Nutcracker syndrome in pregnancy: A tough nut to crack?


  • DOI: 10.1111/j.1479-828X.2007.00813.x

: Dr Ruchi Singh, Department of Obstetrics and Gynaecology, Peninsula Health, PO Box 52, Frankston, Vic. 3199, Australia. Email:


The nutcracker syndrome is a rare but possibly underestimated condition and is seldom suspected in a pregnant patient. It results when the left renal vein is compressed between the aorta and the superior mesenteric artery.

Case report

A 33-year-old Caucasian woman booked in our maternity unit in her second pregnancy. The persistence of vulval varicosities beyond the postnatal period of her previous pregnancy prompted further investigations and multidisciplinary input to arrive at a diagnosis of nutcracker syndrome. The workup involved a computed tomography (CT) and ovarian venography which suggested left ovarian varicosity (> 5 mm) and tortuosity prominent below the left renal vein. Collateral veins from the left ovarian vein were passing laterally and communicating with the external iliac vein passing around the lateral aspect of the mid and lower part of the left kidney. The patient was well antenatally in current pregnancy with multidisciplinary care. Her vulval varicosities were more pronounced from the second trimester of her pregnancy. At 33 weeks a duplex transabdominal ultrasound was suggestive of a significant layer of congested veins lateral to the uterus. The fetal growth was satisfactory throughout and regular midstream urine samples every trimester revealed no haematuria or proteinuria.

Persistent breech presentation at term prompted an elective Caesarean section. A repeat ultrasound prior to the operation did not reveal excessive varicosities over the lower segment hence we performed a Pfannenstiel incision. On opening, the lower segment appeared normal and a transverse incision on the lower segment was taken, avoiding the distended vessels on the left (Fig. 1). The total blood loss was estimated to be about 500 mL. Venous dilatation of left sided pelvic veins consistent with the nutcracker syndrome noted. Recovery was uneventful.

Figure 1.

The distended left ovarian vessels seen intraoperatively.


The nutcracker syndrome is a rare vascular abnormality and the term was first used by Grant1 in anatomical description ‘the left renal vein as it lies between the aorta and the superior mesenteric artery resembles a nut between the jaws of a nutcracker’ and was later used to describe a pathological condition by De Schepper.2 Scanty data exist on pregnancy coexistent with this syndrome; however, a case report described aggravation of the syndrome with pregnancy.3

In the nutcracker syndrome, obstruction of left renal vein outflow causes venous hypertension (> 3 mmHg) with the formation of intra- and extrarenal collaterals with development of gonadal vein reflux. It typically presents with haematuria,4 pelvic congestion syndrome or vulvar varicosities.5 In pregnancy the physiological changes might cause a widening of the diameter of the aorta resulting in compression of the left renal vein and the woman becomes symptomatic.3,6

Now with magnetic resonance imaging, CT and the colour Doppler ultrasound, the diagnosis of the vascular abnormality is possible with non-invasive techniques.7

Our patient had a compensatory condition with no haematuria/proteinuria, and the urologist involved favoured conservative management. Surgical intervention was not required but stenting, embolisation of vessels, vascular transpositions and renal auto transplantation should be considered carefully depending on the clinical presentation.8

As the condition is otherwise benign the prognosis is usually good.


Vulval varicosities seen commonly in pregnancy may be a result of nutcracker syndrome.