高收入国家的多种维生素使用和不良出生结局：系统评价和荟萃分析。

BACKGROUND:

In high-income countries (HIC), a healthy diet is widely accessible. However, a change towards a poor quality diet with a low nutritional value in HIC has led to an inadequate vitamin intake during pregnancy.

OBJECTIVE:

We conducted a systematic review and meta-analysis to evaluate the association between multivitamin use among women in HIC and the risk of adverse birth outcomes (preterm birth (PTB) (primary outcome), low birth weight, small-for-gestational age (SGA), stillbirth, neonatal death, perinatal mortality and congenital anomalies without further specification).

STUDY DESIGN:

We searched electronic databases (MEDLINE, Embase, Cochrane, Scopus and CINAHL) from inception to 17 June 2016 using synonyms of "pregnancy", "study/trial type" and "multivitamins". Eligible studies were all studies in HIC investigating the association between multivitamin use (three or more vitamins or minerals in tablets or capsules) and adverse birth outcomes. We evaluated randomized, controlled trials using the Cochrane Collaboration tool. Observational studies were evaluated using the Newcastle-Ottawa Scale. Meta-analyses were applied on raw data for outcomes with data for at least two studies and were conducted using RevMan (version 5.3). Outcomes were pooled using the random-effect model. The quality of evidence was assessed using the GRADE approach.

RESULTS:

We identified 35 eligible studies including 98,926 women. None of the studies compared the use of folic acid and iron versus use of multivitamins. Use of multivitamin did not change the risk of the primary outcome PTB RR 0.84 (95% CI 0.69-1.03). However, the risk of SGA RR 0.77 (95% CI 0.63-0.93), neural tube defects (NTD) RR 0.67 (95% CI 0.52-0.87), cardiovascular defects RR 0.83 (95% CI 0.70-0.98), urine tract defects RR 0.60 (95% CI 0.46-0.78), and limb deficiencies RR 0.68 (95% CI 0.52-0.89) was decreased. Of the 35 identified studies, only four were RCTs. The degree of clinical evidence according to the GRADE system was low or very low for all outcomes except for recurrence of NTD where a moderate degree of clinical evidence was found.

CONCLUSION:

Routine multivitamin use in HIC can be recommended, but with caution due to the low quality of evidence. RCTs or well-performed, large prospective cohort studies are needed.