At the time of writing this post, we are in the middle of our Frozen Embryo Transfer (FET). Essentially, we’re in the final steps of our IVF cycle. It’s nerve-wracking but exciting. We’ve never been this close before and to think that we’ll be pregnant within the next few days is mind blowing to me.
I wrote a post about our FET timeline, but now I want to go more into detail about what PIO (Progesterone in Oil) is and my first PIO injection experience.

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What are Progesterone Shots (PIO)?
PIO (Progesterone in Oil) is a medication containing progesterone in, well, oil. It’s an injection that prepares the body for pregnancy.
Progesterone is a natural hormone that a female produces after ovulation. It prepares the uterus for the incoming embryo, and if that embryo implants, progesterone triggers the glands to secrete nutrients to nourish the now growing embryo.
During an FET, your body actually won’t ovulate – so it relies solely on the supplements and medication your doctor prescribes to prepare for transfer.
PIO Supplies
When I got my prescription, I got the following items:
- Injection Syringes
- Drawing Needles
- Alcohol Pads
- Progesterone in Oil vials
My First PIO Injection

I’ll write a separate post about how to give PIO injections… but for now let me tell you about my FIRST EVER PIO Injection.
Drawing it up was just like the trigger shot – so I wasn’t new to the process. I’ve heard horror stories about PIO injections and how they hurt and bruise afterward.
Fortunately, my first injection was smooth. My husband had company over so he wasn’t there to help me or administer it himself. I had to sneak off into our office to do the shot since (at the time of writing this) no one knew we were in the middle of a Frozen Embryo Transfer (FET).
The one thing I noticed, however, was that injecting the medicine itself was pretty slow. I chalked it up to being the oil within the medication that made it slow upon injecting. I’ve heard of people warming the oil up first before administering the injection so I’m going to try that tonight!
PIO Side Effects
I didn’t have any immediate side effects after the injection. Later that evening I did experience a headache and went to bed pretty early.
As I’m writing this, it’s the day after my first injection. I do feel some slight bruising at the injection site.
Tips for PIO Injections
- Relax and breathe
- Ice the area if you’re sensitive to needles
- Warm up the oil while in the syringe by holding it under the armpit for 2-5min
- Pull the skin taut in the area of injection – don’t pinch!
- Rub the area after injecting to avoid bumps and to spread the oil faster
- Have a heating pad ready and rest afterward