Maternal childbirth experience and induction of labour in each mode of delivery: a retrospective seven-year cohort study of 95,051 parturients in Finland

Childbirth as a physical, social and emotional event has essential immediate and long-term implications on the health and wellbeing of a mother and the entire family [1]. It is also shown that poor or traumatic childbirth experiences have an impact on future reproduction [2‐4]. The visual analogue scale (VAS) as a simple measure for childbirth experience may not fully capture the holistic nature of the childbirth phenomenon, but its validity and reliability as an overall satisfaction measure has been comprehensively demonstrated [5‐8].

During the past decade several meta-analyses and reviews have indicated benefits benefits from labour induction for the neonate without increased risk for the mother in term and post-term gestations [9, 10]. These studies indicated more desirable perinatal outcomes, as induction decreased the numbers of neonate deaths and lowered the need for the neonatal intensive care unit, and decreased the need for caesarean sections as well. However, the data have been criticised on methodological deficiencies due to inappropriate control groups and different timings of compared trials [11‐13]. The obstetrical arguments for induction in end term or post-term gestations are undeniable [12]. Nevertheless, the association between induction of labour and the maternal experience of childbirth is poorly understood [8, 14]. It has been shown that successfully induced labour resulting in vaginal delivery did not negatively affect birth outcomes but had a partial negative effect on the childbirth experience [15, 16]. In addition, childbirth experience may also depend on the mode of delivery [2, 16‐19].

In this study we investigate how labour induction influences the childbirth experience in different modes of delivery. We distinguish between spontaneous and induced labours and, consequently, address their effects through actual mode of delivery for the childbirth experience.

The childbirth experience is measured by VAS in the postpartum unit of the delivery hospital. The VAS scale in this study is from ‘very negative childbirth experience’ (1) to ‘very positive childbirth experience’ (10). The VAS was collected as a part of a conversation with a midwife before discharge from the postpartum unit. The midwives have been instructed to pursue as safe atmosphere as possible to avoid biased responses. The women rating their childbirth experience with the score of 5 or less on the VAS scale were offered an opportunity to receive additional support.

The VAS is combined with the Medical Birth Register data using the mother’s identification code, given for all citizens and permanent residents of Finland. The Medical Birth Register is a comprehensive medical register kept by the Finnish Institute for Health and Welfare including antenatal, perinatal and postpartum information from all mothers and infants up to 7 days. The data were pseudonymised and therefore parturients’ identities could not be detected in this data.

This study includes all singleton live births at term (gestational age ≥37) in Helsinki and Uusimaa District hospitals from January 2012 to December 2018. The childbirth experience and labour induction in mode of delivery groups being the key concepts of this study, the parturients without these variables were excluded (n=11 635) as well as those having elective caesarean sections (n=6 266). The data inclusion criteria are depicted in Fig. 1. There are specific disparities between primiparous and multiparous women when childbirth and mode of delivery are considered [20‐22] and therefore, these groups are analysed separately throughout the study. The mode of delivery was classified into four categories: unassisted (VD) and instrumental vaginal deliveries (IVD) as well as urgent (UCS) and emergency caesarean sections (ECS).

The Institutional review board gave the permission (HUS/483/2020) to use the data and waived the requirement of the informed consent for the study since it was a register-based study.

The inclusion criteria for this study are depicted in Fig. 1. We included all hospital childbirths of term (≥37 weeks) singleton pregnancy with live infant. Childbirth experience and labour induction being of interest, we excluded the childbirths of elective caesarean sections and those lacking VAS. The final data consisted of 95 051 parturients including 43 403 primiparas and 51 648 multiparas. The share of induced labours in primiparas was 27% and in multiparas 21%.

The characteristics of spontaneous and induced labour groups are presented in Table 1 in categories used in covariance analysis. Difference between distributions of induced and spontaneous groups was detected in all variables except the use of epidural anesthesia among primiparas and maternal age among multiparas. The maternal factors such as mean age (30.1 vs. 29.1 years for primiparas, p<0.001; 32.3 vs. 32.0 years for multiparas, p<0.001) and mean BMI before pregnancy (24.7 vs. 23.2 for primiparas, p<0.001; 26.0 vs. 23.9 for multiparas, p<0.001) were higher in the induced labour group compared to the spontaneous onset of labour group. Gestational age, being one of the common indications for labour induction, was higher in the induced labour group (40.2 vs. 39.7 for primiparas, p<0.001; 39.8 vs. 39.7 for multiparas, p<0.001). Prolonged labour was diagnosed more frequently with induction than with spontaneous labour (p<0.001). The average birth weight was higher for the labour induction group for both primiparas (3516g vs. 3465g, p<0.001) and multiparas (3661g vs. 3616g, p<0.001). In our data preeclampsia (ICD10 codes O11, O14, and O15.0) was diagnosed in 1000 (2.3%) of primiparous and in 431 (0.8%) of multiparous women. Gestational diabetes (ICD10 code O24.4) was diagnosed in 5926 (13.7%) primiparous and in 8415 (16.3%) multiparous women.

The Medical Birth Register does not include complete data about different techniques of induction used in hospitals. However, the used techniques of induction separately in primiparas and multiparas were artificial rupture of membranes (79% and 88%, of induced labours), prostaglandin (28% and 19%) and oxytocin (89% and 74%).

Our study revealed three main findings: 1) The induction of labour in general impaired the childbirth experience, excluding primiparas who underwent an emergency caesarean section. Poor childbirth experience risk is higher in the induced labour group for both primiparas and multiparas. 2) Operational deliveries were perceived more negative if preceded by labour induction, as one fifth of induced primiparas and one seventh of induced multiparas valued their experience as poor. 3) We found a decreased likelihood to achieve vaginal delivery among women who had induced labour.

To compare previous studies assessing childbirth experience, we gathered their main results in Table 5. In our study, we show that induction of labour produces impaired childbirth experience, which is in line with a previous study [15]. The risk of achieving a poor experience was analysed in several studies [2, 7, 8, 24]. Inconsistencies in measurement of experience and definition of a poor or negative experience exist between the studies. However, the overall findings in the previous studies are in line with ours.

In previous studies, the role of the mode of delivery is mostly parallel to our findings. Two studies comparing average experience in mode of delivery groups [17, 18] confirm our finding that vaginal delivery produces the most positive and unplanned caesarean the most negative experience when elective caesarean is not considered. One study did not find association between the modes of delivery [25] and other findings were inconsistent with ours [19], which may be due to the sampling inadequacy (there were only 34 observations in CS group). The risk ratios of negative experience in previous studies indicate similar associations between the mode of delivery and childbirth experience regardless of the fact that we did not compute equivalent risk ratios for modes of delivery in our study.

In our study, we found that induced labour resulting in vaginal delivery was associated with a more positive childbirth experience on average than operational deliveries with spontaneous onset of labour. This leads to the conclusion that successful induction resulting in vaginal delivery does not ruin the positive childbirth experience. However, induction increases the risk for operational delivery which is also shown in previous studies [11, 12, 26, 27]. Operational delivery is likely to impair the childbirth experience, as supported by our findings that the childbirth is experienced more negatively if the labour induction results in caesarean section. It is possible that parturient feel frustration when failing to give vaginal birth together with discomfort and pain due to the unsuccessful labour induction. Our novel approach to evaluate the association of childbirth experience and induction in the mode of delivery should be explored more thoroughly to confirm the findings.

Our study is based on a large comprehensive data set of 95 051 childbirths and it covers 90% of eligible parturients in the study population. The data population covers nearly one third of all Finnish childbirths during the years 2012–2018. The VAS collection was an established routine practice of care, and its simplicity led to minimising the selection bias. The simplicity of the measure also attenuates the possible challenges due to the lack of shared language between the caregiver and the parturient. The national comprehensive Medical Birth Register in combination with the maternal childbirth experience provides reliable data to analyse the associations between the maternal childbirth experience and various factors behind it [28]. Despite the distinct levels of primiparas and multiparas, the resulting nearly identical patterns of childbirth experience confirm the reliability of our data.

Our study also has limitations. Our main outcome measure VAS does not incorporate the multidimensionality of the childbirth experience. However, VAS has been used to measure childbirth experience and satisfaction with childbirth in several previous studies [5‐8, 19]. Furthermore, VAS is moderately correlated with the highly established and validated W-DEQ (Wijma Delivery Expectancy/Experience Questionnaire) scale for measuring childbirth experience [5, 29].

The maternal childbirth experience was collected before the patient was discharged from the post-partum care unit, usually less than 72 hours after the delivery. This could have had an effect on the results, since traumatic experience might take longer to process in the mind [30]. Maimburg and colleagues [31] found similar tendency that women told more negative experiences five years after delivery although women changing their mind had more often experienced operative delivery. In our study setting this would lead to even greater difference. However, there are results that indicate the consistency of childbirth experience from a few days postpartum to few months afterwards [6, 17]. We did not account potential effects of preeclampsia or gestational diabetes which may cause some bias to the results. It has been shown that although gestational diabetes seems to increase the risk of induction, it has no effect on childbirth experience [8]. In the absence of research focusing on the relation between preeclampsia and childbirth experience, the study comparing the mental health indicators after normotensive and hypertensive pregnancies suggests that preeclampsia rises the risk of traumatic childbirth [32].

While the trial of induction is mostly based on obstetrical arguments (suspected fetal macrosomia, post-term gestation, or fear of childbirth) the results of this study are complicated by these underlying factors. By using detailed register data, we attempted to control these effects on the childbirth experience.

Labour induction produces a more negative childbirth experience for both primiparas and multiparas. Women who had induced labour had also decreased likelihood to achieve vaginal delivery. Although the negative effect of labour induction is detected for all modes of delivery, the highest risk for a poor experience is when labour induction results in an operative delivery. Our findings can be used in decision-making related to parturients requesting labour induction without clear obstetrical indications. Furthermore, the parturients facing cumulative obstetrics interventions require special support and counselling from obstetric care during and after delivery.