A 37-year-old primi Rh negative patient is very concerned above her pregnancy at this age. Her pregnancy is 16 weeks and she is HIV negative, hepatitis B surface Ag neg, Rubella nonimmune and has no complain.Her triple test repo is normal but still due to her age she insists on getting an amniocentesis done. Which of the following is the next best step in management:

Amniocentesis Precautions:prior sonographic localisation of placenta is desirable to preventbloody tap and fetomaternal bleeding.Prophylactic administration of 100mg of anti D immunoglobulin in Rh -ve nonimmunised mother.Hazards are reduced significantly when done under direct ultrasound control compared to blind procedure maternal complications: infection,hemorrhage,PROM,maternal isoimmunisation in Rh negative cases fetal complications: fetal loss,trauma.,oligohydramnios,fetal lung hypoplasia,respiratory distress D.C.DUTTA&;S TEXTBOOK OF OBSTETRICS,Pg no:648,7th edition