Sometimes called 17P or p17 or progesterone shots. Used to be called Delalutin. It's the new thing. It's all the rage. It's one of the best proven techniques to stop preterm labor in women pregnant with singletons these days. And the strange thing is, a lot of doctors aren't doing it yet. It's kind of a new thing, well a new, old thing. That's right, my mother-in-law took it when she was pregnant, but they stopped using it, like so many drugs, when there were a few lawsuits against it.
17P shots are a thick substance that must be injected intra-muscularly. They are somewhat painful, and the injection site can become irritated and itchy.
These shots work by relaxing the uterus and preventing it from contracting. They are quite effective. I went into labor at 24 weeks with this last one, and I began taking my Nifedipine pills which make me very miserable. Within a few days my doctor had me on these shots and within a week I was scarcely having any contractions. I did have a handful of days where I had some breakthrough contractions, but they all took place the day before my next shot.
It was actually a fun process for a medically minded person like me to learn how to give myself an injection, my husband did the first few and I did the rest.
Doctors may differ on treatments with these shots. Some start at 16 weeks gestation, others will wait until preterm labor begins. And it is up to you and your doctor to decide when to discontinue treatment. Theory might be that labor will begin within 2 weeks of discontinuing treatment and the hormones are completely out of your system. But it really depends on the cause of preterm labor, and each individual's body. My personal experience was that I didn't dilate at all while on the injections, so once I discontinued, I had 5 weeks before I delivered, but I always dilate early and slowly. I also, discontinued treatment at 30-ish weeks due to the nausea I was having associated with the injections. So it kept me pregnant until 35 weeks which was amazing!
If I was the doctor giving out treatment, I would start injections at 24 weeks and end at 35 weeks. Then if it did take 2 weeks to deliver, the baby will still be term.
I want to mention that I did also receive a steroid shot for the baby's lungs at 32 weeks. At my hospital, the latest they will administer the shot is 32 weeks and it must be done at Labor and Delivery with an hour of fetal/contraction monitoring. If there is any indication prior to 32 weeks that you might deliver prematurely, I would definitely push for the steroid shots before it's too late. Any help for the baby is worth it's weight in gold!
The side effects of these progesterone shots are all those that can be associated with hormones. My body is very sensitive to hormones and thus these injections made me feel like I had returned to my first trimester. Very few people complain of that, but it was still worth prolonging my pregnancy as long as it did.
If you are experiencing or have experienced preterm labor, talk with your dr. to see if they think this is a treatment worth trying. A lot of doctors haven't tried it before and after researching they might be very interested in this treatment.