Definition and management of first trimester miscarriage and retained products of conception (RPOC)
I. DEFINITION OF MISCARRIAGE
The definition has evolved and today we are more conservative in an effort to avoid terminating viable pregnancies.
Conclusive non-viable intrauterine clinical pregnancy
Diagnosis criteria via transvaginal ultrasound:
1. Mean gestational sac (MSD) >25 mm with no fetal pole, or
2. CRL >7mm with no FHR, or
3. CRL < 7 mm with no FHR on two ultrasounds at least 7 days apart, or
4. Any empty MSD on two ultrasounds at least 7 days apart, or
5. Gestational sac with yolk sac, no fetal pole, on two ultrasounds at least 10 days apart
Pregnancies of uncertain viability
Clinical pregnancies:
1. Anembryonic
a. Empty gestational sac
2. Embryonic
a. Fetal pole – use CRL (not LMP) to define the week of intrauterine embryonic demise
b. 5 weeks, with a yolk sac only
Non-visualized pregnancies:
3. Biochemical pregnancy
a. Positive hCG, no ultrasound performed
4. Failed PUL
a. Positive hCG, no pregnancy location established on ultrasound
II. VALUE OF βHCG MONITORING
βHCG monitoring to determine pregnancy viability should only used for non-visualized pregnancies. It has no clinical use to monitor pregnancy visible on ultrasound.
Be cautious of βHCG rise as the amount of rise differs depending on the level of βHCG. The expected minimal rise at 2 days for a viable IUP:
1. Initial hCG < 1500 IU/mL: at least 49%
2. Initial hCG 1500 – 3000 IU/mL: at least 40%
3. Initial hCG > 3000 IU/mL: at least 33%
For pregnancies of uncertain viability, be conservative when to repeat the scan (e.g., EPAC uses a minimum of 10-14 day interval)
III. DEFINITION OF RPOC AND PREDICTIVE FACTORS
No consistent definition exists. There are ultrasound an laboratory predictive factors helpful for predicting RPOCs:
Ultrasound findings:
1. Irregular hyperechoic material versus a uniform stripe
2. Doppler flow within hyperechoic material and vaginal bleeding following miscarriage
3. Endometrial thickness is NOT associated with RPOC, however, endometrial thinness < 10mm can help rule it out
Laboratory predictive factors:
1. With an initial hCG < 5000 IU/mL, it should be negative by 2 weeks, if not, suspect RPOC
III. MANAGEMENT OF MISCARRIAGES AND RPOC
All management options are equally acceptable. No difference in gynaecological infection rate within 14 days in expectant, medical or surgical groups.
Subsequent gynecological infection rates, live birth rates, psychological and activity outcomes are similar. Rate of live birth is 79-82% at 5 years after the index miscarriage.
Expectant management:
Risk of RPOC is associated with both time interval and type of miscarriage.
Rates of success:
Type of miscarriage 1 week 2 weeks 6 weeks
Incomplete 53% 84% 91%
Anembryonic 40% 70% 81%
Embryonic demise 30% 59% 76%
Counselling should include:
1. Realistic expectations regarding duration of waiting. Recommend waiting 14 days prior to opting for surgical management.
2. Variability of success depending on the type of miscarriage.
Medical management:
Appears to be the most cost effective compared with expectant and surgical management.
Rates of success with vaginal misoprostol given 48 hours apart:
– 1 dose of misoprostol, by day 3, is 71%
– 2 doses of misoprostol, by day 8, is 84%
Specific considerations:
– Anembryonic gestation had lower rate of success
– Later gestations have higher rate of success until 11wks
Surgical management:
Vacuum aspiration is a better choice in achieving complete uterine evacuation and preventing RPOC and Asherman’s syndrome compared with sharp curettage alone.
Rates of success by non-randomized trial:
– 97% at 4 weeks with vacuum aspiration
In the only randomized control trial comparing all three methods, the risk of bleeding or RPOC needing an emergency unplanned curettage by 8 weeks after diagnosis of miscarriage:
By 8 weeks after diagnosis
Expectant 44%
Medical 13%
Surgical 5%
Summary of management success rates:
By 2 weeks after diagnosis
Expectant 59-84%
Medical* 84%
Surgical 97%
*2 doses of misoprostol