Compromised chorionic villous vascularization in idiopathic second trimester fetal loss

The importance of folate, vitamins B6 and B12 for the lowering of homocysteine concentrations for patients with recurrent pregnancy loss and MTHFR mutations

In patients with MTHFR (methylenetetrahydrofolate reductase) mutations and hyperhomocysteinemia, recurrent pregnancy loss is a frequent feature. The aim of the study was to evaluate the impact of folic acid, vitamins B6 and B12 supplementation for the lowering of total homocysteine concentrations and pregnancy. 16 patients who had had 3 or more miscarriages and MTHFR mutations were used in the study. They received methylfolate (5mg/day), vitamin B6 (50mg/day) and vitamin B12 (1mg/week). Supplementation induced a decrease in homocysteine from 19.4±5.3μmol/L to 6.9±2.2μmol/L after folate supplementation (p<0.05). During one year 7 women became pregnant and delivered. Two women delivered from the homozygous C677T mutations group (7 patients) and combined heterozygous C677T/A1298C mutations group (5 patients), while 3 deliveries were in A1298C homozygous mutations group (4 patients). In conclusion, supraphysiologic methylfolate, vitamins B6 and B12 supplementation in woman with MTHFR mutations has a beneficial effect on pregnancy outcome.

Macroscopic and microscopic morphology of first trimester miscarriage and subsequent pregnancy outcome - An exploratory study

INTRODUCTION

Reduced chorionic villous vascularization is associated with first trimester miscarriage and second trimester fetal loss. Differences in villous vascularization have been observed in combination with complications in the third trimester of pregnancy. The aim of this study was to investigate whether abnormal morphology and reduced chorionic villous vascularization in first trimester miscarriages are associated with an increased risk on adverse outcome and/or pregnancy complications in subsequent pregnancy. Secondly, to assess the influence of these parameters on the length of the interpregnancy interval and infertility.

METHODS

In a retrospective cohort study 134 consecutive women who underwent dilatation and curettage for a miscarriage were included. The degree of chorionic villous vascularization in miscarriage tissue was determined by a pathologist. Ultrasound details of these miscarriages and clinical data on the subsequent pregnancy of these women were obtained.

RESULTS

Neither reduced vascularization nor early embryonic arrest in first trimester miscarriages are associated with an increased risk of a subsequent miscarriage or adverse obstetric and perinatal outcome of subsequent pregnancy. Abnormal morphology of the first trimester miscarriage did not influence the time to subsequent pregnancy. A shorter mean interpregnancy interval between miscarriages was observed after miscarriages with reduced chorionic villous vascularization (5.5 vs. 10.7 months; p = 0.051), showing a trend towards an association.

DISCUSSION

Chorionic villous vascularization and morphology have no influence on subsequent pregnancy outcome. Therefore it remains unknown what aspects of miscarriage are causing the increased risk on subsequent miscarriage and complications in the third trimester of the subsequent pregnancy.

Hemoglobin Bart hydrops fetalis: A model for studying vascular changes in placental hypoxia

INTRODUCTION

Placental ischemia can be pre-placental (maternal), placental or post-placental (fetal), with corresponding changes in villous vasculature. Hydrops fetalis (HF) resulting from hemoglobin (Hb) Bart disease can serve as a model for intrauterine hypoxia, and placentas from such cases show a distinctive peripheral villous stromal myofibroblastic hypercellularity (PVSH). We hypothesized that Hb Bart disease, which results in profound fetal hypoxia, would lead to placental hypoxia on a post-placental basis.

METHODS

We assessed villous vasculature using computerized morphometry, comparing placentas in 14 Hb Bart HF cases to 18 non-Hb Bart HF cases. Morphometric parameters were matched as closely as possible to those reported in the literature for comparison purposes.

RESULTS

Villous vessels of Hb Bart HF showed significantly increased numbers of vessels (p = 0.001), longer vascular perimeter (p = 0.002), thickening of vascular endothelial layer (p = 0.038) and higher shape coefficient (p = 0.042) indicating a more branching pattern of vessels. In addition, placental villi of Hb Bart HF containing PVSH showed a longer vascular perimeter (p = 0.008) and narrower lumen (p = 0.002), with a higher shape coefficient (p = 0.03), in comparison to villi lacking PVSH.

DISCUSSION

Contrary to expectations, the overall pattern of vascular changes in Hb Bart HF suggested multifactorial hypoxia: pre-placental, on the basis of the marked placentomegaly, compromising blood flow from uterine distention; placental, from hydropic villi causing a generalized diminished intervillous space; and post-placental from the greatly reduced capacity of Hb Bart to extract oxygen from the intervillous space. Standardized vascular morphometry will facilitate comparison between different conditions, for a better understanding of placental hypoxia.