Pocket ObGyn – Spontaneous Abortion (SAB)
See Abbreviations
Definition and Epidemiology (Fertil Steril 2003;79:577; Obstet Gynecol 2005;105:333)
- SAB (miscarriage) occurs before 20 w0d & <500 g
- Early Preg failure complicates 12–15% of known pregnancies & 17–22% of all pregnancies; 80% occur in the 1st 12 w of gest; fertilization ® 30% implantation
failure ® 30% early loss (= 60% loss before recognized clinical Preg) ® 12–15% clinical Preg SAB ® 25% live birth.
- Vaginal bleeding in ~25% known 1st trimester pregnancies ® ~50% of those are SABs
- Once fetal cardiac activity is noted, 90–96% have ongoing Preg
- Risk factors: mat age, prev SAB, heavy smoking, EtOH, cocaine, NSAIDs, fevers, caffeine >200 mg daily may be a/w SAB, chronic mat dz (DM, autoimmune, APLA syn), short interpregnancy interval, uterine
| Types of spontaneous abortions (<20 w 0d) | |||||
|
Name |
Sx |
Bleeding? |
Internal cervical os? |
Tissue passed? |
Notes |
| Missed | No sx; no fetal pole or cardiac activity. No cramping. | ± (may be scant) | Closed | None | Includes
“anembryonic” & “blighted ovum” |
| Threatened | Any bleeding gives dx, ± pain | Yes | Closed | No | Increases loss & ptb rate |
| Inevitable | Imminent miscarriage, usually w/ painful cramps | Yes | Open | No | |
| Incomplete | Bleeding & passage of some POCs | Yes | Open | Partial | Treat medically or surgically |
| Complete | After passage of POCs, ± cramping | Yes or
resolving |
Closed | All POCs passed | Usually no intervention |
| Septic AB | Usually cramping/ uterine tenderness, ± fever/chills/ malaise/ discharge | ± | ± | No or
partial; infected POCs are retained |
May be VERY ill |
| Recurrent | 2–3 consecutive early losses | Any of the above | Refer for RPL w/u | ||
Etiologies
- Chromosomal abnormalities (50%); congen anomalies; trauma (early GA uterus generally protected from blunt trauma); host factors (eg, uterine abnormalities [septum]), mat infxn, mat endocrinopathies or corpus luteum dysfxn, mat inherited or Acq thrombophilia;
- Diff: Cervical bleeding (polyp, malig, trauma), ectopic Preg, infxn, molar Preg, SAB (see above), subchorionic hemorrhage, vaginal
Clinical Manifestations and Physical Exam
- Amenorrhea, vaginal bleeding, &/or pelvic pain/cramping
- Cessation of nml sx of Preg (eg, nausea, breast tenderness)
- Speculum/digital exam to assess cervical dilation, POCs
- Evaluate extent of bleeding (eg, hemorrhage) & mat stability
Diagnostic Workup (Obstet Gynecol 1992;80:670; Ultrasound Obstet Gynecol 1994;3:63)
- Passed tissue: “Float villi” in saline to evaluate frond-like chorionic villi; send to pathology
- Transvaginal US: Distinguishes IUP extrauterine Preg, viable vs. nonviable, presence of gestational trophoblastic dz, retained POCs, ectopic
Missed AB: No fetal cardiac activity + CRL >5 mm OR absence of embryonic cardiac activity w/ menstrual age >6.5 w
Findings suggestive of early Preg failure: Absence of yolk sac w/ MSD >13 mm; absence of embryonic pole w/ MSD >20 mm; enlarged yolk sac (>6 mm), irreg or low lying sac; slow FHT (<100 bpm at 5–7 w); small GS (difference btw MSD & CRL <5 mm); subchorionic hematoma >25% vol of the GS.
- Quantitative beta hCG: Low yield once IUP If no IUP, serial hCGs q48h to rule out ectopic ® ¯ hCG = nonviable IUP or spontaneously resolving ectopic.
Management of First Trimester Abortions
| Management of first trimester abortions | |
| Spont | If evid of complete passage & no excessive bleeding, no further mgmt needed. If highly desired, no infxn/bleeding, & esp if unsure dating, may manage expectantly. |
| Missed, Incomplete, or Inevitable | Expectant mgmt if <13 w w/ stable VS & no e/o infxn. ~40% will need D&C eventually; ~80% success w/ expect mgmt for incomplete.
Medical: Misoprostol (PGE1 analog) in 1st trimester; contraindications, allergy, ectopic or pelvic infxn, hemodynamic instability. Missed AB: 800 mg vaginally q24h up to 3 doses OR 400 mg per vagina q4h ´4 OR 600 mg sublingually q3h ´2 if needed (71% success by 3 d, 84% success by 8 d; 12% need D&C). Incomplete AB: 600 mg PO OR 400 mg sublingually ´1 (82% success by 5 d, 95% success by 7 d; 3% need for D&C). Surgical: Suction D&C or manual vacuum aspiration. Risks include uterine perforation, intrauterine adhesions, cervical trauma, & infxn. Recommended: Doxycycline 100 mg PO preop & 200 mg PO postop. (97% success rate) |
| Threatened | Expectant mgmt: Bleeding precautions, pelvic rest. No effect of progest for threatened AB, but may ¯ recurrent AB. (Cochrane Database Syst Rev 2013;10:CD003511). |
| If Rh(D)-negative & unsensitized, give RhoGAM 50–300 mg IM (prevent alloimmunization). Offer chromosomes/pathology. Grief counseling. Pain meds (NSAID, ± narcotics). Bleeding warnings.Antiemetic for nausea. F/u US in some circumstances (clinical presentation). | |
| From Int J Gynaecol Obstet 2007;99:182; NEJM 2005;353:761; Am J Obstet Gynecol 2005;193:1338. | |