In all my IVF procedures I stopped at around week 12 with no problems. Do worry and start thinking of the beautiful baby you will have in a few more months. You made it through the hardest hurdle. I stop progestrone for this FET round in about three more weeks and so far everything is going okay.
I was scared to stop too but I stopped at 10 weeks and had no problems at all (no cramps, no spotting, no nothing.). Everything was fine and still is at 32 weeks. At 13 weeks you are well past the time the placenta is producing progesterone (it actually starts at like 7 weeks according to my RE). Don't worry, at this point it should not cause a miscarriage! You will be fine!
I wish they would just give me a blood test to see what my level is. Please let me know what you find out... as for me I started them again last night. The stress was too much and I still have some left so I just started them again. I have a doppler to hear the heartbeat (rented) so I listened to the baby's heart and everything is still good.... so I am keeping my fingers crossed. Please let me know what they say... thanks
Please let me know if you find any answers. I will be stopping my 3 daily suppositories in 3 weeks and I am nervous too. I am going to talk to the RE this Friday about any questions I may have. Also on 12/11 I will be seeing my OB and I will tell him how I feel about this as well. I will let you know their responses. Blessings to us both.