New Grad RN needs advice on when to tell about pregnancy

I recently graduated, passed my boards, and found out I was pregnant. I am only about 9 weeks. I was offered a position on a Med/Surg floor and did not disclose at time. I wanted to wait until after my 90 day probation period. The problem is HR called and wants me to fill out paper work and schedule a pre-employee health screening. I have no idea what this involves besides the immunization check, drug test, and standard vitals. Has anyone had a pre-employee screening? I am scared they will do a blood test and see the obvious HCG hormones. I have an appointment with HR this Monday to do the paperwork and I would love to just tell them and get this off my chest but I am terrified they will find a reason not to hire me. I feel horrible like I am hidding a dirty secret :/ I really, really need this job though!
Ask what they are screening your blood for, you have a right to know. Normal pre-employment screening, is to test for immunity against communicable infections. I have never heard of them testing you for HCG, employers are not supposed to be discriminating against pregnant workers. I wouldn't say anything unless they flat out ask you in your health interview. I would wait till after your probation period, if its not obvious yet. Many people wait until after the first trimester, before they reveal their pregnancy to family,friends,work ect.
I, too, am in a similar situation. I am currently 16 weeks pregnant and accepted a new grad offer before back in May, before I knew I was pregnant. By the time I start my employment, I will be 18 weeks pregnant. Needless to say, I am very nervous about how my employers/HR/managers/floor staff are going to receive this information. No woman should ever feel this way but I understand that the real employment world is not always as kind (even in nursing) as it should be.I am also very curious as to what the better way to handle this would be. I had thought of simply waiting until the first day of work, when I find out what unit I am on exactly, before informing the unit nurse manager as well as HR's nurse recruiter. I also would like to know what kind of restrictions I may be facing when I begin working and what kind of patients I will not be able to work with.Thank you :-)
If it were me, I don't think I'd tell them right away...especially if it's early on. I'd wait. I definitely think you have that right. And if by some chance it is revealed in your health screening (although I've never heard of employers testing hcg) I'd just act surprised as if I had no idea. It's not like they'll do an ultrasound, right? Lol