During normal pregnancy, the maximum of urinary protein excretion ranges from 200–300 mg per day. Nephrotic syndrome in pregnancy is very rare.¹ The most common cause is preeclampsia associated with preeclamptic nephropathy. Preeclampsia may have a relation to the molar pregnancy. Twelve percent of molar pregnancies are associated with preeclampsia.² We report a case of nephrotic syndrome associated with complete type of hydatiform mole.

In this young patient with generalized edema, history of hydatiform mole and high βhCG, treatment with chemotherapy was started. There was no evidence of recurrence or metastasis of mole and she remained in complete remission of nephrotic syndrome after chemotherapy. Nephrotic syndrome occurs in 0.012–0.025% of all pregnancies.³ The usual causes are preeclampsia, glomerulonephritis, diabetes, renal vein thrombosis, amyloidosis and hereditary nephritis. Occasionally it is necessary to treat the nephrotic syndrome with steroids. There is no proper response to steroids which can aggravate the problems related to nephrotic syndrome. Thus, it is important to know about histology before starting treatment.² Urinary protein excretion 200–300 mg per day is normal during pregnancy.⁴ Preeclamptic nephropathy is about 80% in nephrotic syndrome during pregnancy. Other cases occur because of membranous nephropathy, focal glumerulosclerosis, minimal change nephropathy, diabetic nephropathy, systemic lupus erythematosus and other renal diseases.⁴ The renal pathologic feature in preeclamptic nephropathy is bloodless glomerular enlargement and the narrowing the capillary lumen due to swelling of the endothelial, mesential and epithelial cells with an expansion of the mesential matrix. The glomerular capillary walls may be thickened but hypercellular change rarely occurs.^5–9 Akhtars case was a preeclamptic nephropathy associated with a partial mole with a coexistent fetus.³ In the Cohen's case they did not performed renal biopsy but the nephritic syndrome was clinically related to a preeclamptic nephropathy. In this case, the hydatiform mole was incomplete type coexisting fetal tissue.¹⁰ Komatsuda reported an older patient revealed a membrano proliferative like lesion by renal biopsy. His case was a nephrotic syndrome associated with a complete type of hydatiform mole.¹¹ Prior to this report, there was a similar case reported in Korean journal.¹² Han reported a 54-year old patient with membrano proliferative glumeronephritis associated with a complete type of hydatiform mole that patient remained renal symptom free for 2 year after the removal of the tumor.⁵ In our case, the hydatiform mole was a complete type and renal biopsy was not performed. The precise relationship between the hyditiform mole and nephrotic syndrome is not clear, because the reported cases were extremely rare. The production of immune complexes and the activation of intravascular coagulation by the hydatiform mole are the supposed pathogenic mechanism.³ These several interesting cases linking the pathogenesis of the glomerulonephritis directly to the gestational trophoblastic disease provide a challenge for future research.

The hydatiform mole might be a cause of the nephrotic syndrome in some cases. Precise follow-up after molar pregnancy may help the specialists for early reorganization of rare situations.

thanks to the staff of Imam Khomaini hospital for their co-operation for gathering information of this case.