Maternal age is the most important factor determining the risk of miscarriage.

The risk of miscarriage can be estimated based on a combination of clinical symptoms and ultrasound findings.

Indicators of a pregnancy at a high risk of miscarriage are:

• Small GS diameter in proportion to CRL
• Oligohydramnios
• Bradycardic embryo (< 90 bpm).
• Discrepancy between scan and menstrual dates of > 10 days

Miscarriage can be classified into Threatened, Inevitable, Incomplete & Complete, Missed & Pregnancy of Uncertain Viability.

Anybody presenting with vaginal bleeding is at risk of a threatened miscarriage. The bleeding is usually mild to moderate bleeding with little or no pain. Although stressful for the patient this can be managed expectantly, and they can be allowed home.

Advise the patient to contact EPU/GAU or attend Emergency Department (ED) out of hours if the bleeding becomes heavy or if there is persistent lower abdominal pain.

In the case of large subchorionic haematoma, a repeat US scan may be arranged 1-2 weeks later to reassure the woman and to evaluate the haematoma.

Management of Threatened Miscarriage with a previous miscarriage

Offer progesterone suppositories (Cyclogest) 400mg twice daily to women with an intrauterine pregnancy confirmed by a scan. If a fetal heartbeat is confirmed, continue progesterone until 16 completed weeks of pregnancy.

This is defined as any pregnant person presenting with bleeding and an open cervical os on examination and/or products of conception protruding through the cervix.

Incomplete miscarriage is the presence of retained products of conception without a well-defined gestational sac.

Complete miscarriage is any of the above presentations with evidence of an intrauterine pregnancy (IUP) previously with either physical evidence of complete removal of products of conception (POC) or scan evidence of an empty uterus. You must not diagnose a complete miscarriage based on history alone, as unless there is evidence of an IUP on scan prior, the incidence of an ectopic cannot be ruled out. The incidence of ectopic in this situation is 5.9%.

A missed miscarriage is when there is a non-viable pregnancy, but there may not be any symptoms of pain or bleeding. This is therefore diagnosed on ultrasound.

This is diagnosed if the clinician cannot reliably diagnose a viable pregnancy or missed miscarriage from a single scan. Usually, a repeat scan is performed in 7-14 days to see if there has been any further development/interval change of the pregnancy.

Miscarriage is suspected when a previously confirmed pregnant woman presents with vaginal bleeding with or without lower abdominal pain and loss of pregnancy symptoms. History alone is unreliable in diagnosis, so scan should be performed where possible.

Missed miscarriage is defined as mean gestational sac diameter (MSD) of equal to or more than 25mm with or without evidence of yolk sac or fetal pole or the presence of fetal pole with Crown Rump Length (CRL) of ≥7mm with no demonstrable fetal cardiac activity on transvaginal ultrasound scan.

MSD should be measured in 3 orthogonal planes (longitudinal, sagittal, and transverse view).

• If the CRL is ≥7mm with a transvaginal ultrasound scan and there is no visible heartbeat, or GS ≥25mm with no fetal pole:
  • seek a second opinion on the viability of the pregnancy or
  • perform a second scan a minimum of 7 days after the first before making a diagnosis.
• If there is no visible heartbeat when the CRL is measured or GS with no fetal pole using a transabdominal ultrasound scan:
  • record the size of the CRL/GS and
  • perform a second scan a minimum of 14 days later, before confirming a diagnosis.

To minimise the risk of error, a senior colleague’s advice should be sought if there is any uncertainty.

If there is any doubt about the diagnosis and/ or patient requests it, a repeat ultrasound scan should be performed 1-2 weeks after the initial scan. If there is no growth and cardiac activity, the diagnosis of missed miscarriage is confirmed.

An ultrasound report should be completed for each scan so comparisons can be made.

Retained products can be seen as heterogeneous irregular echoes in the midline of the uterine cavity or as a well-defined hyperechoic area within the uterine cavity. Blood clots are usually poorly defined. Colour Doppler can be used to differentiate retained products from blood clot.

Investigations

• Speculum examination should be carried out in those with heavy bleeding to assess for an open cervical os with products of conception protruding.

• Any female of reproductive age presenting to A&E with a history of abdominal pain, bleeding, diarrhoea, vomiting, or dizziness should have a urine pregnancy test.

• If there is any suspicion of ectopic pregnancy, a senior opinion should be sought as soon as possible.

• FBC & G&S should be done if clinically indicated according to the severity of the bleeding.

• Serum βhCG should not be routinely done unless a Pregnancy of Unknown Location/Ectopic Pregnancy is diagnosed by ultrasound, as it does not contribute to the diagnosis and management of a miscarriage.

• Baseline observations are helpful if there is heavy vaginal bleeding or abdominal pain to assess the patient’s well-being.

• Any patient presenting with haemodynamic compromise should be assessed and stabilised in A&E prior to being seen in EPU.

This involves awaiting spontaneous miscarriage and is relevant to patients with Incomplete and Missed miscarriage. Varying success rates of complete miscarriage are quoted from 24% to 43% and this should be explained to the patient beforehand. Advise woman to expect bleeding for another 2 weeks and to contact EPU or attend A&E if any concerns.

While awaiting spontaneous miscarriage, the patient will be reviewed in 2 weeks with a repeat scan if the bleeding hasn’t settled. If at the end of two weeks from diagnosis there is no evidence of spontaneous miscarriage, the patient should be advised to have Medical or Surgical Management. If the uterus is empty and bleeding has settled, they should do a pregnancy test in 3 weeks and contact EPU if the test remains positive.

Highly effective in:

• Incomplete miscarriage
• Sac low in the uterine cavity

Lower efficacy rate in:

• Missed miscarriage (complete resolution may take several weeks)

Inclusion criteria:

• <9 weeks size fetus

• No clinical evidence of sepsis

• No heavy active vaginal bleeding

Medical management is an effective, safe alternative to expectant and surgical options and involves giving the patient an initial 200mg of Mifepristone orally followed by 800mcg dose of Misoprostol vaginally/orally to help pass the POC in case of missed miscarriage and 600-800mcg of Misoprostol in case of incomplete miscarriage. The mean time to expulsion is 8 hours after administering Misoprostol.

• Overall satisfaction rates are about 91% with average length of bleeding 8 days.

• The successful expulsion rates are >80% in pregnancies up to 13 weeks gestation.

• If the mean sac diameter >50mm or CRL >22mm (>9 weeks gestation), they should be advised to have surgical management (inpatient medical management may be considered in selected cases)

Treatment can be given but precautions needed for:

• Long term corticosteroid therapy or recent treatment (within 3 months).

• Lactation (avoid breastfeeding for 5 hours after misoprostol administration).

• Those with chronic diarrhoea should be warned that symptoms might be worse during treatment, as it is a side-effect of misoprostol.

If a patient decides to have medical management, a written consent form needs to be completed by a doctor with adequate experience in consent for the process, and FBC/G&S taken if appropriate. Where possible, pre-printed consent forms should be used.

The consent form for medical management should include the intended benefits:

• To treat miscarriage using tablets and performing a pregnancy test after 3 weeks to ensure that the miscarriage is complete

Consent form frequent risks:

• Pain & bleeding like a heavy period

• Side effects of misoprostol (vomiting, diarrhoea, shivering, flatulence, rashes, dizziness)

• Failure to work or incomplete miscarriage needing surgical evacuation (1 in 10)

Consent form uncommon but more serious risks:

• Blood transfusion in the event of heavy bleeding

The vaginal route is preferable for the misoprostol administration due to increased efficacy. Taking the misoprostol orally is a suitable alternative in the event of heavy vaginal bleeding which may disturb absorption – in this situation the patient needs to be counselled about the side effects to expect with oral administration.

The patient should have an open access pathway with EPU in the event of any concerns.

Patients should be offered a take-home prescription of analgesia and/or antiemetic and be told to anticipate bleeding and crampy pain. There are varying regimes available, but a weak opiate combined with paracetamol (such as co-codamol or co-dydramol or codeine and paracetamol) is a good option with an anti-inflammatory such as diclofenac as a suppository or ibuprofen orally.

We do not routinely send the POC for histology after home medical management but if the patient has a personal preference to bring the POC in for histology or has a history of recurrent miscarriage, then it should be sent. Please ensure this is specified and the appropriate sensitive disposal paperwork is completed.

Those who choose to be managed expectantly should be scanned at 14 days until the completion of the miscarriage is confirmed. If the patient opts for medical management, they can have 600mcg or 800mcg PV Misoprostol (see flowchart 4)

Anti D is not required for medical management of miscarriage below 12 weeks (see Anti D section).

For women with 1 or more previous Caesarean Sections, it is at the discretion of the EPU consultant of the day regarding the dosing regimen of misoprostol (may offer 600mcg instead of 800mcg).

Options:

• Manual vacuum aspiration under local anaesthesia when suitable – Refer to MVA guideline

• Suction evacuation under general anaesthesia

Indications for Surgical evacuation under GA:

• Persistent excessive bleeding/Haemodynamic compromise

• Evidence of infected retained tissue

• Suspected molar pregnancy

• Patient’s choice

Pre-operatively:

• FBC

• G&S (for Rhesus status, no need for valid G&S sample unless high bleeding risk)

• Screening for infection, including Chlamydia trachomatis, should be considered in high-risk patients.

• Written consent forms for the procedure and sensitive disposal of products of conception

• Prescribe Misoprostol 400mcg vaginally/orally, ideally 3 hours prior to SMM, but up to 1 hour is acceptable for women who have not had a previous vaginal delivery and have a closed os. For women with previous caesarean section, prescribe Misoprostol 200mcg. If the patient has had 2 or more previous Caesarean sections, the Registrar or Consultant on call should be informed.

• Where infection is suspected, delaying surgical intervention for 12 hours is recommended to allow intravenous antibiotic administration.

• The routine use of oxytocin is not required.

• There is insufficient evidence to recommend routine antibiotic prophylaxis prior to surgical evacuation of uterus.

• Consider ultrasound guidance to assist the procedure in more technically challenging cases

The consent form for SMM/ERPC should include the intended benefits:

• To remove any pregnancy remains from within the womb

Consent form risks:

• Bleeding that lasts for up to 2 weeks is very common but heavy bleeding is uncommon (1–3 in 1000 women).

• Need for repeat procedure if all the pregnancy remains are not removed, up to 40 in 1000 women (common).

• Pelvic infection, 40 in 1000 women (common).

• Development of intrauterine adhesions, 190 in 1000 (common).

Serious risks

• Perforation of the womb, up to 1 in 1000 women (uncommon).

• Significant tear of the neck of the womb, less than 0.1 in 1000 women (rare).

Occasionally, women can bleed very heavily during a miscarriage (expectant / medical) or experience shock (hypotension / tachycardia) requiring emergency attendance at A&E.

Pregnancy tissue (POC) stuck in the cervical os can cause a significant vagal response in some women, leading to shock.

If this occurs:

• Medical staff should be summoned

• Resuscitate in accordance with trust policy – obtain wide bore IV access and bloods for FBC/G&S

• Consider fluids IV

• An early speculum should be performed to detect POC in the cervical canal. If found, remove with sponge holding forceps, not extending further than the internal os. This can be performed by any doctor competent in the procedure.

• If bleeding heavily, give Ergometrine 500mcg IV/IM or Syntometrine 1ml IM (both contraindicated if history of hypertension) or Syntocinon 5-10 units IV/IM or 800mcg PR Misoprostol and Tranexamic acid 1g IV

• Consider bimanual compression.

If the patient is bradycardic/hypotensive, consider giving Atropine for cervical shock:

• If bleeding settles, arrange an ultrasound scan

• If heavy bleeding continues, immediate assessment by senior medical staff and consider surgical evacuation

Management of Suspected Endometritis/Sepsis:

• Assess the clinical situation as to how unwell the patient is.

• Urgent SpR Review

  • Take bloods for FBC, Culture (Blood, Urine & HVS), Group + Save, CRP, lactate (venous blood gas)

• USS to rule out retained products of conception

• Admit and administer IV antibiotics if patient very unwell (rigors, temp>37.5, tachycardia >100BPM, severe abdominal pain, heavy bleeding)

• Co-Amoxiclav 1.2g IV TDS (8 hourly) and review the possibility to switch to oral treatment – total duration 7 days (for Penicillin allergies consult MicroGuide or discuss with Microbiology).

• If previous treatment has failed add Gentamicin (5-7 mg/kg daily) and get advice from microbiology.

• The Gynaecology Consultant on call must be informed.

• Emergency SMM should be organised to remove the remaining RPOC after IV antibiotics have started.

• A senior/experienced clinician should perform the SMM as the risk of complications including perforation of the uterus is higher. They may opt to wait for 12-24 hours depending on clinical state (with a view to allowing time for antibiotics to work), and/or use of ultrasound guidance.

A minimum of 250 IU Anti-D should be given to Rhesus negative women in the following situations:

• Threatened miscarriage 12-20 weeks

• Threatened miscarriage ≤12 weeks only if accompanied by heavy bleeding and abdominal pain

• Complete spontaneous miscarriage >12 weeks

• Surgical management of miscarriage or evacuation of retained products at any gestation

Discharge documentation from the EPU should clearly state whether Anti D was required/given. For SMM, the final clinical responsibility for this lies with the operating surgeon.

Consider thromboprophylaxis in all women who had SMM admitted as inpatient (specific risk factors: BMI>40, smoking, substance abuse, sepsis and surgical complication such as excess blood loss and perforation). Thromboprophylaxis is given for 10 days. Uncomplicated elective SMM patients discharged on the same day do not need thromboprophylaxis.

Please print in colour on high quality paper/card where possible. Amend as appropriate prior to printing.

This guideline has been subject to an Equality Impact Assessment.

Chu, Justin J., et al. "Mifepristone and misoprostol versus misoprostol alone for the management of missed miscarriage (MifeMiso): a randomised, double-blind, placebo-controlled trial." The Lancet 396.10253 (2020): 770-778.

Coomarasamy, Arri, et al. "Progesterone to prevent miscarriage in women with early pregnancy bleeding: the PRISM RCT." Health Technology Assessment (Winchester, England) 24.33 (2020): 1.

Coomarasamy, Arri, et al. "PROMISE: first-trimester progesterone therapy in women with a history of unexplained recurrent miscarriages-a randomised, double-blind, placebo-controlled, international multicentre trial and economic evaluation." Health technology assessment (Winchester, England) 20.41 (2016): 1.

Okeke Ogwulu, C. B., et al. "The cost‐effectiveness of progesterone in preventing miscarriages in women with early pregnancy bleeding: an economic evaluation based on the PRISM trial." BJOG: An International Journal of Obstetrics & Gynaecology 127.6 (2020): 757-767.

Goldstein SR. Embryonic death in early pregnancy: a new look at the first trimester. Obstet Gynecol 1994; 84 (2) :294-7

NICE Guidelines: Ectopic pregnancy and miscarriage: diagnosis and initial management, Nov 2021

Nybo Andersen AM et al. Maternal age and fetal loss: population-based register linkage study. BMJ 2000; 320:1708

Qureshi, H., et al. "BCSH guideline for the use of anti-D immunoglobulin for the prevention of haemolytic disease of the fetus and newborn." Transfus Med 24.1 (2014): 8-20.

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