Eliminating first trimester markers: will replacing PAPP-A and βhCG miss women at risk for small for gestational age?
OBJECTIVE
Placental analytes are traditionally used for aneuploidy screening, although may be replaced by cell-free fetal DNA. Abnormal analytes also identify women at risk for small for gestational age (SGA). We sought to quantify the proportion of women at risk for SGA by low pregnancy-associated plasma protein-A (PAPP-A) or βhCG who would not otherwise be identified by maternal risk factors.


METHODS
We studied first-trimester PAPPA-A and βhCG from 658 euploid singleton pregnancies from a prospective longitudinal cohort. Analytes were standardized for gestational age in multiples of the median (MoM). SGA was defined as birthweight z-score ≤-1.28. Maternal risk factors included chronic hypertension, pre-gestational diabetes and age ≥40.


RESULTS
Mean GA was 38.8 ± 1.9 weeks; 6.8% had a SGA infant. Low PAPP-A and βhCG were identified in 48 (7.4%) and 9 (1.4%) of pregnancies, respectively, of whom 18.9% were SGA (OR 3.0, 95% CI 1.4-6.3). 88% did not have risk factors for SGA. Among women with no risk factors, low PAPP-A was a significant predictor of SGA (OR 3.3, 95% CI 1.5-7.4).


CONCLUSIONS
Most women with abnormal analytes did not have risk factors for SGA. Eliminating PAPP-A and βhCG may present missed opportunities to identify women at risk for SGA.
Department of Obstetrics and Gynecology, Brigham and Women's Hospital , Boston, MA , USA.
Stephanie
S
Dukhovny
Chloe
C
Zera
Sarah E
SE
Little
Thomas
T
McElrath
Louise
L
Wilkins-Haug
D000328:Adult; D015415:Biomarkers / Q000097:blood*; D001724:Birth Weight; D018997:Chorionic Gonadotropin, beta Subunit, Human / Q000097:blood*; D005260:Female; D005317:Fetal Growth Retardation / Q000097:blood / Q000175:diagnosis*; D005865:Gestational Age; D006801:Humans; D007231:Infant, Newborn; D007236:Infant, Small for Gestational Age; D008137:Longitudinal Studies; D011247:Pregnancy; D011261:Pregnancy Trimester, First / Q000097:blood*; D011266:Pregnancy-Associated Plasma Protein-A / Q000032:analysis*; D012307:Risk Factors
D015415:Biomarkers; D018997:Chorionic Gonadotropin, beta Subunit, Human; D011266:Pregnancy-Associated Plasma Protein-A; C579283:PAPPA protein, human
Cell-free fetal DNA; intrauterine growth restriction; placental analytes