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Introduction
Elective cesarean delivery (CD) without labor is one of the most frequent obstetric interventions performed for the convenience of patients or obstetric providers, even in the absence of obstetric indications. Common indications for elective CD include maternal request and increased risks associated with vaginal delivery (abnormal presentation, history of uterine surgery, and other underlying medical conditions).
The advantages of elective CD without labor include lack of fear associated with pain, process, length, and/or complications of labor and vaginal delivery and lack of concerns regarding the need for emergency CD and the risks associated with it [1,2]. The biggest potential advantage of elective CD is scheduled birth, which can prevent sudden disruption of patients’ lives and providers’ work. Studies have shown that the lowest incidence of perinatal morbidity and mortality is at approximately 39–40 weeks of gestation [3]. Since the risk of intrauterine demise is absent once the fetus is delivered, the risk of other complications or stillbirth in elective CD is low [4]. From the point of view of scheduled delivery and neonatal morbidity, a reasonable alternative for elective CD is induction of labor (IOL), which represents the most frequent interventional procedure in obstetric medicine and is reportedly performed in 20–25% of all pregnancies [5,6]. However, induction may fail and lead to an unscheduled cesarean birth. It may also be associated with an increased length of labor, potential patient/provider impatience, and a long latent phase [7,8]. Concomitantly, CD without labor may also be associated with an increased risk of placental attachment disorders [9], uterine rupture in subsequent pregnancies [10,11], maternal morbidity [12,13], and a longer recovery period [14].
The effect of CD without labor on adverse maternal and perinatal outcomes has received increasing attention in the public and scientific literature [15–18]. However, the merits and safety of elective CD and elective d with planned vaginal delivery remain largely unaddressed.
In a contemporary society, pregnant persons’ right to be actively involved in choosing their preferred route of delivery is widely accepted by both clinicians and patients, and performing a CD based on a well-informed patient’s request is considered medically and ethically acceptable [19].
Since elective interventions including CD and IOL are being performed more frequently, their implications on maternal and neonatal risks have gained importance. The risks and benefits of elective CD need to be balanced with the risks and benefits of IOL while deciding the route of delivery.
The present study aimed to investigate and compare the maternal and neonatal morbidities associated with elective CD without labor and those associated with IOL at ≥38 weeks of gestation.
Materials and methods
This observational retrospective study was conducted between January 1, 2013 and December 31, 2020 at the National Health Insurance Service Ilsan Hospital, Republic of Korea. The study was approved by the institutional review board of the National Health Insurance Service Ilsan Hospital (#NHIMC 2021-02-027).
All women at ≥38 weeks of gestation were eligible for inclusion in this study. The following inclusion criteria were applied: 1) nulliparous women; 2) uncomplicated, live, singleton pregnancy; and 3) fetal gestational age ≥38 weeks. Patients with the following conditions were excluded from the study: 1) placenta previa, 2) non-reassuring nonstress test (NST), 3) pregnancies with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection, 4) fetal birth weight <2,500 g, 5) women with spontaneous labor before admission for delivery, and 6) diabetes or gestational diabetes with insulin control. We divided the eligible women into the IOL group or elective CD without labor group. The latter group underwent planned CD. Maternal and neonatal morbidities were evaluated and compared between the groups.
After admission to the delivery room for labor induction, IOL was attempted with oxytocin (intravenous injection of 10 IU/mL pitocin; Jeil Pharmaceutical Co., Ltd, Daegu, Korea) or prostaglandin E2 (intravaginal administration of 10 mg propess; Bukwang Pharm Co., Ltd, Seoul, Korea). Once the patients started experiencing spontaneous labor pain, augmentation with pitocin was attempted if labor was inadequate to progress further. Prostaglandin E2 was administered vaginally and removed 24 hours after insertion or earlier in case of onset of active labor, rupture of membranes, or abnormal cardiotocography findings (uterine tachysystole or other abnormalities in the fetal heart rate pattern).
To evaluate maternal morbidities, data regarding the method of delivery (vaginal or cesarean), maternal age, gestational age, hemoglobin levels, rate of CD, length of hospital stay, outpatient visits after discharge (>2), and readmission within <1 month after discharge were obtained from the institutional electronic medical records.
To evaluate neonatal morbidities, we investigated the 1-minute Apgar score, 5-minute Apgar score, neonatal intensive care unit admission rate, meconium-stained amniotic fluid status, and intubation status.
For statistical analyses, demographic and clinical characteristics were compared between the groups using Student’s t-test for continuous variables and chi-square test or Fisher’s exact test for categorical varaibles. All P-values were two-tailed, with statistical significance set at P<0.05. All analyses were performed using IBM SPSS Statistics version 23.0 (IBM Corp., Armonk, NY, USA).
Results
Altogether, 716 nulliparous women with fetal gestational age ≥38 weeks were recruited. After excluding 274 women who were admitted with spontaneous labor, 11 with placenta previa, two with non-reassuring NST, one with twin pregnancy, one with SARS-CoV-2 infection, and 32 with neonatal weight <2,500 g; the remaining 395 women were included in the final analysis.
Among the 395 women included in the study, 69 were in the elective CD without labor group and 326 were in the IOL group. The flowchart of the study is depicted in Fig. 1.
The demographic data and clinical outcomes are summarized in Table 1. The elective CD without labor group exhibited higher maternal age (34.7±4.2 vs. 31.5±4.5 years, P<0.001) and lower gestational age at birth (38.2±0.5 vs. 39.2±0.8 weeks of gestation, P<0.001) than the IOL group. Fetal body weight did not differ between the groups (Table 1).
No significant differences were observed in pre-pregnancy maternal body mass index (BMI), BMI at term, and neonatal birth weight between the groups (Table 1).
The reasons for selecting IOL or CD are presented in Table 2. The most common reason for IOL was elective without medical indication (56.7%), and the most frequent indication for CD was maternal request before labor (47.8%). The IOL group included mild cases of oligohydramnios, intrauterine growth restriction, and pregnancy-related hypertension; but those who remained pregnant until 38 weeks. No significant difference was observed in terms of underlying medical conditions (hypertensive disorder and diabetes) between the groups (Table 1).
Maternal hospital stay was longer in the elective CD without labor group (6.6±0.8 vs. 4.3±1.5 days, P<0.001). The rate of antibiotic usage after discharge was higher in the IOL group (14.5% vs. 39.5%, P<0.001). In contrast, the rate of uterotonic agent usage after discharge was higher in the elective CD without labor group (27.5% vs. 17.2%, P=0.046). Despite these differences in the usage of pharmaceutical agents, there were no differences in postpartum bleeding, transfusion rate, number of outpatient visits, and readmission rates after discharge between the groups (Table 3). Moreover, there was no statistically significant difference in the rate of postpartum uterine artery embolization due to massive hemorrhage.
In terms of neonatal morbidities, the rate of meconiumstained amniotic fluid was higher in the IOL group (14.3% vs. 4.3%, P=0.025), while gestational age at birth was lower in the elective CD group (38.2±0.5 vs. 39.2±0.8, P<0.001). However, there were no differences between the groups in terms of Apgar score <7 at 5 minutes, rate of neonatal intensive care unit admission, intubation, brain damage, and respiratory distress syndrome (Table 4).
The results of logistic regression analysis of maternal and neonatal outcomes are presented in Table 5. The rate of antibiotic usage after discharge was higher in women who underwent elective CD without labor. However, the incidence of meconium-stained amniotic fluid was similar between the groups.
Multivariate logistic regression after adjusting for maternal age, gestational age, pre-pregnancy BMI, gestational diabetes, and hypertension revealed that pregnant women in both the groups had similar complication rates related to composite maternal morbidity including transfusion, embolization, uterotonic agent usage, and antibiotic usage (relative risk [RR], 0.68; 95% confidence interval [CI], 0.37–1.23; P=0.201). The elective CD group had a lower risk of complications related to composite neonatal morbidities including admission to intensive care unit, meconium-stained amniotic fluid, transient tachypnea of the newborn, brain damage, intubation, and Apgar score <7 in 5 minutes (RR, 0.45; 95% CI, 0.24–0.86; P=0.014).
Discussion
The present study revealed that both elective CD and IOL groups were associated with similar rates of postpartum bleeding episodes, number of outpatient visits, and readmission rates after discharge. However, the elective CD group had a lower rate of obstetric wound infection. In terms of neonatal outcomes, elective CD was associated with a decreased risk of composite neonatal morbidity despite lower gestational age at birth and higher neonatal weight.
CD has become a safer and more common procedure, and women are playing a more active role in their obstetric care. Hence, many women request planned CD without labor (CD upon maternal request). Prevalence of cesarean births on maternal request without medical or obstetrical indications varies widely across countries, ranging from 0.2% to 42% of all deliveries [20]. For example, in China, maternal request has become the most common reason for non-indicated CD without labor in developed areas [21].
Our study showed similar rates of postpartum hemorrhage between elective CD and IOL despite reports indicating that the rate of postpartum hemorrhage is usually higher in CD than in vaginal deliveries. In contrast, some studies have shown that the risk of early postpartum hemorrhage and composite maternal morbidity was lower in elective CD when compared with planned vaginal delivery [22,23], but with similar rates of postpartum hemorrhage and transfusion. In our IOL group, women with failed vaginal deliveries who switched to intrapartum cesarean section during labor exhibited higher transfusion rates.
According to the results of the present study, usage of uterotonic agents was higher in the elective CD group. Uterotonic agents were administered to these patients to treat postpartum hematomas during outpatient follow-up. In the elective CD group, intrauterine hematoma or hematometra may have occurred from an incompletely effaced cervix due to the absence of labor.
Use of antibiotics was higher in the IOL group. At 1 week after discharge, wound examination showed that the perineum bore down in a sitting position compared to the abdomen with a cesarean incision, which may have delayed wound healing, although the wound size was larger in the elective CD group.
Since cesarean birth before the onset of labor reduces or eliminates fetal/neonatal morbidity and mortality associated with the process of labor and vaginal birth [24,25], many pregnant women choose CD. According to Zanardo et al. [26] and Hansen et al. [27] neonatal respiratory problems including respiratory distress syndrome and transient tachypnea of the newborn are more common after planned cesarean section than after vaginal delivery, which may lengthen the neonatal hospital stay. In the present study, most of the neonatal morbidities exhibited similar incidence rates between the groups, although the incidence of meconium-stained amniotic fluid was higher in the elective CD group. In a long-term follow-up of children delivered by cesarean section, Keag et al. [28] reported that these children were at an increased risk of asthma up to the age of 12 years.
Though it was reported that maternal and neonatal adverse outcomes of IOL were similar to those in a spontaneous labor group in uncomplicated nulliparous women [29], IOL may also be associated with increased length of labor, increased length of hospital stay, potential patient/provider impatience, neonatal morbidity including poor fetal lung maturation (if IOL is performed before 38 gestational weeks), and need for CD if IOL fails [7,8]. Particularly, delivery by intrapartum CD during IOL may carry a higher risk of maternal morbidity than elective CD without labor [30].
Some authors have interpreted the available data to conclude that elective CD is safer than planned vaginal delivery [31], which is consistent with the findings of our study.
The present study has several strengths. We collected data from the electronic medical records of a single institution using a uniform, standard protocol. Therefore, we were able to obtain complete patient records and thoroughly analyze patient information. Moreover, to minimize the effect of parity, we enrolled only the women who delivered their first child and excluded those with prior CD. Maternal and neonatal risks associated with first cesarean birth in nulliparous women could be different from those associated with second or subsequent cesarean births. Additionally, risks associated with IOL in nulliparous women could also be different from those in multiparous women.
Despite its strengths, this study has several limitations. It included a small number of women, which may not be sufficient to generalize the data. Since this was a retrospective observational study, it was impossible to eliminate the possibility of confounding bias. The indications for IOL were heterogeneous and looked like a poor fetal condition before delivery in the IOL group when compared with the elective CD group. However, there was no difference in the incidence of hypertensive disorder and gestational diabetes between the groups, and maternal age and lower gestational age at birth in the elective CD group could be risk factors for poor maternal and neonatal outcomes. Most of the patients with uncontrolled blood pressure and those on insulin therapy for diabetes had labor pain before 38 gestational weeks. Therefore, most of the women included in this study were low-risk pregnant women. We did not consider subsequent pregnancy-related complications including uterine rupture, placenta previa, or long-term neonatal complications.
In conclusion, IOL and elective CD without labor were associated with similar rates of composite maternal morbidity. Elective CD had the advantage of a lower rate of obstetric wound infection, but was also associated with longer hospital stay and greater usage of uterotonic agents. Regarding neonatal outcomes, elective CD had a decreased risk of composite neonatal morbidity despite lower gestational age and lower neonatal body weight. To optimize pregnancy outcomes, this information should be considered by women contemplating the preferred mode of delivery and also by the obstetricians counseling them. Furthermore, we should consider patient-specific issues that can affect the choice of delivery route. These include comorbidities, BMI, future reproductive plans, and an individual’s personal philosophy about childbirth.
In the future, properly designed long-term and large-scale studies are needed to further evaluate the effects of CD without labor on the long-term outcomes of mothers and neonates.
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