Mismatch between hCG and ultrasound findings
I’m currently 7w0d with my first pregnancy and waiting for my next transvaginal ultrasound at 8w0d. I’m quite anxious about it not showing positive growth, due to my low-ish hCG levels and various factors that raise my miscarriage risk (Hashimoto’s, SCH, history of thin lining), so I’d appreciate advice.
My hCG readings have been:
17DPO (4w2d) - 99
24DPO (5w2d) - 1610 (doubling time c.42 hours)
30DPO (6w1d) - 6466 (doubling time c.72 hours)
The values and doubling rates are just about inside the lab reference ranges, but they are rather low/slow for the dates and the latest doubling time is really quite a lot slower, even though it’s only just hit 6000+. I haven’t been able to find any other posts with levels like mine that end with a positive outcome 🙁
I had one transvaginal ultrasound done at 5w6d and I was told there was a foetus in the right place with a visible heartbeat (no details provided). I had a private transvaginal ultrasound done at 6w1d and that gave me the following measurements: CRL 4.6mm, yolk sac 4.9mm, HR 117bpm. They also noted an SCH.
I’m a bit confused because this ultrasound has shown a foetus with a heartbeat and a good CRL, yet the hCG on the same day was only 6466 (and a heartbeat was visible on the scan two days earlier, when the hCG was even lower!). I was under the impression that heartbeats generally become visible once hCG exceeds around 10000-20000.
Any thoughts on why my ultrasound findings are a bit mismatched with my hCG levels? And if I should be worried about how low my hCG is for my dates?