Reassuring for Parents-to-be: DHA Supplements During Pregnancy Reduce Preterm Births and Time in NICU 21 Feb 2013
Whether a parent or not, everyone recognizes the vulnerability of newborn infants. Even when healthy, newborns are completely reliant on their caregivers to anticipate their needs and provide the appropriate care. For infants born prematurely or with an unusually low birth weight, care is even more difficult due to health complications. Preterm infants have not had enough time in the womb to fully develop. Infants born small for their gestational age may have had their growth restricted. These infants have a higher risk of illness, the effects which may be life-long. Mortality is also higher in infants with a low birth weight. The World Health Organization estimates that around one quarter of infants is born too small, and this percentage is higher in developing countries. Even in well-nourished populations such as the USA, around 8% of infants have a low birth weight, according to the March of Dimes.
Researchers are looking for ways to reduce the incidence of low birth weight. While access to health care, a healthy diet and lifestyle, and planned pregnancies all contribute to healthy pregnancies, specific nutrition factors may also contribute. The long chain omega-3 polyunsaturated fatty acid DHA has been identified as being important for pregnant women, particularly in the second half of pregnancy. The developing fetus has a high need for DHA because it makes up part of cell membranes, particularly in the brain but also in other tissues (see review by Innis). Low maternal intakes of DHA or its precursors may induce deficiency in the fetus, increasing cell fragility and an inflammatory response that increases risk of pregnancy and birth complications, according to Crawford. Carlson and co-workers reported yesterday in the American Journal of Clinical Nutrition on the effects of DHA supplementation in the second half of pregnancy of women in Kansas city on birth outcomes such as birth weight and risk of preterm birth.
350 women consumed daily three capsules containing 207.5 mg DHA per capsule, or placebo, from enrollment in the study (average 14 weeks, no later than 20 weeks) until birth. Women were followed during pregnancy and their offspring until 18 months of age, with data extracted from their medical records.
The results are very encouraging. The group supplemented with DHA showed a significant increase in the DHA content of red blood cell phospholipids. The length of gestation was 3 days longer in the supplemented group compared to placebo. DHA supplements increased infant birth weight significantly by 172 g. Head circumference was also larger in the supplemented group. While the rate of preterm birth before 37 weeks did not differ, there was a significant reduction in very preterm birth (before 34 weeks) in the supplemented group. The number of infants with a low birth weight (<2500 g) and very low birth weight (<1500 g) was significantly reduced in the supplemented group. The length of time in the Newborn Intensive Care Unit (NICU) was also significantly shorter in the supplemented group, with infants in the unit for only 9 days in the supplemented group compared to 41 days on average in the placebo group.
These very positive results in this population of relatively well-nourished women living in a high-income country provide a possible means to reduce the rate of preterm birth through the use of a single supplement. This study backs up results from observational research and prior randomized controlled trials (systematic review by Imhoff-Kunsch, et al.). Providing adequate DHA to pregnant women should be encouraged to prevent the negative effects on health of low birth weight and preterm birth.-jb-
Susan E Carlson, John Colombo, Byron J Gajewski, Kathleen M Gustafson, David Mundy, John Yeast, Michael K Georgieff, Lisa A Markley, Elizabeth H Kerling, and D Jill Shaddy. DHA supplementation and pregnancy outcomes. Am J Clin Nutr 2013 ajcn.050021; First published online February 20, 2013. doi:10.3945/ajcn.112.050021