3.1. General characteristics
We gathered 1531 studies from databases and other hand search sources. Nine of 1531 studies (Nine full-text papers under six trials) had eligibility criteria and were included in qualitative and quantitative analysis [33-41]. Three of them had the same ethic code (910732) (approval code of research ethics committee) and were different reports of one trial [33-35]. Also two other studies were similar and were different reports of one trial [36-37]. We included all different outcomes (which considered in our systematic review) of the different reports of each trial to the meta-analysis (if the trial had multiple reports). The flowchart of searching and inclusion process of studies is shown in Figure 1(According to PRISMA statement). Five of included studies had used the date palm fruit [33, 36, 39-41], and one study had used date fruit honey [38]. Descriptions and characteristics of the reviewed studies are shown in Table 1. No side effects were reported for date palm in any of the studies. The minimum and maximum intervention durations of founded studies were two days and four weeks, respectively. Date palm and its extracts were orally utilized in all of the studies. Sample sizes of these studies were 89 to 210 participants. 767 participants were included in the analysis, 394 participants in intervention group, and 373 in control group. Ages of participants were ranged from 20 to 40. All of these studies had control groups consisting of placebo and routine cares in one study [38], and routine cares in other studies [33, 36, 39-41]. However, placebo control group was not included in meta-analysis and qualitative analysis.
Table 1: Characteristics of included studies (PICOS)
Number
|
Author/
Year
|
Study design
|
Participants and
Sample size
|
Intervention
|
Control
|
Duration of intervention
|
Outcomes
(considered in this study)
|
Results
|
1
|
Ahmed et al., 2018 [39]
|
Randomized, controlled, clinical trial
|
57 pregnant women
26 intervention group
31 control group
|
7 date's fruits on the permission
|
Routine cares
|
Once
|
(1-3)Duration of first, second and third stage of labor
|
- ↓ Duration of the first and the third stage of labor in intervention groups significantly compared with control group
- ↑ Duration of the second stage of labor in intervention groups but not significantly compare with control group
|
2
|
Razali et al,2017 [40]
|
Randomized controlled clinical trial
|
154 nulliparous singleton pregnant women
77 intervention group
77 control group
|
7 date's fruits
(approximately
80 gram)
|
Routine cares
|
1-4 weeks
|
(1-3)Duration of first, second and third stage of labor
(4) Frequency of caesarian section
|
- ↓ Duration of the first and the third stage of labor in intervention groups but not significantly compare with control group
- ↑ Duration of the second stage of labor in intervention groups but not significantly compare with control group
- No significant difference between two groups in mode of delivery
|
3
|
Kariman and Jadidi et al. , 2015 [36, 37]
|
Randomized, controlled, clinical trial
|
110 nuliparous pregnant women
55 intervention group
55 control group
|
7 date's fruit per day
|
Routine cares
|
From week 38 of pregnancy to onset of delivery signs
|
(1)Duration of active phase of labor
(2)Bishop score
(3)Frequency of caesarian section
|
- Significant ↓ of active phase of labor in intervention group compared with control group
- Significant ↓in bishop score after intervention compared with control group
- No significant differences in mode of delivery between two group
- ↑ Bishop score significantly after intervention compared with control group
- ↑ Cervical dilatation significantly after intervention compared with control group
- ↑ Cervical effacement significantly after intervention compared with control group
- ↑ Spontaneous labor significantly after intervention compared with control group
|
Number
|
Author/
Year
|
Study design
|
Participants and
Sample size
|
Intervention
|
Control
|
Duration of intervention
|
Outcomes
(considered in this study)
|
Results
|
4
|
Kordi et al.,2013,2014 , 2017 [33, 34, 35]
|
Quasi-randomized, controlled, clinical trial
|
210 pregnant women with gestational age of 37-38 weeks
105 intervention group
105 control group
|
70-75 gram date's fruit per day
|
Routine cares
|
1-3 weeks
|
(1)Bishop score
(2)Frequency of caesarian section
(3-5)Duration of first, second and third stage of labor
|
- Significant ↑ of the mean Bishop Score in intervention group compared with control group
- No significant difference between two groups in mode of delivery (↓ frequency of cesarean section in intervention group)
- The average length of the second phase and the third phase in the intervention group was significantly lower than the control group
- Spontaneous start of labor in the intervention group was significantly more than the control group
- No significant difference between average length of active phase of labor in the two
- ↑Cervical dilatation in intervention group compared with control group(significant)
- ↓Length of pregnancy in intervention group compared with control group ( significant)
|
5
|
Al-Kuran et al,2011 [41]
|
Non-randomized controlled clinical trial
|
114 nulliparous and primiparous singleton pregnant women
69 intervention group
45 control group
|
Six date fruits per day in
|
Routine cares
|
4 weeks prior to their estimated date of delivery
|
(1-3)Duration of first, second and third stage of labor
(4) Frequency of caesarian section
|
- ↓ Duration of the first and the third stage of labor in intervention groups significantly compare with control group
- ↑ Duration of the second stage of labor in intervention groups but not significantly compare with control group
- ↓ Frequency of cesarean section in intervention group compared with control group but not significant
|
6
|
Kordi et al.,2010 [38]
|
Randomized double blinded controlled clinical trial
|
60 nuliparous pregnant women with gestational age of 37-42 weeks
30 intervention group
30 control group
|
132 gram date's honey syrup from 4 cm cervix dilatation to labor
|
Routine cares
|
Maximum 1 day
|
(1)Duration of active phase of labor
(2)Duration of second stage of labor
|
Significant ↓in duration of active and second phases of labor
|
3.2. Risk of bias within studies (Figs. 2, 3)
The details of risk of bias within included studies and authors judgment are listed in Table 2.
Random sequence generation
Four studies of 6 studies had used random number table, random generator or computer programmed random sequencing; and thus, they were rated as low risk of bias. Other 2 studies used no reliable randomization method and were evaluated as high risk of bias.
Allocation concealment
One study of included studies had used sealed-envelopes method to the allocation concealment and was evaluated as low risk of bias. Three trials of six included trials did not determine the method of allocation concealment, and were evaluated as unclear risk of bias. Two trials had not concealment and were evaluated as high risk of bias.
Blinding of participants and personnel
Due to the consumption of date fruit as intervention and routine care as control, all of the included studies had not performed blinding and were rated as high risk of bias.
Blinding of outcome assessment
All of these studies were assessed as high risk of bias; because they had no evidence of blinding of outcome assessors.
Incomplete outcome data
Out of 6 trials, 3 trials have mentioned the dropped out and analyzed the intention to treat, and 2 trials had no dropped out or lost to follow up; therefore they were rated as low risk of bias. Also, one study had attrition for missing participants; however, the statistical analysis was not followed by the intention to treat.
Selective reporting
One study had registered protocol; but the reported outcomes did not match with registered outcomes and were given the high risk of bias. Other included studies had reported their expected outcomes and were assessed as low risk of bias.
Other bias
Three trials had registered protocol, specified funding source, appropriate ethical criteria, inclusion and exclusion criteria, specified sample size calculating method, and declaration of conflict of interest; therefore, they were rated as low risk of bias. Other trials did not have some of mentioned cases and were rated as high risk of bias.
Table 2: Risk of bias within studies
Bias
|
Authors judgment
|
Support for judgment
|
Ahmed et al. (2018) [39]
|
|
|
Random sequence generation
|
Low risk
|
Simple random sampling has been used
|
Allocation concealment
|
Unclear risk
|
No specific information
|
Blinding of participants and personnel
|
High risk
|
Open label manner
|
Blinding of outcome assessors
|
High risk
|
Open label manner
|
Incomplete outcome data
|
High risk
|
Intention to treat analysis has not conducted.
|
Selective reporting
|
Low risk
|
Protocol is unavailable but the authors have reported their expected mentioned outcomes
|
Other
|
High risk
|
No registered protocol, sample size calculating method is not specified
|
Razali et al. (2017) [40]
|
|
|
Random sequence generation
|
Low risk
|
Sealed envelope numbers has been used
|
Allocation concealment
|
Low risk
|
It was done using "sealed envelope" manner
|
Blinding of participants and personnel
|
High risk
|
Open label manner
|
Blinding of outcome assessors
|
High risk
|
Open label manner
|
Incomplete outcome data
|
Low risk
|
The dropped out has been mentioned and intention to treat has been analyzed
|
Selective reporting
|
Low risk
|
Protocol is unavailable but the both primary and secondary outcomes have been reported
|
Other
|
Low risk
|
Registered protocol exist, sample size calculating method is specified, Ethical approval exist, Specified inclusion and exclusion criteria, specified funding source, no conflict of interest
|
Kariman and Jadidi et al. (2015) [36, 37]
|
|
|
Random sequence generation
|
Low risk
|
Random number generator has been used
|
Allocation concealment
|
Unclear risk
|
No specific information
|
Blinding of participants and personnel
|
High risk
|
Open label manner
|
Blinding of outcome assessors
|
High risk
|
Open label manner
|
Incomplete outcome data
|
Low risk
|
The dropped out has been mentioned and intention to treat has been analyzed
|
Selective reporting
|
High risk
|
Protocol is available but secondary outcomes have not been reported
|
Other
|
Low risk
|
Registered protocol exist, sample size calculating method is specified, Ethical approval exist, Specified inclusion and exclusion criteria, specified funding source, no conflict of interest
|
Kordi et al.(2013, 2014, 2017) [33-35]
|
|
|
Random sequence generation
|
High risk
|
The days of the Week have been used for randomization
|
Allocation concealment
|
Unclear risk
|
No specific information
|
Blinding of participants and personnel
|
High risk
|
Open label manner
|
Blinding of outcome assessors
|
High risk
|
Open label manner
|
Incomplete outcome data
|
Low risk
|
The dropped out has been mentioned and intention to treat has been analyzed
|
Selective reporting
|
Low risk
|
Protocol is available and both primary and secondary outcomes have been reported
|
Other
|
Low risk
|
Registered protocol exist, sample size calculating method is specified, Ethical approval exist, Specified inclusion and exclusion criteria, specified funding source, no conflict of interest
|
Al-Kuran et al. (2011) [41]
|
|
|
Random sequence generation
|
High risk
|
The participants have been asked to participate in one of two groups
|
Allocation concealment
|
High risk
|
Open label manner
|
Blinding of participants and personnel
|
High risk
|
Open label manner
|
Blinding of outcome assessors
|
High risk
|
Open label manner
|
Incomplete outcome data
|
Low risk
|
No participant dropped out of the treatment
|
Selective reporting
|
Low risk
|
Protocol is unavailable but both primary and secondary outcomes have been reported
|
Other
|
High risk
|
No informed consent, funding source is not specified, no registered protocol, sample size calculating method is not specified
|
Kordi et al. (2010) [38]
|
|
|
Random sequence generation
|
Low risk
|
Simple random sampling has been used
|
Allocation concealment
|
High risk
|
There was no evidence for allocation concealment
|
Blinding of participants and personnel
|
High risk
|
Open label manner
|
Blinding of outcome assessors
|
High risk
|
Open label manner
|
Incomplete outcome data
|
Low risk
|
There was no lost to follow up
|
Selective reporting
|
Low risk
|
Protocol is unavailable but both primary and secondary outcomes have been reported
|
Other
|
High risk
|
Conflict of interest didn't declared, no specified inclusion and exclusion criteria
|
3.3. Outcomes
We considered common outcome among the included studies in quantitative integration, included active phase of labor duration, first stage of labor duration, second stage of labor duration, and third stage of labor duration as primary outcomes; and bishop score and frequency of caesarian section as secondary outcomes. Also, we performed the sensitivity analysis, because two trials of included trials were quasi-randomized and non-randomized studies. The effect of date fruit consumption on the reduction of the duration of first stage of labor and the frequency of cesarean section were statistically significant in primary meta-analysis, but after sensitivity analysis, they were not significant. Sensitivity analysis did not change other results of primary meta-analysis. The summary of sensitivity analysis is shown in Table 3. The forest plots of sensitivity analyses are available in Appendix 2-7 [see Additional file 2]. Moreover, we performed subgroup analysis for two subgroups (Intervention during labor, and intervention during pregnancy). The results of subgroup analyses showed no significant changes in primary meta-analysis results. The forest plots of subgroup analyses are available in Appendix 8-11. [see Additional file 3]
Table 3: The summary of sensitivity analyses
Number
|
Measured outcome
|
Meta-analyses of all studies
(Overall effect statistical significance)
|
Sensitivity Analyses ̽
(Overall effect statistical significance)
|
1
|
First stage of labor
|
P = 0.04 ̽ ̽
|
P = 0.22
|
2
|
Second stage of labor
|
P = 0.44
|
P = 0.64
|
3
|
Third stage of labor
|
P = 0.8
|
P = 0.39
|
4
|
Active phase of labor
|
P = 0.01
|
P = 0.01
|
5
|
Bishop score
|
P ˂ 0.00001
|
P ˂ 0.00001
|
6
|
Frequency of cesarean section
|
P = 0.08
|
P = 0.59
|
̽ Non-randomized and quasi-randomized studies (Al-kuran and kordi 2013, 2014, 2017) removed from meta-analysis.
̽ ̽ The significant values are shown with bold font.
Active phase of labor
Three trials with 380 participants were included (190 in intervention group and 190 in control group). There was moderate heterogeneity among the studies (I2= 89%, P = 0.0002). The quantitative synthesis showed that date consumption significantly reduce the duration of active phase of labor compared with control group (MD= -109.3, 95%CI (-196.32, -22.29), P=0.01). (Fig. 4)
First stage of labor
Three studies reported the duration of first stage of labor. Totally, 325 participants were included (172 in intervention group and 153 in control group). Moderate heterogeneity accompanied (I2= 42%, P = 0.18). In primary meta-analysis, intervention decreased the duration of first stage of labor. Also, the difference between intervention and control groups was statistically significant (MD= -50.90, 95%CI (-100.63, -1.16), P=0.04). (Fig. 5) But after sensitivity analysis, it wasn't significant (MD= -76.16, 95%CI (-198.51, 46.18), P=0.22). (Appendix 2) [see Additional file 2]
Second stage of labor
We collected data from 5 trials with 595 participants (307 in intervention group and 288 in control group). The heterogeneity was high (I2= 91%, P <0.00001). There was no significant difference between two groups (MD=5.41, 95%CI [-19.23, 8.42], P=0.44). (Fig. 6)
Third stage of labor
Four trials with 535 participants (277 in intervention group and 258 in control group) described the duration of the third stage of labor. The intervention cannot decrease the duration of the third stage of labor (MD = 0.31, 95%CI (-2.08, 2.7), P = 0.8). The heterogeneity was high (I2= 83%, P=0.0004). (Fig. 7)
Bishop score
Two trials reported data on the bishop score with 320 participants (160 in intervention group and 160 in control group). There was no heterogeneity (I2= 0%, P=0.60). The intervention significantly improved the bishop score, compared to control group (MD = 2.45, 95%CI (1.87, 3.04), P<0.00001). (Fig. 8)
Frequency of caesarian section
Four trials had showed the effect of intervention on frequency of caesarian section. 588 participants were included in this outcome meta-analysis (306 in intervention group and 282 in control group). Low heterogeneity was accompanied (I2= 9%, P=0.35). In primary meta-analysis, intervention decreased the frequency of caesarian section, significantly. (Risk Ratio= 0.74, 95%CI (0.52, 1.04), P=0.08). (Fig. 9) But, after sensitivity analysis, it was not significant (Risk Ratio= 0.89, 95%CI (0.6, 1.34), P=0.59). (Appendix 6) [see Additional file 2]
Adverse effects
No side effects have been reported in any of the included studies.