Effects of vitamin D supplementation on ovulation and pregnancy in women with polycystic ovary syndrome: a systematic review and meta-analysis.
Study Goal
To evaluate the effect of vitamin D supplementation on pregnancy and ovulation rates in patients with polycystic ovary syndrome (PCOS).
Results Summary
Vitamin D supplementation significantly increased pregnancy, ovulation, and matured oocytes rates while reducing early miscarriage rates, androgen levels, luteinizing hormone, follicle-stimulating hormone, and premature delivery rates. No significant improvements were observed in fertilization rate, cleavage rate, or other secondary outcomes.
Population
Women with polycystic ovary syndrome (PCOS).
Effective Dosage
Not specified
Duration
Not specified
Interactions
None mentioned
| Intervention | Direction | Endpoint | Population | Dosage | Impact | Claim # |
|---|---|---|---|---|---|---|
vitamin D supplementation | increase | pregnancy rate | patients with polycystic ovary syndrome | RR=1.44 (1.28, 1.62) | were significantly higher | #1 |
vitamin D supplementation | increase | ovulation rate | patients with polycystic ovary syndrome | RR=1.42 (1.14, 1.78) | were significantly higher | #2 |
vitamin D supplementation | increase | matured oocytes rate | patients with polycystic ovary syndrome | RR=1.08 (1.03, 1.13) | were significantly higher | #3 |
vitamin D supplementation | decrease | early miscarriage rate | patients with polycystic ovary syndrome | RR=0.44 (0.30, 0.66) | were declined significantly | #4 |
vitamin D supplementation | decrease | androgen level | patients with polycystic ovary syndrome | MD=-2.31 (-3.51, -1.11) | were declined significantly | #5 |
vitamin D supplementation | decrease | luteinizing hormone | patients with polycystic ovary syndrome | MD=-1.47 (-2.57, -0.36) | were declined significantly | #6 |
vitamin D supplementation | decrease | follicle stimulating hormone | patients with polycystic ovary syndrome | MD=-0.15 (-0.24, -0.05) | were declined significantly | #7 |
vitamin D supplementation | decrease | premature delivery rate | patients with polycystic ovary syndrome | RR=0.38, 95% CI (0.21, 0.70) | were declined significantly | #8 |
vitamin D supplementation | increase | progesterone | patients with polycystic ovary syndrome | MD=6.52 (4.52, 8.52) | was increased | #9 |
vitamin D supplementation | no change | biochemical pregnancy rate | patients with polycystic ovary syndrome | RR=0.95 (0.55, 1.63) | no notable difference | #10 |
vitamin D supplementation | no change | gestational hypertension rate | patients with polycystic ovary syndrome | RR=0.40, 95% CI (0.15, 1.11) | no notable difference | #11 |
vitamin D supplementation | no change | gestational diabetes mellitus rate | patients with polycystic ovary syndrome | RR=0.27, 95% CI (0.05, 1.39) | no notable difference | #12 |
vitamin D supplementation | no change | fertilization rate | patients with polycystic ovary syndrome | RR=1.05 (1.00, 1.10) | no notable difference | #13 |
vitamin D supplementation | no change | cleavage rate | patients with polycystic ovary syndrome | RR=1.03 (0.99, 1.06) | no notable difference | #14 |
vitamin D supplementation | no change | high-quality embryo rate | patients with polycystic ovary syndrome | RR=1.08 (0.98, 1.20) | no notable difference | #15 |
vitamin D supplementation | no change | endometrial thickness | patients with polycystic ovary syndrome | MD=0.10, 77 (-0.23, 1.77) | no notable difference | #16 |
vitamin D supplementation | no change | estrogen level | patients with polycystic ovary syndrome | MD=-0.34 (-1.55, 0.87) | no notable difference | #17 |
vitamin D supplementation | no change | LH/FSH | patients with polycystic ovary syndrome | MD=-0.14, 95% CI (-0.48, 0.20) | no notable difference | #18 |
vitamin D supplementation | no change | anti-Mullerian hormone | patients with polycystic ovary syndrome | MD=-0.22 (-0.65, 0.21) | no notable difference | #19 |
OBJECTIVE: To evaluate the effect of vitamin D supplementation on pregnancy and ovulation in patients with polycystic ovary syndrome. METHOD: We searched Pubmed, Medline (via Ovid, 1974 to 2020), EMBASE (via Ovid, 1974 to 2020), Cochrane Central Register of Controlled Trials (via Ovid), Web of Science, CNKI, WangFang and the Vip database from inception until April 2021. Two researchers independently screened articles, collected data and evaluated the quality, with Review manager 5.3 for meta-analysis. RESULTS: Totally 20 randomized controlled studies with 1961 subjects were included. Meta analysis showed that pregnancy rate [RR=1.44 (1.28, 1.62), p<0.00,001], ovulation rate [RR=1.42 (1.14, 1.78), p=0.002] and matured oocytes rate [RR=1.08 (1.03, 1.13), p=0.002] of vitamin D supplementation group were significantly higher than those of control group. Meanwhile, early miscarriage rate [RR=0.44 (0.30, 0.66), p<0.00,001], androgen level [MD=-2.31 (-3.51, -1.11), p=0.0002], luteinizing hormone [MD=-1.47 (-2.57, -0.36), p=0.009], follicle stimulating hormone [MD=-0.15 (-0.24, -0.05), p=0.002], and premature delivery rate [RR=0.38, 95% CI (0.21, 0.70), p=0.002] were declined significantly than the controls. However, only one article suggested that the progesterone [MD=6.52 (4.52, 8.52), p<0.05] in the vitamin D intervention group was increased. There was no notable difference in the biochemical pregnancy rate [RR=0.95 (0.55, 1.63), p=0.84], gestational hypertension rate [RR=0.40, 95% CI (0.15, 1.11), p=0.08], gestational diabetes mellitus rate [RR=0.27, 95% CI (0.05, 1.39), p=0.11], fertilization rate [RR=1.05 (1.00, 1.10), p=0.04], cleavage rate [RR=1.03 (0.99, 1.06), p=0.17], high-quality embryo rate [RR=1.08 (0.98, 1.20), p=0.10], endometrial thickness [MD=0.10], 77 (-0.23, 1.77), p=0.13], estrogen level [MD=-0.34 (-1.55, 0.87), p=0.59], LH/FSH [MD=-0.14, 95% CI (-0.48, 0.20), p=1.00] and anti-Mullerian hormone [MD=-0.22 (-0.65, 0.21), p=0.32]. CONCLUSION: Vitamin D supplementation contribute to the higher pregnancy and ovulation rates, and lower androgen, LH, FSH and early miscarriage rates in women with PCOS, regardless of the use of ovulation induction drugs or assisted reproductive technologies. However, no significant improvement was observed in fertilization rate or cleavage rate. Due to the limitation in quality of involved studies, more high-quality RCTs are needed for further validation. SYSTEMATIC REVIEW REGISTRATION: https://www.crd.york.ac.uk/PROSPERO, identifier CRD42021250284.