The correlation between first-trimester serum biochemical and biophysical markers and skin microvascular reactivity assessed by laser speckle contrast imaging

Objective. To evaluate the correlation between first-trimester serum biochemical and biophysical markers and skin micro­vascular reactivity by using laser speckle contrast imaging (LSCI) combined with post-occlusive reactive hyperaemia (PORH).
Materials and Methods. Thirty-eight women with a singleton gestation were enrolled during routine first-trimester scans. Microvascular skin blood flow was recorded using LSCI coupled with PORH. Skin perfusion was recorded before (baseline flux), during (occlusion flux) and after (peak flux) a 3-minutes occlusion obtained with an inflated pneumatic cuff. The parameters of microvascular reactivity were compared with serum biochemical markers (Pregnancy-associated pro­tein A, PAPP-A, free beta human chorionic gonadotropin, free β-hCG, placental growth factor, PlGF), expressed in multiple of the median, and with maternal biophysical markers (Mean arterial pressure; Uterine artery pulsatility index).
Results. PlGF showed a moderate positive correlation with base-to-peak flux (r = 0.50, p < 0.01). Furthermore, a moderate positive correlation was found between free β-hCG and peak flux (r = 0.50, p < 0.01). Additionally, weak but statistically sig­nificant correlations were observed between free β-hCG and the other markers of microvascular reactivity: base-to-peak flux (r = 0.33, p = 0.045); peak time (r = -0.331, p = 0.042) and time to half recovery (r = -0.396, p = 0.014). A positive correla­tion was also noted between free β-hCG and baseline flux (r = 0.341, p = 0.036). No correlation was found with the other explored biochemical and biophysical markers.
Conclusions. Our study indicates a positive correlation be­tween microvascular reactivity indexes and PlGF and free β-hCG levels. These novel findings suggest that first-trimester skin microvascular reactivity, assessed by LSCI coupled with PORH, could serve as valuable early pregnancy marker for placental function.