I am approx 3 to 4 weeks pregnant and my uterus lining is 17.4 mm thick is this normal?

Normal endometrium: Endometrium at time of implantation can range from 7mm to 14mm. After implantation, the endometrium respond to estrogen and progesterone for growth. Thus your endometrium of 17.4mm 3-4weeks gestation can be normal. For reassurance, you will need: 1. Get qualitative hcg and repeat after 2days for normal rise. 2. Get a follow up scan to confirm normal early fetal growth. Good luck.