared with Pearson Chi-square test. Quantitative variables were expressed as mean, standard deviation, or median-interquartile range values. For qualitative variables, terms of frequency and percentage (%) were used. Confidence interval was set at 95% and P < 0.05 was considered as statistically significant.


   Results Top


Descriptive and perinatal characteristics of our series are shown in [Table 1] and [Table 2]. Age seemed to have a remarkable effect on the mode of delivery, and pregnants with advanced age (≥35 years) were more likely to undergo C/S (P< 0.001). Apgar score at the 1st and 5th min was influenced significantly by advancing GA (P< 0.001), birth weight (P< 0.001), height (P< 0.001), head circumference (P< 0.001), placental weight (P< 0.001), and umbilical cord length (P< 0.001). In spite of these associations, maternal age did not have an influence on Apgar scores at the 1st and 5th min (P = 0.392, P = 0.104, respectively) [Table 3] and [Table 4].
Table 1: Descriptive and obstetric characteristics for our series of 785 consecutive preterm singleton pregnancies

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Table 2: Perinatal characteristics of our preterm singleton birth series

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Table 3: Impacts of gender of the neonates and route of delivery on Apgar scores at the 1st and 5th min

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Table 4: Impacts of perinatal characteristics on Apgar scores at the 1st and 5th min

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Majority of deliveries were performed by C/S (n = 500; 63.7%), and vaginal route was carried out in 285 preterm births (n = 285; 36.3%). Preterm infants delivered through vaginal route had significantly lower Apgar scores at the 1st and 5th min (P< 0.001). A total of 394 preterm infants (50.1%) were female while 391 (49.8%) of neonates were male.

Infants delivered due to acute fetal distress (AFD) indication had remarkably lower Apgar scores at the 1st min (P = 0.039). In contrast, Apgar scores at the 5th min were not affected adversely in infants with AFD (P = 0.055) [Table 5].
Table 5: Distribution of Apgar scores at the 1st and 5th min with respect to diagnosis of antepartum fetal distress

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Interestingly, Apgar scores at the 1st and 5th min were positively correlated with placental weight (r = 0.239, P < 0.001; r = 0.231, P < 0.001) and length of umbilical cord (r = 0.228, P < 0.001; r = 0.211; P < 0.001) [Table 4] and [Table 6].
Table 6: Bivariate correlations among different obstetric features

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   Discussion Top


The objective of the present study was to document our clinical experience with preterm singleton births and to identify whether there is a relationship between the perinatal characteristics and clinical outcomes. Main findings of this study were that C/S was more frequently performed in preterm pregnancies with advanced maternal age. Apgar scores at both 1st and 5th min were improved in parallel to progression of gestational weeks and growth of the fetus. C/S was associated with better Apgar scores, especially in the 5th min.

There is a debate on whether planned preterm cesarean delivery reduces the likelihood of fetal or neonatal demise and birth trauma.[9],[10] Malloy reported that primary C/S may actually increase the risk of neonatal mortality and morbidity for intermediate or late low-risk preterm neonates (32–36 weeks).[11],[12] Since hormonal and physiological alterations associated with labor are essential for pulmonary maturation, C/S can result in an increased risk of respiratory morbidity in neonates.[13]

The term breech trial displayed a noteworthy reduction in perinatal mortality with planned C/S.[14] C/S was associated with 3–5 times higher risks for maternal death, twice higher for hysterectomy and intensive care admission compared to vaginal delivery.[15] Moreover, rates of postnatal infection, thrombosis, pulmonary embolism, and excessive blood loss were higher after C/S.[16] It must be remembered that majority of these complications may be attributed to the underlying causes that subsequently necessitate C/S. This is more obvious if the procedure is carried out as an intrapartum emergency. Hence, planned C/S may serve as a preventive way of intrapartum emergency surgery and its related complications.[17] However, C/S for the first birth is associated with an increased risk of placenta previa and ablation placenta in the second pregnancy.[18] Apgar scores are a result of the complex interaction of pregnancy complications and therapeutic interventions. Low Apgar scores were linked with higher incidences of neonatal interventions, complications, need for positive pressure ventilation, and cardiopulmonary resuscitation.[9] Our results consistently demonstrated better Apgar scores at the 1st and 5th min for babies born with C/S. Especially in the serious asphyxia group (Apgar 0-3), we detected a significant negative trend in the 5th-min Apgar scores of the vaginally born group. Based on the present data, it is impossible to conclude on a preferred mode of delivery in preterm births.

In clinical practice, meconium staining of amniotic fluid and abnormal fetal heart tracing was used as a sign of asphyxia and AFD. Our results for AFD did not demonstrate any significant difference on Apgar scores at the 5th min; however, the 1st-min scores were significantly low (P = 0.039). This reflects that AFD evaluation instruments are limited and barely reliable. Even though Apgar scores at the 1st and 5th min were used to express fetal condition at birth, some publications advocate that only prolonged low scores were consistent with prognostic value for neural development. Topp et al. noted that delivery by C/S was not protective for cerebral palsy in preterm fetuses, and predictive value of Apgar scores was limited.[19]

The secondary outcome of this study was the relation of better Apgar scores with longer cord and heavier placenta. Georgiadis et al. reported that cord length is positively correlated with birth weight, placental weight, and maternal age whereas shorter cord results in ablatio placenta.[20] Our results supports these findings and also adds that higher Apgar scores should be expected in premature fetuses with longer cords. This might be related to that the longer the cord is the better the fetal movement and the cord blood flow and the neurologic development depending on fetal moves might improve better.

The present study has important implications for preterm births. Selection of the mode of delivery must be made on individualized basis, and in this study, we see that advanced age is an important predictor for choice of C/S, but it has limited affect on the fetal outcome. Advancement of the GA and promotion of intrauterine growth of fetus before preterm birth are key points in the achievement of better Apgar scores and clinical outcomes. At this point of view, adding placental weight estimations and trying to evaluate fetal cord length to improve a better algorithm should be established for appropriate care of preterm deliveries. Moreover, AFD must be carefully evaluated in preterm delivery since it may be overconsidered and bring about a substantial risk particularly in the early postpartum period.

Although we did our best to limit the effect of confounding factors such as excluding any pathology that necessitates preterm labor and implementing the appropriate statistical analysis such as multivariate analysis, some subjective factors such as mothers' preconceptional well-being and proper pregnant diet might influence the materno-fetal outcomes.

The main limitations of the current study include the retrospective design and the lack of future information about the neonates. However, this study only focused on the postpartum Apgar scores so larger, prospective, and more sophisticated trials need to be conducted to fully resolve this problem. Furthermore, these findings reflect the experience gathered from a single institution and may not represent the whole community in all aspects.


   Conclusion Top


Advanced maternal age pregnancies have higher C/S rates, but maternal age does not effect Apgar scores. Apgar scores are significantly correlated with infant characteristics according to this study. Umbilical cord length and placental weight might be the new add-on predictors of postpartum well-being in premature infants.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.



 
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Svenvik M, Brudin L, Blomberg M. Preterm birth: A Prominent risk factor for low apgar scores. Biomed Res Int 2015;2015:978079.  Back to cited text no. 4
    
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Hannah ME, Hannah WJ, Hewson SA, Hodnett ED, Saigal S, Willan AR, et al. Planned caesarean section versus planned vaginal birth for breech presentation at term: A randomised multicentre trial. Term Breech Trial Collaborative Group. Lancet 2000;356:1375-83.  Back to cited text no. 14
    
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    Tables

  [Table 1], [Table 2], [Table 3], [Table 4], [Table 5], [Table 6]



 

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