I am very sorry about your miscarriage.
The cause of a chemical miscarriage (which basically means your pregnancy test was positive, but they'd not yet seen a heart beat on ultrasound) is very often chromosomal, but not exclusively. It can also be APS.
There is growing evidence that as well as causing clots in the placenta, APS causes immunological problems in the very early stages of pregnancy, resulting in implantation failure. Traditionally APS was seen as causing late pregnancy loss, and some docotrs seem to have misinterpreted this as ONLY late losses being from APS. That is not true. It can also cause early losses, and probably also subinfertility (where it takes a long time to concieve).
So, was your miscarriage caused by APS? That is very difficult to say. Statistically one miscarriage doesn't say much. The chances that your second pregnancy will result in a normal baby are very good. On the other hand, if you can get your obstetrician to prescribe you asprin and heparin for your second pregnancy, it may be worth it. Technically the guidelines don't reccomend treatment until after 3 miscarriages in a row, but this is pretty emotionally trying, and a kind obstetrician will be sympathetic if you want to try anticoagulants earlier.
I have SLE and APS. I've had 6 miscarriages - 3 without treatment (before diagnosis), and 3 with. One of those was a partial mole (69 chromasomes), so not APS, and the other 2 I was on asprin and heparin from the first day of a positive test. Since even that hasn't worked for me, I now inject heparin from the day of ovulation every month, and take asprin every day. This regime is outside of the protocol, so probably not the way for you to go just yet. It isn't fun injecting 'for nothing', and long term heparin can cause osteoporosis.
Although not a comforting idea, miscarriage amongs the general population is very common. At least 15% of all conceptions miscarry, and with early testing the rate is sprobably more like 50% (ie it happens a lot that the egg fertilises and starts to make HCG but never implants and the woman bleeds at the expected time. So unless she's done a super sensitive early pregnancy test she won't even realise she was pregnant briefly).
The good news is that you still have a very good chance of a sucessful pregnancy in the future. Give yourself time to grieve for this loss, and when you feel ready, try again.
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