AbstractObjectiveTo test the hypothesis that maternal food fortification with omega-3 fatty
acids and multiple micronutrients increases birth weight and gestation
duration, as primary outcomes.DesignNon-blinded, randomised controlled study.SettingPregnant women received powdered milk during their health check-ups at 19
antenatal clinics and delivered at two maternity hospitals in Santiago,
Chile.SubjectPregnant women were assigned to receive regular powdered milk (n = 477) or a milk product fortified with
multiple micronutrients and omega-3 fatty acids (n = 495).ResultsIntention-to-treat analysis showed that mean birth weight was higher in the
intervention group than in controls (65.4 g difference, 95% confidence
interval (CI) 5–126 g; P =
0.03) and the incidence of very preterm birth (<34 weeks) was
lower (0.4% vs. 2.1%; P = 0.03).
On-treatment analysis showed a mean birth weight difference of 118 g (95% CI
47–190 g; P = 0.001) and a
relative fall in both the proportion of birth weight ≤3000 g
(P = 0.015) and the incidence of
pre-eclampsia (P = 0.015). Compliance
with the experimental product was apparent from a haematological study of
red-blood-cell folate at the end of pregnancy, which was performed in a
sub-sample. In both types of analyses, positive differences were also
present for mean gestation duration, birth length and head circumference.
Nevertheless, the relatively small sample sizes allowed a statistical power
of >0.80 just for mean birth weight and birth length in the
on-treatment analysis; birth length in that analysis had a difference of
0.57 cm (95% CI 0.19–0.96 cm; P = 0.003).ConclusionsThe new intervention resulted in increased mean birth weight. Associations
with gestation duration and most secondary outcomes need a larger sample
size for confirmation.