Have You Heard About An Abnormal Pregnancy?

HYDATIFORM MOLE

Hydatiform mole is an abnormal pregnancy that is characterized by vesicular swelling of placenta villi, filling and distending the uterus and usually with absence of an intact fetus. It is a benign form of a spectrum of neoplasm that affects the trophoblastic tissues. They arise from fetal tissue within the maternal host and are composed of both syncytiotrophoblastic and cytotrophoblastic cells.

The incidence of hydatiform mole varies throughout the world and is affected by factors such as rate of contraceptive use, sterilization rates and abortion rates. It is generally known to be higher in the Far East and tropical developing countries than in Europe and America. Incidence of 0.6 – 1.1/1000, 2 – 10/1000 and 0.8 – 4.88/1000 pregnancies have been reported in Europe, Asia and West Africa respectively.



Hydatiform mole could be complete or partial mole. The complete mole is characterized by absent fetus and it results from fertilization of an empty ovum by a haploid (23, X) sperm that totally replaces the maternal contribution and reaches 46XX status by its own duplication. Occasionally 46XY karyotype occurs as a result of dispermic fertilization of the empty egg. Partial mole is associated with an identifiable abnormal fetus, fetal membranes or red blood cells. They have triploid karyotype, usually 69 XXY with the extra haploid set of chromosome derived from the father. Diploid and tetraploid partial moles have been described.

The aetiology of this condition is unknown but factors associated with it include younger age (< 16yrs), older age (>40yrs), low socioeconomic status and dietary deficiency in protein, folic acid and carotene. Clinical presentation include vaginal bleeding associated with passage of vesicles following a period of amenorrhea; exaggerated pregnancy symptoms of nausea and vomiting; early onset of pre-eclampsia; signs of hyperthyroidism; disseminated intravascular coagulopathy and a uterine size larger than date with a doughy feel.

The diagnosis of molar pregnancy is made based on the clinical findings, backed up by the ultrasound findings and hCG estimation. Ultrasound is an effective diagnostic aid. It demonstrate a snowstorm appearance. It is also useful in demonstrating ovarian enlargement as well as excluding other differentials such as threatened abortion and multiple pregnancies. Estimation of B-hCG is central to the diagnosis, treatment as well as follow-up of patients with hydatiform. Other investigations necessary in managing a patient with molar pregnancy include complete blood count, coagulation profile, electrolyte status, grouping and cross matching of blood, chest x ray and thyroid function test.
The ultimate means of diagnosing gestational trophoblastic disease is by histological examination. It is therefore important to subject miscarriage to histological assessment in order to exclude trophoblastic neoplasia.

Treatment in hydatiform mole is aimed at completely evacuating the trophoblastic tissue from the uterine cavity. This can be accomplished in cases of complete mole by the use of suction catheter of upt o a maximum of 12mm independent of uterine size. This procedure is usually done under oxytocin infusion and followed by sharp gentle curettage. The oxytocin infusion is to ensure contractility of the uterus so as to reduce the risk of perforation, reduce haemorrhage and to reduce the risk of tissue embolization. It is however recommended that oxytocic infusion should be commenced only when evacuation has been completed or almost completed, except in situation of significant haemorrhage prior to evacuation, as embolization ans dissemination of trophoblastic tissue through the venous system may occur in situation of increased contractility as seen during the use of oxytocin during evacuation. Hysterectomy may be an option for women who have completed childbearing.

Trophoblastic malignancy occurs in 15-20% of women with complete mole. Patients should therefore be followed up with quantitative determination of hCG levels in the serum or urine.



Contraception during the period of follow-up is also essential because pregnancy at such time would cause confusion in the hCG monitoring. Oral contraceptive pills have been shown by several studies to be effective once the hCG level have normalized. However, like IUCD, oral contraceptive pills may cause abnormal bleeding and mimic the symptoms of the disease. Barrier method is also an option as it has no effect on hormonal system in the body, neither does it cause any form of abnormal bleeding.