Spontaneous Abortion

Question 1

Definition of spontaneous abortion

Answer 1

Clinically recognized pregnancy loss before 20th week of gestation
WHO defines expulsion/extraction of embryo or fetus < 500g

Question 2

Most common complication of early pregnancy

Answer 2

Spontaneous abortion

Question 3

Timing of spontaneous abortion

Answer 3

8-20% clinically recognized pregnancies of less than 20 weeks undergo abortion

80% in first 12 weeks of gestation

Question 4

Classic study on spontaneous abortions

Answer 4

hCG assays were performed, total rate of pregnancy loss was 31%; 70% were not detected clinically

Question 5

Most important risk factor

Answer 5

Advanced maternal age is the most important risk factor

8-17% in 20-30yo, 40% in 40yo, 80% in 45yo

Question 6

Other risk factors for spontaneous abortion

Answer 6

Previous spontaneous abortion (20% after 1 miscarriage)
Medications/substances (smoking, alcohol, cocaine)
Low folate
Extreme maternal BMI
Exposure to teratogen

Question 7

Most common etiology of spontaneous abortion

Answer 7

(50%) chromosomal abnormalities in embryo or exposure to teratogens

Question 8

Breakdown of chromosomal abnormalities in spontaneous abortion

Answer 8

50% autosomal trisomies
20% monosomy
20% polyploidies

Trisomy 16 is the most common autosomal trisomy and is always lethal

Question 9

SAB etiology: teratogens

Answer 9

DM with poor glycemic control
Drugs (isotretinoin)
Physical stress (fever)
Environmental chemicals (mercury)

Question 10

SAB etiology: maternal factor

Answer 10

Uterine abnormalities (septum, fibroids, adhesions)
Active maternal infection (toxo, parvovirus, TORCHES)
Endocrinopathies (thyroid dysfunction, cushing's syndrome, PCOS)

Question 11

Clinical presentation

Answer 11

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

Question 12

Eval for SAB: history

Answer 12

Menstrual history and ultrasound

Question 13

Eval for SAB: PE

Answer 13

Cervix is dilated, product of conception visible at cervix or in vagina.

Question 14

When is fetal cardiac activity present?

Answer 14

6 weeks on US

Question 15

US

Answer 15

Look for size/contour of gestational sac, presence of yolk sac, fetal heart rate

Question 16

Lab Evals

Answer 16

hCG - as baseline

type and screen

Question 17

Drop in beta hCG

Answer 17

baseline of 500 IU/L - drop in 21%

baseline of 5000, drop of > 35%

Question 18

Differential diagnosis for vaginal bleeding and pelvic pain

Answer 18

Physiologic (implantation)
Ectopic pregnancy
Gestational trophoblastic disease
Cervical/vaginal/uterine pathology

Question 19

Classification of abortion

Answer 19

Based on location of product of conception, cervical dilation, guided by US

Question 20

Types of abortion

Answer 20

Threatened
Missed
Inevitable
Incomplete
Complete
Septic

Question 21

Complete abortion

Answer 21

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

Question 22

Incomplete/Inevitable/Missed abortion treatment

Answer 22

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