Underlying placental lesions in small for gestational age (SGA) subgroups: mild SGA, severe SGA, and stillbirth SGA: a cross-sectional data linkage study

Introduction: 

Placental dysfunction contributes to fetal growth restriction (FGR) and stillbirth. The association of major placental lesions with phenotypes of small for gestational age (SGA) is not fully explored. This study describes placental lesions across the spectrum of gestational age in liveborn and stillbirth SGA. 

Methods: 

This was a cross-sectional data linkage study using two Dutch national registries; Palga (the Dutch nationwide pathology databank) and Perined (perinatal data). The primary study outcome was prevalence of placental lesions (maternal vascular malperfusion (MVM), fetal vascular malperfusion (FVM), chronic inflammation (CI) and ‘other’) across gestational age, birthweight percentiles (mild SGA: p3-p10 and severe SGA: <p3) and stillbirth < p10, stratified for hypertensive disorders of pregnancy (HDP). 4.4% of Perined pregnancies were linked to Palga data, representing a selected cohort due to clinical indication for placental examination. 

Results: 

Linkage of the registries (2005 – 2022) resulted in 51,028 SGA cases, including 22,186 liveborn mild SGA, 25,603 liveborn severe SGA, and 3239 stillbirth SGA cases. MVM was the most prevalent lesion. MVM and FVM decreased with increasing gestational age, while CI increased. MVM was more common in HDP, and CI and FVM were slightly more prevalent in non-HDP cases. MVM was present in 55% of severe versus 45% of mild SGA cases. FVM was more present in stillbirth than liveborn SGA cases. Combined MVM lesions were more frequent in stillbirth cases and at term. 

Discussion: 

Differences between the three SGA groups were small, underscoring that the association between reported placental pathology and clinical phenotype is not always straightforward.