Maternal and fetal inflammatory responses in unexplained fetal death

The role of intra-amniotic infection in the etiology of fetal death has been proposed. This study was conducted to determine the prevalence of microbial invasion of the amniotic cavity (MIAC) and the frequency of maternal and/or fetal inflammation in patients presenting with a fetal death.

A prospective study was conducted in patients with a fetal death. Amniocenteses were performed for clinical indications (karyotype), as well as to assess the microbiological and cytological state of the amniotic cavity. Fluid was cultured for aerobic and anaerobic bacteria and genital mycoplasmas. An amniotic fluid white blood cell count and glucose determinations were also performed. Histological examination of the placenta was conducted to identify a maternal inflammatory response (acute chorioamnionitis) or a fetal inflammatory response (funisitis).

This study included 44 patients with intrauterine fetal death. The median gestational age at diagnosis was 30.1 weeks (range 16.3-40.4 weeks). One patient had documented MIAC (1/44). Acute histological chorioamnionitis was found in 20.9% (9/43), but a fetal inflammatory response was observed in only 2.3% (1/43) of cases. One patient had a positive amniotic fluid culture for Streptococcus agalactiae (group B streptococcus).

Histological chorioamnionitis was present in 20.9% of cases, but MIAC could be demonstrated with conventional microbiological techniques in only one case. A fetal inflammatory response was nine times less frequent than a maternal inflammatory response (maternal 20.9% vs. fetal 2.3%, p = 0.008) in cases of fetal death.