Headache in Pregnancy

Summary

Headache is common in pregnancy; most are benign, but serious secondary causes must be excluded. Migraine and tension-type headache are the most frequent primary causes. Hypertensive disorders, stroke, CVT, SAH, and intracranial tumors are critical secondary considerations. A thorough history, examination, and targeted investigations are essential. Safe management requires balancing maternal benefit with fetal safety, with paracetamol as the first-line analgesic and propranolol or amitriptyline for prophylaxis when indicated

Introduction

Headache is a common complaint in pregnancy, affecting more than one-third of women, and may be due to primary or secondary causes. While most headaches are benign, the potential for serious underlying pathology in pregnancy necessitates careful evaluation and recognition of red flags

Primary Headaches

The majority of headaches in pregnancy are primary, with migraine and tension-type headaches being most common. Migraines often improve during pregnancy, particularly after the first trimester, but recurrence postpartum is frequent. 

Notably, a history of migraine is associated with an increased risk of preeclampsia and hypertensive disorders. 

Hormonal influences contribute to the high prevalence of headaches in women of reproductive age, and although symptoms may change during pregnancy, most primary headaches do not indicate serious pathology.

• Management: 

• First-line treatment includes lifestyle modification (adequate hydration, sleep hygiene, avoidance of triggers). 

• Paracetamol is the safest analgesic; codeine or tramadol may be used second-line. 

• NSAIDs are avoided, particularly after 32 weeks, due to fetal risks.

• For frequent migraine attacks, propranolol or amitriptyline may be considered for prophylaxis.

Secondary Headaches

Approximately one-third of headaches in pregnancy are secondary and may be associated with significant morbidity and mortality. Important causes include:

1. Hypertensive disorders (Pre-eclampsia/Eclampsia): Typically present with bilateral, worsening pulsatile headache, often accompanied by visual disturbances, hypertension, proteinuria, and possible seizures. Any woman after 20 weeks with a new headache should have blood pressure and urinalysis checked.
   
   

2. Posterior Reversible Encephalopathy Syndrome (PRES): Characterized by headache, altered consciousness, seizures, and visual disturbance, often in association with preeclampsia, eclampsia, or renal disease.
   
   

3. Cerebrovascular events:
   
   

• Ischemic stroke may present with headache and focal neurological deficits. Thrombolysis is relatively contraindicated, requiring multidisciplinary input.
  
  

• Subarachnoid hemorrhage (SAH): Presents with sudden thunderclap headache, vomiting, and loss of consciousness. Risk increases significantly postpartum.
  
  

• Cerebral venous sinus thrombosis (CVT): Presents with diffuse headache, raised intracranial pressure, or focal deficits; diagnosis requires urgent neuroimaging.
  
  

• Reversible cerebral vasoconstriction syndrome (RCVS): Severe recurrent thunderclap headaches, often postpartum, triggered by exertion or stress.
  
  

• Cervical artery dissection: Rare, may occur postpartum or following labor, presenting with sudden unilateral headache.
  
  

4. Space-occupying lesions: Pituitary adenomas, meningiomas, and gliomas may enlarge in pregnancy and present with raised intracranial pressure, headache, and visual symptoms. Rarely, metastatic pregnancy-associated tumors (e.g., choriocarcinoma) can involve the brain.

Red Flags in Pregnancy

Headaches warrant urgent investigation if associated with:

• Sudden onset, reaching peak within 5 minutes

• New or atypical headache in pregnancy

• Worsening with posture or exertion

• Awakening from sleep

• Neurological deficits, seizures, or altered consciousness

• Hypertension, proteinuria, abnormal liver or platelet function

• Fever, papilledema, cancer, HIV, or thrombosis risk factors

Investigations

• First-line: CT or MRI head (CT is safe for maternal indications; avoid iodinated contrast if possible).
  
  

• Additional: MR/CT angiography, carotid ultrasound, lumbar puncture, EEG.
  
  

• Note: D-dimers are unreliable in pregnancy but may rarely aid exclusion of thrombotic disease.