Postpartum management of hypertensive disorders in pregnancy
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Transcript of Postpartum management of hypertensive disorders in pregnancy
Dr Chan Joe MeeO&G Department
Postpartum Hypertension –a challenge even after childbirth
Postpartum Hypertension ??
Chronic HPT
Preeclampsia Gestational HPT
de novo HPT
CEMD in Malaysia 2006-2008 In 2006-2008, HDP represented 15.4% of total
numbers of maternal death- the 4th main cause in Malaysia after obstetric embolism, PPH and other medical non HDP conditions
There were 396 maternal deaths reported 2006 -2008 ; 61 cases (15.4%) were directly related to complications of Hypertensive Disorders in Pregnancy (HDP)
The average incidence of HDP deaths /year - 20 cases and the trend was not declining over the last decade
Inadequate treatment of systolic hypertension was a recurring theme
The majority of these deaths were seen among mothers whose age was >30; with the minority groups Iban and Orang Asli being the commonest ethnic groups
DefinitionsFor the purposes of this presentation, the following definitions apply:
Chronic hypertension is hypertension that is present at booking / < 20 weeks or if the woman is already taking antihypertensive medication when referred to maternity services. It can be primary / secondary in aetiology
Eclampsia is a convulsive condition associated with pre-eclampsia
HELLP syndrome is haemolysis, elevated liver enzymes and low platelet count
Gestational hypertension is new hypertension presenting >20 weeks without significant proteinuria
Significant proteinuria - if the urinary protein:creatinine ratio (uPCR) is >30 mg/mmol or a validated 24-hour urine collection result shows >300 mg protein. ( Test done following a result of urine albumin >/= 1+)
Pre-eclampsia is new hypertension presenting after 20 weeks with significant proteinuria
Severe pre-eclampsia is pre-eclampsia with severe hypertension &/ with symptoms, &/ biochemical &/ haematological impairment
Classification of Hypertension NICE Guideline - Guideline Development Group (GDG)
Mild hypertension– SBP140–149 mmHg, DBP 90–99 mmHg.
Moderate hypertension – SBP150–159 mmHg, DBP100–109 mmHg.
Severe hypertension – SBP>/= 160 mmHg, DBP >/=110 mmHg.
* Treatment of moderate HPT prevents severe HPT and its complications
Postpartum Hypertension Hypertension should be recognised &
effectively treated to : prevent severe hypertension avoid unnecessary delays in discharge
Poorly managed postpartum hypertension place women at risk of significant complications Appropriate treatment of
postnatal hypertension is essential to prevent maternal morbidity and mortality from cerebral haemorrhage
This presentation seeks to…• Describe the normal postpartum
changes in BP
• Consider which patients should be > closely monitored & treated
• Consider the evidence for different antihypertensive agents & the ass. implications for the mother & baby
Normal Physiology
Following uncomplicated pregnancy over the first 4 days.1 in the postpartum period SBP ↑ average 6 mmHg DBP ↑ average 4 mmHg
Up to 12% of patients will have a recorded DBP > 100 mmHg
This is dt the resolution of the CVS adaptations to pregnancy, ie. mobilisation of fluid accumulated in the extra
vascular space during pregnancy
Immediate postpartum → tendency of an increase in BP
UTERUS CONTRACTED BLOOD RETURNS TO
SYSTEMICCIRCULATION
↑ VENOUSRETURN ↑CARDIAC
OUTPUT
↑BP
Pathophysiology
1/3 of women who have had PIH or Pre-eclampsia (PE) will be sustaining HPT in the postnatal period
Commonly they are normotensive in the early postpartum period, possibly dt depleted intravascular volumes following labour
There is also a group who is acknowledged to hv HPT occuring de novo following delivery
Women particularly at risk of postnatal hypertension are shown in Table 1
_____________
________________
________________________
___________________
In severe PE/EclampsiaDelivery ≠ End of the problem Severe PE/E can develop during post partum
period
44% of eclampsia occur postpartum(has been reported up to 4 weeks)
Initial BP may fall following delivery but usually rise again around 24h post partum
Incidence of severe PE/E fall after the 4th day postpartum
Pre-eclampsia
The potential complications of PE in the postpartum period are largely similar to those in the antenatal period (except for fetal complications)
There is increasing recognition that severe systolic HPT (>160 mmHg) ↑MAPs
should prompt urgent treatment
to prevent
cerebral haemorrhage.7
Evidence
Incidence of complications among patients with PE:
Matthys et al.2 described the outcomes of 151 women readmitted in the postnatal period (up to day 24) who received a diagnosis of PE
The incidence of complications was high: 16% eclampsia 9% pulmonary oedema one maternal death
Similarly, Chames et al.5 : 29 women presenting with postpartum
eclampsia, almost all reported ≥ 1 prodromal symptom
23 (79%) patients had seizures after 48 hours
Lubarsky et al.6 reported a series of 334 cases of eclampsia 16% of seizures - in the postnatal period
( > ½ of these later than 48 hours following delivery).
Together, these data emphasise: the need for prolonged vigilance in the
postpartum period The importance of investigating reported
symptoms in such women
In the current climate of early postnatal discharge, both hospital and community teams need to have referral and management guidelines in place
Consideration of antihypertensive agents The ideal antihypertensive agent to be
used in the postnatal period should reliably and effectively control BP without
diurnal peaks and troughs have minimal maternal side effects be safe for breastfeeding infants be effective with once-daily dosing to
maximise compliance
Due to the paucity of data, it is difficult to recommend one antihypertensive agent over another9
In the absence of such data the clinician should be aware of the pros and cons of available agents (Tables 2 and 3)
1. β-blockers
The most common agents used are labetalol and atenolol
β 2 receptors- effect on peripheral vasodilation
β 1 receptors in cardiac tissue modulate the sympathetic response
Renal receptors mediate changes in renin synthesis-This modest decrement in renin synthesis may contribute to the overall antihypertensive effect in some patients
β -blockers may exacerbate & should be avoided asthma cardiac failure
Individuals who describe respiratory symptoms after commencing a β -blocker (symptoms may not be apparent for several days) should be changed to an alternative agent
Atenolol
Advantage – OD dosing
↑compliance in women who find multiple dosing regimens difficult
The high lipid solubility of the drug means that it is concentrated in breast milk and concerns have previously been raised about transfer to the neonate
However, only a single case of neonatal β -blockade has been reported despite extensive use of the drug in breastfeeding women
The risks in routine clinical practice are therefore minimal
2. Calcium channel blockers
Inhibits Ca2+ influx into vascular myocytes thereby inhibiting vasoconstriction and reducing vascular resistance
Minimal effects on cardiac conduction and HR ; but may be ass. with > headache than β –blockers
There is minimal excretion into breast milk10
Nifedipine - the most commonly prescribed CCB ; dosage- 10-20mg TDS
A 2nd-line alternative is Amlodipine 5–10 mg OD
3. Methyldopa
The most common antihypertensive agent used in the antenatal period is methyldopa- because of its well established safety record with regard to fetal toxicity 11
Centrally acting α-adrenergic agonist- brings about reduced systemic vascular resistance via ↓ sympathetic vascular tone
Whilst methyldopa remains a safe option for treatment of hypertension in the postnatal period, particularly in women who have had good antenatal control with the agent, most authorities advise that it should be discontinued because of its maternal side-effects, in particular: Sedation postural hypotension postnatal depression 12
4. Angiotensin converting enzyme (ACE) inhibitors
ACE inhibitors (such as Enalapril) - commonly used outside of pregnancy to treat hypertension, particularly that ass. with renal disease and proteinuria
Inhibit angiotensin converting enzyme (ACE) → decrease production of angiotensin II (AII) reducing AII mediated vasoconstriction
Ass. with adverse fetal outcomes when used in the antenatal period ; but there are reassuring data concerning their safety in breastfeeding infants
Enalapril can be prescribed as a BD dose of 5–20 mg + :generally well tolerated - : can experience profound hypotension. Association with renal impairment:-
CAUTION: recent deterioration of renal function.
5. Diuretics
Diuretics - rarely used as antihypertensive agents in the postnatal period; except- pulmonary oedema
Postnatal women are > susceptible to postural hypotension
Breastfeeding women may experience excessive thirst
The associated volume contraction may interfere with successful breastfeeding
Treatment of acute episodes ofhypertension Acute episodes of hypertension in the
postnatal period should be managed in the same manner as antenatal / intrapartum episodes
The agents of choice are: labetalol (oral or intravenous) nifedipine (oral) or hydralazine (intravenous)
Labetalol- Advantage - an oral dose can be given before
intravenous access is established Further intravenous doses can be given if
required Hydralazine-
effective ; although its use as a first-line drug has been questioned12
> commonly causes precipitous drops in BP and the associated symptoms are unpleasant for women (;although the concerns about placental perfusion are no longer relevant)
Management of ongoing postnatalhypertension
1. Patients with existing hypertension It is advisable to stop methyldopa following delivery and
switch to the prepregnancy dose of her usual agent/s
Where newer drugs have been prescribed and mothers are wishing to breastfeed, pharmaceutical advice should be sought before delivery
All of the antihypertensive drug groups have examples of preparations where there is reassuring experience with breastfeeding
Women who were previously using diuretics should consider an alternative while they are breastfeeding
Figure 1. (a) Algorithm for the management of postnatal hypertension in women with chronic hypertension.
2. Hypertension arising during pregnancy or in the puerperium
In patients who were normotensive before pregnancy, one of the most difficult problems is deciding which women should have antihypertensives prescribed following delivery
Women who are most likely to benefit from antihypertensisves prescribed following delivery:
required antihypertensives in the antenatal period been delivered < 37 weeks of gestation because of
hypertension had severe hypertension
The perceived advantages of starting treatment in the early postnatal period are : episodes of severe hypertension will be reduced discharge to the community will not be delayed
unnecessarily
Balanced against this possibility of unnecessary treatment SE of medication
A suggested regimen might be labetalol (providing there is no history of asthma) , with second and third-line agents of calcium antagonist
and an ACE inhibitor (such as enalapril)
Figure 1.(b) Algorithm for the management of postnatal hypertension in women without chronic hypertension
3. De novo hypertension
Not clear what thresholds should be used to instigate treatment in women with de novo hypertension in the postnatal period having previously been normotensive
Current NICE postnatal guidance13 recommends medical review: DBP>90 mmHg ,ass. w any symptoms of PEOR Diastolic hypertension sustained >4 hours
No systolic thresholds are suggested but extrapolation from the subsequent hypertension guidelines : SBP >150 mmHg → PE should be excluded
Newly presenting patients should have a history and examination taken to exclude IE and have Ix that include: FBC BUSE/Creat LFT
Inpatient management of ongoing postnatal hypertension
ALL women should be closely monitored with regular recordings of BP and fluid balance (regardless whether antihypertensive agents prescribed immediately following delivery)
Modified obstetric early warning system (MOEWS) charts should be used to facilitate the monitoring of these women in wards
A validation study of the CEMACH recommended modified early obstetric warning system (MEOWS)*
AnaesthesiaVolume 67, Issue 1, pages 12-18, 9 NOV 2011 DOI: 10.1111/j.1365-2044.2011.06896.xhttp://onlinelibrary.wiley.com/doi/10.1111/j.1365-2044.2011.06896.x/full#fa1
The frequency of measuring haematological and biochemical indices will need to be tailored to individual patients(A minimum of OD testing may be required initially in cases where there is concern about thrombocytopenia or renal compromise)
Thereafter frequent sampling - unlikely to change management in the absence of other clinical triggers
Furthermore, unnecessary concern may arise if normal patterns of resolution are not appreciated (for example, ALT reaches peak serum levels 5 days postnatally in normal pregnancy15 )
NICE guidance16 recommends : platelet count transaminases serum creatinine
Up to 44% of eclamptic fits occur in the postnatal period (usually within the first 48 hours following delivery,17) women with PE should be encouraged to delay discharge until day 3
BP at the time of discharge should be <150/100 mmHg
Crucial that the community team receive adequate and prompt documentation regarding the inpatient management and the plans for follow-up
Checked 48–72 hours after birth/
Step down from Level 2 care, and
Thereafter only repeated if abnormal or clinically indicated
Discharge criteria
For mild HDP – no earlier than 24-48 hrs Severe PE/E – no earlier than day 5 DBP has settled <100 mmHg On single/no antihypertensive drug NO end-organ dysfunction Patient:
understands the disease & its complications compliant to medication accessible to a health center
Notification of birth
The importance of continuing post-natal care either at the hospital or health center cannot be overemphasized
To facilitate this, notification of birth to the nearest peripheral health center is vital Phone Fax Report by family members/next of kin to
nearest clinic
Follow-up at the Community
Local experience and facilities will dictate if this review should be by the GP / the hospital maternity assessment unit/ Daycare unit
Hospital review will be required if patients report symptoms of PE / if BP >160/100 mmHg
Most women who commence postnatal antihypertensives will require treatment for ≥ 2 weeks
Some women, esp. with early onset /severe disease may need to continue > 6 weeks18
Management at the Community
EOD follow-up either at the health centre / home visit by the community midwife/nursing/paramedical staff : BP urine for albumin signs and symptoms of PE
The patient has to be seen and examined by a doctor either in the hospital / at health centre fortnightly until 6 weeks post-natal period
Elements to be monitored Frequency of review by nurse
Frequency of review by doctor
•Blood Pressure
•Urine for protein (if B/P > 140/90 mmHg)
•Signs and symptoms of severe HDP and pre-eclampsia
•Signs and symptoms of Deep Vein Thrombosis (Post-natal mothers with history of HDP have a higher risk of developing DVT, as a complication of advocating long rest during antenatal period)
EveryOtherDay
(EOD)
Two weekly
Medication should be reduced when BPs ranged 130–140/80–90 mmHg
Refer for medical review: >150/ 100mmHg - 2x measurements are obtained
>20 minutes apart remains on medication at 2 weeks
Further medical review If medication is required > 6 weeks - to Ix the
possibility of an underlying cause It has been reported - up to 13% of women
initially thought to have a diagnosis of PE or PIH will have underlying disease not suspected antenatally19
Criteria for referral
Referral to hospital to be considered, if:- BP > 140/100 mmHg with proteinuria and/ or
- Signs and symptoms of Impending Eclampsia
- Hypertension and proteinuria persist > 6 weeks postpartum.
6 weeks post partum
The 6-week postnatal visit – establish the diagnosis (PIH/PE/Essential
HPT) discuss implications for future pregnancies
All women who have had a diagnosis of PE should have: BP measured urine tested for proteinuria
Counseling on the importance of contraception and choice with reference to WHO medical eligibility criteria (WHO MEC)
Advise to have an early booking and regular
antenatal care in the next pregnancy
If hypertension and proteinuria persists >6 weeks postpartum, the mother should be referred to a physician
It is important to ascertain whether that renal impairment detected in hypertensive pregnancies is indeed attributable to PE20 Renal biopsies taken in the postpartum
period in 176 women who had been diagnosed in pregnancy as having renal complications of pre-eclampsia established an alternative diagnosis in 1/3 of cases
overall; and this was ↑ to almost 2/3 in multiparous patients
Recurrence of Pre-eclampsia
The risk of pre-eclampsia in a subsequent pregnancy depends on the presentation in the index pregnancy
Severe, early onset pre-eclampsia - recurrence rate up to 40% in future pregnancies21,22 generally the onset of problems is 2–3 weeks
later < severe than in the 1st pregnancy23
Milder disease, nearer to term - risk of recurrence nearer to 10%
Future pregnancy/ risk
Women at increased risk should be offered in a future pregnancy low-dose aspirin increased BP surveillance
Finally….CVD It is increasingly recognised that PE is a risk
factor for developing cardiovascular disease in later life
Patients should be made aware of this - opportunity to make lifestyle choices to minimise risk
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