Basic concepts of spontaneous abortion
Spontaneous abortion.
A miscarriage that occurs in a natural state (not caused by an artificial purpose) is called a spontaneous abortion. Spontaneous abortion occurs in 10-15% of all pregnancies. About 80% of spontaneous abortions occur before 12 weeks of gestation and are early abortions.
Classification of spontaneous abortions by stage of development
Threatened abortion.
A small amount of vaginal bleeding after menopause, with no discharge of pregnancy. Mild lower abdominal pain or lumbosacral distension may occur a few hours to a few days after the bleeding. The cervix is not open and the size of the uterus corresponds to the time of menopause.
Inevitable abortion (inevitable abortion).
On the basis of preterm abortion, there is an increase in vaginal bleeding, increased abdominal pain or rupture of the membranes. The cervix is open, or the fetal sac or embryonic tissue is visible in the cervix, and the size of the uterus corresponds to the time of menopause or is slightly smaller.
Classification by the outcome of spontaneous abortion
Complete abortion (abortion).
Inevitable miscarriage continues to progress, the pregnancy is completely expelled from the uterine cavity, followed by the cessation of vaginal bleeding and the immediate disappearance of abdominal pain. The cervical os is open and the uterus is smaller than the month of menopause.
Incomplete abortion.
Inevitable abortion continues to develop, part of the pregnancy is expelled from the uterine cavity, but some of the pregnancy remains in the uterus or is embedded in the cervical opening, causing poor contraction of the uterus and resulting in heavy or prolonged vaginal bleeding. The cervical os is closed and the uterus is near normal size.
Indolent abortion (missed abortion).
Also known as premature abortion, it is a phenomenon in which the fetus dies in the uterus before it is expelled in time. The typical presentation is a normal early pregnancy process, with a prolonged menopause, the uterus does not increase or becomes smaller. On examination the cervical os is closed and the uterus is not soft in texture and close to normal size.
Classification by the number of spontaneous abortions
History of adverse pregnancy (spontaneous abortion or miscarriage).
The occurrence of one spontaneous abortion is also called a history of adverse pregnancy. Since the incidence of one spontaneous abortion is very common, accounting for 10-15% of all pregnancies. The causes vary; therefore, only common etiologies are examined, and systemic etiologies are not usually done.
Recurrent spontaneous abortion or miscarriage (RSA).
Two or more consecutive spontaneous abortions are also called recurrent spontaneous abortion or miscarriage. The incidence of recurrent abortion is 5-8% of all pregnancies. The chance of recurrence of miscarriage in spontaneous pregnancies in patients with recurrent miscarriage is about 30-50%. This is a new term that has been introduced to focus on the occurrence of spontaneous abortion and to actively intervene in the process of spontaneous abortion.
Habitual abortion (habitual abortion).
The occurrence of three or more consecutive spontaneous abortions is called habitual abortion. The incidence of habitual abortion accounts for 1-2% of all pregnancies. The chance of recurrence of miscarriage in a spontaneous pregnancy is about 70-80%.
Classification of spontaneous abortions by the status observed under ultrasound
Embryonic abortion.
Early pregnancy in which the embryo is found to have stopped developing under ultrasound dynamic observation is called embryonic arrest (or embryonic arrest). The specific indicators are one of the following conditions.
1. a gestational sac ≥ 25 mm, with no yolk sac and no cardiac tube bruit visible.
2. gestational sac ≥ 28 mm, no germ is seen
3. gestational sac ≥ 40 mm, no fetal heart is seen
4.Germ bud >6mm-8mm, no fetal heartbeat.
5, no heart tube movement at gestational age ≥ 8 weeks.
Empty embryo sac.
Early pregnancy is called empty blastocyst when a gestational sac is found under ultrasound, with a gestational sac ≥25mm, no yolk sac or fetal mamma, and no heart tube movement.