In addition to these evidence-based recommendations, the guideline development group also identifies points of best clinical practice in the original guideline document.
Levels of evidence (Ia-IV) and grading of recommendations (A-C) are defined at the end of the "Major Recommendations" field.
Diagnosis of Gestational Trophoblastic Neoplasia
C - Early complete molar pregnancies are commonly associated with the ultrasound diagnosis of delayed miscarriage or anembryonic pregnancy. Complete moles may be associated with suggestive ultrasonographic changes in the placenta. However, ultrasound has limited value in detecting partial molar pregnancies. In twin pregnancies with a viable fetus and a molar pregnancy, the pregnancy should be allowed to proceed.
The ultrasound features of a complete mole are reliable but the ultrasound diagnosis of a partial molar pregnancy is more complex. The finding of multiple soft markers, including both cystic spaces in the placenta and a ratio of transverse to anterior-posterior dimension of the gestation sac of greater than 1.5 is required for the reliable diagnosis of a partial molar pregnancy. Estimation of human chorionic gonadotrophin (hCG) levels may be of value in diagnosing molar pregnancies. When there is diagnostic doubt about the possibility of a combined molar pregnancy with a viable fetus, then ultrasound examination should be repeated before intervention. In the situation of a twin pregnancy, where there is one viable fetus and the other pregnancy is molar, the pregnancy should be allowed to proceed if the mother wishes, following appropriate counselling. [Evidence level III]
Evacuation of Molar Pregnancies
C - Surgical evacuation of molar pregnancies is advisable. Routine repeat evacuation after the diagnosis of a molar pregnancy is not warranted.
Suction curettage is the method of choice of evacuation for complete molar pregnancies. Because of the lack of fetal parts, a suction catheter, up to a maximum of 12 mm, is usually sufficient to evacuate all complete molar pregnancies. Medical termination of complete molar pregnancies, including cervical preparation prior to suction evacuation, should be avoided where possible. There is theoretical concern over the routine use of potent oxytocic agents because of the potential to embolise and disseminate trophoblastic tissue through the venous system. This is known to occur in normal pregnancy, especially when uterine activity is increased (e.g., with accidental haemorrhage). The contraction of the myometrium may force tissue into the venous spaces at the site of the placental bed. The dissemination of this tissue may lead to the profound deterioration in the woman, with embolic and metastatic disease occurring in the lung. [Evidence level III/IV]
While it is recognised that significant haemorrhage may occur as a consequence of evacuating a large uterine cavity, it is recommended, where possible, that oxytocic infusions are only commenced once evacuation has been completed. If the woman is experiencing significant haemorrhage prior to evacuation and some degree of control is required, then use of these agents will be necessary according to the clinical condition. Oxytocic infusions have been in common use for this purpose. It is suggested that prostaglandin analogues should be reserved for cases where oxytocin is ineffective. Because evacuation of a large molar pregnancy is a rare event, advice and help from an experienced colleague should be sought where appropriate. In partial molar pregnancies where the size of the fetal parts deters the use of suction curettage, medical termination can be used. These women may be at an increased risk of requiring treatment for persistent trophoblastic neoplasia, although the proportion of women with partial molar pregnancies needing chemotherapy is low (0.5%).[Evidence level III/IV]
Data from the management of molar pregnancies with mifepristone are limited. Evacuation of complete molar pregnancies with this agent should be avoided at present since it increases the sensitivity of the uterus to prostaglandins. [Evidence level III/IV]
Histological Examination of Products of Conception
C - All products of conception obtained after evacuation (medical or surgical) should undergo histological examination. Products of conception from therapeutic terminations of pregnancy should be examined if there is no evidence of fetal tissue.
In view of the difficulty in making a diagnosis of a molar pregnancy before evacuation, the histological assessment of material obtained from the medical or surgical management of incomplete miscarriage is recommended in order to exclude trophoblastic neoplasia. Ploidy status may help in distinguishing partial from complete moles. Because persistent trophoblastic neoplasia may develop after any pregnancy, it is recommended that all products of conception obtained after repeat evacuation should undergo histological examination. [Evidence level IV]
The Management of Women with Gynaecological Symptoms After Evacuation of a Molar Pregnancy
C - In cases where there are persisting symptoms, such as vaginal bleeding, after initial evacuation, consultation with the screening centre should be sought before surgical intervention.
There is no clinical indication for the routine use of a second uterine evacuation in the management of molar pregnancies. Uterine evacuation may be recommended, in selected cases, by the screening centre as part of the management of persistent trophoblastic neoplasia. [Evidence level IV]
Persistent Gestational Trophoblastic Neoplasia (GTN) after a Nonmolar Pregnancy
C - Women with persistent abnormal vaginal bleeding after a nonmolar pregnancy should undergo a pregnancy test to exclude persistent GTN. Persistent GTN should be considered in any woman developing acute respiratory or neurological symptoms after any pregnancy.
The prognosis for women with GTN after nonmolar pregnancies may be worse (21% mortality after a live birth, 6% after a nonmolar miscarriage) and in part due to the delay in diagnosis (0.5-58.0 months). Urgent referral of such cases should occur. [Evidence level III/IV]
Placental Site Trophoblastic Tumour
C - Advice on the management of these rare tumours should be sought from the appropriate registration centre.
Placental site trophoblastic tumour is now recognised as a variant of GTN. Surgery and multi-agent chemotherapy play major roles in the clinical management of this tumour. [Evidence level III]
Future Pregnancy
C - Women should be advised not to conceive until the hCG level has been normal for six months.
After the conclusion of any further pregnancy, at any gestation, further urine or blood samples for hCG estimation are requested to exclude disease recurrence. Women who undergo chemotherapy are advised not to conceive for one year after completion of treatment. [Evidence level III]
Contraception and Hormone Replacement Therapy
C - The combined oral contraceptive pill and hormone replacement therapy are safe to use after hCG levels have reverted to normal.
Definitions:
Grading of Recommendations
Grade A - Requires at least one randomised controlled trial as part of a body of literature of overall good quality and consistency addressing the specific recommendation (evidence levels Ia, Ib)
Grade B - Requires the availability of well-conducted clinical studies but no randomised clinical trials on the topic of recommendations (evidence levels IIa, IIb, III)
Grade C - Requires evidence obtained from expert committee reports or opinions and/or clinical experience of respected authorities. Indicates an absence of directly applicable clinical studies of good quality (evidence level IV)
Levels of Evidence
Ia: Evidence obtained from meta-analysis of randomised controlled trials
Ib: Evidence obtained from at least one randomised controlled trial
IIa: Evidence obtained from at least one well-designed controlled study without randomisation
IIb: Evidence obtained from at least one other type of well-designed quasi-experimental study
III: Evidence obtained from well-designed non-experimental descriptive studies, such as comparative studies, correlation studies, and case studies
IV: Evidence obtained from expert committee reports or opinions and/or clinical experience of respected authorities
