Biomaterial Database

Absence of selection on birth weight in modern Italy. 2002

L Ulizzi

Dipartimento di Genetica c Biologia Molecolare C. Darwin, Università La Sapienza, Rome, Italy.

The effect of stabilizing and directional selection on birth weight has been analyzed for Italian births from 1954 to 1994, a period of rapid improvement in environmental conditions. The population of newborns was subdivided according to gestational age, one of the main covariates of birth weight. In the last cohort of births, no selection at all (neither stabilizing nor directional) was found in full-term babies, which represent more than 95% of total deliveries. Preterm babies are still selected against, even if at lower rates than in the past. It can therefore be claimed that improved and widely available prenatal and neonatal care has dramatically changed the selection patterns previously associated with birth weight in the majority of the Italian population. The mortality rates associated with birth-weight variations lying in a wide interval (2.5 kg-4.5 kg) are nowadays very similar, and both stabilizing and directional selection have practically disappeared.

UI	MeSH Term	Description	Entries
D007226	Infant Mortality	Postnatal deaths from BIRTH to 365 days after birth in a given population. Postneonatal mortality represents deaths between 28 days and 365 days after birth (as defined by National Center for Health Statistics). Neonatal mortality represents deaths from birth to 27 days after birth.	Neonatal Mortality,Mortality, Infant,Postneonatal Mortality,Infant Mortalities,Mortalities, Infant,Mortalities, Neonatal,Mortalities, Postneonatal,Mortality, Neonatal,Mortality, Postneonatal,Neonatal Mortalities,Postneonatal Mortalities
D007231	Infant, Newborn	An infant during the first 28 days after birth.	Neonate,Newborns,Infants, Newborn,Neonates,Newborn,Newborn Infant,Newborn Infants
D007234	Infant, Premature	A human infant born before 37 weeks of GESTATION.	Neonatal Prematurity,Premature Infants,Preterm Infants,Infant, Preterm,Infants, Premature,Infants, Preterm,Premature Infant,Prematurity, Neonatal,Preterm Infant
D007558	Italy	A country in southern Europe, a peninsula extending into the central Mediterranean Sea, northeast of Tunisia. The capital is Rome.	Sardinia
D008297	Male		Males
D001724	Birth Weight	The mass or quantity of heaviness of an individual at BIRTH. It is expressed by units of pounds or kilograms.	Birthweight,Birth Weights,Birthweights,Weight, Birth,Weights, Birth
D005260	Female		Females
D005865	Gestational Age	The age of the conceptus, beginning from the time of FERTILIZATION. In clinical obstetrics, the gestational age is often estimated from the onset of the last MENSTRUATION which is about 2 weeks before OVULATION and fertilization. It is also estimated to begin from fertilization, estrus, coitus, or artificial insemination.	Embryologic Age,Fetal Maturity, Chronologic,Chronologic Fetal Maturity,Fetal Age,Maturity, Chronologic Fetal,Age, Embryologic,Age, Fetal,Age, Gestational,Ages, Embryologic,Ages, Fetal,Ages, Gestational,Embryologic Ages,Fetal Ages,Gestational Ages
D006801	Humans	Members of the species Homo sapiens.	Homo sapiens,Man (Taxonomy),Human,Man, Modern,Modern Man
D012641	Selection, Genetic	Differential and non-random reproduction of different genotypes, operating to alter the gene frequencies within a population.	Natural Selection,Genetic Selection,Selection, Natural