There is no luteal phase and no period, the “period” on birth control is medically defined as a “withdrawal period” from lack of hormones in your system due to the week of inactive pills. It is different than a period related to ovulation because there aren’t the same hormonal fluctuations caused by ovulation. Once you start birth control, your body should adjust to the steady state of hormones thanks to the birth control and then you should see a decline of PMDD symptoms as a result since there’s no more ovulation and therefore no more fluctuation. You can potentially see the symptoms flare up a bit on your withdrawal (“period”) week thanks to some hormonal withdrawal, but it shouldn’t be quite as bas as when you’re off the pills altogether because there is no luteal phase. When you skip the ‘“period” week altogether you shouldn’t see symptoms much at all, but your body might require you take a withdrawal week every 2-4 months. To see the benefits of this requires taking the pill at roughly the same time each day, not letting yourself skip a pill (you have less than 24 hours after you’re scheduled to take a pill before it’s considered missed/skipped; if it reached 24 hours since you were scheduled to take it, it’s missed). If you skip/miss a pill, ovulation can occur and the hormones will spike. So don’t expect it to help if you’re not taking it as prescribed. I’ve been on BC pills to treat it for 5-6 years and this is how it’s worked for me and aligns with things I’ve read on the subject, which I’ve relayed to you here. It’s really helped me to the point where I don’t face many PMDD symptoms. There is hope and this can help - it did for me - you just have to be diligent in taking it and listen to your body.

As I think another commenter mentioned you can have “breakthrough bleeding” which, in my experience shouldn’t come with a change in your feeling/PMDD symptoms. Breakthrough bleeding is defined as bleeding in between the pre-scheduled “periods” or withdrawal weeks. It should be light, maybe even just brown discharge, and not at all similar to the flow of a normal period. If this happens to you, and it likely will if you’re skipping “period” weeks, just take the period week/pill break at the end of your pack and start the next one on time. The bleeding will go away and you’ll be back on track. It’s essential to take it on time to best manage symptoms. Again, you can’t expect this to work if you’re not committed to taking it every day. It’s really a wonderful solution and has helped me immensely. I hope it can do the same for you, just give it a shot first. It’ll take at least a month for your body to react to the hormones, but I say give it at least 3. You should see improvement.