Early pregnancy assessment
One of the priorities of assessment of early pregnancy symptoms of pain and bleeding is to exclude an ectopic pregnancy, as it can result in loss of life. Traditionally, a history of pain disproportionate to bleeding with signs of pain on vaginal examination (cervical excitation) or reduced blood volume (hypovolaemia) will lead to a laparoscopy (See Gynaesurgeon.co.uk – Laparoscopy) to diagnose and treat the ectopic pregnancy. Over the last ten years, the introduction of routine transvaginal scanning, rapid serum HCG estimation, combined with advances in laparoscopic surgery, has led to a major change in the way that we diagnose and treat ectopic pregnancy.
Approximately 1:300 pregnancies (1:100 in inner city areas) are outside the womb (extra uterine), the vast majority in the fallopian tube. The ampulla or isthmus of the tube is the most common site, typically resulting in a woman presenting with pain and bleeding (>95%) between 6 and 8 weeks gestation (dated from the first day of her last period). If the pregnancy is in the cornua of the fallopian tube, it may enlarge and present around 11 -13 weeks gestation. Where the ectopic has ruptured there will be signs of peritonism (blood in the abdomen causing irritation) or haemodynamic collapse, but the majority of women present before such catastrophic events take place.
A positive urinary pregnancy test confirms that the patient has conceived. A careful history and examination remains an essential first step in the assessment of early pregnancy problems. Ultrasound and HCG values must always be evaluated in light of the clinical evidence, otherwise mistakes are made and unnecessary interventions or discharges take place.
The nearer an ultrasound beam is to the organ to be investigated, the better the resolution of the images obtained.
With the introduction of transvaginal scanning, we removed the sight of distraught women with full bladders waiting for a transabdominal scan, which would often produce inconclusive results. Now women are able to have a scan immediately, which produces a conclusive result in 95% of cases. The majority of women (65 -70%) who present with and bleeding in early pregnancy will have an ongoing viable intrauterine pregnancy. Approximately 20-25% will have signs of a complete, incomplete or missed miscarriage. 1-2% will have clear signs that there is an etopic pregnancy (positive pregnancy test, empty uterus, abundant free fluid in the pelvis or occasionally, the ectopic pregnancy visualized in the tube). In about 5% of scans the diagnosis will be unclear. In these circumstances serum HCG level is obtained (2-3 hours).
Human chorionic gonadotrophin (HCG) is a hormone produced by the placenta (afterbirth) of a pregnancy. The levels of HCG rise very quickly in early pregnancy. It is usually possible to see a pregnancy sac in the womb when the level of HCG is > 2500 i.u. If there is no sac a laparoscopy is usually performed to investigate the possibility of an ectopic pregnancy. If the HCG <2000 i.u., and there is clinical suspicion that the pregnancy is ectopic, the patient may have a laparoscopy.
If there are no clinically suspicious features, it is usual practice to wait 48 hours and repeat the ultrasound and HCG level. In a small number of women, they may require more time for diagnosis to become clear.
If the HCG level is <1000 i.u., or falling rapidly, the patient is usually managed conservatively. It is imperative that such patients are followed up every 48 hours, as it is not unusual for the HCG level to rise quickly to levels associated with tubal rupture. Occasionally in these cases, other treatments such as Methotrexate or Mifepristone may help.
Fortunately, rapid access to early pregnancy assessment means that very few women die as a result of this condition: worldwide it remains a significant cause of maternal mortality.