OBSTETRIC PATHOLOGY Pre-eclamptic toxemia

Pre-eclamptic toxemia syndrome comprises raised blood pressure, proteinuria and peripheral

edema, occurring in about 10% of all pregnant women. Seen particularly in association with multiple pregnancies, primigravidae and women over the age of 35 years, it is a syndrome characterized by increased blood pressure, proteinuria and peripheral edema. Most cases are mild, with the blood pressure under 100 mmHg diastolic and no proteinuria; in severe cases the diastolic pressure is consistently above 100 mmHg, and there is proteinuria and severe peripheral edema. The pre-eclamptic syndrome has hazards for both mother and fetus, but maternal problems are rare, being largely confined to severe pre-eclampsia, which may progress into full-blown eclampsia (see below). A feature of pre-eclampsia is reduced placental blood flow; this may lead to fetal hypoxia in late pregnancy, particularly during labour, with increased risk of perinatal mortality. The fetus may also suffer intrauterine growth retardation and have low birth weight. Pre-eclampsia is predisposed by maternal factors of parity, diabetes and hypertension. First pregnancy carries most risk. A main factor in development is failure of conversion of narrow spiral arteries to low-resistance vascular sinuses in the placenta. Placental ischemia results in poor fetal growth and liberation of substances which cause vasoconstriction and promote hypertension. In the kidney, endothelial cells become swollen, with deposition of fibrin in glomeruli, leading to proteinuria. If untreated, severe hypertension and intravascular

coagulation occur with development of cerebral ischemia and fits.

Eclampsia

Eclampsia is now a rare complication of pregnancy. Rarely, a small proportion of patients with severe pre-eclampsia develop eclampsia. Patients develop severe systemic disturbance, experiencing frontal headaches, rapid and sustained rise in blood pressure, shock, anuria and fits.

Complications and causes of death: patients develop disseminated intravascular coagulation, with widespread occlusion of blood vessels, fibrinoid necrosis of vessel walls, and, in fatal cases, widespread microinfarcts in brain, liver, kidney and other organs.

Ectopic pregnancy

Ectopic pregnancy is the term applied to implantation of the fetus in any site other than normal ferine location. The most common site is within the tubes (approximately 90%). The other sites are the ovary, the abdominal cavity, and the intrauterine portion of the fallopian tube (cornual pregnancy). Ectopic pregnancies occur about once in very 150 pregnancies. The most important predisposing condition in 35% to 50% of patients is chronic salpingitis. Other factors are peritubal adhesions owing

to appendicitis or endometriosis, leiomyomas, and previous surgery. Ovarian pregnancy is presumed to result from the rare fertilization and trapping of the ovum within the follicle just at the time of its rupture. Abdominal pregnancies may develop when the fertilized ovum drops out of the fimbriated end of the tube. In all these abnormal locations, the fertilized ovum undergoes its usual development with the formation of placental tissue, amniotic sac, and fetus, and the host implantation site develops decidual changes.

Morphology. In tubal pregnancy, the placenta is poorly attached to the wall of the tube. Intratubal hemorrhage may thus occur from partial placental separation without tubal rupture. Tubal pregnancy is the most common cause of hematosalpinx and should always be suspected when a tubal hematoma is present. More often, the placental tissue invades the tubal wall and causes tubal rupture and intraperitoneal hemorrhage. Less commonly, the tubal pregnancy may undergo spontaneous regression and resorption of the entire gestation. Still less commonly, the tubal pregnancy is extruded through the fimbriated end into the abdominal cavity (tubal abortion).

Many tubal ectopic pregnancies present as an acute abdominal emergency, with severe lower abdominal pain that is usually localized to the side of the ectopic pregnancy; however, some tubal ectopic rupture, leading to bleeding into the peritoneal cavity,

in which case the pain is less well localized. Rupture usually occurs in the early stages of pregnancy, and the patient may not be aware that she is pregnant; occasionally, ectopic pregnancies do not cause early hemorrhage and may be sustained for some weeks, during which the endometrium develops decidual changes.