Most pregnant women may experience tension headaches at some point during the course of their pregnancy. Though most of them are harmless, the more serious types of headaches, which may occur during and after pregnancy, should not be taken lightly, and may require a full medical evaluation, according to a review published in The Obstetrician & Gynaecologist.

The review lists 85 different types of headaches. During pregnancy, 90 percent are tension or migraine-type headaches. Most women get these during the first trimester, and find that they eventually disappear as the pregnancy progresses. But there are other, rarer kinds of headaches that may result from an underlying condition, and they may get worse during the course of pregnancy.

Statistics from the Confidential Enquiries into Maternal Deaths in the United Kingdom 2006 to 2008 report reveal that neurological conditions caused by direct or indirect effects to the brain are the third most common cause of death among pregnant women. The reviewers of the current study, therefore, stress the need for adequate training of all medical personnel to identify and seek counsel for underlying neurological conditions in pregnant women.

Though pregnancy reduces the occurrence of migraines with aura — that is, experiencing symptoms like visual changes and numbness before the onset of a headache — the occurrence of migraines increases the risk of preeclampsia by more than two times. Pregnant women, according to the reviewers, therefore need to be aware of whether their headache is different from what they usually experience, and if so, they should immediately consult a doctor.

Another rare but serious condition that leads to headache is called idiopathic intracranial hypertension; a neurological disorder that generally affects obese women aged 20 to 40. It is caused by an increase in pressure around the brain. Many women experience it for the first time during pregnancy but previous sufferers may find the symptoms worsening during pregnancy. This condition may lead to a medical emergency if not treated promptly.

Headache caused by cerebral venous thrombosis (CVT), the presence of a blood clot in the dural venous sinuses, which drains blood from the brain, may also be observed during pregnancy. Risk factors include, C-section, systematic infection, vomiting, and anemia.

It’s important while diagnosing and treating these headaches that the brain undergo imaging procedures, which are needed for accuracy and timeliness. They are also safe for pregnant women, who may worry about their effects on their unborn child.

"Headaches are common in life and in pregnancy,” Kirsty Revell, co-author of the review and specialist registrar of obstetrics and gynaecology at the Princess Anne Hospital, Southampton, said in a press release. “Most headaches are benign, for example migraine or tension headaches, but some headache types can be more serious, and an indication that something is seriously wrong. It is vital that both [general practitioners] and obstetricians are aware of the signs and symptoms associated with these conditions and know when to seek advice from a specialist."

Source: Revell K, Morrish P. Headaches in pregnancy. The Obstetrician & Gynaecologist. 2014.