Flu shot reaction???

Pregnancy wouldn't have anything to do with the reaction. Sounds like you nicked a vessel and a hematoma developed. That happens sometimes. I wouldn't worry too much about it. Today I was giving a flu shot to one of our midwives and I hit her bone (shudder).

I did hit the bone on one of our residents earlier in the morning, I think that's why I was hesitant to go too deep with this shot. I've never hit the bone before either so my reaction was much like yours.. *shudder* but I pulled the needle back a bit, aspirated-no blood, and the rest of the shot went fine. And the 20+ shots after that went beautifully until I did the CNA's shot.

It sounds like a hematoma developed, just watch it tomorrow if possible. I used 3/4" length needles on small armed people last year and did not have any problems. Were you using the auto-injection syringe, I have seen this cause bruising. Hope it goes better next time.

You should not aspirate for deltoid IM injections.

It is not recommended that you aspirate with vaccines. One reason is because, even if you hit a vessel in IM sites, you're not going to cannulate it & inadvertently give it IV. Vessels aren't large enough in recommended sites for IM. For the same reason, you should not be worried. Hitting a vessel is inevitable every now & then. Don't worry!

You should not aspirate for deltoid IM injections.

To clarify klone's post, the CDC states "Because there are no large blood vessels in the recommended sites [vastus lateralis and deltoid), aspiration before injection of vaccines (i.e., pulling back on the syringe plunger after needle insertion but before injection) is not necessary"

source: www.cdc.gov/vaccines/pubs/pinkbook/downloads/appendices/d/vacc_admin.pdf

(with other injections you may be required to aspirate, but not with vaccines in these locations. Check manufacturer's instructions if needed.)

Vessels aren't large enough in recommended sites for IM.

With the exception of dorsogluteal. You should aspirate if you inject there. Aspiration should be done over 10 seconds.

You should not aspirate for deltoid IM injections.

OP did not say that he/she aspirated.

Yes, she did.

but I pulled the needle back a bit, aspirated-no blood, and the rest of the shot went fine

Learned something new, I had been taught to aspirate on all IM injections. I'll definitely remember that from now on.

With the exception of dorsogluteal. You should aspirate if you inject there. Aspiration should be done over 10 seconds.

You would never give a vaccine in the dorsogluteal; that site is associated with diminished absorption of vaccines, &, subsequently, lower antibody titers.

You would never give a vaccine in the dorsogluteal; that site is associated with diminished absorption of vaccines, &, subsequently, lower antibody titers.

I wasn't referring to vaccines; I would not give one there either. I was referring to IM injections in general. You stated

Vessels aren't large enough in recommended sites for IM.