HCG - Human Chorionic Gonadotrophin Level Doubling Time Calculator

	Human Chorionic Gonadotrophin - hCG
	The most common test used to detect a pregnancy in the very early weeks uses hCG. The hCG hormone starts to be released into the woman's blood stream soon after the baby implants into the lining of her uterus at about 8 to 12 days after conception. The hCG blood level will initially start off very low (5 mIU/ml), but then rapidly increase, doubling every 2 to 3 days, so that within a few days, to a week or so the hCG level becomes high enough to be detected in the woman's urine, at about 50 to 80 mIU/ml. Once this level is achieved, a urine pregnancy test will show as being 'positive'. hCG Level Doubling Time Calculator Normal hCG levels vary widely between different women and in different pregnancies for the same woman. Be very careful when trying to 'interpret the numbers'. During the first 12 weeks of pregnancy, the level itself is NOT as important, as is, how much it is rising every few days. Some normal pregnancies will have quite low hCG levels and still progress, ending in the birth of a healthy baby. The best way to confirm if a pregnancy is progressing is to repeat with a blood test in 2 to 3 days time, and perhaps again 2 to 3 days after that. This is aimed at seeing if the hCG level is rising adequately.
	Progesterone tests and levels in pregnancy

hCG levels

The following table is a guide to what hCG levels can be during pregnancy.
For those of you who are interested, or are having hCG monitoring, here are the suggested reference ranges for a single baby pregnancy. As you can see the range of normal levels is very wide. hCG levels can be 30 to 50% higher than for a single baby pregnancy, in twin and multiple gestations.

Weeks of pregnancy after last menstrual period	Days after conception	Approximate hCG levels for single baby pregnancy (mIU/ml)
Week 3	7	0 to 5
Week 4	14 (next period due)	5 to 430
Week 5	21	180 to 7400
Week 6	28	1,100 to 56,500
Weeks 7 to 8	35 to 42	7,600 to 230,000
Weeks 9 to 12	49 to 70	25,300 to 290,000
Weeks 13 to 16	77 to 100	14,000 to 243,000
Weeks 17 to 24		4,000 to 165,000
Weeks 25 to birth of baby		3,200 to 90,000
4 to 6 weeks after birth		Less than 5

These should be used as a guide only.
hCG levels double approximately every 48 hours during early normal pregnancy. It reaches a peak at about 10 week of gestation (since last menstrual period). At which time the average hCG levels in samples is around 60,000 mIU/ml. There is a very big variation in individual hCG concentrations. At this time, the extremes of normal levels are approximately 10,000 to 250,000 mIU/ml.

In the next 10 weeks (10 to 20 weeks of gestation), hCG levels decline, reaching a average concentration of about 15,000 mIU/ml. Again, wide variation is found among individuals, concentrations ranging from 3,000 to 90,000 mIU/ml. The hCG concentrations remains at around this level, and with this variation from this time until term (20 to 40 weeks of gestation).

If you have any concerns you should always discuss your results with your Doctor.

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hCG Level Doubling Time Calculator

Enter in your numbers and the doubling time will be calculated automatically.

You can use the calculator above to calculate the doubling time of two beta hCG samples by entering the values of the blood tests and the number of days between the tests.

The hCG levels will usually double approximately every 48 hours [ 2 days ] for the first four weeks of pregnancy.
As pregnancy progresses the doubling time increases. By 6 to 7 weeks gestation beta hCG levels may take as long as 84 hours [ 3½ days ] to double.
The beta hCG may take more than 48 - 72 hours [ 2 to 3 days ] to double in 15% of normal pregnancies.
About 17% of ectopic pregnancies have normal doubling times.

HCG Level	Doubling Time
< 1200	48 - 72 hours
1200 to 6000	72 - 96 hours
> 6000	> 96 hours

Ultrasound findings after five or six weeks of pregnancy are much more predictive of pregnancy outcome than are hCG levels. You won't expect to see a gestational sac or the fetus until the hCG level reaches at least 1,200 mIU/ml.

Twins or Higher Pregnancies:
Twin pregnancies tend to show higher HCG levels on a given day of pregnancy. Twin HCG levels fall within the reported range of singletons, so, you can not assume anything based on the level alone. A higher level on a given day does increase your chances for twins, but there is no level above which you are guaranteed twins.

Your HCG Levels:
Check with your physician about your own levels. In addition, do not try to draw conclusions on either the viability of your fetus or the possibility of multiples, unless you have a series of HCG tests done that clearly indicate a pattern.

Progesterone tests and levels in pregnancy

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	What is hCG?
	Pregnancy begins with fertilisation of the egg and implantation of the fertilised egg in the lining of the uterus. Implantation will normally occur about 8 to 12 days following conception. hCG begins to be produced around the time of implantation. The tiny amount of hCG that enters the maternal circulation around day 21 (less than 5 mIU/ml in serum or plasma, while too small to be detected by pregnancy tests, is sufficient to stimulate the corpus luteum of the ovary to produce progesterone. A pregnancy will usually only continue after implantation if menstruation is prevented. Estrogen and Progesterone are produced by the *Corpus Luteum* and prevent menstruation by maintaining the lining of the uterus. The corpus luteum itself is maintained by hCG that is produced by the trophoblast cells of the placenta after implantation of the fertilised ovum. hCG enters the maternal circulation almost immediately after implantation of the embryo (blastocyst) on about day 21 of the menstrual cycle. Corpus Luteum is a body of cells that forms after ovulation each month and occupies the space formerly occupied by the egg in the follicle. It produces progesterone and estrogen and is programmed by nature to disintegrate in about 14 days. When it does, diminishing hormone levels trigger menstruation. In pregnancy, the corpus luteum, sustained by the pregnancy hormone hCG, continues to grow and produce progesterone and estrogen to nourish the baby until the placenta takes over. In most cases, it starts to shrink approximately 6 or 7 weeks after the last menstrual period and ceases to function at about 10 weeks. Pregnancy tests are based on the detection of elevated levels of human Chorionic Gonadotrophin (hCG) in serum or urine, which is produced by the developing placenta following implantation. Urine and serum samples of non pregnant females usually contain less than 5 mIU/ml hCG. After conception and implantation, levels of hCG will increase rapidly in a normal pregnancy. By the day the period is due hCG levels of approximately 50 - 250 mIU/ml are expected. During the first trimester, levels of hCG should double every 48 - 72 hours with the levels reaching between 50,000 – 300,000 mIU/ml at the end of the first trimester. After the first trimester levels of hCG drop dramatically with the levels remaining well above the base level of 5 mIU/ml throughout the pregnancy. The appearance and rapid rise in the level of hCG makes it an excellent marker for pregnancy.

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	When can hCG be detected?
	The earliest time a hCG test will detect a pregnancy is about 8 days after conception or about 1 week before the next period is due. However, this is only possible for about 5% of women. Most women will show a positive hCG level by about 11 to 12 days after conception or a couple of days before the next period would have been due. By day 28 (first day of missed menses) the hCG level in serum, plasma or urine is about 100 mIU/ml. This should be detectable by all pregnancy tests. There is a very big variation in individual hCG concentrations. At this time, the extremes of normal levels are approximately 5 to 450 mIU/ml in serum or plasma samples. Some pregnant women at this time will have a low level hCG and will not register on HPTs by the time they are a few days late for their period. hCG can also be produced by early pregnancy loss (EPL) or pregnancies that fail to start or properly implant. hCG from these pregnancies can also be detected at this time Women who have hCG injections for fertility treatments can have hCG in their system for 2 to 3 weeks after the injection. This means they may obtain an early 'positive' pregnancy test, yet not be pregnant.

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	How is hCG detected?
	When a women first thinks she may be pregnant she might purchase a home pregnancy test (HPT). Home pregnancy tests (HPTs) are designed to detect hCG, a hormone released by the placenta right after the embryo begins implanting into the uterine lining. When the hormone is released it can be detected in a pregnant woman's blood and urine. If a women visits her Doctor to test, a blood and/or urine sample will be taken. A Urine tests at the doctor's office are not any more sensitive than home tests. These are usually the equivalent to home pregnancy tests, reading an hCG level of 15 to 25 mIU as positive. They are often the same tests as HPTs, bulk packed for Doctors, medical centers and clinics. A quantitative blood test is more accurate, but not necessarily more sensitive. A quantitative blood test, usually called a beta hCG test, measures the exact units of hCG in the blood. That means it will detect even the most minimal level. Common levels for a positive blood test are 10 to 25 units. A *qualitative* hCG blood test will give a simple yes or no answer to whether you are pregnant. This test is more like a urine test in terms of its accuracy. Levels for a positive blood test are 10 to 25 units, a level under 5 is considered negative. A test that is only triggered at 25 units of hCG is not any more sensitive than several of the urine HPTs.

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	How accurate is a positive HPT result?
	Home pregnancy tests only check hCG levels and the hormone hCG is produced in pregnancy, which is released in a pregnant woman's urine. So, unless the woman has been given a medication that contains hCG (Profasi, Pregnyl, Novarel), then a positive HPT should indicate a new pregnancy. If you had an hCG injection (such as Profasi, Pregnyl or Novarel), you should wait 7-14 days after your last injection before the shot is out of your system. If you test too soon, you might get a false positive. Wait 14 days after a 10,000 IU injection, 10 days for a 5,000 IU injection, for 2,500 IU injection 7 days. How accurate is a negative HPT result? If you get a negative HPT result, you may be pregnant and just didn't have a high enough level of hCG to trigger the test. It is possible the test was performed improperly, done to early, that urine was too diluted to give an accurate reading, or that test was not stored properly before use. If you think you are pregnant but got a negative result, re-test on another day. Most pregnant women will register on HPTs by the time they are a few days late for a period, but not everyone will. If you suspect you are pregnant, you should see your doctor for a quantitative hCG blood test no matter what result you get from home pregnancy tests.

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Early low level hCG Problems

It is only in the last ten years or so that it has been possible to carefuly monitor pregnancies in the first half of the first trimester. The early monitoring, if used properly can reassure women during uncertain times and prevent dangerous complications. Pregnancies that will miscarry and ectopic (tubal) pregnancies are likely to show lower levels and slower rises, but often have normal levels initially. Sometimes it takes three or more tests for hCG levels, at least 48 hours apart to get an idea how a pregnancy is progressing.

A single hCG value doesn't give enough information about the health or viability of the pregnancy. Within the first 2 - 4 weeks after fertilization, hCG usually doubles every 48 - 72 hours. That usually corresponds to hCG levels below 1200 mIU/ml. From 1200 - 6000, the hCG usually takes 72-96 hours to double. Above 6000 mIU/ml, the hCG often takes over four days to double. So, the rate of increase in hCG levels normally varies as a pregnancy progresses. hCG that does not double every two to three days does not necessarily indicate a problem with the pregnancy. Some normal pregnancies will have quite low levels of hCG, and result in perfect babies.

Once the hCG levels are above 1000 - 1500 mIU/ml, vaginal sonography usually identifies the presence of an intrauterine pregnancy. At that point an ectopic pregnancy is effectively ruled out. Once the pregnancy is visible on ultrasound, further hCG testing is less reliable than ultrasound for monitoring a pregnancy, as the variations in hCG levels are frequently misleading and cause unnecessary worry.

Since normal levels of hCG can vary tremendously, after 5-6 weeks of pregnancy, sonogram findings are much more predictive of pregnancy outcome than are hCG levels. Once the gestational sac is seen, most doctors will monitor with ultrasounds rather than drawing bloods for hCG tests.

Subsequent monitoring with ultrasound should reveal normal growth of the gestational sac, and the development of a fetal heartbeat by 6 to 7 weeks gestation (6-7 weeks after LMP). Once fetal activity has been detected by ultrasound, the chance of miscarriage is usually less than 10%.

If your home pregnancy test is positive and then a few days later your period arrives. Your period may be heavier than you're used to, which may mean your pregnancy has been lost. Experts estimate that about 20 to 30 per cent of all pregnancies end in miscarriage, so unfortunately this is very common.

It is only since pregnancy tests became so sensitive that people have realised how often early miscarriages can happen. In the past, these very early losses might not even have been noticed, and the woman would never have known she had been pregnant.

Think you are pregnant and got a negative HPT result?

If you get a negative HPT result, you may be pregnant and just didn't have a high enough level of hCG to trigger the test. It is possible the test was performed improperly, done to early, that urine was too diluted to give an accurate reading, or that test was not stored properly before use.

If you think you are pregnant but got a negative result, re-test on another day. Most pregnant women will register on HPTs by the time they are a few days late for a period, but not everyone will.

If you suspect you are pregnant, you should see your doctor for a quantitative hCG blood test no matter what result you get from an HPT.

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