hCG level for twins at 4 weeks Pregnant is around 200 to 1750 mIU/ml. hCG level for twins at 4 weeks Pregnancy is 30% to 50% higher than in single pregnancy. Women may feel strong pregnancy in the early stage.The level of hCG may double every 2-3 days in early pregnancy. Twin and multiple pregnancies has higher hCG levels as compared to the singleton pregnancies. With the help of an ultrasound finding your hCG level, it is confirmed that whether you have single or multiple pregnancy.