Uptake and outcome of postnatal investigations after second-trimester miscarriage, stillbirth and neonatal loss

Clinical practice guidelines recommend a variety of investigations to identify potential causes of second trimester pregnancy loss (STPL), stillbirth (SB) and neonatal death (NND); however, there is a paucity of data regarding their uptake and the results obtained. We aimed to determine the frequency of use of investigations and their positive yield following STPL, SB and NND.

A single centre review of all STPL, SB and NND (excluding termination of pregnancy) between January and December 2024 at a UK tertiary maternity centre was undertaken (n = 121). The investigations performed, and whether their result was abnormal were recorded, together with information about the type of perinatal loss.

72 STPL, 40 SB, and 9 NND cases were included. Placental histopathology found abnormalities evident in 83/105 cases (79.0%). Fetal cytogenetics were abnormal in 2/32 cases (6.3%). Post-mortem demonstrated abnormal findings in 10/16 cases (62.5%). Infection screening was positive in 24/65 placental swabs (36.9%), 8/31 axilla swabs (25.8%) and 4/24 blood cultures (16.7%). Haematological screening yielded abnormal results in 6/78 bile acids (7.7%), 7/75 urate (9.3%) and 23/80 thyroid screens (28.8%). HbA1c, anti-cardiolipin and anti-β2-glycoprotein antibodies were normal.

The frequency with which investigations were performed varied; in some cases, this was due to the clinical context. Placental histopathology, post-mortem, microbiology swabs and thrombophilia screen were more frequently abnormal, though their clinical significance remains unclear. Large-scale studies involving multiple centres, and stratification of patient phenotype, are needed to determine which investigations are most useful after late miscarriage and perinatal death.