The Effect of Maternal Position on Maternal, Fetal and Neonatal Outcomes: A Systematic Review

Maternal health promotion plans should facilitate the provision, maintenance, and enhancement of their health status. In addition, these plans should address the improvement of the quality of labor care, mitigation of side effects, reduction of maternal and neonatal mortality, and satisfaction of mothers with the provided services. The care plans must be evidence-based and prioritize the prevention and health promotion programs over expensive diagnostic and therapeutic strategies (1).

The maternal position is one of the obstetric care in the labour wards (2). Consideration of maternal position in the labour wards is indicative of a supportive environment for delivery leading to an improved sense of competence and personal success in mothers during the intrapartum and postpartum periods (3).

The maternal position is a remarkable point of maternal care during the labor process, which is neglected in many cases by the care providers of the labour wards. Placement of mothers in a lying position during the course of delivery is one of the common interventions in the current century (4). Before the 17^th century, delivery at the upright position was popular in the Western countries (5), and the lying position was performed only in cases with an indication of assisted delivery (3).

Afterward, the lying position became common due to the comfort of the birth companion (6). Nonetheless, delivery at the upright position is still common in the societies lacking modern medicine (7-9). In this regard, Naroll et al. reported that out of 76 studied traditional cultures, only 14 cases chose the maternal supine lying position for labor (10).  

Consideration of maternal rights obligates the care providers to give the choice of childbirth position to the mothers. The position that mothers choose for delivery depends on several complicated factors and the norms of their society. In societies that labor is carried out in the health centers and hospitals, the social norms are affected by the expectations and requests of the obstetricians.

In addition, the limitations imposed by the medical procedures, such as fetal monitoring, intravenous therapy, analgesics, and medical examinations affect such choices. During the second stage of labor, various factors, including perineal support and assistance for spontaneous delivery, limit the selection of a suitable position by the mothers (3, 11, 12).  

In a cohort study conducted on 12,782 parturients in Sweden, it was shown that 83.9% of the births were given in the lying position (13) and the upright positions, such as squatting, were rarely applied. In countries with modern medicine, less than 1% of the women are posed upright in the course of delivery. Furthermore, in a study carried out in Brazil on 1,079 women, it was demonstrated that 82.3% of the individuals completed the delivery in a lying position (11). 

In another study,the frequencies of left-side lying, squatting, all-fours, and standing labor positions were reported as 16%, 0.8%, 0.7%, and 0.2%, respectively (14). Although the lithotomy position seems to be proper for monitoring and interventions during delivery, it negatively affects the labor duration and maternal comfort. Nonetheless, as indicated by the evidence, women prefer to change their position from lying to non-lying during childbirth in case they have a chance.

In recent decades, lying delivery position has gained higher popularity and acceptance (16). This popularity is due to the fact that this position facilitates easier fetal heart rate (FHR) monitoring, maternal monitoring and examination, serum therapy, regional anesthesia, perineal support, and delivery assistance (15).   

Lying delivery results in the elevation of stress hormones in mothers, in addition to the reduction of effective contractions and delivery stage progress (17). Some of the probable benefits mentioned in the literature for non-lying childbirth positions include the positive impact of gravity on delivery, more effective and stronger uterine contractions (18), and more efficient maternal strains during labor. Moreover, the enhanced fetal position, diminished risk of pressure on aorta, improved neonatal acid-base consequences, and decreased abnormal FHR pattern have been pointed out as the advantages of this position (19).

However, some studies have not confirmed these benefits. Other profits proposed for maternal upright childbirth position are increased pelvic diameters (5), modified birth canal (18, 20), labor duration, pain intensity, as well as a difference in delivery route, epidural anesthesia, and postpartum hemorrhage (PPH) (4, 15).  

According to the mentioned findings, the upright delivery position was proposed as a cheap and simple intervention that augments the probability of vaginal delivery in the World Health Organization guidelines for a vaginal birth (1995). Nevertheless, the mentioned data were presented by controversial, dispersed, or unofficial evaluations, in which the researchers recommend further studies in order to prove and execute their proposed intervention as a care plan (5, 21).  

In conclusion, it is required to continuously perform systematic comprehensive investigations in order to propose an evidence-based care plan for mothers, obtain information, and introduce a practical and comprehensive program based on the ethnicity and culture of a society. With this background in mind, the present systematic review aimed to assess the impact of Maternal position during the labor stages on maternal, fetal, and neonatal outcomes.

Materials and Methods

This systematic review was designed considering the criteria of the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) (22). Data collection was gathering through a comprehensive and systematic review of the papers published during 2005-2018.

The articles related to the objective of study were searched in databases such as PubMed Cochrane, Web of Science, Scopus, ProQuest, Magiran, SID, and Google Scholar using authentic Persian and English keywords, such as “Parturition”, “Birth”, “Delivery, Obstetric”, “Labor, Obstetric”, “Labor stage”, “Labor stage, First" ,"Labor stage, Second", "First labor stage", "Second labor stage", "Maternal position", "Mothers' position",  "Delivery rooms", "Childbirth room", "Delivery outcome", “Maternal outcome", " Maternal-fetal outcome", "Fatal outcome", "Newborn infant outcome", and "Neonate outcome". Moreover, the Boolean operators of “AND” and “OR” were applied. 

After the retrieval of the related articles, their reference lists were also checked, and the reference articles were also searched. In order to avoid bias and assure the inclusion of all studies meeting the inclusion criteria, the search process was performed independently by two of the researchers, and the discrepancies were reevaluated by the corresponding author. 

All the English and Persian randomized controlled clinical trials addressing care plans or the interventions related to childbirth position during the first and second stages of labor at labour wards and investigating maternal, fetal, and neonatal outcomes were included in the study.

The papers to which we did not have full access, as well as the review articles, letters to the editor-in-chief, case reports, qualitative articles, and theses were excluded from the study. After searching for the studies related to the issue under investigation, the papers that lacked the inclusion criteria were excluded by two authors independently evaluating the manuscripts.  

In the next stage, the full-text versions of the retrieved articles were assessed by two authors using the JoannaBriggs Institute checklist. This tool is specific for the appraisal of the randomized clinical trials and includes 13 items (23). In this instrument, each item is scored as 0 (lacking the intended criterion) or 1 (having the criterion). Based on the appraisal scores, the papers with the scores of ≥ 75%, 50-75%, and < 50% are divided into three groups of high-, moderate-, and low-quality, respectively. Finally, the low-quality studies were excluded from the review.  

Data extraction was carried out using a checklist based on the predefined criteria. This data extraction checklist entailed such information as the study title, authors, publication year, country, sample size, study design, inclusion and exclusion criteria, assessment instruments, participants’ characteristics, intervention, and maternal, fetal, and neonatal outcomes, in addition to the quality score of the study. 

Results

The search process resulted in the identification of 17 clinical trials, including 9 English and 8 Persian papers. Out of the 9 English studies, 8 cases were performed by foreign authors, while 1 study was carried out by an Iranian researcher. All the 8 reviewed Persian studies were performed by Iranians. The study population of the included studies consisted of 4,848 parturients who were under clinical trials. Figure 1 illustrates the process of study selection in this review (Figure 1).

Tables 1 and 2 summarize the characteristics of the reviewed studies and quality scores, respectively. 

According to the results of this systematic review, 13 clinical trials investigated the impact of maternal delivery position on the duration of labor stages. In addition, in 7 studies (5 and 2 of which were conducted on European/American ethnics and Iranians, respectively) investigating 1,463 women who had recently given birth reported that maternal position had no effect on delivery duration (2, 24-29).

On the other hand, 2 studies performed on 210 Iranian parturients revealed that the upright, freedom and elective of the position chosen by the mother led to the shortening of delivery stages (30, 31). In another study conducted on 1400 women in China, it was concluded that the kneeling position during the second stage of labor resulted in a longer second stage and a shorter third stage of delivery (32). Moreover, in 2 studies carried out on 300 Iranian women with recent childbirth, it was shown that the side-lying position significantly prolonged the first (33) and second (34) stages of labor.    

Persistent OP fetal position as another labor outcome increases the risk for assisted delivery or cesarean section (C-section) and is observed in 18% of the C-sections (35). In the present systematic review, three studies evaluated the influence of maternal position (e.g., kneeling and all-fours) on fetal head rotation and prevention from persistent OP. The mentioned studies did not find a significant difference between the intervention and control groups concerning fetal head rotation and stated there is no policy or plan addressing maternal labor positioning to facilitate the management of labor in case of fetal OP position (24, 27, 36).  

The PPH as a leading cause of mortality and morbidity in mothers is among the delivery outcomes (37,38). Three of the reviewed studies involved the evaluation of hemorrhage intensity in two groups of intervention and control. In two of these studies, the rate of hemorrhage was not significantly different between the two groups (20, 28). Thies-lagergren claims that bleeding of < 1000 ml was more frequent in the intervention group. However, they observed no significant difference between the two groups regarding the mean blood loss at a volume of over 1,000 ml (39). 

In terms of the fetal and neonatal labor outcomes, the reduced risk of pressure on the aorta and improved acid-base outcomes in the newborn were introduced as the benefits of upright delivery position in the maternity ward (40). On the other hand, maternal lying position was reported to negatively affect the FHR pattern (2). However, the latter point was not confirmed in the reviewed studies. Out of 11 investigations reporting the fetal and neonatal health, 9 (81.8%) studies investigating a total of 2,480 participants reported no significant difference between the control and intervention groups in this regard

The assessed fetal and neonatal outcomes included the one- and five-minute Apgar scores, umbilical venous pH, fetal health score, need for neonatal resuscitation, and need for hospitalization in the NICU. These features had been evaluated in the two groups of lying and upright positions at the first and second stages of labor (20, 24, 25, 27, 29-31, 34, 36, 41). Only in two studies (18.2%) on 300 Iranian parturients, it was reported that one-minute Apgar was higher in the group in which the position was selected by the women. In addition, in the mentioned study, the 4-7 minute Apgar score was higher in the side-lying and sitting position groups (33, 42).  

Silva (2017) pointed out that altered maternal position from the left side to lying leads to the reduction of the resistance of the middle cerebral artery, while no change is observed in the resistance of the umbilical artery. They stated that the variations in the cerebral blood flow are seen in the first 5 min and do not persist more than 10 min. Moreover, the change induced in oxygen saturation decreases following maternal position alteration to supine is not sufficient for changing the pressure of the umbilical venous blood flow (43).   

This sty involved the review of the psychological outcomes, such as maternal pain experience, anxiety, and fatigue, in addition to the physiologic outcomes. The influence of delivery position on pain is yet a controversial subject. Miquelut reported that even though the groups were not significantly different in terms of maternal pain score and satisfaction, mothers preferred the upright position (25). This author stated that the selection of the labor position by the mother improves the maternal physiologic and psychologic outcomes (2, 26, 42).

Stremler et al. demonstrated that persistent backache was improved as a result of the all-fours position (36). On the other hand, some studies reported no significant differences among the lithotomy, squatting, and kneeling positions during the second stage of labor in terms of pain, anxiety, fatigue, and experience of childbirth in mothers (41).  

Discussion

The current systematic review aimed to assess the impact of maternal position on the maternal, fetal, and neonatal outcomes of labor. Maternal positions at the first and second stages of labor included the upright (i.e., all-fours, squatting or kneeling, sitting, birthing chair, walking, and waist rotation movements or dancing) and lying positions (i.e., supine, lateral decubitus, and lithotomy position). Duration of the interventions varied from 10 min to the length of the first and second stages. The outcomes were evaluated in two categories of maternal and fetal-neonatal outcomes.

The results of the studies included in the current systematic review were found to be controversial. Moreover, the findings of our systematic review were not consistent with those of the systematic reviews published before 2005. The reviews performed prior to 2005 in countries other than Iran reported that the upright or lateral Maternal position s were accompanied by changes in delivery outcomes, such as shortened first and second labor stages, compared to the lying or lithotomy positions (5, 17, 44, 45). One study revealed diminished NICU hospitalization, delivery pain, and abnormal FHR pattern, in addition to the elevated risk of hemorrhage over 500 mL (5). This discrepancy could be attributed to the differences among the reviewed studies.

Increased rate of assisted delivery and C-section due to persistent OP position were among the evaluated maternal outcomes. The present systematic review did not find a significant difference between the intervention and control groups regarding the fetal head rotation (24, 27, 36). Based on the evidence, there is no maternal labor position-based policy or plan facilitating delivery management in case of fetal OP position (27). 

The PPH was another maternal outcome assessed in the studies. In this systematic review, three studies had evaluated hemorrhage intensity in the two groups of intervention and control. In addition, in two studies, no significant difference was observed between the two groups in terms of hemorrhage (20, 28). However, Thies-lagergren (2011) claimed that a hemorrhage volume of < 1000 mL was more frequent in the intervention group than in the control group. In the mentioned study, the two groups were not significantly different regarding the mean blood loss at a hemorrhage volume of > 1000 mL, (39). 

Concerning the impact of maternal position on the length of delivery stages, the studies evaluating the non-Iranian ethnics reported that labor position does not influence the delivery duration. However, the two studies carried out in the Iranian society observed that the free upright position chosen by mother may result in shorter delivery stages (30, 31). This difference could be due to the larger sample size and a higher number of studies on non-Iranian races. Therefore, further clinical trials with larger sample sizes in the Iranian population are recommended to examine the effect of maternal position on the length of labor stages.   

A meta-analysis conducted on 5,218 women indicated that in 25% of the studies, the first labor stage was shortened as a result of the upright positions with a mean of about 90 min, compared to that after the lying positions. Furthermore, the maternal position at the first stage of delivery was not found to affect the length of the second stage. On the other hand, the upright maternal position during the second stage of labor caused a four-minute decline in the duration of this stage, which is not of clinical significance.

It has been mentioned in the literature that due to the low quality of the studies included in the systematic reviews, the results should be interpreted cautiously and further studies with higher quality are recommended (44). Accordingly, in the present review, we entered the randomized clinical trials with proper quality because this type of study has the least bias and is considered as the best evidence-based study design for finding the evidence related to the intervention.

The fetal-neonatal outcomes investigated in the present study entailed the one- and five-minute Apgar scores, umbilical venous pH, fetal health score, need for neonatal resuscitation, and need for hospitalization in the NICU. All the mentioned outcomes were evaluated among the two groups of lying and upright positions at the first and second labor stages (20, 24, 25, 27, 29-31, 34, 36, 41). Theoretically, the diminished risk of pressure on the aorta and inferior vena cava might contribute to the improvement of fetal-neonatal outcomes at the upright position, compared to the lying position (2, 40). However, the investigations reviewed in the present study did not confirm the latter theory.

Out of the 11 studies on fetal and neonatal health, in 9 (81.8%) studies investigating 2,480 samples in two groups of intervention and control, no significant difference was observed. Only in 2 (18.2%) studies performed on 300 pregnant mothers, it was reported that one-minute Apgar score was higher in the group in which the position was selected by the women and the 4-7 minute Apgar score was higher in the side-lying and sitting positions group (33, 42).

The evidence-based performance involves the adoption of the best existing evidence in clinical decision-making. More comprehensively, evidence-based performance can be defined as the secure, accurate, and efficient application of the best available evidence in making decisions about taking care of all the patients individually (46).

Blinding omits the observer bias in the clinical trials (47); however, in the present review, the blinding of the care provider and mothers was not possible because of the intervention nature. As a result, the appraisal of the studies included in the current systematic review showed that 76.47% of the articles were of moderate quality because the studies did not obtain the score related to the blinding item. It should be mentioned that in some studies the person who completed the analyses was blind. Moreover, the present review study indicated that the data extracted from the studies carried out in and out of Iran were controversial, which could be due to the difference in the study design and intervention type.  

The results of the reviewed studies demonstrated that various Maternal position s during the first and second labor stages, except for maternal comfort, has no effect on fetal-neonatal outcomes. It should be noted that further studies using suitable methods in terms of randomization, blinding, and sample size are required for making decisions regarding the delivery position at the first and second stages of labor. 

Cultural, local, and ethnic contexts can all influence the results of the studies. Therefore, the selection of randomized clinical trials, in addition to the search of international and local databases, could be considered as the strength of the present systematic review. On the other hand, the inclusion of studies limited to the two languages of Persian and English and the lack of possibility of performing a meta-analysis are among the limitations of this review.

Conclusion

     According to the findings of this systematic review, maternal position during the first and second stages of labor do not affect the maternal, fetal, and neonatal outcomes. However, all studies have concluded that low-risk mothers should have the possibility to choose a comfortable position in the labour wards. In order to propose an evidence-based care plan for the delivery position in the labour wards, it is recommended to perform further studies with higher quality concerning the impact of childbirth position at the first and second stages of labor on maternal, fetal, and neonatal outcomes.

Acknowledgements

       Hereby, we thank Mashhad University of Medical Science for funding this study

Conflicts of interest

The authors declare no conflicts of interest.