Second trimester miscarriage, also termed as late miscarriage, occurs less commonly. A new study published in the February 2023 issue of the Journal of Obstetrics and Gynaecology Research has attempted to define the likely etiology and clinical presentation among the various phenotypes of second trimester miscarriage.¹

For this, researchers from the University of Hong Kong retrospectively analysed data of 170 consecutive miscarriages that occurred between 14 + 0 and 23 + 6 weeks from 2012 to 2021. Depending on the clinical presentation, the patients were grouped into three: rupture of membranes (ST-ROM), silent miscarriages (ST-SM) and inevitable miscarriages (ST-IM). The aim of the study was to assess the underlying causes of miscarriage.

Majority (97) of the second trimester miscarriages were silent miscarriages (ST-IM). Twenty-one cases were ST-ROM and the remaining 52 were ST-IM. “Placental histology and karyotype examination were more likely to yield significant results in the cases of ST-ROM and ST-SM (p < 0.05)”, noted the authors. Suspected cervical insufficiency, fetal anomaly, diabetes mellitus were identified as the underlying causes on phenotypic examination. The causes were unknown in some cases.

Cervical length monitoring was undertaken more often among women with history of ST-ROM (66.7%) and ST-IM (44.4%) vis a vis those with history of ST-SM (7.5%). Likewise, cervical cerclage was also performed more among women with history of ST-ROM (16.7%) and ST-IM (22.2%) compared to those with ST-SM (2.5%). Despite these measures, women in the ST-ROM and ST-IM groups were at a greater risk of recurrent second trimester miscarriage versus those in the ST-SM group; 16.7% vs 0%, respectively. Researchers also examined the outcomes of a subsequent pregnancy among the different phenotypes of second trimester miscarriage. In this study, 64 patients achieved a subsequent pregnancy.

The second trimester miscarriage phenotypes provide possible clues to the likely etiology of second trimester miscarriages. They may serve as a guide to the management of subsequent pregnancy following a second trimester miscarriage and also its prognosis.

Reference

1. Cheung KW, et al. Clinical presentation, investigation, underlying causes, and subsequent pregnancy outcomes among different phenotypes of second trimester miscarriage. J Obstet Gynaecol Res. 2023 Feb;49(2):539-547. doi: 10.1111/jog.15514.