sMater | Dr Vishwas Raghunath | Hypertension in Pregnancy

Obstetric Physician and Nephrologist Dr Vishwas Raghunath has a wealth of experience in managing complex medical conditions in high-risk pregnancies.

In this episode of sMater, Vish discusses hypertension, the most common medical problem encountered in pregnancy.

From screening to management and preventative strategies, GPs can hear a range of approaches to ensuring mum and baby remain safe, from conception all the way through the post-partum period.

GP Education activity log:
  Podcast title - sMater: Hypertension in Pregnancy
  Provider - Mater Misericordiae Ltd
  Date published - November 01, 204
  Certificate of completion - click here

To learn more about Mater, visit https://www.mater.org.au/

Transcript

Hello and welcome to this episode of sMater. A podcast by clinicians for clinicians brought to you by Mater, an Australian leader in healthcare for more than a century. My name is Jillian Whiting and we're coming to you from Meanjin the land on which this podcast is being recorded. Hello I'm Maggie Robin, Community GP rural GP obstetrician at Beaudesert Hospital and coordinator of Mater's GP shared care education program.

In this episode we're talking about hypertension in pregnancy with Dr Vishwas Raghunath. Nephrologist and obstetric physician. Vish works at Ipswich and Mater hospitals managing complex medical conditions in high-risk pregnancies and also at the West Morten Kidney Health Service.

We are Mater. We are Mater. We are Mater. This is sMater.

Hi Vish. Welcome to sMater. Hi, thank you so much for having me here.

Now hypertension is the most common medical problem encountered in pregnancy. In Australia 30,000 women each year will develop high blood pressure in pregnancy and for a third of those it leads to preeclampsia so it becomes a health concern for life for these women doesn't it? Yeah absolutely. It's one of those interesting relationships where we certainly believe that pregnancy is a bit like a stress test here where it identifies some women who are at higher sort of cardiovascular risk and then allows them to manifest preclampsia which then translates to a higher future risk as well and what's important there is that the understanding of this future risk has become more apparent just in the last few years whereas historically we used to believe that we could often cure preeclampsia just by birthing baby whereas now we know that that's not entirely true in terms of better guidelines that are being available to follow up these women as well. The SOMANZ  hypertension in pregnancy guideline has recently been updated and approved by the NHMRC. What has changed and what's new in the guidelines? What's new in this guideline is the fact that we've gotten a bit better information about how to screen for women for preeclampsia. How do we have strategies there's some more clarity around prevention strategies for preeclampsia. The management of hypertension in itself hasn't changed too much but there's some clarity around what targets we need to meet and then subsequently once these women have delivered we have a bit more information on what to do after birth. Just making sure that they're linked in for annual health checkups and thereafter so to make sure that the future health is well preserved.

So when we see someone in general practice who perhaps is preconception and planning a pregnancy and perhaps they have some risk factors in their history we know obviously to take their blood pressure and pay attention to that but what other things should we be asking about testing and looking for to prevent preeclampsia here? Oh that's a great question. I think one of the important things is that most of these women will be in the community in primary care so having
primary care working well with the hospital based services to try and identify these women at risk will is quite crucial. A set of risk factors would, the standard high risk factors would be certain pre-existing conditions that we often look for particularly the big ticket items would be pre-existing hypertension pre-existing diabetes either type 1 or type two, underlying autoimmune conditions such as systemic lupus dermatosis or rheumatoid arthritis or nephrotic syndrome for that matter and also previous history of preclampsia so if this woman has had preclampsia in the previous pregnancy there's a good chance that she will get this in the subsequent pregnancy.
Now these are the these are probably most of the main risk factors but you've got a few smaller ones such as advanced maternal age, BMI, IVF pregnancies as well so there quite a few things that we can go through which the guideline highlights as well and often recognizing these
these conditions are a pathway to working towards reducing their risk as well so you could if you have a few risk factors that you do identify you can select these women out and then talk to them about individualize screening to further delineate their risk and then some prevention strategies,
particularly most important will be the use of aspirin and calcium early in the pregnancy. We suggest with the new guidelines that we use 150 milligrams of aspirin every day preferably at night to improve compliance right from about 12 to 16 weeks definitely under 16 weeks and through through the remainder of the pregnancy till about 34 to 36 weeks and that goes a long way in reducing the risk of preclampsia particularly under 34 weeks but also later preeclampsia as well alongside the use of calcium for example in women who have lowish calcium diets would be quite useful as well in reducing the risk of preclampsia and we normally recommend one or two tablets of calcium in this regard based on their dietary intake. 

What about non-pharmacological treatments?
Now traditionally we've known that things like exercise are really good for us but here we have a good body of evidence which has been endorsed in this guideline to show that some good exercise for about 2 and a half to 5 hours a week goes a long way in reducing the risk of preeclampsia.
Now this could be aerobic exercise or even some mild resistance training works really well in this regard so I think that is the most important sort of non-pharmacological measure and a few other things like changes in diet and lifestyle which would be quite important as well.

Vish, what are the type of hypertensive disorders that develop during pregnancy and which ones are the most serious?
This is really important because you've got a wide variety of hypertensive disorders in pregnancy now as you might know historically this used to be termed as pregnancy induced hypertension which we understand now is a bit of a misnomer.

Now you could have pre-existing hypertension that women bring along to the pregnancy journey but if you look at new onset hypertension and pregnancy particularly after the second half after 20 weeks in the pregnancy you're looking at a couple of groups so you've got gestational hypertension which tends to be the more common variant and then you've got preeclampsia which is a marker of gestational hypertension plus some evidence of either maternal or fetal dysfunction and you've also got other smaller kinds of hypertension for example white coat hypertension there is some relevance in pregnancy. Mast hypertension which is a different kind of hypertension where you've got normal blood pressure in the clinic scenario but you've actually got high blood pressure at home some of these you actually need an ambulatory blood pressure monitor to make a diagnosis. What is it about preeclampsia that sets it apart from gestational hypertension or chronic hypertension?

What suddenly tips someone over from that into preeclampsia?

It's a great question. I think the lines are sometimes a bit fairly blurred. The whole mark of preeclampsia would be on so gestational hypertension is purely the development of hypertension where you have a blood pressure of over 140 or 90 millimeters of mercury. The development of preeclampsia requires some marker of maternal organ dysfunction now this could either be traditionally what we'd recognize for proteinuria as a marker which is not necessary for diagnosis anymore it can be there but it's not necessary for diagnosis anymore acute kidney injury for example a serum creatinine that's a bit more elevated than usual now typically in pregnancy a creatinine of more than 90 m per is considered abnormal whereas outside of pregnancy this would very much fall in the normal range so that's something that we have to be attuned for liver dysfunction in the form of transaminitis neurological events such as seizures or intractable headaches and hyperlexia pulmonary edema or periorbital edema some of these are manifestations as well and importantly from 2014 or or rather the 2018 definition when they brought in fetal dysfunction as well so placental dysfunction in the form of growth restriction and that's an important definition as well so these are some of the things that will probably indicate that preclampsia has developed.

Okay so someone who has high blood pressure and fetal growth restriction that would qualify as preeclampsia?
Yes. Based on um the current guidelines so if you have if you're able to demonstrate field growth restriction in the absence of other common conditions such as infections or other purely maternal etiologies then that would amount towards the definition.

You mentioned edema and pregnant women often report edema it seems really common to get swollen feet swollen hands it's not necessarily a diagnostic criterion for preeclampsia though is it?

No that's a very good question. Pulmonary edema like you highlighted  is quite common in pregnancy particularly what the guideline has spoken about is pulmonary edema so if you have a new onset pulmonary edema which often manifests with either orthopnea or PND would be something to consider also when you develop facial or periorbital edema that would be something to raise a red flag as well but yes you're quite right in the sense that the peripheral edema is quite common. 

Looking at the management of a chronic or gestational hypertension, what anti-hypertensives are best for women in pregnancy?

Currently SOMANZ recommends the a few medications that are quite safe. There's good robust data for their safety in pregnancy as well. Traditionally the first line medications would often be labetalol which is a beta blocker. Methyldopa a centrally acting agent and nifedipine which is a calcium channel blocker. Now these three have a good safety data not just in the management of chronic hypertension and pregnancy but also new onset hypertension as well.

They're short acting medications which means that they're they're administered a few times a day which is something that the women need counseling about as opposed to outside of pregnancy where you can get away with once daily medications and we can always consider the use of additional agents such as hydralazine to be used as second line as well.

Any contraindications for those medications?  Beta blockers as we know we have to ask about a history of asthma so they might have some increased bronchial constriction as a consequence of that so we'd like to avoid that. Methyldopa is generally avoided in someone who's got a history of recent clinical depression because it can worsen mode swings as well and that's another variable we don't want to deal with. Nifedipine to highlight that it might cause some headaches in some of these women and you can have some reflex tachic cardia occasionally but again these are some things if you counsel women the right way any of you can pick a first line agent which works really well and often we find that we might as time goes on need combinations of medications so we just talk them through that journey as well.
What about those who are on ACE inhibitors for hypertension before their pregnancy should they be transferred onto something different for pregnancy?

One of the important things is I think historic we used to always say that we have to stop ACE inhibitors prior to even starting their pregnancy planning. Now this is okay if you've got someone with well-controlled hypertension or let's say if they're on an ACE inhibitor
for protura with kidney disease and if it's stable that's fine but you have a cohort of women who either have um uncontrolled hypertension or have significant protura where stopping this quite early and bearing in mind that it can take a while for someone to get pregnant as well might risk further increase in proteinuria which can have consequences as well so the current teachings or the current guidelines recommend continuing an ACE inhibitor or an ARB Angiotensin receptor blocker till you confirm a pregnancy at which point it's safe to stop these medications now I must stress that under no circumstances should we continue using these medications in once the pregnancy has been confirmed particularly in the second and third trimester they're definitely contraindicated then.

What are the challenges with aspirin and dosage and what should GPs know to tell their patients?

Aspirin as I mentioned earlier should be convinced in anyone who's been identified as having a high risk of preclampsia and we generally recommend starting that between before 16 weeks 150 milligrams is the recommended dose so it's still classified as low dose aspirin but it's a bit tricky in Australia because we don't have 150 milligram tablets what we often recommend is using the 300 milligram soluble tablets break it in half but important discarding the other half because they do not stay well using aspirin at night is best recommendation purely because it improves compliance. Now we have shown studies particularly out of Australia as well where compliance has been shown to be linked in with the size effect of aspirin as well and that's why it's really important to use aspirin at night and if you start using aspirin at that point in time and continue through till about 34 to 36 weeks you get the best result for aspirin. There are a small proportion of women however who might have acute gastritis as a consequence of aspirin and that you may have to vary recommendations and also as we're increasingly seeing women who have recently had bariatric surgery but for the most part using aspirin is beneficial.

You mentioned calcium earlier but you said if dietary intake is adequate potentially not needed is that right?

There is yes so in summary yes 
but it's important to clarify their dietary intake now the new guideline also provides a link to a calcium scoring system in the diet and that gives us a better idea it's often hard to quantify how much calcium a woman takes but using a multivitamin or a single dose of calcium on top of their diet isn't unreasonable on a practical basis to make sure that you're getting that added layer of protection as well.

So we've talked a bit about women who have pre-existing hypertension and women with risk factors. What about someone who perhaps has no past history of hypertension and they're pregnant and we discover that their blood pressure is high. What should be our approach in general practice?

To that I think the big number to consider is 140 over 90 milligrams of mercury. Now if their blood pressure is just at or above that range I would definitely recommend getting a baseline set of additional information so we of course when we check the blood pressure in the office setting for the first time we repeat it as we normally do once that has been confirmed I would definitely recommend doing some baseline blood test to look at a full blood count a CHEM-20 panel to look at serum creatinine and liver function tests as well and a urine for a protein creatinine ratio.
Now this would give us that information to see if they meet criteria for preeclampsia. Now if they don't meet criteria for preeclampsia and they then they would be classified as gestational hypertension
and they're clinically well of course the other clinical features of preeclampsia we have to be mindful of as well such as no evidence of

brisk reflexes or clonus, no headaches, no right up a quadrant pain and those sorts of things you we could commence them in any of those first line agents such as labetalol or methyldopa and close monitoring would be crucial so a lot of these women as I've said before the lines between progressing from gestational hypertension to preeclampsia are quite blurred so we would recommend frequent monitoring of these women so at least on a weekly basis and refer them onto a hospital based system because once these women have developed nuance at hypertension we have to try and do as much as we can to gather more information on risk so in general we would recommend transferring their care from Community Based care to a hospital based care so they can get additional Maternal Fetal surveillance. Is there a particular blood pressure cut off where we should be not waiting and not repeating measurements but just sending someone straight to hospital? Absolutely so severe hypertension would amount to a blood pressure of over 160 over 110 millimeters of mercury and regardless of whether they have symptoms or not if this is a confirmed true blood pressure reading they need to be coming to hospital straight away either to the emergency department of your local hospital or the pregnancy Assessment Centre
here at Mater Hospital.

What about due date. Do these women that we're talking about do they need to deliver earlier?

Look that's that's an interesting question, so the timing of delivery is always a difficult question in some women with any hypertensive disorders of pregnancy now if you've got someone with gestation hypertension who's got well-controlled blood pressure on a single agent there's no reason that you'd have to bring this forward any delivery forward we can watch the woman through but the important thing is close surveillance if someone develops preclampsia in in my practice it's uh unusual that they get too many more weeks out of that particular pregnancy and often particularly if they have an increasing requirement for additional antihypertensive agents or some changes in baby's growth then often those would be the triggers for planning for early delivery. Now the recommendations particularly through the new guidelines as well would suggest that at between 36 to 37 nearly 36 to 38 weeks is probably going to be ideal unless you're faced with a situation where you've got rising high blood pressure. 

The Maternal Fetal Medicine Pregnancy Research Centre at the University of Melbourne found that in Australia
preeclampsia is the indication for 20% of labor inductions and 15 of caesarian sections.
It also accounts for 5 to 10% of pre-term deliveries.

Are there times when preeclampsia 
or the other hypertensive disorders in pregnancy become so severe that there's indication for urgent pre-term delivery? Yeah unfortunately  
particularly working at the Mater when we tend to see a lot of quite unwell women as well is that when you have preeclampsia with a particularly severe phenotype and this would be someone who has escalating need for anti-hypertensive medications so there on a number of medications they're having symptoms on and off and they're having changes in their biochemistry and pathology that you can monitor or worsening fetal indices in the form of growth restriction or abnormal findings on dopplers as well these would be women where we'd start planning for delivery early. Now it's always a tight rope walk purely because of the fact that you want to make sure that both mum and bub are healthy. The delivery planning between 36 and 38 weeks becomes very individualized in this setting but yes early delivery planning for the safety of both mum and bub will be considered in them.

And what about earlier gestations than 36 weeks are there any interventions that can help improve the outcome for baby if they need to be born even more pre-term.

Prior to 36 weeks again it's a difficult situation but often if it looks like the chances of baby being born are better than baby being in mum and mum is demonstrating worsening signs and symptoms of preeclampsia then delivery planning would be quite imminent. Now the mode of delivery is something that can be also very individualized now it's not automatically required that someone needs to have an emergency caesarian section. A lot of these women can be induced and have vaginal births as well but it is an issue of timing so if timing is critical then we're probably looking at trying to decide the appropriate mode of delivery. So moving to the the postnatal period mothers left hospital and back to care with their GP what advice do you have for GPs and keeping an eye on these women? 

Now that's an excellent question. Within the first few weeks of delivery we still have to monitor mothers very closely so you it's quite likely that any local hospital whether it's the Mater or any other maternity hospital will be following up these women within the first couple of weeks now once their blood pressure if they've got a blood pressure management plan and they're still on anti-hypertensive medications we often adopt a shared care model with GPs to continue their management of blood pressure thereafter as well. They need to be seen at about 6 to 8 weeks after birth and that's important and the newer guidelines are also recommending there a review at about 3 to 6 months after birth as well and that's important because we don't want to lose this window of opportunity and that's something that's quite crucial in in a woman's journey through pregnancy particularly dealing with these sort of effects of the stress test that the pregnancy is that shows that most women who have any hypertensive disorder in pregnancy tend to have a higher blood pressure than age match cohorts in the first year postpartum. So following them up at the 6 we mark maybe 3 to 6 months depending on what's possible and then thereafter having an annual health check is very crucial. Annual health check would comprise an overall assessment of the cardiovascular health and blood pressure checks and weight gain as well.

When we're treating hypertension postpartum if they're still needing medication do we change the agent? There are a few more medications that are available in our arsenal to manage pressure after delivery as well. Now what we tend to find is particularly as I've highlighted before with methyldopa for example there's a higher risk of mood disturbances and in the immediate postnatal period that could be troublesome as well we often tend to use ACE inhibitor
like enalapril or captopril. They are quite safe in the immediate postpartum period they have been used to be safe in breastfeeding as well. The other benefit of using these groups of medications they can be twice daily medication instead of three times a day medication which and compliance certainly improves with that particularly when they've got a newborn at home.

Vish are there particular biomarkers in early pregnancy that GPs should think about testing for when we're looking for preeclampsia risk?

It's one of my favorite things about preeclampsia is biomarkers as well because there's so much promise now the research is delivering but it's still underway now what everyone may have heard of is this thing called the sFlt-1/PIGF ratio. It's often in other states it's called the PERCH test the Preeclampsia Risk test.

Now sFlt is the soluble FMS like tyrosine kinase molecule and PIGF of course is placental growth factor and all this ratio highlights is the imbalance between sort of pro-angiogenic and anti-angiogenic factors within a woman with preeclampsia. The guideline through SOMANZ

highlighted the fact that if you have a situation where the clinical context is a bit unclear you're not quite sure if this women has preeclampsia but you'd like to know that doing this particular test now bearing in mind that access to this test is very limited as well largely to bigger centres but if you can get a ratio and the number that you may have read in the papers is again under 38 and that's quite reassuring mainly for its negative predictive value so having a ratio of less than 38 would rule out preeclampsia now if you think about the importance of that particularly in Australia would be a lot of women in regional centres that allows us that little bit of time to work them up and then facilitate transfer to larger centers as opposed to having to do it in a fairy rushed way which might have some unknown consequences as well. So it's an important area of research there's a lot of work happening within Australia as well there are it's not quite become a purely diagnostic marker yet. The committee acknowledges that there's a fair bit of research going on and certainly the future will be promising in this space because you will have the presence of some more guidance around how to use this better outside of the current use. Vish it sounds like there's lots of work being done in in this area at the moment what do you see as the future in treating hypertension and pregnancy?

The future is bright the future is promising. There's a lot of work happening in Australia and it's so great to be part of the Obstetric Medicine Group in Australia because I think we're amongst the world leaders in this space where the the kind of research that's happening here with International collaborators is quite excellent. There's a lot of work happening in preventative strategies as can be seen through the SOMANZ guideline as well there are quite a few promising um groups of medicines that have been that are being trialed to see if they have a good benefit as either in adjunct to aspirin to prevent preeclampsia so that's an interesting space to watch out. We're getting better at personalizing treatment and I think that's important so the future certainly will move towards a personalized approach where we want to fine-tune treatment strategies not only looking at how they respond with a blood pressure point of view but can we use any other investigative markers. Now there's some studies that have looked at using echocardiography as a way to guide treatment management as well in these women and that certainly has been used in some centres but we're just waiting for more data to make that a bit more applicable generally. The postpartum space is something that I'm quite passionate about, it's extremely important and as I've said before it's a unique window of opportunity that only a woman gets to try and identify their cardiovascular health and whatever intervention you do in the first few years after a diagnosis of any hypertensive disease in pregnancy has lasting benefits for more than 10, 20, 30 years into the future. Unfortunately preeclampsia is associated with a two to four times high risk of heart failure, stroke, death and chronic kidney disease so making a difference where you can look at adjusting their cardiovascular risk is quite crucial and there's definitely something happening in the area as well that we would work towards improving their healthcare.

Sounds very promising Vish thank you so much for joining us today. Thank you very much for having me. It's been great. Before you go though we have a little surprise. It's a segment we like to call The Checkup. So we have five quick questions from Maggie and they're just finding out a little bit about you as a medical professional and as a person as well. You ready to go? Yep sure let's give it a go. Vish when you were a little boy what did you want to be when you grew up? Ooh an astronaut. 
Yes didn't work out quite that way but I still love astronomy so I love stargazing. 

Describe your handwriting my handwriting? Well I'd like to think it's quite legible I quite enjoy writing and I think that's one of the I'm very much a paper and pen kind of a person so I still make notes.

What do you like to do to unwind? I love listening to music, going for hikes they there're some of the things that I'd love to do with the kids and the family it's great I mean we're such we're lucky to live in a place that has access to um walking tracks and hiking tracks that's brilliant.

What's the best outfit that you have ever worn to a costume party? Elvis Presley actually and I won the best dressed award which is interesting given that I have two left feet and I just can't dance so you look the part. I looked the part.

If you had a medical student with you right now what single piece of advice would you like to impart to them about their future? I think just drawing on my own personal experience being open to opportunity is something that I always 
encourage. I tell all my juniors that my own journey towards obstetric medicine and nephrology has been not quite - it's not that I wanted to be an obstetric physician when I first started off. I became a nephologist and I sort of stumbled into obstetric medicine when I worked with someone who was quite passionate with it and I just found that it clicked and I think just being open to that just the fact that sometimes opportunities come laterally and if you're able to seize them I think you'll be happier.

It's been great having you here today Vish, thanks for joining us on sMater. Thank you so much for your time it's been great fun.

For our listeners at home or in the car or having a well-deserved break between patients,
thanks for tuning in. See you next time on sMater.