Mode of delivery was associated with transient changes in the metabolomic profile of neonates.

AIMS: To estimate potential differences in neonatal metabolomic profiles at birth and at the time of newborn screening by delivery mode. METHODS: A prospective study at Women's Clinic at Landspitali-The National University Hospital of Iceland. Women having normal vaginal birth or elective caesarean section from November 2013 to April 2014 were offered participation. Blood samples from mothers before birth and umbilical cord at birth were collected and amino acids and acylcarnitines measured by tandem mass spectrometry. Results from the Newborn screening programme in Iceland were collected. Amino acids and acylcarnitines from different samples were compared by delivery mode. RESULTS: Eighty three normal vaginal births and 32 elective caesarean sections were included. Mean differences at birth were higher for numerous amino acids, and some acylcarnitines in neonates born vaginally compared to elective caesarean section. Maternal blood samples and newborn screening results showed small differences that lost significance after correction for multiple testing. Many amino acids and some acylcarnitines were numerically higher in cord blood compared to maternal. Many amino acids and most acylcarnitines were numerically higher in newborn screening results compared to cord blood. CONCLUSION: We observed transient yet distinct differences in metabolomic profiles between neonates by delivery mode.

Does metabolomic profile differ with regard to birth weight?

BACKGROUND: Macrosomia and child obesity are growing health-care issues worldwide. The purpose of the study was to evaluate how extremely high or low birth weight affects metabolic markers evaluated in newborn screening. METHODS: The study was register-based and included full-term singletons born in Iceland from 2009 to 2012 with newborn screening samples taken 72-96 h after birth. Three groups based on birth weight were compared: low birth weight (<2500 g), appropriate-for-gestational age, and extreme macrosomia (≥5000 g). The comparison was adjusted for possible confounding factors. RESULTS: Compared to appropriate-for-gestational age neonates, both low birth weight and extreme macrosomia were associated with higher levels of glutamic acid. The amino acids alanine and threonine were increased in low birth weight neonates. Free carnitine and some medium- and long-chain acylcarnitines were higher in low birth weight infants. Hydroxybutyrylcarnitine was lower in low birth weight infants, but higher in extremely macrosomic neonates. Acetylcarnitine was higher in low birth weight and extremely macrosomic neonates. Succinylcarnitine was lower and hexadecenoylcarnitine higher in macrosomic newborns. CONCLUSION: Low birth weight and extremely macrosomic neonates show distinctive differences in their metabolomic profile compared to appropriate-for-gestational age newborns. The differences are not explained by gestational age. IMPACT: The key message of this article is that both low birth weight and extremely macrosomic newborns show dissimilar metabolomic profiles compared to appropriate-for-gestational age neonates. The article contributes to knowledge on what affects evaluation of results in newborn screening. The impact of this article is to provide information on metabolism at both ends of the birth weight range after accounting for confounding factors including gestational age.

Obstetric and neonatal risks among extremely macrosomic babies and their mothers.

OBJECTIVE: We estimated the risk of complications at birth of extremely large babies (≥5000 g). STUDY DESIGN: This was a cohort study including all births of extremely large babies in 1996 through 2005 and comparison cohort with normal birthweight (1:2) identified in the national birth registration. RESULTS: There were 343 extremely large babies or 0.9% of all singletons. Compared to the normal birthweight cohort (n = 679), there were increased odds of shoulder dystocia (odds ratio [OR], 26.9; 95% confidence interval [CI], 11.1-65.1), emergency cesarean section (OR, 5.2; 95% CI, 3.4-8.0), and failed labor induction (OR, 4.3; 95% CI, 1.7-11.0). The risk of elective section was not increased (OR, 1.1; 95% CI, 0.6-2.0). Minor congenital malformations were more frequent (OR, 2.1; 95% CI, 1.2-3.7), as were birth injuries (OR, 3.7; 95% CI, 2.1-6.8) and minor metabolic disturbance (OR, 2.5; 95% CI, 1.1-6.2), but not asphyxial births. CONCLUSION: The risk of shoulder dystocia for very large babies is markedly raised, as are minor complications, while for mothers the main risk is emergency section.