title: Birth weight for gestational age norms for a large cohort of infants born to HIV-negative women in Botswana compared with norms for U.S.-born black infants.
abstract: BACKGROUND
  Standard values for birth weight by gestational age are not available for sub-Saharan Africa, but are needed to evaluate incidence and risk factors for intrauterine growth retardation in settings where HIV, antiretrovirals, and other in utero exposures may impact birth outcomes.
  
  
  METHODS
  Birth weight data were collected from six hospitals in Botswana. Infants born to HIV-negative women between 26-44 weeks gestation were analyzed to construct birth weight for gestational age charts. These data were compared with published norms for black infants in the United States.
  
  
  RESULTS
  During a 29 month period from 2007-2010, birth records were reviewed in real-time from 6 hospitals and clinics in Botswana. Of these, 11,753 live infants born to HIV-negative women were included in the analysis. The median gestational age at birth was 39 weeks (1st quartile 38, 3rd quartile 40 weeks), and the median birth weight was 3100 grams (1st quartile 2800, 3rd quartile 3400 grams). We constructed estimated percentile curves for birth weight by gestational age which demonstrate increasing slope during the third trimester and leveling off beyond 40 weeks. Compared with black infants in the United States, Botswana-born infants had lower median birth weight for gestational age from weeks 37 through 42 (p < .02).
  
  
  CONCLUSIONS
  We present birth weight for gestational age norms for Botswana, which are lower at term than norms for black infants in the United States. These findings suggest the importance of regional birth weight norms to identify and define risk factors for higher risk births. These data serve as a reference for Botswana, may apply to southern Africa, and may help to identify infants at risk for perinatal complications and inform comparisons among infants exposed to HIV and antiretrovirals in utero.
authors.affiliation: Beth Israel Deaconess Medical Center, Division of Infectious Disease, Boston, MA 02115, USA. ltmatthe@bidmc.harvard.edu
authors.forename: Lynn T
authors.initials: LT
authors.lastname: Matthews
authors.forename: Heather J
authors.initials: HJ
authors.lastname: Ribaudo
authors.forename: Natasha K
authors.initials: NK
authors.lastname: Parekh
authors.forename: Jennifer Y
authors.initials: JY
authors.lastname: Chen
authors.forename: Kelebogile
authors.initials: K
authors.lastname: Binda
authors.forename: Anthony
authors.initials: A
authors.lastname: Ogwu
authors.forename: Joseph
authors.initials: J
authors.lastname: Makhema
authors.forename: Sajini
authors.initials: S
authors.lastname: Souda
authors.forename: Shahin
authors.initials: S
authors.lastname: Lockman
authors.forename: Max
authors.initials: M
authors.lastname: Essex
authors.forename: Roger L
authors.initials: RL
authors.lastname: Shapiro
mesh_terms: D001741:Black or African American; D001719:Birth Certificates; D001724:Birth Weight; D001902:Botswana / Q000453:epidemiology; D005260:Female; D005865:Gestational Age; D006678:HIV / Q000276:immunology*; D015483:HIV Antibodies / Q000032:analysis; D015658:HIV Infections / Q000208:ethnology* / Q000821:virology; D018023:HIV Seronegativity; D006801:Humans; D007231:Infant, Newborn; D011247:Pregnancy; D011251:Pregnancy Complications, Infectious / Q000208:ethnology* / Q000821:virology; D012307:Risk Factors; D014481:United States / Q000453:epidemiology
chemical_list: D015483:HIV Antibodies