Oxford Handbook of Midwifery (77 page)

Mild hypertensive disorder

A pregnant woman with mild hypertensive disorder may be admitted labouring to the delivery suite. On admission:

consultant care, and liaise with the obstetric registrar.

>150mmHg systolic or >100mmHg diastolic requires treatment. Discuss this with the obstetrician.

During established labour

Avoid active second-stage pushing, which may affect blood pressure. Allow descent of the fetal head to the perineum then encourage spontaneous efforts at pushing.

Avoid ergometrine/Syntometrine
^®
for the third stage of labour. It may aggravate hypertension. Syntocinon
^®
10IU IM is preferred.

CHAPTER 18
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334

Pre-eclampsia

• A woman with pre-eclampsia may be admitted to the delivery suite for assessment and possible induction of labour or caesarean section.
  
• Alert the consultant obstetrician, who will perform a full examination of woman and fetus. This includes neurological assessment.
  
• Prepare a quiet private examination room for the woman and her
  partner. Ensure it is equipped with:
  
  • A suitable sphygmomanometer (the manual sphygmomanometer
    

    gives a more accurate reading than an automated machine, which sometimes under-records hypertension)
    

  • Stethoscope
    
  • Thermometer
    
  • Patella hammer
    
  • Ophthalmoscope
    
  • CTG monitor
    
  • Ultrasound scanner
    
  • Equipment to site IV infusion and to take blood samples, MSU, and to perform vaginal examination.
    
• Try to alleviate any stress the woman may experience. Listen to preferences, explain procedures, and answer questions.
  

  Maternal assessment
  

  Observe the signs of pre-eclampsia:
  

• Measure the woman’s blood pressure accurately.
  
  • Use the appropriate cuff size. The standard cuff may be too small and may give an overestimation. If the arm is >33cm in circumference, use a large cuff.
    
  • Ensure a correct sitting position, with the machine at the level of the woman’s heart.
    
  • Use Korotkoff phase 5 (disappearance of the sound) and note the final digit. It should be recorded accurately and not rounded up or down.
    
  • Note that the mean arterial pressure (MAP) is used by some obstetricians: a value >125mmHg must be reported.
    
  • Study the present findings alongside the woman’s previous antenatal record. 20–25mmHg above the baseline diastolic reading may be significant.
    
• Assess urine accurately for proteinuria.
  
  • Ask the woman to produce a clean MSU. If positive to 2+(>1g/L) on the reagent strip, exclude infection:
    
    • Assess maternal temperature
      
    • Send the urine sample to the laboratory for culture and assessment of antibiotic sensitivity
      
  • Review previous records: 24h urine collection, a value of
    

    >300mg/24h suggests that the woman is at risk.
    

• Take a careful history and enquire about the following symptoms:
  
  • Headaches: usually frontal and occipital; worse on standing
    
  • Visual disturbances: flashing lights, loss of patches of visual field (scotomata), photophobia
    
  • Epigastric pain: probably due to liver oedema, stretching of the capsule
    
  • Facial oedema (general oedema is no longer rated as a symptom)
    

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    335
    

    • Sometimes no symptoms are discernable
      
    • In severe cases:
      
      • Nausea, vomiting, and generally feeling unwell
        
      • Irritability, on edge, occasionally drowsy (because of cerebral oedema).
        

obstetrician. Site large-bore IV access, take and dispatch the required
samples for:

• FBC:
  
  • Haemoglobin: enables red blood cells to transport oxygen.
    

    A low count indicates anaemia
    

  • White cell count: a high count is indicative of stimulation of the immune system and may suggest infection.
    
• Clotting screen:
  
  • Platelets, thrombin, prothrombin time; these indicate the clotting time of plasma
    
  • D-dimer/fibrinogen degradation products; detect the break- down of fibrin and may suggest thrombosis.
    
• U/E: indicate renal function since waste products of metabolism are excreted via the kidneys
  
• Creatinine; may be raised when filtration of blood by the glomeruli in the kidneys is impaired
  
• LFTs: will assess the extent of liver damage
  
• G&S: to assess Rh grouping and save serum in case of bleeding.
  

• Abdominal tenderness: fundal tenderness might suggest abruption, hepatic tenderness might indicate a worsening condition
  
• Blood loss via the vagina (per vaginam, PV)
  
• Uterine contractions indicative of labour.
  

  Fetal assessment
  

• Symphysis—fundal height, for growth
  
• Fetal movements
  
• Begin continuous fetal monitoring (CTG).
  

Maternal and fetal assessment by the obstetrician

The obstetrician will:

pre-eclampsia the reflexes are brisk (clonus), there may be difficulty in focusing and papilloedema may be present

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Maternal monitoring, management, and treatment

Monitor blood pressure every 15min. Aim to achieve a slow reduction in both systolic and diastolic blood pressure and stabilize. The blood pres- sure must be stable before a decision about delivery is made.

• Admission to a high dependency unit (if available) may be necessary if the woman's blood pressure is ≥160/110mmHg.
  

  •
  Oral labetalol, a B-blocker, may be prescribed in milder cases.
  

• Labetalol should be avoided when a woman is known to be asthmatic.
  
• The obstetrician may recommend 200mg oral labetalol, if there is time and no immediate risk to woman or fetus. The woman’s BP should
  

  fall by 10mmHg within 1h. If the response is positive and adequate, maintain the dose orally: 200mg three times a day. 1200mg daily is maximum dose.
  

• Oral nifedipine 10mg can be given as an alternative. If the BP remains
  

  >160/110mmHg after 30min the consultant may prescribe a further 10mg orally.
  

• If the BP does not fall in 1h, an IV infusion of labetalol may be prescribed: 300mg (5mg/mL) via a 60mL syringe and pump, beginning at 10mL/50mg per hour. The maternal diastolic blood pressure should be maintained at 95–105mmHg. The rate can be changed (increased or reduced) by 2mL/10mg hourly. The maximum rate is 32mL/160mg hourly.
  
• Hydralazine may also be used. It acts directly on smooth muscle in arteriolar walls, causing vasodilatation. The dose is 5mg as a slow bolus. It may be repeated at an interval of 20min, depending on the woman’s BP, or after giving a loading dose an infusion via a syringe driver pump may be prescribed according to local protocol. However, side-effects can be troublesome, e.g. nausea/vomiting, tachycardia, headache. Maternal and fetal condition should be carefully monitored.
  

  In all circumstances, follow the instructions of the medical staff carefully, and abide by local protocols.
  

  IV antihypertensive drugs may cause fetal compromise if the blood pressure is reduced too rapidly. Monitor the fetal heart rate continuously. Monitor the woman’s progress and report any side-effects or changes in condition to the obstetrician. Note that lowering the BP may mask
  

  symptoms and does not remove the risk of eclampsia.
  

• Monitor and restrict IV/oral fluids to approximately 85mL/h, measured via an electronic monitor.
  
• Measure the oxygen saturation and respiratory rate, using a pulse oximeter. Report levels <95% to medical staff. Low oxygen saturation may indicate pulmonary oedema due to fluid retention.
  
• Observe the woman’s colour and level of consciousness.
  
• Measure her temperature every 2h.
  
• Monitor and record her urine output and fluid balance:
  
  • A bladder catheter is usually recommended. Output is measured hourly using a urometer; 30mL/h is acceptable.
    
• A doctor should assess tendon reflexes hourly.
  
• A central venous pressure (CVP)/arterial line may be indicated for accurate measurement of maternal BP.
  

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