Table 9.

Randomized double-blind trials investigating the effectiveness and safety of ginger for pregnancy.

Objective	Population	Number	Treatment	Ginger Definition	Duration	Results	Adverse Events	Reference
To determine the effectiveness of ginger for the treatment of NVP	Women NVP < 17 weeks of gestation	n = 67 35 placebo 32 ginger	1000 mg/day (4 × 250 mg) of ginger (powder capsules) vs. placebo	Fresh ginger root	4 days + follow-up visit 7 days later	Significant decrease of nausea in the ginger group vs. placebo group (p = 0.014) Significant decrease of vomiting in the ginger group vs. placebo group (p < 0.001) Follow-up visits:Significant symptom improvement in the ginger group vs. placebo group (p < 0.001)	Headache: - 5 in the placebo group - 6 in the ginger group. Ginger group: - 1 abdominal discomfort - 1 heartburn - 1 diarrhoea for one day Side effects reported as minor. Spontaneous abortions: - 3 in the placebo group - 1 in the ginger group Term delivery: - 91.4% in the placebo group - 96.9% in the ginger group Cesarean deliveries: - 4 in the placebo group - 6 in the ginger group No infants had any congenital anomalies recognized. No significant adverse effect of ginger on pregnancy outcome was reported.	Vutyavanich et al., 2001 [80]
To compare the effectiveness of ginger and vitamin B6 for treatment of NVP	Women NVP < 16 weeks of gestation	n = 123 62 vit. B6 61 ginger	1950 mg/day of ginger (3 × 650 mg) or 75 mg/day of vitamin B6 (3 × 25 mg)	Fresh ginger root	4 days	Nausea/vomiting: Improvement of nausea vomiting scores in both group from baseline The average score change in the ginger group was better than that of vitamin B6 group (p < 0.05)	Side effects: - 16 in ginger group - 15 in B6 group (NS) Heartburn: - 8 in ginger group - 2 in B6 group Sedation: - 7 in ginger group - 11 in B6 group Arrhythmia: - 1 in ginger group Headache: - 2 in B6 group Side effects were reported to be minor	Chittumma et al., 2007 [81]
To determine the effectiveness of ginger for the treatment of NVP	Women NVP < 20 weeks of gestation	n = 67 35 placebo 32 ginger	1000 mg/day (4 × 250 mg) of ginger (powder capsules)	Ginger root powder (Zintoma, Goldaroo Company, Tehran, Iran)	4 days	Nausea: Significant improvement in 84% of ginger users vs. 56% in the control group (p < 0.05) Vomiting: Significant improvement in the treated group vs. the control group (p < 0.05)	No complication during the treatment period was reported Reported as a safe remedy to improve the nausea and vomiting of pregnancy.	Ozgoli et al., 2009 [82]
To compare the effectiveness of ginger and vitamin B6 for the treatment of NVP	Women with nausea with or without vomiting < 17 weeks of gestation	n = 69 34 vit. B6 35 ginger	1000 mg/day (2 × 500 mg) of ginger (powder capsules) or 40 mg/day of vitamin B6 (2 × 20 mg)	Fresh ginger root	4 days + follow-up visit 7 days later	Nausea score: Better score in the ginger group vs. the vitamin group (p = 0.024) Vomiting episodes: No significant difference between the groups Follow-up visits: 82.8% reported an improvement in the ginger group vs. 67.6% in the vitamin group (p = 0.52)	Spontaneous abortions: - 2 in the ginger group - 1 in the B6 group (p > 0.05) Term birth: - 82.9% in the ginger group - 82.4% in the B6 group Caesarean deliveries: - 4 in the ginger group - 6 in the B6 group (p > 0.05) No babies had any congenital anomalies All were discharged in good condition No adverse effects of ginger on pregnancy outcome were reported	Ensiyeh et al., 2009 [83]
To compare the effects of ginger on nausea and vomiting caused by pregnancy and compares it with metoclopramide medicine	Women NVP < 20 weeks of gestation	n = 102 34 placebo 34 metoclopramide 34 ginger	600 mg/day (3 × 200 mg) ginger;30 mg/day (3 × 10 mg) metoclopramide;600 mg/day (3 × 200 mg) placebo	Ginger essence	5 days	Intensity of nausea: Significant difference in the two supplemented groups (ginger or metoclopramide) vs. placebo (p < 0.05) Not statistically significant between treated groups	-	Mohammadbeigi et al., 2011 [84]
To determine if ginger syrup mixed in water is an effective remedy for the relief of NVP	Women with nausea with or without vomiting first trimester	n = 23 10 placebo 13 ginger	1 g/day (4 × 250 mg) ginger (tablespoon) vs placebo	Ginger including 1 mg pungent compounds from ginger rhizome juice, 1 mg of 20% pungent compounds and 5% zingiberene coming from CO2 supercritical extract of ginger rhizome	2 weeks	Nausea: 77% improvement in ginger group vs. 20% in placebo group Vomiting: 67% in ginger group stop vomiting at day 6 vs 20% in placebo group	Delivered viable infant at term without major complications Safe option in the treatment of NVP	Keating et al., 2002 [78]
To investigate the effect of a ginger extract (EV.EXT35) on the symptoms of morning sickness.	Women with morning sickness < 20 weeks of gestation	n = 9951 placebo48 ginger	500 mg/day (4 × 125 mg) eq. 6 g/day ginger vs. placebo	EV.EXT35: ginger extract (125 mg eq to 1.5 g of dried ginger)	4 days	Nausea experience score: - except for day 3, the difference parameter for each day post-baseline, was significantly less than zero Vomiting: - no significant difference between the groups	Spontaneous abortion: - 3 in the ginger group - 1 in the placebo group Intolerance of the treatment: - 4 in the ginger group Worsening of treatment requiring further medical assistance: - 1 in the ginger group - 2 in the placebo group Allergic reaction to treatment: - 1 ginger group No apparent increased risk of fetal abnormalities or low birth weight.	Willetts et al., 2003 [85]
To estimate whether the use of ginger to treat nausea or vomiting in pregnancy is equivalent to pyridoxine hydrochloride (vitamin B6)	Women NVP Between 8 and 16 weeks of gestation	n = 235 115 vit. B6 120 ginger	1.05 g/day ginger (3 × 350 mg) vs. 75 mg/day vitamin B6 (3 × 25 mg)	-	3 weeks	53% reported an improvement taking ginger, and 55% reported an improvement with vitamin B6 Ginger was equivalent to vitamin B6 for improving nausea, dry retching, and vomiting	Belching: - ginger (9%) vs. B6 (0%) (p < 0.05) Dry retching after swallowing: - ginger (52%) vs. B6 (56%) Vomiting after ingestion: - ginger (2%) vs. B6 (1%) Burning sensation: - ginger (2%) vs. B6 (2%) Pregnancy outcome: - 272 (93%) gave birth to 278 infants - 12 women with spontaneous abortion (first or second trimester) - 3 women with stillbirth - No differences were found between study groups - 9 babies born with congenital abnormality (3 ginger, 6 B6) (NS) - 6 cases of urogenital disorders - 2 cases of minor gastrointestinal abnormalities -1 case of a minor congenital heart defect	Smith et al., 2004 [79]
To examine the evidence for the safety and effectiveness of ginger for NVP	Women NVP Between 7 and 17 weeks of gestation	n = 62 30 placebo 32 ginger	5 biscuits/day (2.5 g of ginger) vs. placebo	-	4 days + follow-up visit 7 days later	Nausea scores: - significantly greater in the ginger group vs. in placebo group (p = 0.01) Vomiting episodes: - no significant difference (p = 0.243) No vomiting after 4 days: - 34% in ginger group vs. 18% in placebo group Follow-up visits: - 87.5% ginger group reported improvement vs. 70% in placebo group (p = 0.043)	In ginger group: - 1 dizziness - 1 heartburn The side effects reported as minor. No abnormal pregnancy and delivery outcome occurred. No infants had any congenital abnormalities recognized. All discharged in good condition	Basirat et al., 2009 [86]
To compare the breast milk volume during the early postpartum period between women receiving dried ginger capsules with those receiving placebo	Women ≥ 37 weeks gestation	n = 63 33 placebo 30 ginger	1 g of ginger (500 mg × 2) vs. placebo	Dried ginger powder	7 days	Breast milk volume: - day 3 ginger group has higher milk volume than the placebo group (p < 0.01) - day 7, the ginger group does not differ from the placebo group Prolactin levels is similar in both groups	No notable side effects	Paritakul et al., 2016 [74]
To study the efficacy of ginger and dimenhydrinate in the treatment of NVP	Women NVP < 16 weeks of gestation	n = 170 85 dimenhydrinate 85 ginger	1 g (500 mg × 2) of ginger vs. 100 mg (50 mg × 2) of dimenhydrinate	-	1 week	Nausea: - the mean score in day 1-7 decreased in both groups - daily mean scores between both groups were not statistically different Vomiting: - frequency of vomiting times in day 1-7 decreased in both groups - daily mean vomiting times in the dimenhydrinate group in day 1-2 were less than the ginger group (p < 0.05) - after day 3–7 post treatment, the daily mean vomiting times in both groups were not statistically different	Drowsiness: - 5/85 in the ginger group vs. 66/85 in dimenhydrinate group (p < 0.01) Heart burn: - 13/85 in the ginger group vs. 9/85 in dimenhydrinate group (p = 0.403) No other adverse effect was reported in both groups	Pongrojpaw et al., 2007 [75]
To study the efficacy of ginger and placebo in hyperemesis gravidarum.	Women hyperemesis gravidarum < 20 weeks of gestation	n = 27 13 lactose 14 ginger	1 g (250 mg × 4) of ginger vs. placebo	Powdered root	2 × 4 days 2 days washout	The preference: - ginger treatment period was statistically significant (p = 0.003) Relief of the hyperemesis symptoms: - significantly greater in ginger group vs. placebo (p = 0.035)	One spontaneous abortion, which was not a suspicious high rate of fetal wastage in early pregnancy No side effects were observed All infants were without deformities and discharged in good condition.	Fischer-Rasmussen et al., 1991 [63]
To compare the effectiveness of ginger and acupressure in the treatment of NVP	Women NVP < 16 weeks of gestation	n = 143 45 control 48 acupressure	750 mg (250 mg × 3) of ginger vs. acupressure	-	7 days - 3 with no intervention - 4 with treatment	Rhodes index scores: - better in the ginger group vs. acupressure and control (p < 0.001) - reduced 49% in ginger group and 29% in acupressure group. - increased up to 0.06% in control group Post hoc test showed significant differences in vomiting, nausea, retching, and total scores between the groups except for vomiting score between acupressure and control groups and for retching score between acupressure and ginger groups	1 case of heartburn with ginger capsules	Saberi et al., 2013 [76]
To determine the effect of ginger to relieve NVP	Women NVP < 16 weeks of gestation	n = 106 36 placebo 33 control 37 ginger	750 mg (250 mg × 3) of ginger vs. acupressure	-	7 days - 3 with no intervention - 4 with treatment	Rhodes index scores: - greater in the ginger group vs. placebo and control (p < 0.001) - reduced 48% in ginger group,13% in placebo group and -10% in control group Post hoc test showed significant difference between the groups in reduction of vomiting, nausea, retching and total Rhodes Index scores (p < 0.001)	1 case of heartburn with ginger capsules	Saberi et al., 2014 [77]
To compare the effects of ginger, pyridoxine (vitamin B6), and placebo for the treatment of NVP	Women between 6 and 16 weeks of pregnancy; mild and moderate NVP	n = 77 23 placebo 26 vit. B6 28 ginger	1 g (500 mg × 2) ginger capsules 80 mg (40 mg × 2) Vit. B6 capsules	-	4 days	Rhodes index scores: - ginger > placebo (p = 0.039) - Vit. B6 > placebo (p = 0.007) - ginger = Vit. B6 (p = 0.128) Ginger was more effective for - nausea intensity - nausea distress - distress of vomiting	Ginger is effective and safe	Sharifzadeh et al., 2017 [70]