Secondary headaches in pregnant women are likely to be associated with an additional medical complaint, according to a retrospective study of patients who presented to a tertiary-care center.

A team led by Dr. Matthew S. Robbins of Montefiore Headache Center in the Bronx, N.Y., assessed characteristics of 68 consecutive women who had an inpatient neurologic consultation for acute headache in pregnancy over a 2.5-year period at Montefiore Medical Center.

Secondary headaches were diagnosed in 57% of these women. Women with secondary headaches were more likely to have hypertension and some other chief complaint along with headache. Women with primary headaches were more likely to have a history of migraine and to have photophobia, phonophobia, and lacrimation on exam.

Three cases (4%) were noteworthy in that the headache led to discovery of an unrecognized pregnancy. All of these patients had secondary headache, and life-threatening but treatable medical conditions.

“In the acute care setting, vigilance for secondary headache in the pregnant population should be heightened, particularly in those patients who may have headache in addition to other symptoms, the lack of a migraine history, and elevated blood pressure acutely,” Dr. Robbins recommended. “Because of our sad corollary [of three cases], we should … always consider a pregnancy test in all women presenting with headache during childbearing years.”

He acknowledged that a study limitation was the highly selected patient population. “This is not only patients presenting to the acute care setting, but patients who are then referred by the [emergency department] doctors or obstetricians for a neurologic consultation. So we are probably not capturing the routine cases of preeclampsia that are obvious, or other diagnoses that, in our center, the obstetricians don’t feel warrant neurologic consultation,” he commented at the annual meeting of the American Headache Society.

Session attendee Dr. Peter J. Goadsby of the University of California, San Francisco, noted that about a fifth of patients with primary headache were classified as having an abnormal neurologic exam. “That wouldn’t be consistent with primary headache, would it? So what’s abnormal mean?” he asked.

“Most of the abnormal exam findings in the primary headache group were sensory abnormalities,” such as unilateral facial numbness, which – although documented as abnormal – might not be clinically relevant. “It was up to the discretion of the treating team whether that patient had a primary or secondary diagnosis with the exam and abnormality combined,” Dr. Robbins replied.

“Clinical experience, at least ours, suggests that consultation in the acute care setting for headache in pregnant women is not such an uncommon experience,” he noted, explaining the study’s rationale. However, “there are very few guidelines that address this. It is mostly review articles in the obstetrics and gynecology literature that are not really validated, and clinical series are not well reported.”

On average, the 68 women the investigators studied were 29 years old, and they were predominantly Hispanic (43%) and black (41%). The mean gestational age was 28.6 weeks, with 60% of women in their third trimester.

In terms of diagnoses, made via the ICHD-II (International Classification of Headache Disorders, second edition) system, 57% of the women had secondary headache and 43% had primary headache.

Headache class was predominantly migraine (43%), preeclampsia or eclampsia (25%), intercurrent infection (7%), and pituitary adenoma/apoplexy (6%).

The patients with primary headache and the patients with secondary headache were statistically indistinguishable in terms of most demographic, pregnancy, and clinical characteristics, according to Dr. Robbins.

But patients in the secondary headache group were less likely to have a history of migraine (39% vs. 90%; P less than .0001) and, on exam, photophobia (67% vs. 93%; P = .02), phonophobia (36% vs. 79%; P = .0004), and lacrimation (0% vs. 17%; P = .01).

On the flip side, those in the secondary headache group were more likely to have headache plus some other chief complaint such as seizure, shortness of breath, or visual disturbances (54% vs. 14%; P = .0009) and hypertension (49% vs. 0%; P less than .0001).

Of the three cases in which headache led to the discovery of an unrecognized pregnancy, one had diagnoses of PRES (posterior reversible encephalopathy syndrome) and eclampsia; one had diagnoses of PRES, RCVS (reversible cerebral vasoconstriction syndrome), and eclampsia; and one had diagnoses of hyperkalemia and renal failure in systemic lupus erythematous.

Dr. Robbins disclosed no relevant conflicts of interest.