Trying to Conceive Community

I'm currently TTC after miscarriage also. The whole process is terrifying 99% of the time! I'm so very sorry for your losses.

Generally they won't run more extensive testing until you've had 3 losses. However, there are things that you can ask about at your next appt. I know a few women who had clotting disorders that prevented them from carrying, or progesterone deficiencies that wouldn't allow them to sustain pregnancy also. Without genetic things to pinpoint, you could start researching recurrent miscarriage and see if there is anything you would like to consult your ob about.

I am so sorry for your losses. The prior responder is correct that recurrent pregnancy loss is usually evaluated after three losses if no delay to pregnancy and after two if also having delays to conception. That said, the fact that your losses were later in the first trimester (and in the case of the 13 week one, I presume after a heartbeat had been seen on ultrasound?), a visit to your doctor to carefully go over your personal and family history may be worthwhile. Some of the causes of recurrent miscarriages include: Genetics, blood clotting disorders, uterine cavity differences, hormones, or environmental.
Genetics: While many pregnancies are lost because the embryo made a mistake in cell division (a spuratic event which does not increase risk for recurrence), some couples have differences in their chromosomes called translocations that can cause an increase in the chance of loss. Normal chromosomes on the second loss make this less likely, but not impossible (if the chromosomes were normal female, they may have cultured out maternal cells instead of the pregnancy cells)
Clotting: Blood clotting disorders can increase the risk of loss. Losses later in the first trimester, or a family history of clotting can trigger testing.
Uterine cavity: Fibroids, polyps, septums, scar tissue, uterine cavity differences can increase the chance for loss. An ultrasound with fluid inside the uterus can be used to evaluate the cavity.
Hormones: Thyroid, prolactin and progesterone hormone differences and diabetes can all increase the chance for loss.
Environment: Smoking, alcohol, and obesity can all increase the chance for loss.
Since there are many possible causes, I recommended sitting down with your OB/Gyn to go over your personal and family history and discuss if any testing is prudent at this time. That said, the fact that you have a son and have less than three losses means that you have a good chance for pregnancy success next time. Good Luck!