Low hCG levels in early pregnancy do not necessarily indicate an impending miscarriage or complications during pregnancy. Read on to know about low and normal hCG levels during pregnancy…
Human Chorionic Gonadotropin or hCG is a hormone released by the growing embryo. Naturally, a surge in hCG levels is noticed in women after fertilization. Detection of high hCG levels in blood test (over 25mIU/ml concentration) performed in a lab or detection of hCG in urine when a pregnancy test is performed at home, confirms pregnancy. After implantation, the amount of hCG doubles after every 2 or 3 days, in the first few weeks of pregnancy, in majority of women.
hCG Levels During Pregnancy
Several factors influence the hCG levels in women. The normal hCG levels may vary from woman to woman, but for providing guidelines, here are normal hCG numbers. The length of the pregnancy is measured here from the last menstrual period.
The unit of hCG measurement is mIU/ml (milli-international units per milliliter).
- Non-pregnant women: less than 5.0
- 3 weeks: 5 – 50
- 4 weeks: 5 – 426
- 5 weeks: 18 – 7,340
- 6 weeks: 1,080 – 56,500
- 7-8 weeks: 7, 650 – 229,000
- 9-12 weeks: 25,700 – 288,000
- 13-16 weeks: 13,300 – 254,000
- 17-24 weeks: 4,060 – 165,400
- 25-40 weeks: 3,640 – 117,000
Slow rising hCG (not doubling within two or three days) indicates a possible miscarriage or ectopic pregnancy but there are examples of women giving birth to healthy babies, without any health complications, with low hCG levels. About 85% of women show the rise in hCG levels similar to the pattern shown by the figures, mentioned above. But 15% women don’t exhibit the above pattern. About 15% women show slower hCG doubling times. In some cases however, slow rising hCG is responsible for health complications.
Until about 6-7 weeks after the last menstrual period, hCG doubling time helps check whether the pregnancy is progressing normally. For those who are at a higher risk of miscarriage, lower than normal hCG at 6 weeks can be a cause of concern. To measure the hCG doubling time, one single hCG reading is not useful. Repetitive tests are performed to know the hCG doubling time. Normal fetal heartbeat after 6-7 weeks along with normal hCG doubling time rule out the possibility of ectopic pregnancy and miscarriage. They indicate a viable pregnancy.
Causes of Low hCG During Pregnancy
The rise in the level of hCG may vary from woman to woman. A 60% rise in hCG levels in 48 hours is considered as normal. Although, about 15% of normal pregnancies show low hCG levels, lower than the expected hCG rise suggests that a miscarriage is possible. Lower than normal hCG and slower rises are mostly seen in ectopic pregnancies (embryo growing not in the uterus but elsewhere).
Sometimes, women who experience miscarriages have normal hCG levels initially. But it is a fact that hCG rise is quite slower in an ectopic pregnancy than in a normal one. Sometimes miscalculation of dates is the reason behind lower than normal hCG.
As a part of infertility treatment, hCG injections are given to trigger ovulation or to lengthen the luteal phase. In such cases, small amount of hCG can be present in the body up to 14-15 days after the last hCG injection. This is sometimes the reason for a false positive result for a pregnancy test.
Normal hCG levels during pregnancy vary widely from woman to woman. Women can avoid low hCG levels during pregnancy by following a healthy and balanced diet and by exercising regularly. Leading a stress free lifestyle, taking medications and supplements on time (as suggested by the doctor), avoiding excess caffeine, alcohol, drugs, smoking help improve hormonal levels.
Routine checkup helps detect a problem at an early stage. It helps avoid the complications. A pregnant woman should not panic after seeing abnormal hCG count. She should always consult her doctor before interpreting the test results.