Diagnosing an Ectopic Pregnancy
Please do be vigilant and take symptoms that concern you seriously until absolutely proven otherwise. If your instincts are screaming at you that something does not feel right it is OK to trust them and ask medical professionals for a reassessment at any time. The EPT considers that any woman or person capable of conceiving of childbearing age, who is sexually active or undergoing assisted reproductive technology (ART) treatment, who has ectopic pregnancy symptoms, should be considered to be pregnant until proven otherwise.
Detailed general information can be found here on our website. Please remember that online medical information is no substitute for expert medical care from your own healthcare team. In diagnosing an ectopic pregnancy, medical professionals are likely to undertake some or all of the following tests.
Urinary pregnancy tests
The first, useful basic test is a urinary pregnancy test. These tests check for human Chorionic Gonadotropin (hCG), a pregnancy hormone produced by a fertilised egg after conception. Urinary pregnancy tests can sometimes produce a negative result in pregnancy, because the hormone level is not yet high enough.
Whether you have a positive urinary pregnancy test or not, if you have ectopic pregnancy symptoms, good practice would be to speak to your local general practitioner or early pregnancy assessment unit (EPAU). If they decide an ultrasound scan is appropriate, this will be arranged within 24 hours. It is likely that a transvaginal (internal) ultrasound scan will be required, where a specialised probe is placed into the vagina to get a more detailed look at the reproductive organs. A transvaginal ultrasound scan is safe in pregnancy.
If during the scan a pregnancy – that is a gestation (pregnancy) sac, a foetal pole and a beating heart – can be seen in the uterus (womb), the chance of a coexisting ectopic pregnancy, whilst possible, is rare. Nonetheless a complete check will be performed with every scan.
If a pregnancy is seen in the uterus, bleeding may be due to implantation and development of the fertilised egg during a healthy pregnancy, or a sign of an impending miscarriage. Pain may be caused by a normal, healthy corpus luteum cyst, which forms on the ovary after every ovulation, swelling to cause pain. Changes to the bowel and bladder may be attributed to hormonal changes, causing you to pass urine (wee) more often and possibly even be a little constipated (hard to open the bowels to have a poo).
If a pregnancy cannot be seen in the uterus but there is evidence of internal bleeding and/or a swelling in the approximate location of the Fallopian tubes, your doctor will likely suspect an ectopic pregnancy. An initial transvaginal scan will detect over 70% of ectopic pregnancies, and most ectopic pregnancies will be seen as an area of pregnancy tissue, with or without a gestation (pregnancy) sac, a foetal pole or a beating heart that is not correctly placed in the uterus.
Pregnancy of Unknown Location (PUL)
If a pregnancy cannot be seen inside or outside the uterine cavity (womb), or if the sonographer is not certain, you may hear this situation being classified as a Pregnancy of Unknown Location, or PUL. It is important to understand that PUL is not a diagnosis; it is a label given until the final location of the pregnancy can be identified with certainty. It is also important to note that this classification does not necessarily mean there is an ectopic pregnancy, as PUL also include healthy pregnancies that are initially too small to see on ultrasound as well as failing pregnancies that are too small to visualise.
In the event of a PUL, blood will be taken to measure hCG (the same hormone measured in urinary pregnancy tests) and another pregnancy hormone called progesterone. The hCG test may be repeated 48 hours later depending on the first results, and this will help the doctors plan if a repeat ultrasound scan is needed in order to identify the location of the pregnancy.
The reason for this is that until the location of the pregnancy is known with certainty, or the hormone levels have decreased to below pregnancy levels, there is a risk of complications associated with an ectopic pregnancy which has not yet been identified. For every 100 pregnancies initially classified as a PUL, approximately 12 will subsequently be ectopic. Importantly, of these 12, some will not need any treatment. Your doctors will discuss the possible treatment options with you.
All PUL will be followed up until a final early pregnancy location is confirmed as ectopic, or within the uterine cavity. Sometimes a location cannot be confirmed, which is why the hormone level tests may continue for a little longer.
HCG and progesterone blood tests
The hormone hCG is produced during pregnancy by the early developing placenta regardless of where the pregnancy is. HCG can first be detected by a blood test approximately 11 days after conception and, in a healthy pregnancy, will typically increase during the first 8 to 11 weeks of pregnancy, then fall or level off for the remainder of the pregnancy. It is hCG that leads to the ‘morning sickness’ some experience in early pregnancy.
Progesterone is the hormone made by the corpus luteum cyst, which forms on the ovary after every ovulation. If not pregnant, progesterone is only made for two weeks, after which the corpus luteum disappears, a period starts, and a new cycle begins. In pregnancy, this cyst is encouraged to remain and continue releasing progesterone for the first 13 weeks of pregnancy.
HCG and progesterone are used to guide the management of a PUL. The progesterone is measured at the time of a first visit by some doctors, whilst the hCG is measured at the first visit and then in most cases 48 hours later. . Low progesterone and falling hCG levels may indicate the pregnancy is no longer growing, or that the pregnancy has unfortunately already passed as a miscarriage.
High progesterone and a normally rising hCG results are associated with a pregnancy that is still present, even if it is not visible on a scan. In this situation, the pregnancy most likely to be in the correct place in the uterus. Occasionally, however, the hCG levels rise suboptimally, and this can indicate the development of an ectopic pregnancy. The doctor caring for you will interpret these results in order to plan the next steps of your care safely.
HCG is also used to help decide the best way to treat an ectopic pregnancy. These results will be assessed by your doctor alongside your symptoms and your ultrasound scan findings.
Doctors are at liberty to follow their own hospital protocols in the UK but there are guidelines available to help steer medical professionals. For example:
The National Institute for Health and Care Excellence (NICE) was established in 1999 to reduce variation in the availability and quality of NHS treatments and care. In 2005, it merged with the Health Development Agency and began developing public health guidelines. It is a non-departmental public body sponsored by and accountable to the Department of Health although the guidelines are created by independent committees of experts.
The EPT was fortunate to sit representing lived experiences on NICE’s Ectopic Pregnancy and Miscarriage guidelines committee and consider them to be a step in the improvement of diagnosis, treatment, and care for ectopic pregnancy. We have further been involved in subsequent updates to the guidelines.
The Royal College of Obstetricians and Gynaecologists (RCOG) encourages the study and advancement of the science and practice of obstetrics and gynecology and the majority of professionals in the field are members. It produces Green-top Guidelines which include Diagnosis and Management of Ectopic Pregnancy (Green-top Guideline No. 21).
Our section for Professionals has further information and links to relevant UK guidelines. The guidelines are designed to be used by doctors rather than the general public so some of the words used may be very technical.