In a small study of 13 pregnant women with IIH, most remained stable without developing disc edema from pre- to post-pregnancy despite having gained weight, which is a known risk factor for papilledema in IIH. Photo: Mark Dunbar, OD. Click image to enlarge.

While research has shown that weight gain is likely a risk factor for recurrent papilledema in idiopathic intracranial hypertension (IIH), this may not apply to pregnancy-related weight gain, as suggested by the findings of a recent small study. When the researchers examined the clinical data of 13 pregnant women with IIH, they noted that the risk presented by weight gain was not as significant as it is in non-IIH patients. Rather, the cohort demonstrated a high rate of stable or even decreased disc edema despite medication discontinuation and excess pregnancy weight gain.

The retrospective chart review analyzed OCT findings and Humphrey visual field data, determined excess pregnancy weight gain using body mass index-adjusted weight gain goals and correlated IIH symptom worsening to changes in papilledema. The 13 patients included had at least two visits with neuro-ophthalmology during pregnancy, and data were compared from clinic visits before, during and after pregnancy.

At the baseline visit, three patients had low-grade disc edema and 10 had none. During pregnancy, three patients had increased papilledema, two of which developed new peripheral visual field defects that persisted after delivery. The other 10 patients had either stable or improved disc edema during pregnancy, despite the fact that all patients showed more than the 6% weight gain that is typically observed in recurrent IIH, 11 gained more than their weight from initial diagnosis and eight had excess pregnancy weight gain. Six patients had also discontinued their medication for IIH.

Of the seven patients who attended post-pregnancy clinic visits, one had increased disc edema (>100µm), one had improved disc edema and five were stable without any disc edema.

The researchers suggest the reduced risk of weight gain on IIH in expectant mothers may be related to weight distribution or endocrine changes during pregnancy. They elaborate on this hypothesis in their paper on the study, published in the Journal of Neuro-Ophthalmology: “Potential explanations may include a different distribution of weight (abdomen rather than neck and therefore less reduction in venous return from the brain), pregnancy hormonal changes, ‘lean body weight gain’ of the fetus and placenta rather than additional adipose tissue, or other less obvious causes.”

Due to this study’s small sample size, further research will need to be conducted before using this data to counsel IIH patients who are or plan to become pregnant.