Ectopic Pregnancy
Definition
Implantation of fertilised ovum in any location other than endometrium
Cornual (interstitial) pregnancy: 0.4-4% ectopic pregnancies; uterine rupture early in pregnancy 
severe haemorrhage, high morbidity and mortality
Heterotropic pregnancy: IUP + ectopic; incidence 1:4000 pregnancies; if find IUP on USS, ectopic virtually
excluded unless specific risk factor for it
Epidemiology
Leading cause of maternal death in 1st trimester (10%); occurs in 2% pregnancies (10/1000); incidence in
standard population 20/1000; 60% women with ectopic pregnancy will conceive naturally again  2530% ectopic pregnancy rate in subsequent pregnancies
80% ampullary, 10% isthmic, 6% fimbrial, 1.5% cornual, 1.5% abdominal (usually from ruptured tubal
ectopic), 0.2% ovarian, 0.2% cervical
Risk Factors
Previous tubal STD / surgery, old mum, endometriosis / atropic endometrium, abnormal anatomy, IUD /
assisted reproduction, smoking, OCP (especially progestrogen only eg. Norethisterone). Family history is
NOT a risk factor (according to MCQ).
For heterotropic pregnancy: use of follicular stimulation (1:100-500), PID, IUCD, tubal surgery, assisted r
reproduction
Assessment
History: 90% abdominal pain (highest sensitivity), 50% irregular PV bleeding (usually 4-12/52
amenorrhoea); pain, no PV bleeding in 10%; no PV bleeding or pain in 10%; shoulder tip pain = rupture;
syncope; PV bleeding + pain = ectopic pregnancy until proven otherwise
Examination: 75% abnormal abdominal mass; 50% adnexal mass; 30% uterine enlargement; relative
bradycardia common
80% patient with PV bleeding + pain + adnexal mass do not have ectopic
BetahCG
Urine: urine = plasma concentration in normal hydrated patient; urine false negative rate
<1%; false negative in dilute urine / early pregnancy; low false positive rate; can detect from
beta-hCG 25iu/L; not helpful in ectopic; should do quantitative level (ie. Plasma) in ?ectopic;
will remain positive for 2-3/52 after surgery for ectopic, but should be <20 after 2/52; level
may continue to  for 3/7 after methotrexate
Home pregnancy test: detects beta-hCG >500; positive by 4/40; sensitivity 50%, specificity
77-94%
Serum: Should  1.6-2x per 48hrs ( exponentially) in 1st 6/40  plateau at 10-12/40  
at 12/40; elimination half life 9hrs; positive within few days of conception;
linear  in ectopic
Beta-hCG  >50% in 2/7 suggests viable pregnancy
 <50% in 2/7 suggests ectopic
 <35% in 2/7 suggests ectopic
 >35% in 2/7 suggests miscarriage
Investigation
Progesterone level: produced by corpus luteum in viable pregnancy; distinguishes IUP from
ectopic/miscarriage; <16nmol/L = 100% sensitivity for non-viable pregnancy
TVUS: discriminatory zone beta-hCG >1500-2400 (ie. >4.5/40)
5/40 = beta-hCG >15
= gestational sac (= 1/52 after missed period)
5.5/40 = beta-hCG 2500-5000
= yolk sac
6/40 = beta-hCG 5000-17000 = fetal pole and cardiac activity
Gestational sac >5mm + yolk sac / fetal pole / double decidual sac sign
USS
In
Pregnancy
TAUS: discriminatory zone beta-hCG >3000-6000
= TAUS (lag behind TVUS by 1/52)
If >6/40 and IUP with fetal heart beat seen  discharge with early pregnancy
clinic follow up
If >6/40 and no IUP seen  formal TVUS
5/40 = gestational sac
6/40 = yolk sac
7/40 = fetal heart
Pros: non-invasive; less expertise required
Cons: less sensitive than TVUS
USS
Investigation
(cntd)
In
Ectopic
Will be indeterminate in 15%
Findings: empty uterus (25% have ectopic, LR 2.2), tubal ring outside uterus,
extrauterine mass +/- cardiac activity, interstitial / heterotropic pregnancy,
extrauterine empty gestational sac, free fluid (in pouch of Douglas 70%
sensitivity and specificity for ectopic; large amount 50% sensitivity, 95%
specificity), nonspecific anechoic intrauterine fluid collections (3% have ectopic,
LR 1)
If beta-hCG above discriminatory zone (>2000) and no IUP, or mass in ovary / tube = likely ectopic (90%
PPV)
If beta-hCG >6500 and no fetal heart seen on USS = 80% chance of miscarriage
If beta-hCG below discriminatory zone (<2000) and inconclusive scan = pregnancy unknown location 
48hr follow up (serial beta-hCG’s or repeat USS)
Treatment
Indications for conservative treatment (observation): beta-hCG <1000 and falling
Indications for surgery: cardiovascular instability, cervical pregnancy, ectopic fetal heart activity,
>100ml free fluid in Pouch of Douglas
Indications for salpingectomy: severe tubal damage, uncontrolled bleeding, recurrent ectopics of same
tube, tubal pregnancy >5cm
Indications for salpingotomy and salpingostomy: unruptured tubal pregnancy <4cm
Methotrexate: inhibits cell division in rapidly growing tissues
Indications: asymptomatic, high compliance, beta-hCG <3500, tubal size <3cm, no fetal heart activity on
TVUS; 87% success rate single dose, 95% success rate multiple dose (give if beta-hCG day 7 > day 4;
required in 10%)
Side effects = stomatitis, photosens, impaired LFTs, gastritis, bone marrow suppression, alopecia, fever.
Risk of rupture so review if abdominal pain.
Rh prophylaxis: 250-625iu IM