Birth weight

The normal weight of a newborn oscillates according to gestational age and there are reference values and percentiles that determine the appropriate weight. Exceeding or not reaching these reference values can sometimes trigger complications for the newborn that require closer pediatric follow-up or for the mother.

Birth weight is defined as the weight of an infant immediately after birth. This value is directly related to the age at which the baby was born and can be estimated during pregnancy by measuring the fundal height. Most babies born between 37 and 40 weeks gestation (term birth) weigh between 2.5 and 4 kg. Below or above this range is considered underweight or overweight, respectively.

A neonate within the normal range of weight for gestational age is considered appropriate for gestational age (AEG), whereas a neonate born above or below the defined gestational age limit will be exposed to fetal development that predisposes it to complications for both its health and that of its mother.

There are several factors that can affect the size of a baby at birth, such as the length of pregnancy, the size and height of the parents, multiple pregnancies, the order of birth, and the size of the fetus.There are several factors that can affect the size of a baby at birth such as the length of the pregnancy, the size and height of the parents, multiple pregnancies, birth order (firstborns are sometimes smaller), gender (girls tend to be smaller), or the mother's health during pregnancy.

Maternal factors that can lead to lower birth weight include hypertension, heart problems, smoking, alcohol or drug use. If the mother has diabetes or obesity, the baby may weigh more at birth (macrosomia). In addition, excessive maternal weight gain during pregnancy may increase the chances that a baby will be born at a higher than average weight.

Identification of small-for-gestational-age (SGA) children is important because they are at increased risk for perinatal morbidity and cardiovascular disease in adulthood. Small-for-gestational-age infant is defined as a newborn who presents length and/or birth weight < 2 SD (standard deviations) or P3 (percentile 3) for gestational age. On the other hand, fetal macrosomia is associated with a higher incidence of cesarean section and mortality is higher. Several studies link fetal macrosomia in children of diabetic, obese mothers and even in normal population, with an increased risk of developing type 2 diabetes mellitus (DM2), obesity and metabolic syndrome in childhood or adulthood.

Number of observed variants

13.5 million variants

Number of loci analyzed

145 loci

Genes analyzed

ABCG1 ACTBL2 ACTL9 ADAM17 ADCY5 ADGRG6 ADRB1 AMPD3 AMZ1 ANGPT2 ANO1 APOLD1 ARFGEF2 ARHGAP21 ARMC2 ARMS2 ATAD2B ATP8B1 C9 CABLES1 CCND1 CCNL1 CDKAL1 CDKN1C CEBPA CENPW CLDN7 CLINT1 COG6 COMMD7 CPA3 CYTIP DCST2 DCUN1D2 DDC DLK1 DNLZ DNMT1 EBF1 EDEM2 EDNRB EGFL8 ENPP2 ENTPD4 EPAS1 ESR1 FAM118A FAM133B FAM98B FANCC FCGR2B FCGR3A FCGR3B FES FGFR1 FKBP5 FLT1 FOXA2 FUT2 GCLC GJE1 GLI2 GOLGA6A GPR139 H4C4 HAAO HEATR5A HHEX HHIP HKDC1 HLA-C HMGA1 HNF1A HSPB2 ICE2 IGF1 IGF1R IGF2 IGF2BP3 IGFBP3 IL1B IL6 INTS7 IRS1 ITGA1 ITM2A ITPR2 JADE2 JAG1 JARID2 KCNJ16 KCNJ2 KCNJ8 KCNN3 KCNQ1 KL KLHL24 KLHL25 KREMEN1 L3MBTL3 LILRB3 LIMS1 LLPH LPAR1 LRIG1 LRRC4 MAFB MAFF MARCHF7 MED9 MIGA1 MLN MLXIPL MSI2 MTNR1B MYADML2 MYC MYL3 NCAPG NFIL3 NKX6-3 NOC3L NPEPL1 NR2F2 NRIP1 ONECUT1 OR5B3 PAPPA PDE10A PDE4B PDX1 PHF19 PIK3R1 PIM1 PIM3 PLAG1 PLCG1 PLEKHA1 PROX1 PSG6 PSMD2 PTGR2 PTPDC1 PTPN14 RABGAP1 RB1 RIPPLY3 RIT1 RNLS RNPS1 RPEL1 SCAMP1 SH2B3 SKP2 SLC2A1 SLC35D1 SLC38A1 SLC45A4 SLC6A2 SMNDC1 SMPD3 SNU13 SNX32 STAT1 STC2 TBX15 TBX20 TCF15 TEFM TET2 TNFSF12-TNFSF13 TNS3 TRIB1 TSPAN14 TTC9B UHRF1 WNT3A WNT4 WNT7B WSB1 WT1 XRN1 ZBTB46 ZFPM2 ZNF469 ZNF512B ZNF557 ZNF783

Bibliography

Haven't you taken a DNA test yet?

Get your genetic test and find out all about yourself.

starter

Ancestry, Traits and Wellness

advanced

Health, Ancestry, Traits and Wellness

Special offer Christmas

Until December 26

-15% on our DNA tests

Use our code XMAS15