Hyperemesis gravidarum and nonspecific abnormal EEG findings: a preliminary report

To evaluate central nervous system abnormalities in a group of otherwise healthy pregnant women with hyperemesis gravidarum (HG) during the first trimester.

In a case-control study, 17 pregnant women with HG during the first trimester (study group) were compared with 18 pregnant women without nausea and vomiting in pregnancy (NVP). The latter group included women who were planning first-trimester termination of pregnancy for reasons other than health (control group). All the pregnant women enrolled in the study answered a questionnaire and underwent a physical examination, blood tests, urinalysis, EEG, and visual evoked potential (VEP) and brainstem auditory evoked response (BAER) tests.

An abnormal EEG was found in 5 of the 17 women in the study group (29.4%), whereas none of the 18 women in the control group had an abnormal EEG (p = 0.013). The VEP and BAER tests were normal among the women in both groups. There were no clinically significant differences between the 2 groups with regard to maternal age, gravidity, parity, weeks of gestational age, blood count, renal function, liver function or electrolytes. Low thyroid stimulating hormone levels were found in 6 of the 17 women in the study group (35.3%) as compared to 1 of the 18 in the control group (5.5%) (p = 0.028). None of the women in either group had hyperthyroidism. HG in previous pregnancies was a significant risk factor for HG in the present pregnancy.

In pregnant women with HG during the first trimester, the frequency of abnormal EEG findings is significantly higher as compared to that in pregnant women without NVP. However, the mechanism and implications of these findings are yet to be clarified.