A recently published meta-analysis in Human Reproduction has found a relationship between a woman’s vitamin D levels and the success rate of assisted reproduction therapy (ART). The researchers found that women undergoing ART who have sufficient levels of vitamin D have a higher live birth rate than women who are vitamin D deficient.
Using a systematic review and meta-analysis of 11 published cohort studies, which included 2700 women, the researchers looked at primary articles that studied women undergoing any form of ART (In vitro fertilization [IVF], intracytoplasmic sperm injection [ICSI], and frozen embryo transfer [FET]) and also had their vitamin D status checked. The primary outcome was live birth rates according to vitamin D status and secondary outcomes included biochemical pregnancy rates and clinical pregnancy rates. Two of the researchers assessed the quality of the studies by using the Newcastle-Ottawa Quality Assessment Scales. The researchers extracted live birth, biochemical pregnancy, clinical pregnancy and miscarriage rates from each of the included studies according to Vitamin D levels.
Of the 11 studies, live birth was reported in seven of them, which included 2026 patients. Live birth was found to be more likely in women with sufficient levels of vitamin D when compared to with deficient levels of vitamin D (OR 1.33 [1.08-1.65]). Five studies (1700 patients) found that women replete in vitamin D were more likely to achieve a positive pregnancy test than women deficient in vitamin D (OR 1.34 [1.04-1.73]). All 11 of the studies, reported clinical pregnancy as an outcome. Clinical pregnancy was found to be more likely in women with replete levels of vitamin D (OR 1.46 [1.05-2.02]). Six studies (1635 patients) reported miscarriage by vitamin D concentrations, but no association between vitamin D levels and miscarriage were found (OR 1.12 [0.81-1.54]).
The researchers note a couple of limitations with their study. All of the included studies looked primarily at heterogeneous populations and fertility treatment protocols. But ultimately, the researchers note that their findings illustrate a connection between vitamin D levels and fertility likelihood. While vitamin D deficiency has been associated with abnormal pregnancy implications, the researchers suggest that vitamin D levels might also play a role in early pregnancy outcomes as well.