postpartum pituitary necrosis , or sheehan 's syndrome , is a relatively familiar condition to obstetricians and is known to be related to massive bleeding during or after delivery ( 1 ) . the specific mechanism of pituitary necrosis is unclear , and it is generally accepted that hypotension incurs pituitary ischemia leading to necrosis ( 2 ) . however , antepartum pituitary necrosis which is unrelated to massive intra or postpartum hemorrhage , is a very rare condition in pregnancy and has only been reported in patients with long standing type i diabetes mellitus ( dm ) ( 3 ) . in this case report we present for the first time antepartum pituitary necrosis that complicated a pregnant patient with uncontrolled gestational diabetes mellitus ( gdm ) . a 32-yr - old multipara with gdm was referred at 33 weeks and 2 days of her second pregnancy from a private clinic to the emergency room of our institute and presented with severe headache , blurred vision , dizziness , and vomiting for 2 days . her first pregnancy was uneventful and she delivered by cesarean section due to failure to progress . the referral note indicated that all antenatal screening tests , including the initial serum glucose level performed in the first trimester to the present pregnancy , were within normal range . however , at 25 weeks and 5 days , she was diagnosed with gdm based on 1-hr 50-g glucose tolerance test , the result of which was 240 mg / dl . since then , she was instructed to control blood glucose level by diet modification only . two days prior to admission , severe headache , blurred vision , dizziness , and vomiting suddenly developed , and she went to a private clinic where she was admitted for conservative care . she was informed that her blood glucose levels ranged from 140 to 200 mg / dl and that she had polyhydramnios . due to persistent vomiting and poor intake for 2 days , she was transferred to our emergency room for further diagnosis and care . on physical examination , the patient was acute - ill looking with alert mental status . blood pressure was 120/85 mmhg ; pulse rate , 95 bpm ; body temperature , 36.8 and respiratory rate , 20 times / min . hematology lab results were normal and high sensitivity c - reactive protein ( crp ) was increased to 15.1 mg / dl ( 0 - 3.0 ) . l ( normal , 135 - 145 mm / l ) , serum electrolyte levels were normal . increased serum fasting glucose level of 164 mg / dl ( normal , 70 - 110 mg / dl ) was accompanied by hba1c level of 7.7% suggesting poorly controlled diabetes . random urine test results denoted increased specific gravity with ketone secretion and glucose and protein were absent . arterial blood gas analysis showed a normal ph , however , the anion gap increased to 19 mm / l . fetal sonogram showed a structurally normal fetus large for gestational age accompanied by polyhydramnios ( amniotic fluid index=32.4 cm ) . due to her presenting symptoms , brain magnetic resonance ( mr ) imaging was scheduled to rule out intracranial pathology . however , tococardiogram performed prior to brain mr imaging demonstrated persistent severe variable decelerations ( fig . a female baby weighing 2,570 g was delivered at 1 min and 5 min with an apgar score of 2 and 6 , respectively . during surgery , maternal vital signs about 9 hr after surgery , brain mr imaging was performed because her symptoms persisted . the scan revealed an enlarged anterior pituitary gland with no area of enhancement in the center of the pituitary gland after contrast administration , suggesting pituitary necrosis ( fig . the synacthen test result was normal and other pituitary hormones were within normal range ( adrenocorticotrophic hormone [ acth ] 16.1 pg / ml [ 10 - 60 ] , growth hormone [ gh ] 0.8 ng / ml [ 0 - 9.5 ] , prolactin 24.3 ng / ml [ 0 - 15 ] , thyroid - stimulating hormone [ tsh ] 0.75 iu / ml [ 0.35 - 5.50 ] , free thyroxine [ ft4 ] 0.99 ng / dl [ 0.89 - 1.76 ] , luteinizing hormone [ lh ] 0.78 miu / ml , and folliclestimulating hormone [ fsh ] 0.31 miu / ml ) on pituitary function investigation . postoperatively , elevated blood sugar was controlled with regular insulin for 2 days , and her initial presenting symptoms resolved over few days . she was discharged without medication after a week of uneventful postoperative recovery . at 2 months follow up , although serum glucose level and pituitary function test results were unremarkable , follow - up brain mr imaging depicted progressive shrinkage of the pituitary gland ; she failed to lactate and was amenorrheic ( fig . the pituitary gland , especially the anterior lobe normally , enlarges and the blood supply requirement increases during pregnancy ( 4 ) . when diabetic vasculopathy and hypercoagulability superimposes the aforementioned physiologic change , the pituitary gland becomes more prone to ischemia and necrosis ( 5 ) . this is the suggested pathophysiological explanation of pituitary necrosis that occurs in diabetic pregnancy . to date , reports of antepartum pituitary necrosis associated with dm are rare . based on the 8 cases described so far ( 4 , 6 - 10 ) , all pregnant patients associated with this condition had preexisting insulin - dependent dm duration that ranged from 1 to 25 yr . most frequently , antepartum pituitary necrosis occurred in the third trimester , where common symptoms and signs to incur suspicion of pituitary necrosis were intractable headache and the houssay phenomenon ( frequent episodes of hypoglycemia caused by gh or acth deficiency , resulting in a sudden decrease in insulin requirement ) ( 7 ) . our case is distinguished from previous cases in that the patient had uncontrolled gdm , not pre - existing insulin - dependent dm . nonetheless , gestational age at diagnosis and presenting symptoms were similar to previous dm cases . the houssay phenomenon was not observed in the present case , and this may be ascribed to the normal acth and gh levels . based on the present observation , we speculated that the mechanism of pituitary necrosis complicating type i dm might equally apply to gdm . reported that inflammation indicated by elevated crp together with hyperglycemia indicated by increased hba1c was associated with increased risk for microvascular lesions in the brain and stroke ( 11 ) . similarly , previous studies demonstrated an increase in cerebrovascular ischemia when crp elevation and insulin resistance coexisted ( 11 - 13 ) . our patient also had increased serum crp level and uncontrolled hyperglycemia indicated by elevated hba1c , polyhydramnios , and macrosomia , and furthermore had gdm , which is known to be caused by insulin intolerance . thus , coexistence of these risk factors may have increased the risk and caused microvasculopathy and necrosis to occur in the pituitary gland in this patient . some may argue that pituitary necrosis observed in the present case may not have existed due to intrapartum hemorrhage but rather developed at postpartum by a combination of vascular disease and abnormalities in coagulation . however , we would like to refute this by highlighting the fact that the central nervous system - related symptoms such as headache and vomiting that developed a few days prior to delivery and the time interval between surgery and mr imaging was only about 9 hr . we did not encounter heavy bleeding or hypotension during surgery or postpartum , and the patient did not require transfusion because postpartum hemoglobin level was 10.4 g / dl . in the present case , pituitary function on serum hormone levels was not compromised initially or at 2-month follow up . nonetheless , postpartum lactation failure and amenorrhea together with a shrunken pituitary gland detected on follow - up mr imaging strongly suggest pending hypopituitarism . the clinical feature of the present case demonstrated that pituitary gland necrosis may be complicated with not only type i dm but also gdm pregnancy when glucose levels are uncontrolled . this should alert obstetricians to include antepartum pituitary necrosis in the differential diagnosis in uncontrolled gdm patients presenting with intractable headache , blurred vision , and vomiting .
antepartum pituitary necrosis is a rare medical condition that has only been reported in pregnant women with type i diabetes attributable to diabetes - related vasculopathy and hypercoagulability . 
 we present for the first time a case of antepartum pituitary necrosis occurring in an uncontrolled gestational diabetes mellitus ( gdm ) patient . 
 the patient was a 32-yr - old woman at 33 weeks and 2 days of gestation . 
 she suffered from severe headache , blurred vision , dizziness , and vomiting . 
 her baby was delivered by cesarean section . 
 the brain magnetic resonance images revealed pituitary necrosis . 
 this suggests that pituitary gland necrosis may also complicate gdm pregnancy when glucose levels are uncontrolled .