Headaches During Pregnancy

About 16% of all women experience migraine headaches whether pregnant or not.

During pregnancy, it is quite likely that the amount of migraine will reduce, by as much as 50%, especially in the second and third trimesters.

This is probably due to the increase in pain threshold brought about by pregnancy hormones.

The usual reason for being consulted during pregnancy is for headache and some sort of other accompanying symptom like numbness, visual disturbance or speech disturbance.

In my own experience (borne out by a recent study from Norway) almost all of these new headaches and neurological symptoms during pregnancy are due to migraine.

A severe headache disorder occurring for the first time during pregnancy is actually quite rare.

The other severe headaches in pregnancy that cause concern are:

1. Reversible Cerebral Vasoconstriction Syndrome
• Associated with eclampsia
• Not associated with eclampsia - so called post-partum angiopathy
Both of these conditions usually cause a sudden severe headache called Thunderclap Headache. If you experience a sudden headache out of the blue during pregnancy you must seek urgent medical advice.
2. Posterior Reversible Leucoencephalopathy
This can causes visual symptoms like blurring, associated with either a dull headache or a Thunderclap Headache. It can be associated with a diagnosis of eclampsia.
3. Venous Sinus Thrombosis
During and following pregnancy your blood is at an increased risk of clotting. If this happens to one of the veins in your head, it can cause a sudden severe headache.

Sometimes it can cause a progressively worsening headache with focal symptoms like speech difficulty, visual loss or even partial epileptic seizures.

It is treated with anti-coagulants like heparin or warfarin.

4. Low pressure headache complicating epidural anaesthesia
• Inadvertent CSF leak
• Iatrogenic Pneumocephalus (if air injection was used to site epidural needle)

Pneumocephalus is usually best diagnosed by a CT Brain scan.

5. Headaches associated with eclampsia
These can resemble migraine, but Blood Pressure will be increased and protein found on testing a urine sample.
6. Hemicrania Continua
This is a rare cause of a persistent one-sided headache. Unfortunately if it develops in pregnancy, the best drug, Indomethacin, is not advised, as prolonged use is associated with a congenital heart problem in children called a persistent patent ductus arteriosus.