An imbalance between angiogenic and anti-angiogenic factors precedes fetal death in a subset of patients: results of a longitudinal study.

OBJECTIVE

Women with a fetal death at the time of diagnosis have higher maternal plasma concentrations of the anti-angiogenic factor, soluble vascular endothelial growth factor receptor (sVEGFR)-1, than women with a normal pregnancy. An important question is whether these changes are the cause or consequence of fetal death. To address this issue, we conducted a longitudinal study and measured the maternal plasma concentrations of selective angiogenic and anti-angiogenic factors before the diagnosis of a fetal death. The anti-angiogenic factors studied were sVEGFR-1 and soluble endoglin (sEng), and the angiogenic factor, placental growth factor (PlGF).

METHODS

This retrospective longitudinal nested case-control study included 143 singleton pregnancies in the following groups: (1) patients with uncomplicated pregnancies who delivered a term infant with an appropriate weight for gestational age (n=124); and (2) patients who had a fetal death (n=19). Blood samples were collected at each prenatal visit, scheduled at 4-week intervals from the first trimester until delivery. Plasma concentrations of sVEGFR-1, sEng, and PlGF were determined by specific and sensitive ELISA. A linear mixed-effects model was used for analysis.

RESULTS

(1) The average profiles of analyte concentrations as a function of gestational age for sVEGFR-1, sEng and PlGF were different between women destined to have a fetal death and those with a normal pregnancy after adjusting for covariates (p<0.05); (2) Plasma sVEGFR-1 concentrations in patients destined to have a fetal death were significantly lower between 7 and 11 weeks of gestation and became significantly higher than those of women with a normal pregnancy between 20 and 37 weeks of gestation (p<0.05); (3) Similarly, plasma sEng concentrations of women destined to have a fetal death were lower at 7 weeks of gestation (p=0.04) and became higher than those of controls between 20 and 40 weeks of gestation (p<0.05); (4) In contrast, plasma PlGF concentrations were higher among patients destined to develop a fetal death between 7 and 14 weeks of gestation and became significantly lower than those in the control group between 22 and 39 weeks of gestation (p<0.05); (5) The ratio of PlGF/(sVEGFR-1 × sEng) was significantly higher in women destined to have a fetal death between 7 and 13 weeks of gestation (94-781%) and significantly lower (44-75%) than those in normal pregnant women between 20 and 40 weeks of gestation (p<0.05); (6) Similar results were obtained when patients with a fetal death were stratified into those who were diagnosed before or after 37 weeks of gestation.

CONCLUSIONS

Fetal death is characterised by higher maternal plasma concentrations of PlGF during the first trimester compared to normal pregnancy. This profile changes into an anti-angiogenic one during the second and third trimesters.