3.1. General characteristics
We gathered 1531 studies from databases and other hand search sorces.9 of 1531 studies had eligibility criteria [31–39] but three of them had the same ethic code (910732) (approval code of research ethics committee) [31–31]. One of them with higher numbers of participants was included to study and others were excluded. Two another studies were the same and were duplicated published [34–35]. One of them was included to this study. Finally six studies were included in qualitative and quantitative analysis after excluding duplicate published and inappropriate studies [31, 34, 36–39]. 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 and one study had used date fruit honey. Descriptions and characteristics of the reviewed studies are shown in Table 1. No side effects were observed for date palm in any of the studies. The minimum and maximum intervention durations of founded studies are two days and four weeks respectively. Date palm and that’s extracts were utilized orally in all of the studies. Sample sizes of these studies were 89 to 210 people. 767 participants were included in the analysis, 394 participants in intervention group and 373 in control group. Ages of participants were 20 to 40. All of these studies had control groups that consists placebo and routine cares in one study and routine cares in other studies. But placebo control group was not included in meta-analysis and qualitative analysis.
Figure 1: Flowchart of selection strategy and method (PRISMA statement)
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 [37]
|
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
|
1. ↓ Duration of the first and the third stage of labor in intervention groups significantly compare with control group
2. ↑ Duration of the second stage of labor in intervention groups but not significantly compare with control group
|
2
|
Razali et al,2017 [38]
|
Randomized controlled clinical trial
|
154 nulliparous singleton pregnant women
77 intervention group
77 control group
|
7 date's fruits
(approximately
80 gram)
|
Routine cares
|
Not
Defined
|
(1-3)Duration of first, second and third stage of labor
(4) Frequency of caesarian section
|
1. ↓ Duration of the first and the third stage of labor in intervention groups but not significantly compare with control group
2. ↑ Duration of the second stage of labor in intervention groups but not significantly compare with control group
3. No significant difference between two groups in mode of delivery
|
3
|
Kariman et al., 2015 [34]
|
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
|
1. Significant ↓ of active phase of labor in intervention group compared with control group
2. Significant ↓in bishop score after intervention compared with control group
3. ↓ Frequency of cesarean section in intervention group compared with control group but not significant
|
Table 1: Continue
Number
|
Author/
Year
|
Study design
|
Participants and
Sample size
|
Intervention
|
Control
|
Duration of intervention
|
Outcomes
(considered in this study)
|
Results
|
4
|
Kordi et al.,2014 [31]
|
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
|
until the onset of labor pain
(1-3 weeks)
|
(1)Bishop score
(2)Frequency of caesarian section
|
1. Significant ↑ of the mean Bishop Score in intervention group compared with control group
2. No significant difference between two groups in mode of delivery (↓ frequency of cesarean section in intervention group)
|
5
|
Al-Kuran et al,2011 [39]
|
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
|
1. ↓ Duration of the first and the third stage of labor in intervention groups significantly compare with control group
2. ↑ Duration of the second stage of labor in intervention groups but not significantly compare with control group
3. ↓ Frequency of cesarean section in intervention group compared with control group but not significant
|
6
|
Kordi et al.,2010 [36]
|
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 listed in table 2.
Random sequence generation
4 studies of 6 studies had used random number table, random generator or computer programmed random sequencing, and thus were evaluated as low risk of bias. Other 2 studies didn't use any 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 studies of six included studies did not determine the method of allocation concealment and were evaluated as unclear risk of bias. Two studies 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 evaluated as high risk of bias.
Blinding of outcome assessment
All of these studies were evaluated as high risk of bias because they had no evidence of blinding of outcome assessors.
Incomplete outcome data
Of 6 studies, 3 studies have mentioned the dropped out and have analyzed the intention to treat and 2 studies had not any dropped out or lost to follow up, thus they were rated as low risk of bias. One study had attrition for missing participants but the statistical analysis had not followed by the intention to treat.
Selective reporting
One study had registered protocol but reported outcomes did not match with registered outcomes and were given high risk of bias. Expected outcomes of two studies had not determined and were evaluated as unclear risk of bias. Other included studies had reported their expected outcomes and were rated as low risk of bias.
Fig. 2 Risk of bias graph
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, bishop score and frequency of caesarian section as secondary outcomes. We used Random effect in the moderate and high heterogeneity (H>75) and fixed effect in low heterogeneity.
Active phase of labor
Two studies were included with 170 participants (85 in intervention group and 85 in control group). There was moderate heterogeneity among the studies (I2 = 64%, P = 0.09). The quantitative synthesis showed that date consumption significantly reduce during of active phase of labor compared with control group (MD = –60.26, 95%CI (–107.18, –13.34), P = 0.01). (Fig. 4)
Fig. 4 Forest plot of the duration of active phase of labor
First stage of labor
Three studies reported the duration of first stage of labor. 325 participants were included (172 in intervention group and 153 in control group). Moderate heterogeneity accompanied (I2 = 42%, P = 0.18). Intervention decreased duration of first stage of labor. The difference between intervention and control groups was statistically significant (MD = –50.90, 95%CI (–100.63, –1.16), P = 0.04). (Fig. 5)
Fig. 5 Forest plot of the duration of first stage of labor
Second stage of labor
We gathered data from 4 studies involving 385 participants (202 in intervention group and 183 in control group). The heterogeneity was high (I2 = 90%, P <0.00001). There was no significant difference between two groups (MD = 4.29, 95%CI [–24.91, 15.01], P = 0.63). (Fig. 6)
Fig. 6 Forest plot of the duration of second stage of labor
Third stage of labor
Three studies with 325 participants were described the duration of the third stage of labor. The intervention cannot decrease the duration of the third stage of labor (MD = 1.10, 95%CI (–1.32, 3.53), P = 0.37). The heterogeneity was moderate (I2 = 73%, P = 0.02). (Fig. 7)
Fig. 7 Forest plot of the duration of third stage of labor
Bishop score
Two studies reported data on the bishop score with 320 participants. There was no heterogeneity (I2 = 0%, P = 0.60). The intervention was improved significantly bishop score rather than control group (MD = 2.45, 95%CI (1.87, 3.04), P<0.00001). (Fig. 8)
Fig. 8 Forest plot of the bishop score
Frequency of caesarian section
Four studies 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 = 6%, P = 0.36). The intervention had decreased frequency of caesarian section, but the difference between the two group is not significant (Odds Ratio = 0.67, 95%CI (0.44, 1.02), P = 0.06). (Fig. 9)
Fig. 9 Forest plot of the caesarian section frequency