High-risk pregnancy in general practice: twins, ADIPS GDM, CGM, and when growth looks wrong

Gold Coast obstetrician and gynaecologist

The Otter file does not state a speaker name. Clinic context as spoken: rooms at Pindara; a bulk-billed early pregnancy loss clinic; close work with Pink Elephant. No name is invented here.

The early pregnancy loss clinic, and why this talk

He opened with two handouts. One was a spiel about a clinic he runs. The other is the information sheet he gives every patient after a miscarriage — Gold Coast support services, and the psychologists he has used for women’s health and pregnancy loss over about fourteen years.

The clinic is an early pregnancy loss clinic, run out of his rooms at Pindara. Fully bulk-billed. They do not need private health. Refer miscarriage, recurrent miscarriage, or ectopic. He said he will see them within about forty-eight hours and manage it. It has dwindled a little because he did not advertise it; he used to keep a morning slot every day. He is happy to look after them again.

Photocopy the support sheet, or paste it onto your own letterhead. He works closely with Pink Elephant. Bears of Hope and SANDS are on the list as well.

Then the actual topic: high-risk pregnancy, pitched at GPs, because Gold Coast Health is doing more and more share care and passing more high-risk patients back to general practice. Learning points he named: when to get urgent specialist involvement; the new ADIPS guidelines and who gets an early GTT; CGM, which he is using a lot more; ultrasound findings in fetal growth restriction; what Dopplers mean, because they are easy to miss and should not be missed; and when to make an urgent tertiary referral.

Three twin types: DCDA, MCDA, MCMA

Three chorionicity/amnionicity groups. You already know them. He still walked them, because the referral threshold is different for each.

Why more twins if IVF is now strict about one embryo? Ageing population, he thought, and a lot of letrozole being written. Not so much IVF.

NIPT, vanishing twins, and who should scan after 16–20 weeks

Early DCDA management is the same as a singleton: NIPT, 13-week scan. One thing you cannot do well in twins is the preeclampsia risk algorithm — it does not work. NIPT is still useful. Interpret it carefully.

Vanishing twin: a twin pregnancy at six weeks, one gone by eight. Postpone NIPT. The vanished twin’s DNA is often abnormal, and the test can come back abnormal for that reason. They often suggest waiting until later in the first trimester. Sex chromosomes: two girls you can say; any Y chromosome and you do not know whether it is one boy or two.

From 20 weeks, DCDA twins need a morphology scan and then a scan every four weeks, and it should be tertiary-level. Lots of good services on the Gold Coast. From 20 weeks it should not be Paradise or South Coast. Private: Queensland For Women. Public: MFM at Gold Coast Health. Those are the places he named for twin ultrasounds from that point.

MCDA and MCMA: normal NIPT, normal 13-week scan, then from 16 weeks, every two weeks. The principle: DCDA has no TTTS and no TAPS, so you can wait until 20 weeks and go four-weekly. Monochorionic twins cannot.

The two tertiary-level private scanners on the coast have an agreement that after five scans the rest are bulk-billed — because you hit five quickly: dating, NIPT-era scan, 13-week, then 20 and 24.

TTTS versus TAPS, and growth discordance

Twin–twin transfusion and twin anaemia-polycythaemia sequence both come from abnormal placental vascular connections and preferential flow. They do not look the same on a report.

• TTTS: a big twin and a small twin, polyhydramnios and oligohydramnios. The donor is small.
• TAPS: it is about haemoglobin and viscosity. Growth and liquor may look almost the same. Equal-size twins can still have TAPS. The clue is a significantly abnormal middle-cerebral-artery Doppler (MCA PSV).

Ironic physiology he wanted GPs to hear: when they are born, the small twin often does better. The bigger twin is often the one in trouble, and in severe TTTS it is often the bigger twin that dies. The theory he gave: the smaller twin has been under stress, organs mature faster, cortisol is high, lungs are further along.

DCDA is still two pregnancies sharing one uterus. You can still get significant growth problems from uterine blood flow and placental function. Some discordance is normal. Around 20% discordance is where you start getting worried. 25% is very concerning. In MCDA, after about 25% you are pretty much assuming twin–twin transfusion until proven otherwise. One twin below the 10th percentile is also an absolute refer. Abnormal Dopplers — later in the talk — the same.

Blood pressure and urine: preeclampsia is much more common in twins. Take it seriously. Reduced movements: he is much more cautious with twins. Two babies in there; if she says movements are down, it is generally real. He asks people to try to identify twin-one and twin-two movements. Sometimes they can say one is still moving and the other is not. Decreased fetal movement is always taken seriously.

ADIPS GDM: 5.3 / 10.6 / 9.0, and who still needs an early GTT

The GDM thresholds were changed about twelve months before this talk, after an earlier shift about seven or eight years ago. That earlier shift dropped fasting from 5.5 to 5.0. They expected GDM to rise by about 5 percentage points. It went from about 10% to about 23%. A large group of diet-controlled babies were being born with a GDM label and no issues. So they sat in a room, he said, and chose halfway: 5.3. No dedicated trial of 5.3 versus 5.0. “Some smart people sitting in a room saying let’s choose halfway.” Ambiguous, but that is the number now.

The diagnostic set he walked: fasting 5.3, one-hour (the middle one — “significant”), two-hour 9.0. In the room he first said 10.5 then 10.9; a GP corrected him to 10.6 and he agreed. Request a standard GTT and you should get fasting, one hour, and two hour. Do not ignore a high one-hour just because fasting and two-hour look fine — how they handle the glucose load still matters. Higher numbers on that GTT diagnose type 2 diabetes, not GDM. A fasting above that threshold: he would consider going straight to insulin.

HbA1c is the last three months of sugar. She should not have had gestational diabetes for three months at the start of pregnancy, so he is not a massive fan of HbA1c as a stand-alone GDM test. It still has a use at booking.

Who gets an early GTT now

The old list of high-risk people all got an early GTT: previous GDM, BMI above 25, maternal age, PCOS, family history, previous macrosomic baby (four kilos), previous stillbirth, multiparity, hyperthyroidism, high-risk ethnicity (he named Aboriginal and Asian as the middle-sort of risk).

The tweak: for most of that list, an early HbA1c and a fasting glucose at booking is now good enough. A raised booking HbA1c is quite a red flag. A fasting glucose above 5.5 was the number he named in that sentence. The only people who still need a proper early GTT, as he summarised the new balance: previous GDM (he strongly recommends it), and those whose booking HbA1c or fasting glucose is high. If HbA1c is under 6, you actually do not need that early GTT just because they sit on the high-risk table. A GP in the room asked about 6.0–6.4; he said not less than 6 — that is what the guidelines are saying.

He likes this. Plenty of young, lean, fit women with PCOS do not need a GTT just for the label. Twenty years ago you could see PCOS across the room. That is not the cohort in front of you now.

Guidelines after a high booking result say early GTT as early as possible. He thinks doing it at 10–11 weeks is mean. Personally he times it around 15 weeks: after the 13-week scan, so you know the pregnancy is ongoing. He has had people do a GTT, then miscarry, and blame the test. By 15 weeks they are usually happier to drink the load. The room noted vomiting; he agreed. Someone mentioned condensed juice solids beforehand; he said that does not affect the outcome either.

Universal screening still: every person should have a GTT around the usual 24–28 week mark, with a few exceptions — which is where CGM comes in.

CGM when they refuse a GTT, or after a gastric sleeve

He has started using CGM a lot more in diagnosing GDM. He said, twice, that there are no official guidelines that say CGM diagnoses GDM yet. He is not advocating that you ignore the guideline. A lot of people are already using it, and he feels there is worthwhile evidence, but technically it is not the same level of evidence as a GTT.

Seven or ten days depending on the device. Same window as the GTT: 24–28 weeks; he usually does 26–28. Target he named: 80% of fastings below 5.5, and 80% of postprandials below 6.8. They Bluetooth to the phone, hit the app on waking and two hours after meals. A bit of patient work. A lot of his patients love it. You get a printout: 50%, 80%, 90% in range.

Any diabetes educator can put one on; a heap of GPs put them on as well. It sticks on. The room talked cost and websites; those figures were mumbled and are not repeated here as a price list.

One GP had worn a sensor at a conference, got a faulty high-glucose alarm, called technical support, and was told to finger-prick — without a meter. His reply: a real patient with diabetes would usually have a finger-prick option; he has not had patients ringing with that problem yet.

Three high readings: diet, metformin, insulin

When do people go from diet to metformin, metformin to insulin? Three high readings in one week when diet is already optimised. Interrogate the week. Christmas party, Maccas, baby shower: understandable, not a reason to start a medicine that day. Chicken and broccoli, they did their best, still high: that is the week that earns a step-up.

SGA versus FGR, ethnicity, and brain sparing

Small for gestational age versus fetal growth restriction. The difference he named: less than the 10th percentile versus less than the 3rd. Not all small babies are pathological.

The estimated-fetal-weight algorithm in common use is an Australian one. It does not take ethnicity into account. Aboriginal, Asian, and subcontinent babies are often smaller. A symmetrically small baby may be constitutionally small. Symmetry is a thing he looks for: head circumference and abdominal circumference should be pretty much the same.

Symmetrical restriction that is early, and not just constitutional, worries him more — aneuploidy is the big differential, especially if they have not had NIPT. Congenital infection is the other, especially CMV.

Asymmetrical growth restriction is the classic placental story: head relatively spared, body small — head 30th, body 5th. That is brain sparing. The placenta is giving everything to the brain. He called it a big warning sign.

CMV, AFI, Dopplers, velocity

Guidelines: test CMV at the start of pregnancy if they are high risk — anyone around small children, healthcare workers, childcare workers. That is pretty much 90% of his mums now, so he universally tests CMV with the antenatal bloods and suggested everyone else does too.

A GP asked about counselling childcare workers who refuse to change nappies. He tests them hoping they are already immune — then he can say, fine, keep going. If not: saliva and urine are the two ways you catch it. Pedantic hand washing. Do not share food. Do not share drink bottles. The one people forget: wiping kids’ noses and coughs.

Do not just look at estimated fetal weight. AFI matters: liquor is fetal urine; if they have been fed they should be weeing. Dopplers matter. He had a Doppler-by-Doppler section planned and ran out of time, so this write-up does not invent the missing PI cut-offs. Growth velocity matters. A baby on the 5th, then the 5th, then the 5th, is growing along its line. 80th to 60th to 40th is not reaching growth potential, even if it is not a “really small” baby.

He closed by pointing at the forms again. His mobile number is on the letterhead. Call about patients even if they are not coming to him. His diabetes educator works in the rooms, also with Gold Coast Health, independent — Type 1 and Type 2 as well. You can refer to her without referring to him.

Take-home messages for clinic

1. Early pregnancy loss clinic, Pindara rooms, bulk-billed. Miscarriage, recurrent miscarriage, ectopic, about 48 hours. Pink Elephant, Bears of Hope, SANDS. Copy the support sheet.
2. DCDA (~80%) is two pregnancies in one uterus. MCDA is TTTS/TAPS/sFGR. MCMA is tertiary, often birth at 30–32 weeks for cord entanglement. More twins: age and letrozole, not just IVF.
3. Vanishing twin: delay NIPT. Twin preeclampsia algorithms do not work. From 20 weeks DCDA, and from 16 weeks monochorionic, use tertiary twin scans (QFW or MFM GCH) — not a generalist shop.
4. TTTS = size + liquor discordance. TAPS can be equal size with a very abnormal MCA. The small twin often does better at birth. Discordance: worry from ~20%, very concerned at 25%. One twin <10th: refer. Reduced movements in twins: take it seriously.
5. GDM diagnose on 5.3 / 10.6 / 9.0 as spoken (one-hour corrected in the room). A high one-hour still counts. Higher values are type 2, not GDM.
6. Most high-risk women now get booking HbA1c + fasting, not an automatic early GTT. Early GTT still: previous GDM, or a high booking result. He times that GTT around 15 weeks. Universal GTT still at 24–28 weeks.
7. CGM is not an official GDM diagnostic yet. He uses it anyway for people who refuse a GTT, and for gastric-sleeve patients who must not have a GTT. 80% fasting <5.5 and 80% post-meal <6.8 was his working rule.
8. Three high readings in a genuinely diet-optimised week is when he steps up from diet toward metformin or insulin. Party weeks do not count.
9. SGA is not automatically FGR. Australian EFW ignores ethnicity. Symmetric may be constitutional; early symmetric raises aneuploidy and CMV. Asymmetric = brain sparing = placenta. Look at AFI, Dopplers, and velocity, not only EFW.
10. CMV: he tests everyone with the booking bloods. High-risk in the guideline is almost all his patients. Hand hygiene, no shared bottles, noses and coughs.

Dr Kotha · Gold Coast · high-risk-pregnancy.drkotha.com