Ectopic pregnancy: Causes, Management and prevention

What is an ectopic pregnancy?

Ectopic pregnancy is otherwise known as extrauterine pregnancy — meaning  a pregnancy where implantation occurs at sites other than the uterine cavity. That’s, it is a pregnancy that occurred when the fertilised egg embeds or implants outside the uterus(e.g. ampulla or cervix).

It is an emergency obstetric condition that requires prompt and appropriate treatment of the woman.

Early diagnosis and treatment tend to reduce its life-threatening outcomes such as uterine tube rupture, haemorrhage or shock, or even deaths.

How common is ectopic pregnancy?

About 1% of all pregnancies are ectopic or extrauterine. Few other women tend to recur ectopic pregnancy in subsequent pregnancy especially if its underlying cause is not treated or removed.

Sites for ectopic pregnancy

Types depend on where the ectopic pregnancy is found or site of implantation and may include: 

  • Tubal pregnancy
  • Ovarian pregnancy
  • Cervical pregnancy
  • Abdominal pregnancy

In tubal pregnancy, the implantation can occur anywhere along the Fallopian tube but ampulla is the commonest site, followed by the isthmus and interstitial part (least common) respectively. 

Physiology of tubal pregnancy

During normal intrauterine pregnancy, the blastocyst implants or embeds in the deciduae (pregnant endometrium) and the trophoblast invades or erodes the maternal tissues in order to anchor the developing and growing embryo. 

In tubal pregnancy, the blastocyst rapidly erodes the tubal epithelium and attaches itself in the muscle layer. The blastocyst grows and expands within the wall, thereby distending the uterine tube.

The pressure from the pregnancy and penetration of the trophoblast tends to increase until it results in ruptured ectopic pregnancy.

Signs & symptoms of ectopic pregnancy   

Signs of ectopic pregnancy at 6 weeks are:

Acute symptoms result from the tubal rupture and the related degree of haemorrhage. These symptoms include: 

  • pelvic pain or pain in the rectum
  • Shoulder pain which is suggestive of bleeding into the peritoneal cavity. (ectopic pregnancy shoulder pain may be felt at right or left in relation to location of the ectopic)
  • Lower abdominal pain or sharp abdominal cramps
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Diagnosis

Apart from history-taking and using a pregnancy test kit to detect human gonadotropin hormone (hCG) in a woman’s urine — which is a non-sensitive test of pregnancy, ultrasound ectopic pregnancy is also available in most health facilities. 

Ultrasound can detect or diagnose it early as five to six weeks gestation thereby confirming  or ruling  out an ectopic pregnancy. 

Thus, 6 week ultrasound is readily available in both developed or developing countries.

What causes ectopic pregnancy?   

Its causes and risk factors are multifaceted. But the actual cause of extra-uterine gestation is not properly understood. 

However, the more you have any  of these factors below, the higher your chances of having this form of pregnancy. 

  • Congenital abnormality of the uterus  and /or damaged fallopian tube
  •   cigarettes/tobacco smoking
  • Advanced maternal age (35 and above)
  • STI(sexually transmitted infection)/pelvic inflammatory disease (PID)
  • scarred oviducts from pelvic surgery or surgery on the uterine tube
  • Previous history of   ectopic pregnancy
  • Failed tubal ligation  and/or  tubal ligation reversal.
  • Assisted reproductive techniques(ARTs) such as use of fertility drugs(e g. Clomid),  or vitro fertilization (IVF)
  • Use of or having intrauterine contraceptive devices (IUDs) in-situ
  • Partial stenosis of the tube

Note: Untreated infection alters the ciliated lining or peristaltic action of the oviducts. It  also leaves adhesions both inside and surrounding the Fallopian tube, thereby restricting its normal functions.

Ectopic pregnancy

Ectopic pregnancy treatment

The treatment involves either use of chemotherapy or surgery. I shall consider each  more deeply:

Chemotherapy

Methotrexate remains the main chemotherapy for tubal pregnancy.

It takes about 32 days for a single dose of methotrexate or 58 days when receiving two doses or more for ectopic pregnancy to resolve. Methotrexate can be injected once a week at the site of the ectopic pregnancy to dissolve it. 

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What to expect after taking methotrexate ?

Methotrexate otherwise known as MTX has a success rate of about 65 to 95% and 67–80.7% fertility rate with delivery after medical treatment for ectopic pregnancy. 

Common side effects associated with taking methotrexate are:

  • mild nausea or vomiting
  • headaches
  • bleeding much like your menstrual period.
  • discomfort and pain in lower abdomen which may not be severe
  •  fatigue and an overall “blah” feeling — a condition known as “methotrexate fog” 
  • mouth ulcers or sores(not common)
  • Vaginal brown discharge lasting for  2 to 3 weeks
  • pregnancy hormones begin to decrease in few weeks later(hCG levels become undetectable from 6 to 8 weeks of post-ectopic pregnancy)

Surgical Interventions   

If ectopic pregnancy is detected earlier, prompt surgical intervention can be taken to prevent rupture — which is a fatal complication. The surgery are of two types, with aims of removing the trophoblast and preserving the affected tube where possible.

The  main surgical options are:

Partial salpingectomy: salpingectomy remains the treatment option for tubal conception.  It involves the removal of part of the tube where ectopic conceptus is found. 

Salpingostomy: Salpingostomy may be the safest or best  choice for ectopic pregnancy, particularly when the obstetrician is making efforts to preserve the affected tube where possible. 

The surgery involves leaving the tube in a place and removing the ectopic (embryo) through an incision in the wall of the tube with the help of a laparoscope. 

Laparotomy: This is another surgical intervention for  ectopic pregnancy, which usually recommended in obese patients or patients with extensive pelvic adhesion.  

Success of this surgery depends on the experience and the training of the operator or doctor in laparoscopic surgery.

What to expect after the surgery?

Once the procedure is carried out under strict aseptic techniques, ectopic pregnancy surgery wounds heals quickly and fertility (ovulation after ectopic pregnancy) is likely to return within 6-8 weeks following the ectopic pregnancy surgery.  And unprotected sex within this period is far more likely to result in another pregnancy.

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The surgery is associated with the  increased risk of ectopic pregnancy in subsequent pregnancy especially if the healing process forms scars in the uterine tube. 

However, women who had this surgery are advised to maintain adequate nutrition, personal hygiene, quit smoking and/or avoid risk factors of ectopic pregnancy,  and use safer contraceptives to prevent pregnancy. 

Tubal abortion: Tubal abortion is more common with ampullary implantation. It occurs when the developing conceptus separates and is expelled through the fimbriated end of the Fallopian tube.

Outcomes of tubal pregnancy 

Bleeding around the embryo results in its demise: The blood clots around the conceptus tend to enclose it, impairing its survival. These products are retained in the uterine tube and may need surgical intervention to remove it. 

Tubal rupture: The wall of the tube is distended by  pregnancy and extensive penetration by the trophoblast results in its rupture. The rupture of the tube may be a gradual or acute episode.

Abdominal pregnancy: Abdominal pregnancy is a rare type of ectopic pregnancy— occurring when the fertilized egg embeds in the peritoneal cavity exclusive of tubal, ovarian, or intraligamentary locations. 

Abdominal pregnancy is a life-threatening condition, characterized by nonspecific symptoms such as nausea and vomiting,abdominal cramps, palpable fetal parts, pain on fetal movement, or displacement of the cervix. It can be situated mainly in the  the peritoneal cavity  and/or secondary to a ruptured pregnancy (tubal abortion). 

Life after an Ectopic Pregnancy

Early antenatal booking is recommended also for women who have suffered ectopic pregnancy in order to ensure safe motherhood. 

Getting pregnant faster after the treatment is still possible. It is advisable to use contraception such as condoms if subsequent pregnancy is undesired.