HCG levels are suppose to double every 48-72 hours so you would need to do another blood test 48 hours after your initial one. A reading of 400 hcg is normal in early pregnancy but you did not state how many weeks pregnant you are, also you need to know that rates vary from woman to woman and also in multiple gestation pregnacies hcg levels tend to be on the high side.
Getting pregnant on clomid does not increase the risk of miscarriage, it increases the risk of multiple births. If you are concerned about your hcg levels then speak to your doctor their are medications (progesterone) you can take up to week 13 to help the hcg levels rise as needed, its not guaranteed but it may help you.
Guideline to hCG levels during pregnancy:
hCG levels in weeks from LMP (gestational age)* :
3 weeks LMP: 5 - 50 mIU/ml
4 weeks LMP: 5 - 426 mIU/ml
5 weeks LMP: 18 - 7,340 mIU/ml
6 weeks LMP: 1,080 - 56,500 mIU/ml
7 - 8 weeks LMP: 7, 650 - 229,000 mIU/ml
9 - 12 weeks LMP: 25,700 - 288,000 mIU/ml
13 - 16 weeks LMP: 13,300 - 254,000 mIU/ml
17 - 24 weeks LMP: 4,060 - 165,400 mIU/ml
25 - 40 weeks LMP: 3,640 - 117,000 mIU/ml
Non-pregnant females: <5.0 mIU/ml
Postmenopausal females: <9.5 mIU/ml
hCG Levels : American Pregnancy Association
Linear Mode
