Measuring HCG Levels in Early Pregnancy

Patient Information

Gynaecology Services

• Author ID: JK
• Leaflet Ref: Gyn 052
• Version: 7
• Leaflet title: Measuring HCG Levels in Early Pregnancy
• Last review: May 2025
• Expiry Date: May 2027

Measuring Human Chorionic Gonadotrophin (HCG) levels in early pregnancy

We understand waiting to be given clear answers about what is happening in your pregnancy can be emotionally difficult. This leaflet aims to give you a better understanding about what is happening, and we hope this will provide answers to some of your questions.

Why is it necessary to check HCG levels?

Your ultrasound scan today has not given a clear answer as to what is happening with your pregnancy. To get a better understanding, we intend to measure the levels of HCG (Human Chorionic Gonadotrophin) in your blood over several days. HCG is a blood test that monitors the hormones in pregnancy. It is the same pregnancy hormone that is in urine. However a urine result will only give a positive or negative result. The blood test is more accurate telling us how much hormone is present and is especially useful in very early pregnancy when scan findings are sometimes inconclusive.

How often will I need blood taken?

HCG is produced in large quantities during early pregnancy. By monitoring the level of this hormone in the blood, we can determine whether your pregnancy is still on-going. The test is performed by taking a sample of blood and measuring the level of HCG in it. The HCG levels should be taken 48 hours apart to give meaningful assessment. It is often necessary to take several blood tests 48hours apart to establish the pattern of results and monitor whether the hormone level rises or falls with time.

Possible outcomes

There are three possible outcomes in this situation:

1. That you have a continuing but very early pregnancy. A pregnancy that is developing in the womb where it should be will result in the levels of hormone in the blood approximately doubling every 48hrs. This is reassuring but you will have another scan when we hope to see more clearly how the pregnancy is progressing.
2. That you have sadly suffered a miscarriage.   An HCG level that is already low or continually decreasing generally indicates that a pregnancy is miscarrying or failing to develop. However, follow up is still important, so that an ectopic pregnancy is not missed, particularly if we have seen no signs of a pregnancy on ultrasound scan. 
3. That the pregnancy has become lodged outside the womb, usually in the fallopian tube. This is known as an ectopic pregnancy.  HCG levels that remain static or rise very slowly combined with a scan showing an empty womb can indicate an ectopic pregnancy. You will be asked to return to hospital as further investigations will be required.

What is an Ectopic Pregnancy?

An ectopic pregnancy is a pregnancy that develops outside the cavity of the womb. Most ectopic pregnancies occur in the fallopian tube (95%); however they can occur in places such as the ovary, the cervix, caesarean section scar and inside the abdomen (tummy). Since the fallopian tubes are not large enough to accommodate a growing embryo, the pregnancy cannot continue normally.   

If the problem is identified early, the ectopic pregnancy can be removed either with an operation (surgical treatment) or by giving an injection (medical treatment).   If your ectopic pregnancy is suitable for medical treatment, you will require close monitoring of HCG following the treatment until the level becomes very low.

If the problem is not identified early, in some cases, the embryo grows until the fallopian tube stretches and ruptures (bursts). Rupture of the fallopian tubes is a medical emergency because of internal bleeding, causing abdominal pain and collapse and very occasionally can even result in death.

What happens now?

After your blood test you can go home. Individual follow-up will be discussed with the doctor and a member of staff will advise you if and when to return for more blood tests, and/or a repeat scan. Please note results will not be left on answer phones or with any relatives. We ask that you contact the Early Pregnancy Assessment Unit (EPAU) or the Gynaecology Assessment Ward on the numbers provided at the end of this leaflet if you have not heard from us by 7pm.

What symptoms do I need to look out for?

If you feel unwell or there is any change in your condition or experience any of the following, you must contact EPAU at Leigh Infirmary or the Gynaecology Assessment - Swinley Ward at RAEI at once to seek medical advice. 

• New or increased abdominal pain
• Increased bleeding
• Feeling dizzy, lightheaded or pains in the tip of the shoulder
• Faint or pass out (in this case you must come to hospital immediately)

Useful contact numbers

Early Pregnancy Assessment Unit (EPAU)    01942 264852

Ward 2 Leigh Infirmary Monday to Friday 7:30 am until 4pm.

Gynaecology Assessment Room                   01942 822072

Swinley Ward RAEI 24 hours                           01942 822016   

Counselling Service                                         01942 264308

See also patient information leaflet, REF: 

Gyn 021 Counselling Services-Obstetrics and Gynaecology

https://www.wwl.nhs.uk/leaflets/download/wwl-5fec914f6ae660.28074332 or scan the QR code.