Headaches in pregnancy – when to worry

New onset of headaches is always worrisome, but even more so in a pregnant woman. Neurologists at the Montefiore Headache clinic in the Bronx conducted a 5-year retrospective study of pregnant women who presented with an acute headache, were hospitalized, and received a neurologic consultation. The study was published in Neurology.

The researchers identified 140 women with a mean age of 29 years. About 56% of these women presented in the third trimester. Primary headaches was present in 65% and secondary (due to an underlying disease) was found in 35% of women. The most common primary headache disorder was migraine and it was found in 91%, while the most common secondary headache disorder present in 51% was high blood pressure.

Primary headaches included migraine without aura, seen in 37%, migraine with aura, in 24%, chronic migraine, in 6%, episodic tension-type headache, in 3%, chronic tension-type headache, in 1%, and primary stabbing headache, in 2% (this adds up to more than 65% because some had more than one type of headaches). Besides hypertensive disorders such as preeclampsia and eclampsia (18%), secondary headache diagnoses included pituitary adenoma or apoplexy in 4%, infections in 2%, stroke in 3%. Pregnant women with secondary headaches were less likely to have had headaches in the past (37% in secondary vs 13% in primary) and were more likely to have seizures (12% vs 0%), elevated blood pressure (55% vs 9%), fever (8% vs 0%), and an abnormal neurologic examination (35% vs 17%). Psychiatric comorbidity (presence of depression, anxiety, bipolar, etc) and phonophobia (sensitivity to light) were less likely with secondary headache.

The authors concluded that among pregnant women receiving inpatient neurologic consultation, more than one-third have secondary headache. Doctors should be particularly vigilant in the absence of a headache history and if seizures, hypertension, or fever are present. On the other hand, specific headache features such as location of the pain, throbbing character, sensitivity to light and noise are less helpful in distinguish primary vs secondary headaches. The neurologists who conducted this review recommend low thresholds for neuroimaging (CT or MRI scan) and monitoring for preeclampsia and eclampsia. Preeclampsia and eclampsia are complications of pregnancy with elevated blood pressure, sometimes seizures, and kidney problems, which can be life-threatening and which are treated with intravenous infusions of magnesium.