Episode 21 Miscarriage

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This page contains information directly transcribed from the MOGCAST podcast. You can listen to the episode on Spotify.

My name is Alison Bryant-Smith. I'm a consultant obstetrician-gynaecologist, currently working at the Northern Hospital in Epping, plus privately at Epworth Richmond. I specialise in advanced laparoscopic gynaecology and love being involved in teaching.

This MOGCAST episode will be about miscarriage. I'd like to add a content warning. This topic may be triggering or upsetting for some listeners. If so, feel free to skip forward to the next episode. Otherwise, please make sure you've got some supports in place before you keep listening.

Miscarriage is a really important topic to cover in the MOGCAST series. It's incredibly common. Sadly, approximately one in six pregnancies will end in a miscarriage. It's important that clinicians, whether in general practice, emergency or gynaecology, have a good understanding of the definition, terminology and management options.

So what is a miscarriage? In Australia, miscarriage is defined as the loss of an intrauterine pregnancy prior to 20 weeks gestation. And this compares to the loss after 20 weeks, which is called a fetal death in utero or FDIU.

You may hear the terms abortion and failed pregnancy used interchangeably with the phrase miscarriage. Please don't do this. Abortion is the termination of a viable intrauterine pregnancy and is a very emotive term. The phrase failed pregnancy may be interpreted by women as suggesting a personal failure on their behalf. So please avoid using abortion or failed pregnancy when miscarriage is more accurate.

So what are the causes of and risk factors for miscarriage? Well, of all miscarriages that occur in the first trimester, 60% of embryos are chromosomally abnormal or aneuploid. When I chat with women after they've had a miscarriage, I explain this to them by saying that her genes and her partner's genes just didn't match up correctly, and the miscarriage was nature's way of saying that this wasn't going to be a happy, healthy baby.

I hope that this assuages any guilt the women might have about what she's done, anything that she thinks might have caused the miscarriage, such as a hot bath, a vigorous session at the gym, having an alcoholic drink or two, etc.

One key risk factor for miscarriage is increasing maternal age. For example, the risk of miscarriage in women aged 25 to 29 is 10%. This rises to 17% in women who are 35 to 39 years old and is as high as 57% by the age of 44. A confounder here is that the risk of aneuploidy also increases with increasing maternal age, particularly from 35 years old and beyond.

Another risk factor for miscarriage is a history of previous miscarriage. As in many other areas of medicine, with miscarriage, history tends to repeat. We've said that the baseline risk of miscarriage in your first pregnancy is approximately 15%. Once you've had one miscarriage, the risk of another is 23%. Once you've had two miscarriages, the risk of a third is 33%. Once you've had three miscarriages, the risk of a fourth jumps to 60%. And this is all independent of maternal age.

To summarise what we've covered so far, miscarriage is the loss of an intrauterine pregnancy prior to 20 weeks' gestation. Approximately 15% of pregnancies will end in miscarriage. There's an underlying fetal chromosomal abnormality in 60% of first trimester miscarriages.

And notable risk factors include increasing maternal age and having had a previous miscarriage. So next, I'll move on to clarifying the confusing terminology about different types of miscarriage.

The five types of miscarriage that I'll cover include missed, threatened, incomplete, inevitable and complete.

First up, missed miscarriage, which is M-I-S-S-E-D. A missed miscarriage is when the embryo stops growing and there are no symptoms, so no vaginal bleeding or pain. It's often an incidental finding on a dating scan. The patient presents for her routine dating scan at 8 to 10 weeks' gestation, and sadly the embryo is found to only be 6 to 7 weeks' size without any fetal heartbeat.

Next, threatened miscarriage. This is the broad term used when a woman has bleeding in the first 20 weeks of pregnancy. Essentially, any bleeding in the first half of pregnancy is a threatened miscarriage, and this occurs in about 20% of all pregnancies. Once an ultrasound has been performed, the findings of a viable intrauterine pregnancy, i.e. with a fetal heartbeat present, will confirm the diagnosis of a threatened miscarriage.

Next, incomplete miscarriage. This term is used to describe the situation when some of the products of conception have been passed vaginally and some remain in situ in the uterus. And products of conception is an umbrella term for placental tissue, fetal tissue and the amniotic sac. In an incomplete miscarriage, the patient will give a history of bleeding and pain which occurred when parts of the products of conception were being passed. Ultrasound will not show any evidence of viability. A classic presentation of an incomplete miscarriage is in the early second trimester, such as at 16 weeks' gestation. The fetus may be passed vaginally, the umbilical cord snaps, and the placenta and the membranes remain in utero.

Next, inevitable miscarriage. This is when there's bleeding and cramps with cervical dilatation. In this scenario, the products of conception will definitely be expelled, i.e. the embryo will definitely miscarry.

And finally, complete miscarriage, which is when all of the products of conception has passed vaginally. The patient would have had significant pain and bleeding when the products of conception were being passed, which may have settled by the time you see her. The cervix may be open if the miscarriage is recent or closing back up again if not.

So to consolidate your understanding of the different types of miscarriage, I'll now talk you through the natural history of a complete miscarriage, with stops along the way of threatened, inevitable, and incomplete.

So first off, the patient experiences some vaginal bleeding in the first 20 weeks of pregnancy. By definition, she's having a threatened miscarriage. There may or may not be pain. The cervix will still be closed on examination. In addition to bleeding, she then develops cramping pain, and the cervix opens up.

By definition, this is an inevitable miscarriage. If she then progresses to have worsening bleeding and pain and passes some of the products of conception, this is an incomplete miscarriage. Once all of the products of conception have been passed, she's experienced a complete miscarriage.

As you can see, taking a thorough gynae history and performing a speculum examination to determine whether the cervix is closed or open are key to working out what type of miscarriage a woman may be experiencing.

So, so far we've covered the definition of miscarriage, risk factors, and some terminology. Moving on now to the management of miscarriage.

One key feature that will clarify how a patient is managed is whether or not they're clinically stable. A minority of patients with a miscarriage will present to ED clinically unstable. They may give a history of heavy bleeding and severe pain and may be hypotensive on examination.

Take a quick history and ask if she's had an ultrasound this pregnancy. If she's had a high-quality ultrasound in the community showing an intrauterine pregnancy, i.e. not an ectopic, and then she presents with bleeding, by definition she is experiencing a threatened miscarriage. Given she's clinically unstable, insert two wide-bore IV cannulae, send off a full blood count, a blood group, and cross-match two units of blood.

Provide IV fluid resuscitation. Examine the patient, including a speculum examination. Is the cervix open or closed? Are there products of conception sitting in the cervix, holding it open? And products of conception may look like a pink or grey, fleshy mass, or even just a large blood clot.

If products can be visualised, use a tissue forceps to remove them. Sometimes this alone is enough to resuscitate the patient. Cervical dilatation and stimulation can cause so-called cervical shock, which leads to stimulation of the vagal nerve and the paradoxical clinical combination of hypotension and bradycardia.

Removing the products from the cervix will immediately treat the cervical shock, and the patient will be instantaneously revived. Send any products off for histopathology, keep the patient fasted, and discuss her with the on-call gynae registrar. So that was the immediate management of an unstable patient.

The vast majority of patients with a miscarriage are clinically stable. In this situation, as always, take a thorough gynae history and examine the patient. On speculum examination, assess the amount of bleeding, whether the cervix is open or closed, and whether there are any visible products of conception.

Arrange for a blood group and antibody screen. Organise a transvaginal ultrasound, which can be performed as an outpatient. Refer the patient to the hospital's Early Pregnancy Assessment Service, or EPAS.

These clinics are often run by a combination of specialist nurses and gynaecology trainees. The EPAS team will assess the patient's symptoms, signs, serial beta-hCG results, and the ultrasound reports to determine exactly what type of miscarriage she's experienced. The management of miscarriage patients thereafter can be broken down into the broad categories of expectant, medical, and surgical management, which I'll now outline in turn.

Expectant management, which is essentially watchful waiting, is appropriate for women who've had an inevitable, incomplete, or complete miscarriage and who are clinically stable. Medical management involves a dose of vaginal misoprostol, which is a prostaglandin analogue. It softens and dilates the cervix and causes myometrial contractions.

Its use in miscarriage patients is to promote expulsion of the products of conception. A standard protocol for medical management is to admit the patient, administer 800 micrograms of vaginal misoprostol, then observe the patient for four hours. If she doesn't complete her miscarriage in that time, a second dose is given, and the patient is discharged to complete her miscarriage at home.

Medical management is most successful in incomplete miscarriages when some of the products of conception have already been passed. Benefits of medical management include that it's inexpensive and safe. Drawbacks are that women may bleed for up to four weeks.

An ultrasound is required down the track to confirm that the uterine cavity is empty.

Surgical management involves the patient having a general anaesthetic, then a so-called suction, dilatation, and curettage. Performed vaginally, the cervix is gently dilated, then a plastic suction device is passed through the cervix into the uterine cavity. It's then rotated so that any retained products of conception are sucked out. Indications for surgical management include persistent heavy bleeding, a hemodynamically unstable patient, a missed miscarriage when expectant or medical management is less likely to be successful, and if it's the woman's third miscarriage. This is because the products of conception need to be sent to the lab for karyotyping to investigate so-called recurrent miscarriage.

Depending on the type of miscarriage a woman is experiencing, the likely success rates of expectant versus medical versus surgical management for that type of miscarriage, the gynaecology team may suggest one management modality over another.

Whether she has expectant, medical, or surgical management, there are a few other aspects of care to consider. If she's rhesus negative blood group, she may need to be given a stat dose of anti-D to prevent alloimmunization in future pregnancies.

It's important to offer psychological support to both the patient and her partner. I always make a point of trying to assuage any guilt a woman may have. Women are very good at blaming themselves for their miscarriage.

As alluded to earlier, I mentioned that in 60% of early miscarriages, aneuploidy is to blame. I also make a point of reassuring the patient, if relevant, that statistically speaking, her next pregnancy is likely to result in a happy, healthy baby.

Women often ask when they can start trying to conceive again. Physically, they should wait until after their next period, so that, should they conceive immediately, we can date the next pregnancy from their last menstrual period. Emotionally, many women take much longer to recover from the heartbreak of having a miscarriage. If they're going to start trying sooner rather than later, it's worth mentioning that they should start taking a pregnancy multivitamin and folate prior to conception.

So, to summarise some take-home messages from this podcast episode. Miscarriage is the loss of an intrauterine pregnancy prior to 20 weeks' gestation. Miscarriage is very common, with approximately 15% of all pregnancies ending in a miscarriage.

Risk factors include increasing maternal age, especially over 35 years old, and a history of previous miscarriage. Different types of miscarriage include missed miscarriage, which is asymptomatic; threatened miscarriage, in which there's vaginal bleeding; inevitable miscarriage, when the cervix is open; incomplete miscarriage, when some of the products of conception have passed and some remain in utero and complete miscarriage, when all the products of conception have been passed.

Broadly speaking, management options include expectant management, or watchful waiting, medical management, which entails vaginal misoprostol, and surgical management, which is a suction, dilatation, and curettage.

Additional considerations include the need for anti-D, emotional and psychological support, and counselling regarding future pregnancies. So if you're keen to read a little bit more about miscarriages, there's good patient information pamphlets on the websites of the RCOG, which is the UK's Royal College of Obstetricians and Gynaecologists. There's also a good patient info pamphlet on the website for Safer Care Victoria.

Hopefully you found this podcast informative. If you found anything distressing, please find someone to talk to, whether through the Melbourne Uni Student Support Services or a colleague, partner, family, or friend. All the best with your women's health rotation, and stay tuned for more gynaecology podcast episodes over the coming months.