Growth check 34 weeks

So I had a growth check and they also checked my placenta n cirvix cause this is my 5th C-section well I get a call yesterday saying they couldn't get pictures of my cirvix so they wanna check again next week and to have a full blatter but this past ultrasound i did have a full blatter and they didn't see it.... Just made me concerned on why any ladies have this happen to them and what was the outcome...? I was just in the hospital the other day due to loosing my mucus plug and contracting every 4-7 mins bp was 146/99 & I've had high blood pressure past couple of on visits one where I had extreme amounts of protein in my urine