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There are many different types of headaches that can strike women during pregnancy, but today let’s focus on those headaches that are more painful and harder to treat than the common stress headache that involves muscles, but that are not due to injury, masses pushing inside the head, or other processes that typically get continuously worse. The types of headaches that we’re talking about are migraine headache and cluster headaches. In the past, these headaches used to be grouped together in a category called vascular headaches, based on the idea that they were caused by abnormalities in the function of blood vessels. Today, it is known that the underlying problems in these conditions is more complex, involving many components, including issues with blood vessels, especially blood vessels related to a nerve in the head called the trigeminal nerve.
Migraine headache —also is known as migraine disorder, or migraine disease, because it includes effects other than headaches— is extremely common, occurring in 12 percent of the human population and 25 percent of women, so we are talking about an extremely large number of women who can suffer from migraine effects while pregnant. In contrast, cluster headaches strike only about one per one thousand people and are about twice as common in men than women. In 60-70 percent of female migrainers who become pregnant, the disorder actually improves over the course of pregnancy, and in 20 percent the headaches disappear all together. After delivery, however, your symptoms may soon return.
Both migraine and cluster headaches produce extreme pain, usually on one side of the head, but people tend to feel migraines tends over a larger area, from the top to the bottom of the head, whereas cluster headache is most severe around the eye of the affected side. Whereas a migraine attack typically features no more than one headache in a day, with variations in how often these attacks come (a few times a year, once a month, most days, etc), cluster headaches get their name because they come on cluster of headaches over a short period of time (such as 5 or 10 severe headaches over a few hours). The intensity of cluster headaches can be so severe that they have been nicknamed suicide headaches, based on cases of people attempting or succeeding ending their lives in order to end their suffering. Migraines also can be extremely painful, and attacks also can feature any of a range of non-headache symptoms, such as neck pain, fatigue, nausea, cognitive dysfunction (difficulty thinking and concentrating), and fatigue, photophobia (discomfort when exposed to light) and photophobia (discomfort when exposed to sounds). Migrainers also can experience phenomena called aura that can tack the form of flashes of light, blind spots, or face or hand tingling prior to or during the headache. In both conditions, the headaches tend to have a pulsating character.
Generally, migraine disorder is diagnosed clinically, meaning based on an interview and physical examination conducted by a doctor with specialized knowledge, such as a neurologist, and with some help from some basic tests. For instance, the doctor will evaluate whether your headache is located on one side of the head and has a pulsating quality (throbbing) and will determine the level of pain as being moderate to severe (doctors may do this by asking you to rate the severity of pain on a scale of 1-10. If you think it is 5 or higher this would count as a migraine characteristic). If the pain is aggravated by routine physical activity, or causes you to avoid such activity, this also suggests that you have the condition. In many cases, but not all, migraines attacks develop following an aura, which can be of a visual nature (flashing/flickering lights, spots, or lines, or temporary loss of vision), body sensations (such as feelings of pins and needles or numbness in a body part, or speech disturbances. An aura symptom typically develops over up to five minutes and may last from five minutes to one hour. The migraine typically begins with 60 minutes of the beginning of the aura. The aura may continue during the migraine, or it may end. If a patient reports headaches with these characteristics coming on attacks over the past few days, particularly within the past 4-72 hours, this is all very suggestive of migraine headache. Migraines are more common in women than men, and if the patient is a woman who has suffered migraines in the past, this is generally enough to diagnose the attacks as being migraine headache and there will be no need for imaging of the head.
In many cases, doctors will also want to conduct imaging studies of the head. Particularly for pregnant women, the choice of imaging will be magnetic resonance imaging (MRI), as this is not know to carry any risk to the fetus. As for the effects of the condition itself on the baby, numerous studies have demonstrated that migraine headache and cluster headache does not have any negative consequences in terms of birth defects, miscarriage, or other bad outcomes, but sometimes other conditions can be confused with migraine headaches. This is why the patient’s history is extremely important and why imaging is important as well.
Over the years, many different drugs have been used to treat migraine disorder, but the main workhorse family of drugs for migraines is called triptans, which include drugs, such as naratriptan, rizatriptan, and sumatriptan, all of which are considered probably safe in pregnancy. Triptans do not work on everyone with migraine, but a newer family of drugs, called calcitonin gene-related peptide (CGRP)-blocking monoclonal antibodies (MAbs), also called CGRP inhibitors, is proving to be very effective in many people. CGRP inhibitors require more testing before doctors can be certain that they are safe during pregnancy. However, while MAb drugs are known to cross the placenta from maternal blood, studies of such drugs in experimental animals have not suggested that there is a danger if they do enter the baby’s system.
There is also another type of treatment called neuromodulation in which electrical current or magnetic fields are used to stimulate certain nerves in a way that modifies the generation of pain in the head. Neuromodulation treatment is administered through devices that you wear on your head (or in some cases the neck) for short periods of time each day, such as for an hour or so. The clinical research in this area is in an early stage but has produced very promising results that are likely to help many migrainers who either do not respond well to drug treatment, or who prefer to avoid medications.