Effect of multivitamin use on neonatals.
Preterm birth (PTB) and fetal growth restriction are leading risk factors of neonatal morbidity and mortality. Although thought to have distinct pathogeneses, certain risk factors overlap: black race, maternal smoking, nulliparity and lean maternal BMI.
Nutrition plays a role in the pathogenesis of adverse pregnancy outcomes including PTB and fetal growth restriction. The intake of periconceptional multivitamins may decrease the risk of PTBs or small for gestational age (SGA) births. This study aimed to relate the timing and frequency of periconceptional multivitamin use to risk of a PTB or delivery of SGA infants.
The periconceptional period was defined as 4 weeks before the last menstrual period (LMP) through to 8 weeks after the LMP, further categorised as preconception and postconception. The authors hypothesised that the relation of multivitamin supplementation with these pregnancy outcomes would be strongest for women with regular use throughout the periconceptional period because this would provide the most comprehensive supplementation.
Results were drawn from the Danish National Birth Cohort, a large (n = 35 897) well characterised cohort of pregnant women, recruited early in gestation, who reported multivitamin use during a 12 week periconceptional period. Follow up started at gestational day 155 and ended at the date of birth, date of fetal death or date of emigration.
Frequency of multivitamin use was categorised as partial use (1-3 weeks out of 6 possible weeks) or regular use (4-6 weeks out of 6 possible weeks) for the preconception and postconception periods. Folate only supplement use was analysed in the same way as multivitamin use and was evaluated to determine whether the effect appeared to be different in this group than in multivitamin users.
Overall 21 785 women (60.7%) reported any multivitamin use in the periconceptional period. Multivitamin users compared with nonusers were more likely to be >25 years of age, have a pre pregnancy BMI <25, nulliparous and to report a mid pregnancy diet that was classified as health conscious and a >12 month waiting time to pregnancy.
Women with regular preconception and postconception multivitamin use had modestly lower rates of a PTB than did nonusers (4.3% compared with 5.3%; P=0.02). Women with regular postconception multivitamin use, regardless of the preconception use pattern, had lower rates of an SGA than did nonusers (2.4-2.8% compared with 4.3%; P<0.01 for each comparison with nonusers). Compared with women with no reported supplement use there was no association between folate only use and PTBs or SGA births [adjusted HR (95% CI): 1.00 (0.91, 1.11) and 0.96 (0.84, 1.08) respectively].
In non overweight women (pregravid BMI <25), multivitamin use was associated with a 16% reduced risk of preterm delivery [HR (95% CI): 0.84 (0.73, 0.95)]. There was no association between multivitamin use and PTB risk in overweight women [HR (95% CI): 1.03 (0.85, 1.26)]. All patterns of multivitamin use in the periconceptional period were associated with 17-27% reduced risk of spontaneous labour cases in non overweight women.
Any periconceptional multivitamin use was associated with reduced risk of SGA after adjustment for confounders [HR (95% CI):0.83 (0.73, 0.95)] with no difference in non overweight and overweight women. Although all patterns of periconceptional multivitamin use appeared to be associated with 10-20% reduced risk of SGA, regular postconception only use was associated with a 33% reduction in risk [HR (95% CI): 0.67 (0.54, 0.86)].
The study concluded that there is a strong association between periconceptional multivitamin use and reduced risk for PTBs and SGA births in non overweight women.
Kathleen Murphy MNHAA
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|Publication:||Australian Journal of Medical Herbalism|
|Date:||Dec 22, 2011|
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