Get small vulnerable newborn categories using multiple vectors and the INTERGROWTH-21st weight-for-gestational age standard
Source:R/growth_compute.R
compute_svn.Rd
Get small vulnerable newborn categories using multiple vectors and the INTERGROWTH-21st weight-for-gestational age standard
Arguments
- weight_kg
Numeric vector of length one or more with weight value(s) in kg. It is assumed that weight measurements provided to this function are birth weights recorded <12 hours after an infant's birth.
- gest_days
Numeric vector of length one or more with gestational ages in days. Classifications can only be computed when
gest_days
is between168
and300
, as these are the limits of the INTERGROWTH-21st Newborn Size standards (including the Very Preterm standards). By default, gigs will warn you about elements ofgest_days
which are either outside these bounds, areNA
, or areInf
. You can customise this behaviour using the GIGS package-level options.- sex
Character vector of length one or more with sex(es), either
"M"
(male) or"F"
(female). This argument is case-sensitive. By default, gigs will replace elements ofsex
which are not"M"
or"F"
withNA
and warn you. You can customise this behaviour using the GIGS package-level options.
Value
An object of class factor with the same length as the longest input
vector, containing small vulnerable newborn classifications. Its levels
are c("Preterm SGA", "Preterm AGA", "Preterm LGA", "Term SGA", "Term AGA", "Term LGA")
. By default, gigs will inform you this object contains unused
factor levels. You can change this behaviour using the
GIGS package-level option
.gigs_options$handle_unused_levels
.
Details
Cut-offs for small, vulnerable newborn categorisations are:
SVN category | Factor level | Centile bounds | Gestational age range |
Preterm-SGA | "Preterm SGA" | p < 0.1 | gest_days < 259 |
Preterm-AGA | "Preterm AGA" | 0.1 =< p =< 0.9 | gest_days < 259 |
Preterm-LGA | "Preterm LGA" | p > 0.9 | gest_days < 259 |
Term-SGA | "Term SGA" | p < 0.1 | gest_days >= 259 |
Term-AGA | "Term AGA" | 0.1 =< p =< 0.9 | gest_days >= 259 |
Term-LGA | "Term LGA" | p > 0.9 | gest_days >= 259 |
Abbreviations: SGA, small-for-gestational age; AGA, appropriate-for-gestational age; LGA, large-for-gestational age.
Note
Input vectors are recycled by vctrs::vec_recycle_common()
, and must
adhere to the vctrs recycling rules.
References
Lawn JE, Ohuma EO, Bradley E, Idueta LS, Hazel E, Okwaraji YB et al. Small babies, big risks: global estimates of prevalence and mortality for vulnerable newborns to accelerate change and improve counting. The Lancet 2023, 401(10389):1707-1719. doi:10.1016/S0140-6736(23)00522-6
Examples
compute_svn(
weight_kg = c(1.5, 2.6, 2.6, 3.5),
gest_days = c(235, 257, 275, 295),
sex = c("F", "M", "F", "M")
)
#> ! Unused factor levels kept after small vulnerable newborn categorisation:
#> "Preterm LGA" and "Term LGA".
#> [1] Preterm SGA Preterm AGA Term SGA Term AGA
#> Levels: Preterm SGA Preterm AGA Preterm LGA Term SGA Term AGA Term LGA