MEDICAL BIOLOGY, HUMAN ANATOMY, PHYSIOLOGY AND PATHOLOGY - Ya.I. Fedoniuk 2010

ANATOMY, PHYSIOLOGY, PATHOLOGY

CHAPTER 9. REPRODUCTIVE PROCESSES

PATHOLOGY OF THE REPRODUCTIVE SYSTEM

ECTOPIC PREGNANCY

A Pregnancy is termed ectopic, or extrauterine, when the fertilized ovum implants outside the uterine cavity, in a Location that lacks a natural passage for childbirth. Ectopic Pregnancy may develop in the fallopian tube, Abdominal cavity, or Ovary; this pathology also includes pregnancies developing within a closed rudimentary uterine horn. Tubal Pregnancy is by far the most common, accounting for 99.5% of cases.

Primary and secondary abdominal pregnancies are also distinguished.

In an ectopic pregnancy, the fertilized ovum implants in a gestational sac (such as the tube, ovary, or abdominal cavity) that is unsuited to support the further Development of the pregnancy. Consequently, ectopic pregnancies typically terminate prematurely, which can lead to life-threatening internal Hemorrhage.

Most commonly, ectopic pregnancies terminate in the early stages (up to 5-6 weeks); it is significantly rarer to diagnose an unruptured, progressive ectopic pregnancy.

As a rule, tubal pregnancy terminates no later than the 5th to 6th week.

Depending on the site of ovum implantation and The Mechanism of termination, two main forms of tubal pregnancy are distinguished: tubal rupture and tubal abortion.

Tubal rupture may occur in the upper semicircle of the tube, resulting in the expulsion of the ovum and significant Hemorrhage into the free peritoneal cavity. When rupture occurs in the lower semicircle of the tube, the ovum and hematoma become localized between the leaves of the broad ligament of the Uterus. In other cases, an ovum implanted in the infundibulum or ampulla of the tube detaches from the tubal wall due to contractions, becomes surrounded by Blood clots, and either undergoes necrosis or is expelled into the abdominal cavity—a process known as tubal abortion.

The outcome of tubal rupture is predominantly unfavorable, leading to embryonic death; much less frequently, if the amnion remains intact and the placental attachments to the tube are undisturbed, the pregnancy may continue to progress.

Abdominal pregnancy is very rare, occurring in 0.4–0.11% of cases. It can be primary or secondary. Primary abdominal pregnancy occurs when the fertilized ovum implants directly within the abdominal cavity (on the Peritoneum, omentum, intestines, Liver, Stomach, or Spleen), while the fallopian tubes, Ovaries, and broad ligaments remain unaltered. Such pregnancies are exceedingly rare and are typically documented as clinical curiosities.

More frequently, abdominal pregnancy is secondary, arising after the termination of a tubal pregnancy. In these cases, the Placenta implants close to the tube—within the broad ligament—and the gestational sac is formed by the amnion, adjacent omentum, and intestinal loops.

The outcome of such a pregnancy is unfavorable: rupture of the gestational sac can occur at any moment, accompanied by massive hemorrhage, which poses a lethal threat to the woman's life.

Ovarian Pregnancy is extremely rare (0.1–0.2% of all cases). It can be true (intrafollicular) or perifollicular. In the first type, the fertilized ovum implants inside a ruptured follicle, whereas In the second, the ovum implants On the surface of the follicle. As a rule, ovarian pregnancy terminates in the early stages.