Ectopic pregnancy can result in life-threatening hemorrhage if not detected and treated early. An algorithm using measurement of serum progesterone and beta-HCG can aid in the diagnosis and management of women with possible ectopic pregnancy.


Test Ordering:

(1) serum progesterone in ng/mL: with a positive pregnancy test, a serum progesterone level of >= 25 ng/mL indicates a normal intrauterine pregnancy, while a value <= 5 ng/mL indicates a nonviable fetus

(2) serum beta-HCG in mIU/mL






>= 25 ng/mL


>= 100,000 mIU/mL

Viable intrauterine pregnancy

< 25 but > 5 ng/mL



Perform transvaginal ultrasound. If intrauterine gestational sac not seen, look for ectopic sac and measure diameter.

<= 5 ng/mL


abnormal rise (see below)

Perform D & C. If chorionic villi seen, then completed abortion. If no chorionic villi seen, monitor beta-HCG at 12 hours (see below).


Rise in serum HCG during pregnancy:

(1) normal: with intrauterine pregnancy, serum beta-HCG should rise by at least 66% over the initial level at 24 hours

(2) abnormal: an increase of serum beta-HCG by less than 66% indicates a pregnancy not developing normally, and could indicate an ectopic pregnancy


Management if no chorionic villi seen at D & C:

(1) if beta-HCG at 12 hours after D & C has decreased by at least 15%, then diagnosis consistent with completed abortion

(2) if beta-HCG at 12 hours after D & C has not decreased by at least 15%, then perform transvaginal ultrasound and look for ectopic gestational sac and measure diameter.


Management of ectopic pregnancy based on gestational sac diameter:

(1) if sac size is < 4 cm: administer methotrexate

(2) if sac size is >= 4 cm: treat surgically


To read more or access our algorithms and calculators, please log in or register.