Ectopic pregnancy

Fertilized ovum implants outside of normal uterine cavity

Sites for ectopic pregnancy :- 

Fallopian tube (Most common) > Ovary > Abdomen > Cervix

Fallopian tube / Tubal ectopic pregnancy (Ampulla > Isthmus > Infundibulum with associated Fimbriae > Interstitium)

Other sites - 

Caesarean scar pregnancy (Type 1 and Type 2)

Cornual ectopic pregnancy - (In Horn of Uterus - Non communicating , Functional Rudimentary cornua of unicornuate uterus , cornua of bicornuate uterus or septate uterus)

Note  - "Heterotopic Pregnancy" - Multiple gestations i.e..,  Ectopic pregnancy outside uterus with concurrent intrauterine pregnancy

Risk factors :-

Pelvic Inflammatory Disease (Most common)

Previous ectopic pregnancy (Highest risk for present ectopic pregnancy)

Prior tubal ligation

Prior Pelvic / abdominal surgery

IUD usage

Smoking

Endometriosis

Bicornate uterus

Maternal age >35yrs

Use of assisted reproductive technology like IVF ( Invitro fertilization ) 

History of infertility (Kartagener syndrome)

Diethylstillbestrol (DES)

Hormonal therapy

Symptoms :-

Pelvic pain / discomfort

Abdominal pain / discomfort & Guarding (often Confused as appendicitis)

Nausea / Vomiting

Syncope 

Lightheadedness

Vaginal bleeding

Abnormal uterine bleeding (A fall in levels of Progesterone and hCG will cause Endometrial sloughing and uterine bleeding in ectopic pregnancy)

Symptoms due to Tubal rupture  :- 

Interstitial segment of tube is relatively thick segment with greater capacity to expand than distal segment of Fallopian tube. Moreover interstitium is close to uterine myometrium which provides support as pregnancy progresses

So unlike tubal ectopic pregnancy which usually ruptures at 6 to 8 weeks of gestation , Interstitial ectopic pregnancy may progress without symptoms until rupture occurs at 12-16 weeks

Sudden acute severe lower abdominal pain with catastrophic hemorrhage and hemorrhagic shock features appear with rupture of tubal pregnancy (especially interstitial pregnancy rupture)

Shock index :-

To detect hemodynamic instability and hypovolemia

Shock index = Heart rate / Systolic blood pressure 

Normal = 0.5 to 0.7 (Non-Pregnant women) ; 0.7 to 0.9 (In Pregnant women ; Obstetrical shock index)

>0.85 shock index and SBP <110mmhg is seen in ruptured ectopic pregnancy leading to massive blood loss

Criteria's for ectopic pregnancy :-

1) Spiegelberg's criteria - Ovarian ectopic pregnancy

• Intact ipsilateral tube , clearly separate from ovary

• Gestation occupying normal position of ovary

• Gestational sac connected to uterus by utero-ovarian ligament

• Ovarian tissue in the wall of gestational sac

2) Studdiford criteria - Abdominal ectopic pregnancy

• Presence of Normal Bilateral tubes and ovaries with no evidence of recent or past pregnancy

• No evidence of uteroperitoneal fistula

• presence of pregnancy , related exclusively to peritoneal surface , early enough to eliminate possibility of secondary implantation after primary tubal nidation

3) Rubin criteria Modified by Paalman and McElin - Cervical pregnancy

• Painless bleeding from uterus after period of amenorrhea

• Soft & Disproportionately enlarged cervix

• Ovular tissue completely placed in endocervix

• Closed internal cervical os 

• Partially opened external cervical os

Diagnosis :-

1. Bagel sign (Blob sign / Tubal ring sign) in ultrasound - Unruptured tubal ectopic pregnancy

2. Ring of fire sign (Ring of vascularity) on color doppler - Hypervascular ring with low impedence (Placental blood flow) Tubal ectopic pregnancy

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