Strength and limitations
The strength of this study is that this birth dataset is the most
extensive compilation to date from Latin America, including data from
four countries and more than 67,000 births. In addition to the increased
data quantity, we simultaneously evaluated the two current prescriptive
international fetal growth standards to adjust the risk estimation of
adverse perinatal outcomes and anthropometric measures associated with
FGR. Differences in maternal age and antenatal care across countries
might be due to population characteristics, culture, and obstetric
practice. However, non-black Hispanics are currently used to agglomerate
the Latin American population worldwide, so we did not consider ethnic
differences within our population. Study limitations include the
retrospective nature of this study. Another limitation of our study is
that we only reported APGAR scores. However, this is an objective
measure used to identify babies with a high risk of perinatal morbidity
and poor neurological development. In addition, stillbirths were
excluded because of uncertainty regarding their classification as SGA by
birth weight. Other large series have shown that
IG21st standards miss a fraction of babies at risk for
this complex event (62). It is also a limitation of our study that we
could not compare the performance of customized standards due to the
lack of published and validated coefficients for all the participating
countries. Although customized curves have been proposed (63–65), their
superiority in identifying adverse perinatal outcomes has not been
supported by more recent literature (66,67). Finally, although WHO
detected a significantly higher proportion of SGA fetuses, this fraction
of small fetuses likely contains instances of adverse outcomes that the
data available (only Apgar) could not reveal.