In Preg-nancy tvus



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In Preg-nancy

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

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

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

Progesterone level: produced by corpus luteum in viable pregnancy; distinguishes IUP from

ectopic/miscarriage; <16nmol/L = 100% sensitivity for non-viable pregnancy



Investigation

USS

Beta-hCG

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

Assessment

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



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  25-

30% 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

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



Ectopic Pregnancy

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

Investigation

(cntd)


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)

USS

In Ecto-pic

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)


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