Effects of prenatal small-quantity lipid-based nutrient supplements on pregnancy, birth, and infant outcomes: a systematic review and meta-analysis of individual participant data from randomized controlled trials in low- and middle-income countries

Background: Undernutrition during pregnancy increases the risk of giving birth to a small vulnerable newborn. Small-quantity lipid-based nutrient supplements (SQ-LNSs) contain both macro- and micronutrients and can help prevent multiple nutritional deficiencies.

Objectives: We examined the effects of SQ-LNSs provided during pregnancy compared with 1) iron and folic acid or standard of care (IFA/SOC) or 2) multiple micronutrient supplements (MMSs) and identified characteristics that modified the estimates of effects of SQ-LNSs on birth outcomes.

Methods: We conducted a 2-stage meta-analysis of individual participant data from 4 randomized controlled trials of SQ-LNSs provided during pregnancy (n = 5273). We generated study-specific and subgroup estimates of SQ-LNS compared with IFA/SOC or MMS and pooled the estimates. In sensitivity analyses, we examined whether the results differed depending on methods for gestational age dating, birth anthropometry, or study design.

Results: SQ-LNSs (compared with IFA/SOC) increased birth weight [mean difference: +49 g; 95% confidence interval (CI): 26, 71 g] and all birth anthropometric z-scores (+0.10-0.13 standard deviation); they reduced risk of low birth weight by 11%, newborn stunting by 17%, newborn wasting by 11%, and small head size by 15%. Only 2 trials compared SQ-LNSs and MMSs; P values for birth outcomes were >0.10 except for head circumference (e.g., z-score for gestational age: +0.11; 95% CI: -0.01, 0.23). Effect estimates for SQ-LNSs compared with IFA/SOC were greater among female infants and, for certain outcomes, among mothers with body mass index <20 kg/m², inflammation, malaria, or household food insecurity. Effect estimates for SQ-LNSs compared with MMSs were greater for certain outcomes among female infants, first-born infants, and mothers <25 y.

Conclusions: SQ-LNSs had positive impacts on multiple outcomes compared to IFA/SOC, but further research directly comparing SQ-LNSs and MMSs is needed. Targeting SQ-LNSs to vulnerable subgroups may be worth considering.

Clinical trial registry: This study was registered at PROSPERO as CRD42021283391.