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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