Spontaneous abortion

Dr.Renu Singh

Definition

• Clinically recognised pregnancy loss before 20th week of gestation

• Expulsion or extraction of an embryo or fetus weighing 500gm or less(WHO)

• Synonymous with miscarriage• Latin :aboriri: to miscarry

Incidence

• MC early pregnancy complication• Frequency decreases with increasing

gestational age• Incidence:8-20%(clinically recognised

pregnancies)• Women who had a child: 5% incidence of

miscarriage• 80% spontaneous abortion :< 12 wks

Risk factors

• Advanced maternal age• Previous spontaneous abortion• Medications & substances (smoking)• Mechanisms responsible for abortion: not

apparent• Death of fetus precedes spont. expulsion,

finding cause involves ascertaining the cause of fetal death

Maternal age

• Most important risk factor in healthy women

• 30yrs:9-17%• 35yrs:20%• 40yrs:40%• 45yrs: 80%

Previous spontaneous abortion

• Previous successful pregnancy: 5% risk

• 1 miscarriage: 20% • 2 consecutive miscarriages:28%• ≥3 consecutive miscarriages:43%

Medications or substances

• Heavy smoking(>10 cigarettes/day) : vasoconstrictive & antimetabolic effects of tobacco smoke

• Moderate to high alcohol consumption(>3 drinks/week)

• NSAIDS use(acetaminophen) :abnormal implantation & pregnancy failure due to antiprostaglandin effect

Other factors

• Low plasma folate levels(≤2.19ng/ml): no specific evidence to support

• Extremes of maternal weight: prepregnancy BMI<18.5 OR >25kg/m2

• Maternal fever:100°F(37.8°C), no evidence to support

Etiology

• Fetal • Maternal • unexplained

Etiology

• Foetal factors– Chromosomal abnormalities(50% ),• aneuplodies ,monosomy X,Triploidy• Trisomy 16 : mc autosomal trisomy,lethal• Abnormalities arise de novo

– Congenital anomalies– Trauma: invasive prenatal diagnostic procedures

Aetiology :Maternal factors

– Maternal endocrinopathies: hypothyroidism, insulin dependant diabetes

– Congenital or acquired uterine abnormalities: interfere with implantation & growth

– Maternal diseases: acute maternal infection (listeria, toxo, parvo B19,rubella,CMV) : inconclusive

– Radiation in therapeutic doses – Hypercoagulable state(thrombophillias) : RPL

Clinical presentation

• Vaginal bleeding – Scant brown spotting to heavy vaginal bleeding– Amount /pattern does not predict outcome– May be accompanied by passage of fetal tissue

• Pelvic pain– Crampy /dull in character– Constant/intermittent

• Incidental finding on pelvic ultrasound in asymptomatic patient

Diagnostic evaluation

• History– Period of amenorrhea ,LMP/USG

• Physical examination: Complete pelvic examination:– P/S,:source, amount of bleeding, dilated cervix,

POC visible at Os/in vagina– P/V: uterine size(consistent with GA)

• Pelvic ultrasound

Pelvic ultrasound

• Most useful test in diagnostic evaluation of women with suspected spontaneous abortion

• Foetal cardiac activity: most important (5.5-6wks)

• Foetal heart rate• Size & contour of G.sac• Presence of yolk sac• Best evaluated ,transvaginal approach(TVS)

Pelvic USG: criteria for spontaneous abortion

• Gestational sac ≥ 25mm in mean diameter that does not contain a yolk sac or embryo

• An embryo with CRL ≥7 mm with no cardiac activity

If the GS or embryo is smaller than these dimensions: repeat pelvic USG in 1-2 weeks

Differential diagnosis

• Physiologic: placental sign• Ectopic pregnancy• Gestational trophoblastic disease• Cervical/vaginal/uterine pathology

• Physical examination• Transvaginal sonography(TVS)• Serial quantitative ßhCG

Lab evaluation

• Human chorionic gonadotropin: serial, quantitative, useful in inconclusive USG findings

• ABO ,Rh: need for 50/300µg anti D• Haemoglobin/hematocrit• Serum progesterone<5ng/ml(nonviable

pregnancy)

Post diagnostic classification

• Based upon the location of POC• Degree of cervical dilatation(pelvic exam)• Pelvic ultrasound• Categorization impacts clinical management– Threatened– Inevitable– Incomplete/complete– Missed

Threatened abortion

• Vaginal bleeding has occurred• The cervical os is closed• Diagnostic criteria for spontaneous abortion

has not met• Managed expectantly: until symptoms resolve

or progresses

Threatened abortion: m/m

• Expectant• Progestin treatment: most promising, efficacy

not established• Bed rest: randomised trials have refuted the

role • Avoid vigorous activity• Avoid heavy lifting• Avoid sexual intercourse

Threatened abortion :m/m

• Counsel about risk of miscarriage• Return to hospital in case of additional vaginal

bleeding, pelvic cramping or passage of tissue from vagina

• Repeat pelvic USG until a viable pregnancy is confirmed or excluded

• Viable pregnancy, resolved symptoms: prenatal care• If symptoms continue: monitor for progression to

inevitable, incomplete, or complete abortion

Inevitable abortion

• Vaginal bleeding, typically accompanied by crampy pelvic pain

• Dilated cervix( internal os)• Products of conception felt or visualised

through the internal os

Incomplete abortion

• Vaginal bleeding and/or pain present• Cervix is dilated • Products of conception partially expelled out • Uterine size less than period of amenorrhea

Missed abortion

• Non viable intrauterine pregnancy• Cervical os is closed• POC not expelled • May notice that symptoms associated with

early pregnancy have abated

Management

• Complete evacuation of uterine contents(POC)

• Surgical methods: suction evacuation/suction curettage/dilation & evacuation

• Medical methods: Misoprostol,mifepristone• Expectant

• All have similar efficacy

Surgical evacuation

• Performed under IV sedation & paracervical block

• Prophylactic antibiotics• Operating room/procedure room• Potential complications

• Anaesthesia related,• uterine perforation, cervical trauma,• infection, intrauterine adhesions

Medical methods

• Misoprostol: drug of choice• Efficacy depends on dose & route of

administration• 400mcg vaginally every 4 hours for 4 doses• Expulsion rate : 50-70%• Low cost, low incidence of side effects, stable

at room temperature, readily available, timing of use can be controlled by patient

Misoprostol

• WHO consensus report on misoprostol regimen– Missed abortion: 800mcg vaginally,or 600 mcg

sublingually– Incomplete abortion: 600mcg orally

• Expulsion rate: 70-90%

Choosing the method

• Surgical evacuation : heavy bleeding, intrauterine sepsis, medical co morbidities, misoprostol is contraindicated– Shorter time to completion of treatment– Lowers risk of unplanned admissions– Lower need for subsequent treatment

Expectant m/m

• Stable vital signs• No evidence of infection• Offered after proper counseling• If unsuccessful after 4 wks ,surgical evacuation

is needed

Complete abortion

• POC expelled completely from uterus & cervix

• Cervical os is closed• Uterus small in size (GA)• Resolved or minimal vaginal bleeding & pain • Aim of t/t: ensure that bleeding is not

excessive & all POC have expelled• Theoretically does not need treatment

Abortion : complications

• Hemorrhage• Uterine perforation• Retained products of conception• Endometritis• Septic abortion: abortion accompanying

intrauterine infection

Summary

• Clinically recognised pregnany losses <20 wks gestation

• Most common complication of early pregnancy

• Advanced maternal age, previous spontaneous abortion, maternal smoking: risk factors

• Mostly due to fetal structural/chromosomal abnormalities

Summary

• Present with menstrual delay, vaginal bleeding& pelvic pain

• D/D: uterine or other genital tract bleeding in viable pregnancy, ectopic,& GTD

• Pelvic examination & pelvic ultrasound: key elements for diagnosis

• Spontaneous abortion diagnosed based on USG criteria

• Categorised as threatened/incomplete/missed

Summary

• Preconceptual & prenatal counseling & care regarding modifiable aetiologies ,risk factors are most imp intervention

• Normal menstrual cycle resumes in 4-6 weeks• hCG returns to normal 2-4wks

Prevention of spont.abortion

• Preconception & prenatal counseling• Routine screening & optimal disease

control(diabetes, thyroid, thrombophilia)• Correction of uterine structural

anomalies(septum, submucosal myoma, intrauterine adhesions) prior to pregnancy

• Avoiding exposure to teratogen or infections• Modifiable risk factors