Docosahexaenoic acid (DHA) is a member of the fatty acid family of n3 longchain polyunsaturated fatty acids (LCPUFAs). Studies have shown that the nutritional status of DHA during pregnancy and lactation is closely related to maternal and infant health. In order to guide the practice of clinical care during pregnancy and childbirth, international academic organizations such as the Food and Agriculture Organization of the United Nations (FAO) expert committee have formed a consensus on DHA supplementation based on a large literature review. Compared with developed countries, Chinese research on DHA has lagged behind and no Chinese version of the consensus has been found so far. To this end, the Chinese expert group on maternal and infant DHA supplementation has developed this expert consensus based on the evidence from Chinese population studies and international consensus, in order to promote Chinese medical professionals to pay attention to maternal and infant DHA nutrition, standardize nutrition guidance, and improve maternal and infant health. A 2012 meta-analysis pooled 15 randomized controlled trials (RCT) and found that supplementation with n3 LCPUFAs during pregnancy reduced the risk of early preterm birth by 26% and increased the mean birth weight of infants by 42.2g, but had no significant effect on birth length and head circumference. There was no significant effect on birth length and head circumference. A previously published meta-analysis including six RCTs also found that fish oil supplementation during pregnancy prolonged gestational age by 2.6 d and reduced the risk of early preterm birth by 31%. In a recent RCT conducted in Kansas City, USA (n = 350), 600 mg of DHA supplementation daily until delivery at 20 weeks of gestation was found to increase gestational age by 2.9 d, birth weight by 172 g, birth length by 0.7 cm and head circumference by 0.5 cm. An ecological study in 2002 analyzed the correlation between seafood intake and breast milk DHA levels and postpartum depression in more than 20 countries and found that seafood intake and breast milk DHA levels were significantly and negatively associated with postpartum depression, suggesting that low DHA levels may be a risk factor for postpartum depression. A recent systematic review summarized the results of 5 RCTs and 2 pilot studies, of which 4 RCTs and 1 pilot study suggested that DHA supplementation during pregnancy and postpartum did not improve postpartum depression, while the other 2 studies suggested that DHA supplementation improved postpartum depression. The doses of DHA supplementation in these 2 studies were greater than in the first 5 studies. In summary, the causal association between DHA and postpartum depression remains to be confirmed, and the effect of relatively high doses of DHA supplementation is worth exploring. 2, the relationship between DHA and infant development (1), neurological development In 1992, a study on fatty acid concentrations in brain tissue of dead infants found a linear increase in brain tissue DHA concentrations from mid-late pregnancy to 2 years of age, which is a critical period for rapid central nervous development of fetal infants, suggesting that DHA may be important for neurological development of fetal infants. Subsequent observational studies have found that inadequate maternal seafood intake during pregnancy affects the development of neurological functions such as intelligence, behavior, and fine motor skills in children. A 2003 Norwegian RCT found that daily supplementation of cod liver oil (1183 mg/10 ml of DHA) from 18 weeks of gestation to 3 months postpartum significantly improved the mental development of children up to 4 years of age (Kaufman Assessment Battery for Children). In 2013, Colombo et al. published an RCT-based follow-up study of 62 children aged 0 to 12 months who received different levels of n3 LCPUFAs in the RCT. The study found that LCPUFAs improved general learning skills (Dimensional Change Card Sort test) from 3 to 5 years of age, language learning skills (Peabody Picture Vocabulary Test) at 5 years of age, and the ability to learn the language at 6 years of age. Peabody Picture Vocabulary Test) and intellectual development at age 6 (Weschler Primary Preschool Scales of Intelligence), but not language, behavioral development at 18 months of age, nor spatial memory (Delayed A 2008 meta-analysis examined the effects of LCPUFAs on the neurological development of preterm infants and found that preterm infants fed LCPUFAs had better IQ scores (Bayley Scales of Infant The authors suggest that this may be related to the different versions of the assessment tools or the bias of the researchers. The positive role of DHA in brain development was supported by a 2014 article of the European Food Safety Authority (EFSA) Expert Committee. In summary, DHA has a positive effect on the neurological development of infants and young children, but there are still more scientific questions that need to be further investigated. (2), DHA and infant visual development Basic studies have confirmed that DHA accounts for 93% of the total retinal n3 LCPUFAs, and that DHA increases the plasticity of retinal discs and facilitates the curvature of the cell membrane to better adapt to changes in retinal conformation. Clinical studies have found that DHA supplementation during pregnancy and infancy is associated with infant visual development. A US RCT (n = 30) found that DHA supplementation (214 mg/d) between 24 weeks of gestation and delivery significantly improved visual acuity in infants and children. Another RCT found that the visual acuity of infants fed powdered formula containing DHA up to 17 and 52 weeks postnatal was similar to that of breastfed infants and significantly better than that of infants fed powdered formula without DHA. A 2010 RCT confirmed that the addition of DHA to powdered formula at 0.32% of total fatty acids was effective in improving infant visual acuity, but there was no additional benefit from adding higher doses of DHA. 2011 a meta-analysis pooled nine RCTs, four studies showed that LCPUFAs improved visual acuity in term infants, and five studies found no significant benefit. In 2009, the EFSA Expert Committee pointed out that “the addition of not less than 0.3% of the total fatty acid content of DHA to powdered formula can help to improve the development of visual function of infants at 12 months of age”. （A Swedish RCT (n = 145) found that daily supplementation of n3 LCPUFAs (containing 1.1 g DHA) from 25 weeks of gestation to lactation by mothers with a history of allergy significantly reduced the incidence of food allergy and IgE-associated eczema in their infants. Another follow-up study based on an RCT (n = 523) found that maternal supplementation with fish oil containing DHA from 30 weeks of gestation to delivery significantly reduced the risk of allergic asthma in offspring from birth to 16 years of age. increased gamma interferon levels at 12 months of age, further suggesting the immunomodulatory efficacy of DHA. In conclusion, the role of DHA in the regulation of immune function deserves further study. (4), DHA and infant sleep An observational study in 2002 found that maternal plasma DHA concentrations in late pregnancy were associated with neonatal sleep status, as evidenced by a smaller ratio of active to quiet sleep, less active sleep time and higher sleep quality in newborns born to mothers with high DHA concentrations. A subsequent RCT (n = 48) found that DHA supplementation (214 mg/d) between 24 weeks of gestation and delivery significantly reduced the number of sleep awakenings in newborns. In summary, DHA has the potential to improve infant sleep, but there are few relevant studies that warrant further exploration. 3, the safety of DHA supplementation Comprehensive evidence from existing studies suggests that moderate amounts of DHA supplementation are safe. In the RCT conducted by Carlson et al, no serious adverse events related to DHA were observed in pregnant mothers or newborns when supplementing with 600 mg DHA daily from 20 weeks of pregnancy to delivery. In 2012, the Chinese Health and Family Planning Commission issued the “Standard for the Use of Food Fortification”, which permits the addition of DHA from algae and tuna oil to milk powder, and requires that the percentage of DHA in the total fatty acids of milk powder for children is ≤0.5%. A dietary survey in 2004 found that the average intake of DHA in Chinese pregnant women ranged from 11.83 to 55.30 mg/d, and the intake in inland areas was significantly lower than that in rivers, lakes and coastal areas. A 2011 study on the fatty acid composition of mature milk suggested that the DHA content of breast milk per 100 g was 0.47 g, 0.41 g and 0.24 g in coastal, river, lake and inland areas, respectively, and was significantly lower in inland areas than in river, lake and coastal areas. It can be seen that the level of DHA intake and breast milk DHA content in China showed significant geographical differences. In addition, some scholars compared the DHA content of breast milk in nine countries around the world and found that the DHA content of breast milk in China was 0.35% of total fatty acids, which was higher than that in Canada and the United States (0.17%) but lower than that in Japan (0.99%). At present, there are few studies related to DHA in Chinese children and need to be strengthened. 5.Summary The expert group summarized and evaluated the evidence on DHA studies at home and abroad, and referred to the relevant recommendations of authoritative organizations (FAO Expert Committee/EFSA Expert Committee/Chinese Nutrition Society DRIs) at home and abroad, and formed the following consensus on maternal and infant DHA intake and supplementation in China: (1) Maintaining appropriate levels of DHA in the body is beneficial for improving pregnancy outcomes, infant (1) Maintaining appropriate levels of DHA is beneficial for improving pregnancy outcomes, early neurological and visual development, and may also be beneficial for improving postpartum depression, as well as infant immune function and sleep patterns. (2) Pregnant women and lactating mothers need to eat a reasonable diet to maintain DHA levels for the health of mother and child. DHA intake. The consumption of fat-rich seafood also requires consideration of possible contaminants. The intake of DHA in China varies over a wide area and it is appropriate to evaluate the intake of DHA in pregnant women at an appropriate time. If the diet cannot meet the recommended intake of DHA, it is advisable to adjust the dietary structure individually; if the recommended intake cannot be achieved after adjusting the dietary structure, DHA supplements can be applied. （Breast milk is the main source of DHA nutrition for infants, it is advisable to advocate and encourage breastfeeding, and breastfed full-term infants do not need additional DHA supplementation. For young children, it is advisable to adjust the diet to meet their DHA requirements. Special attention should be paid to the DHA requirements of premature infants. The European Society of Pediatric Gastroenterology, Hepatology and Nutrition recommends a daily DHA intake of 12-30 mg/kg for preterm infants; the American Academy of Pediatrics recommends a daily intake of ≥21 mg/kg for preterm infants with a birth weight of less than 1000 g and ≥18 mg/kg for those with a birth weight of less than 1500 g. (4), the level of DHA intake of Chinese mothers and infants, the nutritional status and related intervention studies Evidence is scarce, and relevant studies are urgently needed.