gitelman syndrome ( gs ) is a rare autosomal - recessive inherited disorder with 99% penetrance caused by inactivating mutations in the slc12a3 gene , localized on the 16q13 chromosome . this genetic defect impairs the function of the thiazide - sensitive sodium - chloride cotransporter in the distal convoluted renal tubule . gs is the hypocalciuric , hypomagnesemic variant of bartter syndrome , which was first described in 1966 . , we describe the management and pregnancy course of a 27-year - old patient with gs . we report the course of a pregnancy in a 27-year - old woman previously diagnosed with gs . her pregnancy was uneventful and she remained asymptomatic despite persistent hypokalemia . potassium levels were followed at a regular basis and ranged between 2.3 and 3.1 mmol / l ( 2.3 and 3.1 meq / l ) . she was electively admitted to hospital at 39 weeks of gestational age for full - term induction of labor . the patient received 240 meq of intravenous potassium chloride and 180 meq per oral , as well as 4 g of intravenous magnesium sulfate and 1200 meq of oral magnesium oxide . she was continued on 150 mg daily of eplerenone . despite aggressive electrolyte replacement , her potassium and magnesium levels ranged between 2.0 and 3.0 meq / l ) and 1.1 and 2.6 mmol / l ( 1.1 and 2.6 meq / l ) , respectively . the baby was born healthy with 2863 g , and apgar measurements were 8 and 9 at 1 and 5 min , respectively . first described in 1966 by gitelman et al . , gs is a rare autosomal - recessive condition characterized by hypokalemia , metabolic alkalosis and hypomagnesemia . it has since been shown to result from a mutation in the slc12a3 gene on chromosome 16 leading to a loss of function mutation in the sodium - chloride cotransporter in the distal convoluted tubule . this leads to potassium and magnesium wasting into the cortical collecting duct as the increase in delivered sodium is reabsorbed through the epithelial sodium channel . despite being normotensive aldosterone axis . to date , 24 pregnancies in 18 women with gs have been described in the literature [ 315 ] . twenty of the pregnancies had no reported fetal complication ( table 1 ) , six pregnancies were complicated by oligohydramnios [ 5 , 8 , 9 , 12 , 13 ] and one was complicated by intrauterine growth retardation . kaliuresis does not typically ensue presumably due to the antimineralocorticoid effects of progesterone demonstrated by ehrlich and lindheimer in 1972 . de haan et al . have suggested that this protective mechanism may be impaired in gs patients thus resulting in an exacerbation of potassium and magnesium losses . the increase in the requirement for oral potassium during pregnancy has been documented by several authors including talaulikar et al . in 2005 who reported a 6-fold increase in potassium and magnesium requirements in their patient . mmol / l ( 3.64.0 meq / l ) range [ 10 , 14 ] . it has been suggested that normalization of potassium and magnesium levels is not required for a good obstetric and neonatal outcome . worsening of the symptoms of gs such as fatigue , cramping , tetany and dizziness has been described in the gs pregnancies [ 7 , 12 , 13 ] . the symptoms may be exacerbated by hyperemesis and fetal demand for potassium [ 9 , 12 ] . worsening of symptoms is cited as a reason for the modification of therapy [ 3 , 4 , 611 , 13 ] . our patient did not exhibit symptoms during her pregnancy , and we felt that intravenous potassium loading would be inefficient and unnecessary in the absence of symptoms . beyond the use of supplemental cations , the management of patients with gs has included the use of potassium - sparing diuretics . the us food and drug administration has deemed spironolactone a category c drug in pregnancy . this is consistent with the findings of mascetti et al . who describe a series of spironolactone - exposed children born to a group of mothers with bartter syndrome , another potassium - wasting nephropathy . the use of amiloride and eplerenone , both class b drugs in pregnancy , has been previously documented in gs [ 4 , 9 , 14 , 15 ] . in contrast to bartter syndrome , the use of non - steroidal anti - inflammatory drugs ( nsaids ) to inhibit prostaglandin synthase is theoretically of no benefit as gs is not a hyperprostaglandinemic state . angiotensin - converting enzyme inhibitors are contraindicated in pregnancy due to teratogenic effects as well as impaired fetal growth . there has been a concern over the potential for a ventricular tachyarrhythmia during pregnancy and childbirth due to hypokalemia . fortunately , no such complication has been observed in any of the documented gs pregnancies . the extensive work of calo et al . in this area suggests however that the upregulation of the nitric oxide system and vasodilation seen in gs may limit the physiologic response to increased myocardial demand [ 19 , 20 ] . it is also suggested in subsequent work that increased angiotensin 17 levels seen in gs may be antiarrhythmic at low levels and proarrhythmic at very high levels . the small number of documented gs pregnancies precludes any rigorously studied recommendations for management in the peripartum period . the anesthesia literature describes a risk of complications in gs patients in the perioperative setting . these include electrocardiographic changes as well as vasodilation , electrolyte imbalance and alkalemia complicating the ventilatory management of the patient . given the expected physiologic demands of labor and delivery , it appears that an elective , multidisciplinary approach to the delivery of the child is most prudent . baseline electrocardiography should be obtained as up to 50% of patients with gs have qt interval prolongation . frequent monitoring of electrolytes is advisable as is blood pressure monitoring given the propensity of gs patients have vasodilation . the postpartum period is associated with natriuresis ; however , this would not explain a drop in potassium during active labor . it may be , however , that the drop in serum potassium observed here is related to a shift in potassium from the extracellular to intracellular space as could be seen in any patient and is not unique to gs . in our patient pretreatment with a thiazide diuretic was associated with a more significant drop in serum potassium during epinephrine loading than that seen in the control group receiving epinephrine alone . as gs mimics the effects of thiazide diuretics , one could assume a similar effect in these patients . table 1.summary with the cases of gitelman syndrome during pregnancyauthorage at diagnosis ( years)diagnosismaternal age ( years)number of patientsnumber of pregnanciessymptomsjones jm et al . 17before pregnancy1 ) 24131st- asymptomatic except for tiredness in 3rd trimester2 ) 252nd- asymptomatic3 ) 273rd- asymptomatictalaulikar gs et al . 20before pregnancy1 ) 22121 ) increasing tiredness , muscle cramps . required 3 hospitalizationskwan et al . 2 ) n / abefore pregnancy1 ) 24211st- symptomatic , not specified2 ) 272nd- muscle weakness , fatiguede arriba g et al . 201st trimester ( 10 weeks)2011tiredness , muscle weakness , decreased muscle strength and tenderness bilaterally in lower extremitiesmccarthy fp et al . n / an / a1 ) 27561 , 2 , 3 , 4 ) uneventful 5 ) tiredness and tetanic seizures2 ) 323 ) 284 ) 335 ) 33/35calo la et al . meq / l1.3 meq / lk and mg supplementationoligohydramniosinduced vaginal deliveryhealthy female infant , 2410 g36 weeksn / an / ak and mg supplementation1 , 2 and 3 ) none1st- spontaneous labor1st- healthy male infant . 2620 g1st-35 weeks1st- k range = 2.32.8 mmol / l1st- mg range = 0.530.58 mmol / l1st- k and mg supplementation2nd- spontaneous labor2nd- healthy female infant , 2910 g2nd- 38 weeks2nd- maximum level = 3.1 mmol / l2nd- maximum level = 0.56 mmol / l2nd- k and mg supplementation3rd - spontaneous labor3- healthy female infant . n / a3rd- n / a3rd - n / a1 ) nonenormal deliveryhealthy infant1 ) n / ak range = 2.33.4 mmol / l1 and 2)n / a1 and 2 ) k and mg supplementation2 ) gestational diabeteselective c - sectionn / a2 ) 39 weeksn / anoneuncomplicated vaginal delivery , induced for post - term pregnancyhealthy female infant , 3250 g41 weeks and 4 daysn / an / ak and mg supplementation1st - oligohydramnios , partial placenta previa , intrauterine growth restriction.1st- primary c - section , healthy infanthealthy female infant , 3970 g1 and 2 ) 38 weeksn / an / ak and mg supplementation . healthy infanthealthy male infant , 3845 goligohydramniosprogrammed c - section , w / o complicationshealthy infant , 3000 gn / a2.42.8 meq / ln / ak and mg supplementation , spironolactone.oligohydramnioselective c - section ( breech presentation)healthy female baby , 3350 g273maximum level = 3.0 mmol / lmaximum level = 0.68 mmol / lk and mg supplementationoligohydramniosinduced c - section ( failure to progress in the first stage)healthy female baby , 2940 g266k range = 2.63.3 mmol / lmg range = 0.470.66 mmol / lk and mg supplementation , amiloride . supplementation of k and mgfetal macrosomia ( patient had gestational diabetes)induced c - sectionhealthy male baby , 3080 gn / an / an / ak and mg supplementation , amiloride ( 1st trimester ) . supplementation of k and mg.nonevaginal deliveryhealthy female baby , 3630 g2732.62.9 mmol / ln / aepleronone1 , 2 , 3 , 4 and 5 ) nonen / ahealthy male baby . 4080 g40 weeksn / an / ak and mg homeopathy k , amiloride k , mg none ( 1st pregnancy ) / k ( 2nd pregnacy)healthy female baby , 3380 g38 weekshealthy female baby , 2420 g37 weekshealthy male baby . 2810 g41 weekshealthy male baby , 2830 g / healthy male baby , 2640 g38 weeks/36 weeks1 and 2 ) nonen / ahealthy female baby 2900 gat termn / an / a1 and 2 ) k and mg supplementationhealthy female baby 3125 g / healthy female baby 3400 gat term / at term summary with the cases of gitelman syndrome during pregnancy in conclusion , the experience of clinicians treating pregnant women with gs is limited but is also being described with more frequency . there is no evidence of significant risk to the fetus but maternal symptoms may worsen during the pregnancy . the management of gs should be focused on the replacement of potassium and magnesium though routine intravenous supplementation and should be reserved for cases of worsened symptoms . cautious use of adjunctive treatment with potassium - sparing agents should be considered as the potassium requirement may increase significantly during pregnancy . in addition to gs - related potassium and magnesium loss , hypokalemia can be exacerbated by cellular shift as well as extrarenal losses of cations which can affect any patient . no consensus recommendations exist for the perinatal management of the pregnant gs patient but an elective delivery in a setting with appropriate cardiac monitoring and central venous access is prudent as potassium and magnesium aberrations during active labor may be seen .