Ectopic Pregnancy: Risk Factors & Locations

• Ectopic pregnancy happens when a fertilized ovum implants outside the normal endometrium.
• It is a life-threatening surgical emergency in gynaecological practice.
• Ectopic pregnancies can occur any time between menarche and menopause.
• 40% of ectopic pregnancies occur in women aged 20-29 years.

Risk Factors

• Ectopic pregnancy is more common in infertile women.
• Ectopic pregnancy is more common in women in lower socioeconomic groups.
• Ectopic pregnancy is more common in women with a previous history of ectopic pregnancy.
• It is more common in women treated for salpingitis or who have had tuboplasty.
• Advanced maternal age, smoking, endometriosis, abdominal surgeries and sexual transmitted infections are also implicated as risk factors.

Incidence

• Ectopic pregnancy incidence in Nigeria varies from 1 in 37 to 1 in 350 deliveries.
• Ectopic pregnancies can recur.
• Ectopic pregnancies can occur in both fallopian tubes.
• Ectopic pregnancies can co-exist with intrauterine pregnancy.

Classifications/Sites of Ectopic Pregnancy

• Tubal: isthmic, ampullary, fimbrial, interstitial, or bilateral
• Uterine: cornual, angular, or in a uterine diverticulum
• Cervical canal
• Intraligamentary
• Ovarian, tubo-ovarian, or abdomino-ovarian (secondary abdominal pregnancy)
• Abdominal: primary, secondary, abdomino-ovarian, or tubo-abdominal
• Associated with hysterectomy: following total or subtotal hysterectomy, in a uterine tube, in a prolapsed uterine tube (fimbria), in the vesicovaginal space, or in a cervical stump.
• Combined with intrauterine pregnancy, also known as compound pregnancy (heterotopic pregnancy), occurs in 1 in 25,000–30,000 pregnancies while the IVF incidence increases to 1%.

Tubal Pregnancy

• At least 95% of extrauterine pregnancies are tubal.
• More than half of tubal pregnancies occur in the right tube.
• The most common site in the tube is the ampulla portion, accounting for 55% of all ectopic pregnancies.

Aetiology

• Any alteration of the normal function of the uterine tube in transporting the fertilized ovum or gamete contributes to the risk of ectopic pregnancy.
• Pelvic inflammatory disease, e.g., salpingitis leads to ciliary destruction and interferences with tube peristalsis, perisalpingitis, parametritis, tubal adhesion, and oedema, which predispose the tube to ectopic pregnancy.
• Congenital abnormalities of the tube, such as diverticulum, hyperplasia, unusual tortuosity, and accessory tubes and ostia, can cause ectopic pregnancy.
• IUDs and progestogen contraceptive drugs can cause ectopic pregnancy.
• Assisted reproductive techniques such as IVF/ET, GIFT, and ZIFT can cause ectopic pregnancy.
• Adjacent uterine tumours, such as intramural or subserous myomas, which often occlude or impair the tubal lumen in the interstitial area, or an ovarian cyst can cause ectopic pregnancy.

Physiology of Tubal Pregnancy

• In intrauterine pregnancy, the blastocyst embeds in decidua, and the trophoblast erodes the maternal tissue anchoring the developing embryo within the decidua of the myometrium.
• In tubal pregnancy, the blastocyst rapidly erodes the epithelium and attaches to the muscular layer of the tube.
• It grows and expands within the wall, thus distending the tube, and maternal vessels are exposed.
• The pressure caused by the resultant blood flow can destroy the embryo.

Outcomes of Tubal Pregnancy

• Tubal abortion happens when the developing conceptus separates and is expelled through the fimbriated end of the uterine tube and it is more common with ampullary implantation.
• Tubal mole presents with bleeding around the embryo that results in its death.
• The blood clots around the conceptus enclose the retained products of the conceptus within the tube, thus forming a mole, and this mole pregnancy may need removal.
• Tubal rupture happens when the wall of the tube is distended by the growing pregnancy and penetrated by the trophoblast to such an extent that it ruptures, which can be gradual or acute.
• Spontaneous resolution.

Clinical Findings/Presentations

• Acute Ruptured Ectopic Tubal Pregnancy occurs in 40% of tubal ectopic gestations and may be life threatening.
• Acute Ruptured Ectopic Tubal Pregnancy presents with sharp abdominal or pelvic pain, an adnexal mass may be felt, and signs of peritoneal irritation, with shoulder and back pain.
• There are symptoms of shock- weakness, thirst, profuse perspiration, air hunger, and oliguria.
• Chronic Ruptured Ectopic Tubal Pregnancy or silent ectopic tubal gestation or chronic leaking ectopic tubal pregnancy occurs in about 60% of all ectopic pregnancies.
• When the point of rupture is small, and bleeding is coming out slowly, the symptoms are generally vague and inconclusive.
• Unruptured Ectopic Tubal Pregnancy, this occurs about in 2%of all tubal pregnancies.
• It may be suspected if there is a history of amenorrhoea, with symptoms and signs of early pregnancy, scanty dark vaginal bleeding, and discomfort in the affected adnexal area, especially when the uterus is moved.

Differential Diagnosis

• Abortion
• Ruptured or twisted ovarian cyst
• Ruptured bleeding corpus luteum
• Pelvic inflammatory disease
• Appendicitis
• Degenerated fibroid.

Investigations

• If acute ruptured ectopic tubal pregnancy, pre-operative preparation and resuscitation are carried out, like HB, or PCV, blood grouping and crossmatching.
• In such a situation, urgent surgery is the only sensible course open to the surgeon.
• Where the diagnosis is in doubt, ultrasound will help in excluding intrauterine pregnancy.
• Laparoscopy
• Pregnancy test with urine
• If the serum B-HCG is below 5miu/ml it is negative for pregnancy, above 6500miu/ml and there is no intrauterine pregnancy seen on scan, this is an indication of ectopic pregnancy.
• A lower quadrant abdominal tap with a needle and syringe is controversial; paracentesis abdominus or culdocentesis.
• The presence of Arias-Stella cells in the endometrial curetting may occur in some cases suggesting ectopic pregnancy and this occurs in about 20% of cases.

Management

• For acute ruptured ectopic tubal pregnancy resuscitation is promptly done and emergency laparotomy performed
• Blood should be given to combat shock if available, otherwise, transfuse plasma expander or saline and arrange for urgent laparotomy

Ruptured and unruptured ectopic tubal pregnancies

• Pain is relieved with pethidine, morphine, or pentozicine.
• Auto-transfusion of fresh blood scooped out of the abdominal cavity and filtered into a citrated bottle could be lifesaving.
• Ruptured and unruptured ectopic tubal pregnancies should be clamped and excised (salpingectomy) Milking out of the sac in the unruptured tube through the fimbriated end is carried out (Salpingostomy).
• Linear salpingostomy, where enucleation of the pregnancy from the tube is done and tubal reconstruction is done.
• This conservative approach is rare.

Medical Management of Unruptured Ectopic Tubal Pregnancy

• Expectancy management, based on the fact that a significant proportion of all tubal pregnancies will resolve through regression or tubal abortion without any treatment.
• The serum B-HGC is monitored, and the size of the ectopic gestation is assessed to see if it is increasing Size.
• In some cases, the ectopic tubal pregnancy resolves spontaneously.
• Systemic therapy uses parenteral drugs that kill the embryo that are given after the product is later absolved

Intratubal Therapy

• Drugs like methotrexate, hypertonic glucose, hypertonic saline, and potassium iodide are used.

Complications of ectopic tubal pregnancy

• Ruptured ectopic pregnancy leads to severe shock and death.
• A chronic leaking ectopic tubal pregnancy may form a haematocele.
• The fetus may die in the tube and is retained to form a tubal mole.
• Abdominal pregnancy.
• Abdominal pregnancy dies and becomes mummified or calcified to form a lithopaedion

Prognosis

• There is a higher rate of secondary infertility in women with previous ectopic pregnancy.
• Recurrent ectopic pregnancy is more likely in the remaining tube.
• Intrauterine pregnancy occurs in 50% of cases.

Fertility Prognosis

• The chances of intrauterine pregnancy in subsequent pregnancies are 40% after salpingectomy, 60% after conservative tubal surgery, and 87% after medical treatment.
• Recurrent ectopic pregnancy rates after radical and conservative management are similar (10–20%).

Explore ectopic pregnancy risks, locations & factors. Understand risk factors, including pelvic inflammatory disease (PID) and tubal surgery. Identify less likely ectopic pregnancy locations post-hysterectomy.