Copyright 2010
Definition
Spontaneous abortion is the expulsion of a non viable embryo or fetus usually caused by to chromosomal aberrations or environmental factors, occurring before the 20the week, though most occur before 12 weeks.
Structural changes that can lead to spontaneous abortion include uterine septae and anatomic anomalies like bicornuate uterus. Spontaneous abortions in the first trimester usually occur due to chromosomal anomalies of the fetus.
However, functional changes due to maternal infection or toxin exposure can lead to spontaneous abortion in the second trimester.
There are 4 clinical entities including threatened, inevitable, incomplete and complete spontaneous abortion.
Clinically threatened abortion is diagnosed and characterized by some bleeding and sometimes accompanied by pain in the first trimester. About half of these patients will recover and proceed to full term pregnancies.
When the symptoms are accompanied by a dilated cervix then abortion becomes “inevitable”. Bleeding and cramps are usually more prominent with inevitable abortion. The presence of products of conception in the discharged blood warrants examination by ultrasound. If products of conception are identified in the endometrial cavity the diagnosis is compatible with incomplete abortion and their absence confirms the diagnosis of a complete spontaneous abortion. Pain and bleeding subside when the abortion is complete.
Treatment depends on the stage of the the spontaneous abortion. A complete abortion requires no further treatment. An incomplete or inevitable abortion before 13 weeks is treated with suction dilatation and curettage though medical therapy (misorostol) can be used.
Gestational Sac Bulging into the Cervix |
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The history is one of a young female presenting with vaginal bleeding with previous positive pregnancy test. The images show a deformed gestational sac bulging into the cervix. By ultrasound the gestational sac measured 3.49 cms consistent with GA of 9 weeks and CRL measures .49cms consistent with a gestational age of 6weeks and 3 days. No fetal heart was identified. An evolving spontaneous abortion was diagnosed uterus Courtesy Ashley Davidoff MD Copyright 2010 46592c01 |
Retained Products of Conception |
| The ultrasound is from a 46 patient who presents with bleeding and pain 9 weeks into her pregnancy. Doppler study shows no fetal pole nor fetal heart beat. Findings include a thickened endometrium (light pink) with a focal area in the posterior and fundal portion of the endometrium (dark pink with red blood vessel inside) that enhances, consistent with retained products of conception and spontaneous abortion.
SAB US ultrasound USscan Courtesy Ashley Davidoff MD copyright |