In about 85% of viable pregnancies, the mother’s hCG level typically doubles every 2 to 3 days. When your hCG level is doubling as expected, it’s a good sign that your pregnancy is developing normally.
A Rise in HCG Levels During Early Pregnancy
Your hCG level is likely to double at this rate (every 2–3 days) throughout the first 4 weeks or so of pregnancy. As your pregnancy progresses and your hCG level passes approximately 1,200 mIU/ml, it tends to take longer to double. By week six or seven, for example—about halfway through your first trimester—it may take about 3.5 days. After your hCG level passes 6,000 mIU/ml, it may take more than 4 days to double. You can usually expect your hCG level to stop rising between week eight and week 11 of pregnancy. That is the time period during which the hormone tends to reach its peak. But keep in mind, everyone is different, so these are just ballpark estimates.
Monitoring Your HCG Levels
Your doctor is likely to keep a close eye on your hCG level throughout your first trimester. If your hCG level is considered to be within the normal range for your stage of pregnancy (and the ranges are very wide), your doctor may never even bring it up to discuss. If you are curious about your level, ask your physician for the level. A slow-rising hCG level can be a sign of a problem with the pregnancy, such as a miscarriage or an ectopic pregnancy. This occurs when the fertilized egg implants outside the uterus, such as in the fallopian tubes, and can’t survive. However, hCG rises slowly in about 8% of normal pregnancies, so it’s not always a cause for concern. But any hCG level that decreases in the first trimester is almost always a sign of miscarriage.
When HCG Levels Don’t Follow a Normal Schedule
If your hCG level isn’t doubling on the expected schedule mentioned earlier, it can naturally be a source of intense worry and anxiety—especially if the reason your doctor ordered hCG blood tests is that he or she is concerned about a potential miscarriage. But do keep in mind that if you’re more than six weeks pregnant, hCG results may not be the best judge of whether your pregnancy is viable. By 6 to 7 weeks of gestation, if your pregnancy is viable, your baby should have a visible heartbeat on an ultrasound (also known as a sonogram). Serial ultrasounds should always show growth that’s consistent with your baby’s gestational age, and in women who are having miscarriage symptoms, an ultrasound will give the most accurate answer to what is happening. Remember, measuring your hCG level is one tool that your doctor will use to monitor your pregnancy, but it’s not the only one.
