Effect of Vitamin D Supplementation on Unexplained Recurrent Spontaneous Abortion: A Double-Blind Randomized Controlled Trial

Samimi, Mansooreh; Foroozanfard, Fatemeh; Amini, Farzaneh; Sehat, Mojtaba

doi:10.5539/gjhs.v9n3p95

Cited by 18 publications

(21 citation statements)

References 45 publications

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“…We identified 10 eligible studies conducted in pregnant women [29–38] (Table 1, Appendix 2). Nine studies were from Iran and one study was from UAE.…”

Section: Resultsmentioning

confidence: 99%

“…Nine studies were from Iran and one study was from UAE. Five studies were conducted in healthy pregnant women, while the others were conducted in women with multiple sclerosis (MS) [33], at risk of preeclampsia [34, 35], gestational diabetes mellitus [36], or recurrent unexplained abortions [38]. The mean BMI of participants varied between 25 and 28.7 kg/m 2 .…”

Section: Resultsmentioning

confidence: 99%

“…Vitamin D supplementation was started at 12–20 weeks of gestation, with the exception of two studies, where vitamin D supplementation was started at 26–28 weeks of gestation [29, 37], and another one where supplementation started as soon as pregnancy was confirmed by abdominal US and βhCG level [38] (Table 1, Appendix 2). All studies administered vitamin D until delivery, except the trials by Karamali et al, Shahgheibi et al and Samimi et al where supplementation was stopped in the third trimester [34, 36, 38]. In four trials comparing a high dose to placebo, all participants received additional vitamin D supplementation of 200–400 IU daily [30, 34, 35, 37].…”

Section: Resultsmentioning

confidence: 99%

“…Etemadifar et al reported maternal 25(OH)D levels at 6 months post-partum and not at delivery [33]. In the trial assessing the effect of vitamin D on unexplained recurrent abortions, Samimi et al reported 25(OH)D level at 20 weeks gestation, rather than at delivery [38]. Shakiba et al reported only on 25(OH)D levels in venous cord blood [31].…”

Section: Resultsmentioning

confidence: 99%

“…We identified two studies were identified in this category [36, 38]. Samimi et al administered 400 IU/d vitamin D to deficient pregnant women early in their first trimester and assessed response at 20 weeks gestation [38].…”

Section: Resultsmentioning

confidence: 99%

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Vitamin D replacement in children, adolescents and pregnant women in the Middle East and North Africa

et al. 2017

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Introduction Hypovitaminosis D affects one-third to two-thirds of children and pregnant women from the Middle East and North Africa (MENA) region. Objective To evaluate in infants, children, adolescents and pregnant women, from the MENA region, the effect of supplementation with different vitamin D doses on the change in 25-hydroxyvitamin D [25(OH)D] level reached, and other skeletal and non-skeletal outcomes. Methods This is a systematic review of randomized controlled trials of vitamin D supplementation conducted in the MENA region. We conducted a comprehensive literature search in 7 databases, without language or time restriction, until November 2016. Two reviewers abstracted data from the included studies, independently and in duplicate. We calculated the mean difference (MD) and 95% CI of 25(OH)D level reached when at least 2 studies were eligible in each comparison (low (< 800 IU), intermediate (800–2,000 IU) or high (> 2,000 IU) daily dose of vitamin D, or placebo). We pooled data using RevMan version 5.3. Results We identified a total of 15 eligible trials: one in infants, 4 in children and adolescents and 10 in pregnant women. In children and adolescents, an intermediate vitamin D dose (1,901 IU/d), resulted in a mean difference in 25(OH)D level of 13.5 (95% Confidence Interval (CI) 8.1;18.8) ng/ml, compared to placebo, favoring the intermediate dose (p < 0.001). The proportion of children and adolescents reaching a 25(OH)D level ≥ 20 ng/ml was 74% in the intermediate dose group. In pregnant women, four trials started supplementation at 12–16 weeks of gestation and continued until delivery, and six trials started supplementation at 20–28 weeks gestation and stopped it at delivery. The MD in 25(OH)D level reached was 8.6 (95% CI 5.3–11.9) ng/ml (p <0.001) comparing the high dose (3,662 IU/d) to the intermediate dose (1,836 IU/d), and 12.3 (95% CI 6.4–18.2) ng/ml (p <0.001), comparing the high dose (3,399 IU/d) to the low dose (375 IU/d). Comparing the intermediate (1,832 IU/d) to the low dose (301 IU/d), the MD in 25(OH)D level achieved was 7.8 (95% CI 4.5–10.8) ng/ml (p < 0.001). The proportion of pregnant women reaching a 25(OH)D level ≥ 20 ng/ml was 80–90%, 73% and 27–43% in the high, intermediate, and low dose groups, respectively. The risk of bias in the included studies, for children, adolescents and pregnant women, ranged from low to high. Conclusion In children, adolescents and pregnant women from the MENA, an intermediate vitamin D dose of 1,000–2,000 IU seems necessary to allow for the majority of the population to reach a desirable 25(OH)D level of 20 ng/ml. Further high quality RCTs are required to confirm/refute the beneficial impact of vitamin D supplementation on various clinically important outcomes.

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“…We identified 10 eligible studies conducted in pregnant women [29–38] (Table 1, Appendix 2). Nine studies were from Iran and one study was from UAE.…”

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

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Vitamin D replacement in children, adolescents and pregnant women in the Middle East and North Africa

et al. 2017

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Vitamin D supplementation for women during pregnancy

Palacios

Kostiuk

Peña-Rosas

2019

Cochrane Database of Systematic Reviews

200

203

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BACKGROUND: Vitamin D deficiency or insufficiency is thought to be common among pregnant women. Vitamin D supplementation during pregnancy has been suggested as an intervention to protect against adverse pregnancy outcomes. OBJECTIVES: To examine whether oral supplements with vitamin D alone or in combination with calcium or other vitamins and minerals given to women during pregnancy can safely improve maternal and neonatal outcomes. METHODS: Search methods: We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (23 February 2015), the International Clinical Trials Registry Platform (31 January 2015), the Networked Digital Library of Theses and Dissertations (28 January 2015) and also contacted relevant organisations (31 January 2015). Selection criteria: Randomized and quasi-randomized trials with randomization at either individual or cluster level, evaluating the effect of supplementation with vitamin D alone or in combination with other micronutrients for women during pregnancy. Data collection and analysis: Two review authors independently i) assessed the eligibility of studies against the inclusion criteria ii) extracted data from included studies, and iii) assessed the risk of bias of the included studies. Data were checked for accuracy. The quality of the evidence was assessed using the GRADE approach. MAIN RESULTS: In this updated review we included 15 trials assessing a total of 2833 women, excluded 27 trials, and 23 trials are still ongoing or unpublished. Nine trials compared the effects of vitamin D alone versus no supplementation or a placebo and six trials compared the effects of vitamin D and calcium with no supplementation. Risk of bias in the majority of trials was unclear and many studies were at high risk of bias for blinding and attrition rates. • Vitamin D alone versus no supplementation or a placebo Data from seven trials involving 868 women consistently show that women who received vitamin D supplements alone, particularly on a daily basis, had higher 25-hydroxyvitamin D than those receiving no intervention or placebo, but this response was highly heterogeneous. Also, data from two trials involving 219 women suggest that women who received vitamin D supplements may have a lower risk of pre-eclampsia than those receiving no intervention or placebo (8.9% versus 15.5%; risk ratio (RR) 0.52; 95% CI 0.25 to 1.05, low quality). Data from two trials involving 219 women suggest a similar risk of gestational diabetes among those taking vitamin D supplements or no intervention/ placebo (RR 0.43; 95% CI 0.05, 3.45, very low quality). There were no clear differences in adverse effects, with only one reported case of nephritic syndrome in the control group in one study (RR 0.17; 95% CI 0.01 to 4.06;

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