# Relevant Condition at Death and customized birthweight centiles for stillbirth classification: A retrospective cohort study

## TL;DR

This study shows that using customized birthweight centiles helps classify most stillbirths, reducing unexplained cases and improving understanding of causes.

## Contribution

The study demonstrates the effectiveness of the ReCoDe classification system in reducing unexplained stillbirths by using customized birthweight centiles.

## Key findings

- Fetal growth restriction (FGR) was the most common diagnosis in stillbirth cases.
- Only 7.1% of stillbirths remained unclassified after applying the ReCoDe classification system.
- Customized birthweight centiles significantly improved the classification of stillbirths.

## Abstract

Stillbirths (SBs) remain the largest contributor to perinatal mortality, with nearly two-thirds of SBs consistently reported as unexplained. Studies have consistently shown fetal growth restriction (FGR) as a major contributor to SB. Early detection and appropriate management are vital to reducing SB, and the Relevant Condition at Death (ReCoDe) classification utilizes customized birthweight (CBW) centiles to diagnose FGR, decreasing the proportion of SB remaining unclassified.

This was a retrospective cohort study to classify SBs using the ReCoDe classification system. A random sample of SBs above 24 weeks’ gestational age was included, and relevant clinical, laboratory, and histopathological diagnoses were extracted from medical records. The birthweights were customized according to maternal height, weight, ethnicity, parity, fetal biological sex, andgestational age at diagnosis of SB to obtain CBW centiles. FGR was defined as CBW centiles <10 percentile.

The mean age of the 254 women included was 30.5 (standard deviation = 6.2) years, with 17% being <25 years and 9.1% being ≥40 years. The majority were multiparous, 12% grand multiparous. The mean body mass index at booking was 28.6 ± 5.6 kg/m2, with 31% being in the obese category (?30 kg/m2). FGR was the most common diagnosis (52%), followed by maternal diabetes (24.0%), placental abruption (16.5%), other major placental insufficiency (15.4%), lethal congenital anomalies (13.8%), and chorioamnionitis (13.8%). The most common primary diagnosis was FGR (37.0%), followed by congenital anomalies (13.8%), placental abruption (9.1%), and maternal diabetes (6.7%). FGR remained the leading primary diagnosis in non-anomalous babies (43%), with >63% with a secondary diagnosis. The most common secondary diagnosis associated with FGR was other placental insufficiency (23.4%), followed by abruption and maternal conditions. After applying the classification system, only 18 cases remained unclassified (7.1%).

Applying the ReCoDe classification with CBW centiles, we were able to classify most of our SBs, with only 7.1% remaining unclassified. Appropriate classification of SB is vital for understanding what went wrong, counselling bereaved families, planning future pregnancies, and improving perinatal care. Early identification of FGR will allow appropriate monitoring and timely delivery.