The effect of Chorionic Villus Sampling on placental perfusion: a prospective observational study.

Objective- To assess the potential effect of Chorionic Villus Sampling (CVS) on placental perfusion by examining change in uterine artery pulsatility index (UtA-PI) between first and second trimesters of pregnancy. Design- It was a prospective observational study conducted between August 2017 to January 2019. Setting- Department of Obstetrics and Gynecology, Maulana Azad Medical College, New Delhi. Study Sample- Twenty-one singleton pregnancies where CVS was planned were included in the case group whereas forty-two low-risk singleton pregnancies with no invasive testing constituted the control group. Pregnancy resulting in miscarriage or, termination of pregnancy for affected fetus, or demise of fetus beyond 23 weeks or subsequent detection of anomaly or chromosomal defects were excluded. Methods- Dating scan along with first and second trimester UtA doppler study was done at 11-13+6 weeks and 22-24+6 weeks respectively using an ultrasound machine with 2-5 MHz trans-abdominal transducer. Main Outcome Measures- The primary outcome was to evaluate the change in UtA-PI between first and second trimesters of women undergoing CVS and comparing it with control group. Results- The difference between first and second trimester mean PI of case and control group were 0.71± 0.35 and 0.44± 0.45 respectively. This difference of fall in PI between the two groups was statistically significant (p= 0.010) with the change being higher in the CVS group. Conclusions- CVS does not cause undesirable effect on the UtA doppler. UtA doppler being a predictive marker of development of pre-eclampsia or FGR; this study affirms the safety of CVS in experienced hands.