sMater | Preterm Births: Recognising the Risks | Dr Huda Safa

Introducing you to sMater, a podcast ‘by clinicians for clinicians’, brought to you by Mater, one of Australia’s leading healthcare providers.

Season one focuses on mothers, babies and women’s health, featuring world-class Mater obstetricians, neonatologists, midwives and other clinicians on the important topic of pre-term birth prevention. 

In episode one, we're joined by Dr Huda Safa, Senior Staff Specialist, Obstetrics & Gynaecology, Mater Mothers’ Hospital, who shares her invaluable insights into the women at increased risk of preterm birth and how to recognise the warning signs. 

GP Education activity log:

•   Podcast title - sMater: Preterm Births: Recognising the Risks
•   Provider - Mater Misericordiae Ltd 
•   Date published - November 17, 2023
•   Learning hours - 20 minutes
•   Certificate of completion - Download 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 I'm Katherine Cooper Clinical Specialty Coordinator for Mothers Babies and Women's Health at Mater and we're coming to you from Meanjin the land on which this podcast is being recorded.

Today we are joined by Huda Safa, Senior Specialist In Obstetrics and Gynecology at Mater Mother's Hospitals. Huda has a wealth of experience in high-risk pregnancies and is dedicated to maintaining a patient centered care approach. She's actively involved in the medical education of specialist trainees,
Junior doctors and medical students and is also a senior lecturer and on the board of examiners at the University of Queensland.

Today she's joining us to talk about pre-term births: recognizing the risks.

Mater caring for the community for more than a century,
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home to world class clinical facilities, Australia's largest and leading scientific discoveries

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

[Music]

Huda, welcome to sMater. Thank you. Thanks for having me.

Let's set the scene. Who's most at risk of preterm birth? Risk factors for pre-term birth are

well published and described in National and international guidelines  and one of the most um predictive risk factors is a history of previous pre-term birth in the woman herself but also other risk factors like multiple pregnancy, previous history of substantial cervical surgery like biopsy or a multiple procedures. These are usually procedures undertaken to treat cervical dysplasia which is encountered in the  context of abnormal pap smears so when an abnormal pap smear is detected surgery sometimes is required. There are other risk factors largely related to demographics and socioeconomic factors associated with 
preterm birth like smoking for example 

but good percentage of women who develop preton birth unfortunately lack any identified risk factors.

How much attention should we pay to those socio demographic factors compared to say cervical surgery or smoking?

That is very good question actually Katherine and the evidence doesn't exactly tell us the weight of each risk factor that is associated with pre-term birth

but I believe the focus should be on what we call modifiable risk factors and definitely socioeconomic factors are in that category. You cannot do much about previous cervical surgery risk or risk I did not mention is risk of congenital uterine abnormalities or mullerian abnormalities. There's not much that can be done about that but definitely investing in modifying risks such as smoking early in the piece is such an investment to reduce a range of perinatal adverse outcomes not just pre-term birth and of course goes beyond pregnancy years so I totally agree we should focus there.

What about women who don't tick any of those boxes that that you've mentioned there how then do you identify risk?

That's a brilliant question Jillian and actually the subject of a large national collaborative aiming at reduction of pre-term birth so a good percentage of women like I indicated earlier will lack risk factors and have a short cervix incidentally found at midtrimester scan. We believe we can target that cohort of women to make a difference to pre-term birth risk in this country.

Wo when do we do that scan? Is there a strict window for when you do that?

So this is a scan that is also known as a morphology scan so it's the main ultrasound scan that most pregnant women will choose to have during the journey of pregnancy.
And that is usually perform between 18 and  20 weeks and the evidence for the purpose of reduction preterm birth is strongest for that window if you like so if we identify short cervix in that scan that's an opportunity to intervene and prescribe progesterone to reduce the risk of preterm birth because a short cervix even though incidental, i.e. there's no symptoms, is a powerful predictor of increased risk of preterm birth.

So once you've identified someone as being at risk what conversations or what support do you give those women, 
particularly around those who probably may not be expecting it? 
Yeah that's a very good question. I think the conversation should start before we identify the risk especially in the context of those women in whom a short cervix is identified by educating them because women do expect to have that morphology scan around that mid trimester and we need to explain to them that measurement of the cervical
length is routine part of that ultrasound scan and there is a possibility that the cervix might be identified to be short and if that's the case they need to either present to us at the hospital where we can address that and start progesterone therapy or go back to their GP as soon as they can  to get that support and um follow-up programs in place to try and make sure that we have a cervical surveillance program for them.

So education is key and helping them feel safe and that there is a clear pathway.

Exactly right so it's there's no unknowns or mysteries or surprises of clear communication pathways.

In a best practice statement reviewed in 2021 RANZCOG, the Royal Australian and New Zealand College of Obstetricians and Gynecologists,
supports the use of trans abdominal screening of low-risk women with singleton pregnancies at the mid-trimester scan with additional transvaginal assessment for those with a short cervical length or a full cervical length unable to be clearly viewed.

Let's talk about that in a bit more detail please Huda. So women who go through that midtrimester scan as you mentioned the morphology scan which they're familiar with where the cervix is measured trans abdominally,
how long should that cervix be and at what point does it ring alarm bells for you?

Yes that is the new message we trying to get through to our sonographers, radiologists and women themselves is that the cervical length is usually measured on abdominal modality, transabdominal modality and if the length that is measured is less than 35 mm or indeed the cervix cannot be clearly visualized that is when the next step is indicated which is offering\that woman a trans vaginal ultrasound scan to get a more accurate look at 
that cervical length and the cut off value that we look for as significant is less than 25 mm so a transvaginally measured cervical length of less than 25 mm is defined as short and requires an intervention ideally that same day.

Howdid we determine that length of 25 mm?

So very good question Katherine. The 25 mm seems to be the cut off where the risk prediction matches uh a lot of studies that have been done in this space for intervention and it matches the shortest 10th centile of what a cervix should be in mid trimester.

So some women I assume would not be prepared for a transvaginal scan. Do some say they're uncomfortable or refuse even. That is I think comes down to lack of knowledge of the role of this let's say intrusive examination for some women and that's why part of our collaborative at Mater to reduce risk of preterm

birth we've produced some patient education brochures about cervical length for Education. I personally have a conversation with woman about their morphology scan and say that this is a detailed ultrasound scan that has three objectives one is assessing your baby one is looking at your placenta and its relationship to the uterus and one is to look at your cervical length and in a small percentage of women it will be short on trans abdominal modality and that needs to be checked on a trans um vaginal modality. In fact there is evidence to support a high level of acceptability in the population when women are educated and expectations are set about the role of this test they appreciate the diligence and the care that's provided to the to identify a risk that is mitigable.

Huda, what happens if the woman does decline the transvaginal scan like what are the options available to the clinician like transabdominally is not as clear as transvaginal?

The transabdominal modality does have pitfalls and limitations because usually performed with a full bladder in pressure with the probe on the abdominal wall which can falsely elongate the cervix and again backed by evidence when you eliminate these factors because for a transvaginal

modality the woman needs to empty hair bladder and the probe is different is inter vaginally so it looks closer at the cervix and it's if you like the source of truth. If a woman does decline we always maintain patient centered care and uphold the principles of respecting patients autonomy. We then shift and focus from approaching this in proactive prophylactic way to a more reactive way should a woman present later on in pregnancy with symptoms suggestive of preterm birth, contractions, pelvic pressure we then use transvaginal ultrasound scan for cervical length assessment as our diagnostic tool to say you have increased risk of pre birth in the next seven days and then there's a different protocol to try and suppress contractions start steroids antenatal steroids on board so we always try and approach things in a proactive way but I respect some patients might have different reasons for declining a recommended intervention. We go into more of this in a future episode but can you go into a little bit more detail about the preferred methods of intervention when someone with preterm birth is identified?

Yes, that is also a very good question. What is available to and backed by evidence is two interventions. 
The least invasive and associated with no known harms or risk is vaginal progesterone.

Natural vaginal progesterone started on that same day that the short cervix is identified has been proven to reduce the risk of pre-term birth and that's the preferred first line option this is in the context of a woman who's had a short cervix identified at midtrimester scan. The other option is an operation called cervical cerclage. It's a surgical procedure under general anesthetic or spinal anesthetic where a stitch is placed in the cervix a permanent stitch

that's usually removed 36 weeks to support that structural integrity of the cervix. As you might appreciate it's a more invasive approach so it's not usually first line but there'll be select group of patients for whom it might be an appropriate first line for example a woman who is that comes to mind who is started on progesterone and despite that there's progressive cervical shortening that we would detect with that surveillance program I was talking about before. In those women a stitch is indicates probably a more appropriate option.

Another scenario where a stitch is an appropriate first line option is a woman who had previous history of sometimes more than once of preterm birth or second trimester loss in those women a cerclage is superior to Progesterone as an intervention. There are obviously many other interventions that have been studied and are not really backed by evidence so we don't tend to use them. 

A major risk factor for premature labor is being pregnant with multiple babies. The Australian Bureau of Statistics reports that in 2021 mothers who had a multiple pregnancy accounted for 1.4% of all women who gave birth.
Queensland in the Australian Capital territory had higher proportions of multiple births than any other state or territory.

When we're talking about women with multiple pregnancy and the risk of preterm birth, what is the rate how common is that for those particular patients?

Oh multiple pregnancies is a different kettle of fish all together. Yes in fact if you look at our statistics from Queensland our preterm birth for multiples in um 2021 Q1 QPC report was as high 69% but can I say only a third of those were spontaneous preterm birth. It is important to acknowledge that about 20 to 30% of preterm births are atherogenic initiated by us because of a risk that's been identified to either the mother or the baby and unfortunately in multiple pregnancies depending on the type of twins which are the most common type of multiple pregnancies there's so many other risks that prompt atherogenic earlier delivery so they have in multiple pregnancies to answer your question Jillian have increased risk inherently of preterm

birth both medically indicated and spontaneous. You mentioned progesterone and cervical cerclage. Are they suitable for multiple pregnancies can we use them?

Yes and no. So if it's an unselected multiple pregnancy i.e. there's no previous um history of pre-term birth there is no short cervix in this pregnancy using progesterone prophylactically has not been successful in reducing the risk of preterm birth in this cohort however if you have a multiple pregnancy with a short cervix absolutely progesterone and potentially cerclage in some studies and not others has been effective in reducing the risk of preterm birth.

One of the risk factors for preterm birth that we haven't discussed is infection. What infection are we talking about?

Yeah infection and inflammation were actually some of the earliest risk factors that were studied in this space and yes of course there is systemic infections like the flu and COVID and pyelonephritis any maternal systemic serious infection could start a cascade of preterm contractions and preterm labor but I guess in this space we're talking about localized infection or probably even colonization of the genital tract with some bacterial species that are not strictly in infection although can be associated with some infections like STIs
that have been in older studies associated with increased risk of preterm birth. The problem with looking for infection routinely is that the results of studies have been conflicting about effectiveness especially in asymptomatic population going and screening all women for the risk of presence of some bacterial species in the vagina for the purpose of giving them antibiotic treatment has not been effective in reducing preterm birth however we do screen for other infections for example asymptomatic bacteria we routinely perform a urine test for these women to reduce maternal disease and risk of infection transmission so there other areas where we do screen routinely for infection like syphilis for example to reduce some risks but not on population basis. So one of the things that I'm personally passionate about obviously midwifery continuity of care understand that can make a difference to outcomes?
Absolutely,  absolutely Katherine in fact it's one of the core seven strategies of the pre-term birth prevention collaborative is that women should have access to a know Midwife throughout their pregnancy if possible and we are very lucky at Mater that we do offer continuity of care to a variety of our pregnant population  cohort including preterm birth prevention clinic now. I think we have at least two publications from Mater 
attesting to the value of continuity of care in both of these two populations one is a First Nations woman bio or birthing in our community model of care and the other one is young women so that's another high risk group for a number of adverse perinatal outcomes. So these two studies have both demonstrated reduction in preterm birth rate when there is a care by a known Midwife so that is some of a larger pool of evidence there so that's undebatable in my mind at least.

Seem like good news makes you very happy! It does, it does.

Before we go Huda we'd like to introduce you to a little segment called The Checkup.

So we want to know more about Huda the medical professional and Huda the person so Catherine's going to ask you five quick very simple questions.

Are you ready? Yes okay. How do you want patients to see you? How do I want patients to see me? As a caring, compassionate, supportive and approachable doctor. Beautiful. How would you describe your handwriting? Oh can we not? Okay moving on. Who was the last person you FaceTimed? My dad.

What TV show best portrays your profession? Oh Greys Anatomy. Oh come. Where all the doctors do all the nurses work! But it is very unrealistic. Look to answer that question most medical TV shows don't reflect the reality that we live in but I thoroughly enjoy watching such a good show though. And what's your superstition?
I don't have many I don't have many. 

I just take it as it comes. Beautiful.

Huda, thank you so much for joining us on sMater. That was fantastic. Thank you for having me.

For our listeners at home or in the car or having a well deserved break between patients, thank you for tuning in.

See you next time on sMater.