Neonatal outcomes associated with obstetric interventions performed during labor in nulliparous women

Objective: to analyze neonatal outcomes associated with obstetric interventions performed during labor in low-risk nulliparous women. Methods: a cross-sectional observational study of 534 low-risk nulliparous women. Results: interruption of skin-to-skin contact after delivery was shown to be associated with obstetric interventions such as cardiotocography at admission, oxytocin in labor, amniotomy, and episiotomy. The need for positive pressure ventilation and oxygen therapy was associated with the encouragement of the Valsalva maneuver; the performance of this maneuver was also associated with interventions such as amniotomy, episiotomy and directed pulling. Conclusion: the study showed that the use of obstetric interventions during labor in low-risk women is associated with unfavorable neonatal outcomes that lead to the need for further interventions after delivery. Descriptors: Infant, Newborn; Obstetric Nursing; Labor, Obstetric. *Extraído da dissertação “Análise dos resultados maternos e neonatais associados às intervenções realizadas durante o trabalho de parto de nulíparas de baixo risco”, Universidade Federal do Ceará, 2019. 1Universidade Federal do Ceará. Fortaleza, CE, Brasil. 2Centro Universitário Estácio do Ceará. Fortaleza, CE, Brasil. Autor correspondente: Paloma Gabrielly Amorim Monteiro Rua Irineu de Souza, 107, Álvaro Weyne. CEP: 60337180. Fortaleza, CE, Brasil. E-mail: pmonteeiro@hotmail.com EDITOR CHEFE: Ana Fatima Carvalho Fernandes EDITOR ASSOCIADO: Renan Alves Silva Paloma Gabrielly Amorim Monteiro1 Tatiane da Silva Coelho1 Adriana Moreno de Lima1 Uly Reis Ferreira1 Maria Salete Barbosa Monteiro2 Cinthia Maria Gomes da Costa Escoto Esteche1 Ana Kelve de Castro Damasceno1 Como citar este artigo: Monteiro PGA, Coelho TS, Lima AM, Ferreira UR, Monteiro MSB, Esteche CMGCE, et al. Neonatal outcomes associated with obstetric interventions performed during labor in nulliparous women. Rev Rene. 2021;22:e67921. DOI: https://doi.org/10.15253/2175-6783.20212267921 Monteiro PGA, Coelho TS, Lima AM, Ferreira UR, Monteiro MSB, Esteche CMGCE, et al Rev Rene. 2021;22:e67921. 2 Introdução Nas últimas duas décadas, com o intuito de resgatar a experiência do nascimento como um evento familiar, centrado na mulher e no seu protagonismo, onde as influências hospitalocêntricas intervencionistas são minimizadas, foram criadas estratégias para garantir uma atenção mais humanizada na gestação, parto e puerpério. Evidências científicas mostram que uma parcela considerável de complicações obstétricas pode ser reduzida com o uso adequado de tecnologia e intervenções por meio da atuação de profissionais qualificados que assumam papel coadjuvante, sem controlar ou interferir no processo fisiológico do parto, para não expor parturientes saudáveis às práticas iatrogênicas(1-2). De acordo com a Organização Mundial da Saúde, as intervenções que aceleram o processo do trabalho de parto realizadas pelo obstetra, sem necessariamente trazer benefícios à saúde da gestante ou, ainda, sem respaldo científico são consideradas intervenções desnecessárias e/ou danosas, principalmente em parturientes de baixo risco. Desde a década de 80, a Organização Mundial da Saúde e o Ministério da Saúde do Brasil vêm revisando as práticas da obstetrícia, propondo uma assistência baseada em evidências científicas, de forma a promover uma melhor experiência de parto e nascimento com desfechos maternos e fetais mais favoráveis(3-4). Estudo realizado, no Brasil fez um levantamento sobre as intervenções utilizadas no Sistema Único de Saúde e os indicadores de resultado da assistência, mostrando que 70,0% dos óbitos na infância ocorreram no período neonatal por prematuridade e baixo peso ao nascer. O uso rotineiro, ou não baseado em evidência científica, de intervenções obstétricas e neonatais pode gerar trauma obstétrico e asfixia, sendo este último um dos fatores mais frequentes dos óbitos neonatais precoces de recém-nascidos a termo. Evidencia, com isso, elevada proporção de óbitos por causas evitáveis, o que não ocorreria caso houvesse adequado atendimento à gestante no pré-natal e no parto e apropriada assistência ao recém-nascido(5-7). As pesquisas que abordam a influência de intervenções obstétricas sobre o bem-estar fetal são iniciativas ainda recentes e não costumam estar associadas a tais intervenções e desfechos neonatais, Estas realizam apenas a análise dos modelos de atenção ao parto, de forma geral e suas repercussões nos resultados perinatais ou investigam o uso de intervenções de forma individualizada e sua associação aos desfechos neonatais ocorridos, tal como o explanado na pesquisa que traz a associação da analgesia no trabalho de parto à ocorrência de manobras de reanimação e encaminhamento para unidade de terapia intensiva neonatal(8-9). Portanto, busca-se aprofundar a compreensão sobre a implementação das práticas assistenciais no cenário do parto e nascimento, trazendo a associação dos resultados neonatais evidenciados em cada intervenção obstétrica utilizada. De modo a subsidiar ações que possam reduzir danos neonatais, averiguando falhas e fragilidades na sua implementação. Diante do exposto, levantou-se o seguinte questionamento: Quais são os desfechos neonatais quando intervenções obstétricas são realizadas durante o trabalho de parto de nulíparas de baixo risco? Dessa forma, o estudo objetivou analisar os desfechos neonatais associados às intervenções obstétricas realizadas no trabalho de parto em nulíparas de baixo risco.


Introduction
In the last two decades, to rescue the experience of birth as a family event, centered on the woman and her protagonist role, where the hospital-centered interventionist influences are minimized, strategies have been created to ensure a more humanized care in pregnancy, delivery, and puerperium. Scientific evidence shows that a considerable portion of obstetric complications can be reduced with the appropriate use of technology and interventions through the performance of qualified professionals who assume a supporting role, without controlling or interfering in the physiological process of delivery, in order not to expose healthy parturient to iatrogenic practices (1)(2) .
According to the World Health Organization, interventions performed by the obstetrician that accelerate the labor process without necessarily bringing benefits to the health of the pregnant woman, or without scientific support, are considered unnecessary and/or harmful interventions, especially in low risk parturient. Since the 1980s, the World Health Organization and the Brazilian Ministry of Health have been reviewing obstetric practices, proposing an assistance based on scientific evidence to promote a better delivery and birth experience with more favorable maternal and fetal outcomes (3)(4) .
A study conducted in Brazil surveyed the interventions used in the Brazilian Unified Health System and the outcome indicators of care, showing that 70.0% of deaths in childhood occurred in the neonatal period due to prematurity and low birth weight. The routine use, or not based on scientific evidence, of obstetric and neonatal interventions can generate obstetric trauma and asphyxia, the latter being one of the most frequent factors in early neonatal deaths of term newborns. Thus, it evidences a high proportion of deaths from preventable causes, which would not occur if there were adequate prenatal and delivery care for pregnant women and appropriate assistance to the newborn (5)(6)(7) .
Researches addressing the influence of obste-tric interventions on fetal well-being are still recent initiatives and are not usually associated with such interventions and neonatal outcomes, They only analyze models of delivery care in general and their repercussions on perinatal outcomes or investigate the use of interventions individually and their association with neonatal outcomes, such as the one explained in the study that shows the association of labor analgesia with the occurrence of resuscitation maneuvers and referral to the neonatal intensive care unit (8)(9) . Therefore, it seeks to deepen the understanding of the implementation of care practices in the scenario of delivery and birth, bringing the association of neonatal outcomes evidenced in each obstetric intervention used. To support actions that can reduce neonatal damage, ascertaining failures and weaknesses in their implementation.
Given the above, the following question was raised: What are the neonatal outcomes when obstetric interventions are performed during labor in low-risk nulliparous women? Thus, the study aimed to analyze neonatal outcomes associated with obstetric interventions performed during labor in low-risk nulliparous women.

Methods
Observational, cross-sectional study, guided by the Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) tool for methodological structuring with descriptive and analytical components. This study is part of a larger project entitled "Maternal and neonatal outcomes associated with labor interventions in low-risk nulliparous women" and exclusively addresses neonatal outcomes resulting from obstetric interventions performed during labor.
This study was developed in a tertiary-level Maternity-School in the city of Fortaleza, Ceará, Brazil, linked to the Brazilian Unified Health System and recognized as a center of support for good practices in obstetrics and neonatology of the Stork Network and as a member of the Hospital Amigo da Criança Initiative. The sample was delimited in a non-probabilistic, consecutive type, consisting of all patients classified as low obstetric risk and admitted to the obstetric center of the maternity hospital under study in the period from February to August 2018.
Inclusion criteria were low-risk parturient; single gestation; full-term; cephalic vertex presentation; spontaneous labor; healthy women and fetuses; no comorbidities; and experiencing labor for the first time. Exclusion criteria were parturient admitted during the expulsion period or who presented any alteration during labor and were considered high-risk.
For the evaluation of labor and delivery, the independent variables were considered, namely the interventions performed during labor and delivery, such as: cardiotocography upon admission; use of oxytocin; amniotomy; neuraxial analgesia; encouragement of Valsalva maneuver; directed pulling; episiotomy; and Kristeller maneuver. As dependent variables, the following were assessed: skin-to-skin contact for 60 minutes; reason for removing the newborn from skin-to--skin contact; Apgar score at 5 minutes of life; positive pressure ventilation (PPV); oxygen therapy and destination of the newborn after delivery; and whether the newborn remained with the mother or was referred to the intensive care or intermediate care unit.
A questionnaire with closed questions was used, applied through direct observation of all the assistance provided in the process of parturition of pregnant women admitted to the obstetric center and the data collection instrument was filled out by the researcher. In addition, the search for sociodemographic and obstetric data in medical records was carried out, in addition to the use of the monitoring forms of assistance to delivery and birth of the Stork Network, with a view to the full filling of the interventions performed during labor of these women.
The data were organized using the Redcap program and processed in R Studio version 4.0.3. They were also analyzed using descriptive and analytical statistics and the Chi-square and Fisher's exact test were applied, being considered statistically significant the p-values <0.05 shown in tables.
The study complied with National Health Council Resolution 466/12 and was authorized in the Research Ethics Committee by opinion number 2,510,987/2018.

Results
The study obtained a sample of 534 low-risk deliveries, of which 323 were vaginal and 211 cesarean deliveries. Represented by women between 13 and 39 years of age, most of who had a partner at the time of hospitalization, were self-declared as brown, from the capital and metropolitan region, and reported having between 6 and 10 years of schooling, corresponding to elementary school. Most women in the study had no income.
No stillbirths or neonatal deaths were observed. Regarding the management of the newborn, 377 (70.6%) had no skin-to-skin contact for 60 minutes after birth. As for the Apgar score, 5 (0.9%) newborns had a score lower than 7. After birth, 108 (20.2%) were assisted in the neonatal intensive care unit, 35 (6.6%) underwent neonatal resuscitation by positive pressure ventilation, oxygen support was offered to 76 (14.2%), and 16 (3.0%) were referred to the neonatal intensive care unit. The reasons for removing the baby from skin-to-skin contact were lack of availability of a professional in 187 cases (35.0%); request by the professional in 88 (16.5%); and impaired fetal vitality signs in 30 (5.6%). In addition, the average time of skin-to-skin contact was 25 minutes.
It was observed that the interventions cardiotocography at admission, use of oxytocin in labor, amniotomy and episiotomy were associated with the outcome skin-to-skin contact for 60 minutes and that most patients who experienced these interventions did not have skin-to-skin contact with their newborns. It was also possible to observe that the variables of intervention in labor did not show association with the outcome Apgar score at the 5 th minute of life (Table 1).  Table 2 shows that the variable Valsalva maneuver encouragement was associated with the outcome need for positive pressure ventilation and, in terms of frequency, most newborns did not need to be submitted to positive pressure ventilation at birth. The interventions amniotomy, Valsalva maneuver incentive, directed pulling, and episiotomy were associated with the outcome oxygen therapy, with p<0.05.
Regarding the destination of the newborn after delivery, an association was perceived with the variables amniotomy, encouragement of Valsalva maneuver and episiotomy. According to the distribution of this variable, it was observed that most patients stayed with their children in a rooming-in unit (Table 3).

Discussion
The study presented limitations related to the very design of cross-sectional studies, for having less capacity to establish causal relations, verifying only the association between the variables of interventions and the outcome. The association results identified bring a rich contribution to obstetric practice by offering useful information about the implications generated by interventions in the health of the newborn, providing theoretical foundations for a humanized and safe care, avoiding the use of unnecessary and/or harmful interventions.
The use of obstetric interventions such as cardiotocography, amniotomy, Valsalva maneuver, and directed pulling was very prevalent during the assistance to low-risk parturient women. These results were like those found in a cross-sectional study conducted with 768 postpartum in 11 maternity hospitals in the state of Sergipe, and in a multicenter study conducted in three tertiary hospitals in Shanghai. Both showed that the use of cardiotocography, greater exposure of nulliparous women to oxytocin infusion, episiotomy, Kristeller maneuver, and performance of amniotomy also occurred at high rates (10)(11) .
The analysis of the results related to the outcome uninterrupted skin-to-skin contact for 60 minutes showed an association between cardiotocography upon admission and the occurrence of skinto-skin contact. Skin-to-skin contact soon after birth, as recommended by the Brazilian Pediatric Society, is important for the newborn's adaptation to extrauterine life by reducing the risk of neonatal hypoglycemia, favoring thermoregulation, increasing the chances of successful breastfeeding, and stabilizing the airways. Recent studies show that admission cardiotocography in low-risk parturient does not confer benefits to the woman or the fetus; furthermore, it may increase cesarean section rates by approximately 20% and does not guarantee any improvement in perinatal outcomes (12)(13)(14) .
It is sometimes understood that safe delivery care is associated with the use of interventions to prevent negative maternal and neonatal outcomes to shorten labor, even in women classified as low risk. In a study on advances in delivery care, it was shown that the persistent use of procedures not recommended by scientific evidence and the inappropriate use of technologies in labor can have repercussions on perinatal outcomes. Thus, they show the importance of seeking to reduce unnecessary interventions, such as the use of episiotomy and Kristeller maneuver, to ensure better maternal-fetal care (15) . The use of oxytocin, amniotomy and episiotomy were also associated with the outcome skin-to-skin contact, but the results may underestimate the association if these interventions occurred to accelerate labor due to unsatisfactory evolution or signs of impaired fetal vitality. A possible answer to the association between the breaking of the bond between mother and child in the first hours of life and the performance of episiotomy is the fact that this intervention is a risk factor for postpartum hemorrhage, considered one of the complications that usually causes the withdrawal of the newborn from skin-to-skin contact (16) .
The outcome Apgar score at the 5 th minute of life was not associated with interventions performed during labor. One factor to be considered may be the fact that the variable presents an unbalanced distribution, i.e., a large difference in the distribution in the categories listed. The 1-and 5-minute Apgar score is recognized as a predictor of neonatal morbidity; scores less than 7 at the 5 minutes are associated with neurological damage and cognitive impairment, respiratory distress, gastrointestinal morbidity, feeding problems, hypothermia, and sepsis, increasing the occurrence of neonatal and infant mortality. These adverse outcomes increase considerably as the 5-minute Apgar score decreases (17) .
An association between the need for neonatal resuscitation by positive pressure ventilation and the encouragement of the Valsalva maneuver by the parturient woman was observed. A randomized clinical trial in Iran with low-risk nulliparous women conclu-ded that use of the Valsalva maneuver was related to lower levels of oxygen in the umbilical cord blood of newborns when compared to spontaneous pulling, thus increasing the chances of neonatal resuscitation. Such effects are not usually observed during spontaneous pulling since there is no exaggerated and forced inspiration and the efforts to push are shorter (18) .
Although an association between the need for oxygen therapy and the use of amniotomy has been identified, a study of nulliparous parturient who underwent this intervention showed no association between its occurrence and adverse perinatal outcome (19) . As to the occurrence of directed pulling, a study carried out with 42,539 parturient in Sweden showed that the rates of umbilical cord acidosis in vaginal deliveries increase with the performance of this intervention, which may cause asphyxia in the newborn and, consequently, admission to the intensive care unit (20) .

Conclusion
This study showed that the use of interventions such as cardiotocography, oxytocin use, amniotomy, encouragement of Valsalva maneuver, directed pulling, and episiotomy during labor in low-risk women are associated with unfavorable neonatal outcomes that lead to the need for further interventions after delivery.
The cautious use of these obstetric interventions, especially in low-risk parturient is an obstacle that must be overcome to promote the improvement of the labor and birth assistance process.

Collaborations
Monteiro PGA and Coelho TS participated in the project conception, data analysis and interpretation, and article writing. Lima AM, Ferreira UR and Monteiro MSB contributed to the writing of the article. Esteche CMGCE and Damasceno AKC contributed to the relevant critical review of the intellectual content and approval of the final version to be published