TTC after loss-- are you likely to get BFP earlier because of residual HCG?

[buko]

Just curious if this makes any sense...  Feel free to skip below the line for the main point of this post.

A bit about me...

I had a natural m/c around 10.5 weeks, though I was expecting it, as it had been a missed m/c and baby stopped developing in the 6-7 week range.  I decided to go ahead and TTC in the cycle immediately following the m/c, before my first "real" AF.

Now, I never did have an HCG blood test, as it was all a bit moot (I wasn't even supposed to see my MWs for the first time until 11 weeks and I never needed a D&C, so nobody bothered).  However, I took some HPTs after I clearly passed the sac, etc., and saw the line get a bit lighter over a few days, then, about 1.5 weeks ago, well before I ovulated, I took a HPT and got a VERY clear BFN.

So, I have no idea what my exact HCG was at any point, including now, but I can guess that, if not 0, then 1.5 weeks ago, probably below 15 or so, and almost certainly below 25.  (My HPT of choice officially detects at 25+, but in trials, detects more like 10-15+.)

Here's my situation with this cycle...

I suspect low progesterone, and my MW and I worked out a "deal" wherein I didn't start progesterone at 3 dpo because I might not be pregnant and we don't want to "mess with things" too much without confirmed low progesterone.  I am 6 dpo, and having her give me a blood test tomorrow (7 dpo, or "CD21") as per the usual progesterone testing protocol.  Our plan is to start me on progesterone IF mine is low AND I turn up pregnant (ASAP after I find out I am pregnant).  I will probably know something about my progesterone by 8 or 9 dpo in any event.

Normally, and particularly given my heightened emotional state, I wouldn't POAS until at least 10 dpo, so as not to get disheartened unnecessarily.  However, see above-- if I do have low progesterone AND turn up pregnant, I want to start that progesterone supplementation ASAP!  So finding out if I'm pregnant becomes a bit more urgent.

I'm trying to find a balance, but I am admittedly antsy and wondering if I should go ahead and test tomorrow-- 7 dpo (boy, could I overthink this any more!??!  )

Oh, and FWIW, I started testing at 7 dpo with my first (it was my first time TTC!) and got my first BFP at 12 dpo, so not particularly early.

--------------------------------------

Of course I know it's possible, but rare, to get a BFN at 7 dpo.  But what I'm wondering is, if you have "some" HCG in your system from a previous pregnancy, would it make sense that you might get a true BFP earlier for the next one?  (Of course, you'd have to rule out the fact that a light BFP was exclusively a result of the previous pregnancy, but I feel I have done that.)  I guess I'm thinking of a scenario where, say, my HPT detects at 15.  Say my HCG is or would be at 8 (if we were only looking at what was being produced by the "old" pregnancy), so I get a BFN.  But then my new embryo implants and I can test positive when that embryo is only producing an HCG level of 7 (7 "new" +8 "old," for a total of 15) instead of having to produce a whole 15 on its own (say, a day or two later).

Make any sense?  Anyone have any experience with this?  Thanks!

[Chloe'sMama]

So sorry for your loss. Someone may have better info, but I don't think your body will ovulate until all hcg is out of your system. Good luck.

[buko]

Thanks, Chloe'sMama, but that's not what my midwife told me...  I am too foggy-headed to look it up, but I was told that as long as HCG is low, one could still ovulate.  Also, what about people who get HCG trigger shots TO ovulate?  I am definitely no expert!  But that was my understanding...

[Chloe'sMama]

Just did a little research and seems hcg does not need to be 0 to ovulate. I don't know about the other part. Sorry.

[SKJ2011]

From personal experience, I ovulated twice in a row before my hcg was zero. First time, hcg was around 37. Second time, hcg was less than 4, but above 0.

Here's my thought, if you've gotten a BFN, you'll only get a BFP after the next pregnancy implants and produces enough hcg to show up on a test. So, the difference between a BFN and a BFP would likely be only a day or two. For example, if you still have an hcg level of 10 and you test after the new pregnancy has contributed 10 (total of 20), then that would show up a day or two before it would show up if your original level was zero. Does that make sense? FWIW, I tried the cycle after my first post D&C AF. I tested at 9 DPO and it was a BFN. It was a lot harder to accept that I wasn't pg than I thought it would be. So, my personal advice is to wait as long as possible to test so that you know for sure it's accurate and then get on the progesterone. Your body seems to be able to hold a pregnancy for at least long enough for you to get on progesterone, so I don't thnk worrying yourself over a few days is worth it. If I were in your shoes (which I'm not), I would hold off until 12 dpo, unless you blood work comes back with information sooner.

Good luck and fingers crossed for you.

[BaileyB]

I don't have the answer to your question but I just had a m/c that began on the 8th. 5 days ago my hcg was 1600-something and I am having O pain and symptoms today. I haven't taken any hpt's since getting pregnant nor have I had my hcg run again although I would like to have it checked when I go in on Monday just because I am curious.

[buko]

SKJ-- that was what I was thinking-- that it might only make a day's difference.  I admit I did test at 8 and 9 dpo (BFN-- big surprise!)    But I'm not worried about it.  The good news/consolation prize is that even if I am not PG this time, my luteal phase is definitely getting longer.

I went off BCP in November, and had luteal phases of 13, 6 and 11 days before getting PG, BUT if you stop counting when I first had any spotting, then my luteal phases were a dismal 3-5 days.  In fact, exactly 5 days was the longest. This time, I went 8.5 days before I got a touch of spotting (just 30 minutes ago-- today is 9 dpo).  I figure it's more likely the end of my luteal phase, but if I'm really lucky, might be implantation bleeding.  I had a touch of spotting at 9 dpo in my last pregnancy, and got a BFP at 12 dpo...  So, fingers crossed!  But like I said, my consolation prize is that my LP does seem to be lengthening...  So even if I did have a progesterone issue/LPD, maybe (?) it is starting to resolve itself, if it was only a temporary result of having been on the pill for so long, and only having gone off it a few months ago.  We will see-- I had my blood tested on 7 dpo and should know the progesterone levels today or Monday, at the latest.