Spontaneous Abortion Flashcards
Definition of spontaneous abortion
Clinically recognized pregnancy loss before 20th week of gestation
WHO defines expulsion/extraction of embryo or fetus < 500g
Most common complication of early pregnancy
Spontaneous abortion
Timing of spontaneous abortion
8-20% clinically recognized pregnancies of less than 20 weeks undergo abortion
80% in first 12 weeks of gestation
Classic study on spontaneous abortions
hCG assays were performed, total rate of pregnancy loss was 31%; 70% were not detected clinically
Most important risk factor
Advanced maternal age is the most important risk factor
8-17% in 20-30yo, 40% in 40yo, 80% in 45yo
Other risk factors for spontaneous abortion
Previous spontaneous abortion (20% after 1 miscarriage)
Medications/substances (smoking, alcohol, cocaine)
Low folate
Extreme maternal BMI
Exposure to teratogen
Most common etiology of spontaneous abortion
(50%) chromosomal abnormalities in embryo or exposure to teratogens
Breakdown of chromosomal abnormalities in spontaneous abortion
50% autosomal trisomies
20% monosomy
20% polyploidies
Trisomy 16 is the most common autosomal trisomy and is always lethal
SAB etiology: teratogens
DM with poor glycemic control
Drugs (isotretinoin)
Physical stress (fever)
Environmental chemicals (mercury)
SAB etiology: maternal factor
Uterine abnormalities (septum, fibroids, adhesions) Active maternal infection (toxo, parvovirus, TORCHES) Endocrinopathies (thyroid dysfunction, cushing's syndrome, PCOS)
Clinical presentation
vaginal bleeding or pelvic pain
volume and pattern of bleed does not predict spontaneous abortion
passage of fetal tissue - solid and white mass covered with blood; may be mistaken for blood clot, accompanied by severe cramping
Pain: crampy/dull and may be constant/intermittent
Eval for SAB: history
Menstrual history and ultrasound
Eval for SAB: PE
Cervix is dilated, product of conception visible at cervix or in vagina.
When is fetal cardiac activity present?
6 weeks on US
US
Look for size/contour of gestational sac, presence of yolk sac, fetal heart rate
Lab Evals
hCG - as baseline
type and screen
Drop in beta hCG
baseline of 500 IU/L - drop in 21%
baseline of 5000, drop of > 35%
Differential diagnosis for vaginal bleeding and pelvic pain
Physiologic (implantation)
Ectopic pregnancy
Gestational trophoblastic disease
Cervical/vaginal/uterine pathology
Classification of abortion
Based on location of product of conception, cervical dilation, guided by US
Types of abortion
Threatened Missed Inevitable Incomplete Complete Septic
Complete abortion
POC entirely out of uterus and cervix; cervix is closed and uterus is small and well contracted
Common before 12 weeks GA
Cannot be reliably distinguished from incomplete either clinically or US
Incomplete/Inevitable/Missed abortion treatment
surgical management by D&C to prevent potential hemorrhagic/infectious complications from retained POC; risks for anesthesia/uterine adhesions/trauma/infection
Misoprostol in 1st trimester (repeat 2 days later, then vacuum on day 8)
longer duration of bleed and drop in hematocrit
