Zinc and birth weight in uncomplicated pregnancies

Association of selenium, zinc and copper concentrations during pregnancy with birth weight: A systematic review and meta-analysis

BACKGROUND

Normal fetal growth is associated with maternal nutrition. Trace elements play important roles in fetus growth. This review aims to provide a summary of the literature evaluating the relation between selenium, zinc and copper levels during pregnancy with birth weight.

METHOD

A systematic literature search was conducted in Medline database (PubMed), Scopus, Web of science and Google scholar up to September 2020. Fifty observational studies were included in the final analyses. The desired pooled effect size was considered as standardized mean differences with 95 % CI or correlation. Cochran's Q statistic was used to test the heterogeneity between the included studies (I²).

RESULT

A significant differences were found between pooled standardized mean differences (SMD) of umbilical cord blood copper levels in small-for-gestational age birth weight (SGA) and appropriate-for-gestational age birth weight (AGA) (SMD: 0.34 μg/L, 95 % CI: 0.13 to 0.56). There was a significant pooled correlation between umbilical cord blood selenium concentrations and birth weight (r: 0.08, 95 % CI: 0.01 to 0.16). A significant pooled correlation was found between umbilical cord blood zinc concentrations and birth weight (r: 0.09, 95 % CI: 0.04 to 0.15), with significant heterogeneity (I² % = 0.63). There was significant positive association between maternal blood zinc concentrations and birth weight.

CONCLUSION

Findings showed the association of trace elements including selenium, zinc and copper during pregnancy with birth weight. There was significant correlation between umbilical cord and maternal blood selenium and zinc levels with birth weight. The umbilical cord blood copper levels in SGA birth weight was higher than copper levels in AGA birth weight.

Study of serum zinc in neonates and their mothers in Shimla hills (Himachal Pradesh)

Serum zinc level in cord blood of 159 neonates was estimated by atomic absorption spectrophotometer. The cases were classified according to birth weight and gestation of babies as Term appropriate for date (TAFD), Term small for date (TSFD), Term large for date (TLFD), Preterm appropriate for date (PAFD), Preterm small for date (PSFD) and Preterm large for date (PLFD). The zinc level were also estimated in mothers of these groups at the time of delivery, and compared with cord blood levels of those in non-pregnant mothers. Mean serum zinc level in infant born full term AFD, full term SFD, full term LFD, preterm AFD, preterm SFD and preterm LFD were 79.6 +/- 17.8 micrograms/dl, 58.2 +/- 13.4 micrograms/dl, 84.1 +/- 21.1 micrograms/dl, 81 +/- 25.2 micrograms/dl, 51.2 +/- 51.7 micrograms/dl and 76 +/- 14.7 micrograms/dl respectively. The maternal zinc levels in respective groups were 67 +/- 9.6 micrograms/dl, 56.5 +/- 7.5 micrograms/dl, 63.6 +/- 14.4 micrograms/dl, 62.7 +/- 21.1 micrograms/dl, 54.5 +/- 5.4 micrograms/dl, and 58.2 +/- 2.7 micrograms/dl. The mean serum zinc values in mothers and babies in birth weight group ranging from 1500-2000 gm were 55.3 +/- 4.3 micrograms/dl and 60 +/- 23.1 micrograms/dl, 2001-2500 gm were 59.5 +/- 11.3 and 65.8 +/- 17 micrograms/dl, 2501-3000 gm were 69.2 +/- 9.5 and 84.7 +/- 14 micrograms/dl, 3001-3500 gm were 65.8 +/- 12.7 micrograms/dl, 82.2 +/- 20.8 micrograms/dl and 3501 and above were 70.5 +/- 8.2 micrograms/dl and 85 +/- 14.3 micrograms/dl respectively. Statistically significant low zinc levels were observed in SFD babies and their mothers.(ABSTRACT TRUNCATED AT 250 WORDS)