Miscarriage

Miscarriage
Other names	spontaneous abortion, early pregnancy loss
An ultrasound showing a gestational sac containing a yolk sac but no embryo
Specialty	Obstetrics and Gynaecology, Neonatology, Pediatrics
Symptoms	Vaginal bleeding with or without pain[1]
Complications	Infection, bleeding,[2] sadness, anxiety, guilt[3]
Usual onset	Before 20 weeks of pregnancy[4]
Causes	Chromosomal abnormalities,[1][5] uterine abnormalities[6]
Risk factors	Being an older parent, previous miscarriage, exposure to tobacco smoke, obesity, diabetes, autoimmune diseases, drug or alcohol use[7][8][9]
Diagnostic method	Physical examination, human chorionic gonadotropin, ultrasound[10]
Differential diagnosis	Ectopic pregnancy, implantation bleeding.[1]
Prevention	Prenatal care[11]
Treatment	Expectant management, vacuum aspiration, emotional support[8][12]
Medication	misoprostol
Frequency	10–50% of pregnancies[1][7]

Miscarriage, also known in medical terms as a spontaneous abortion, is the death and expulsion of an embryo or fetus before it can survive independently.^[1][4] The term miscarriage is sometimes used to refer to all forms of pregnancy loss and pregnancy with abortive outcomes before 20 weeks of gestation.

Miscarriage before 6 weeks of gestation is defined by ESHRE as biochemical loss.^[13][14] Once ultrasound or histological evidence shows that a pregnancy has existed, the term used is clinical miscarriage, which can be "early" before 12 weeks and "late" between 12 and 21 weeks.^[13] Fetal death after 20 weeks of gestation is also known as a stillbirth.^[15] The most common symptom of a miscarriage is vaginal bleeding with or without pain.^[1] Sadness, anxiety, and guilt may occur afterwards.^[3][16] Tissue and clot-like material may leave the uterus and pass through and out of the vagina.^[17] Recurrent miscarriage (also referred to medically as Recurrent Spontaneous Abortion or RSA)^[18] may also be considered a form of infertility.^[19]

Risk factors for miscarriage include being an older parent, previous miscarriage, exposure to tobacco smoke, obesity, diabetes, thyroid problems, and drug or alcohol use.^[7][8] About 80% of miscarriages occur in the first 12 weeks of pregnancy (the first trimester).^[1] The underlying cause in about half of cases involves chromosomal abnormalities.^[5][1] Diagnosis of a miscarriage may involve checking to see if the cervix is open or sealed, testing blood levels of human chorionic gonadotropin (hCG), and an ultrasound.^[10] Other conditions that can produce similar symptoms include an ectopic pregnancy and implantation bleeding.^[1]

Prevention is occasionally possible with good prenatal care.^[11] Avoiding drugs, alcohol, infectious diseases, and radiation may decrease the risk of miscarriage.^[11] No specific treatment is usually needed during the first 7 to 14 days.^[8][12] Most miscarriages will be completed without additional interventions.^[8] Occasionally the medication misoprostol or a procedure such as vacuum aspiration is used to remove the remaining tissue.^[12][20] Women who have a blood type of rhesus negative (Rh negative) may require Rho(D) immune globulin.^[8] Pain medication may be beneficial.^[12] Emotional support may help with processing the loss.^[12]

Miscarriage is the most common complication of early pregnancy.^[21] Among women who know they are pregnant, the miscarriage rate is roughly 10% to 20%, while rates among all fertilisation is around 30% to 50%.^[1][7] In those under the age of 35, the risk is about 10% while in those over the age of 40, the risk is about 45%.^[1] Risk begins to increase around the age of 30.^[7] About 5% of women have two miscarriages in a row.^[22] Some recommend not using the term "abortion" in discussions with those experiencing a miscarriage to decrease distress.^[23] In Britain, the term "miscarriage" has replaced any use of the term "spontaneous abortion" for pregnancy loss and in response to complaints of insensitivity towards women who had suffered such loss.^[24] An additional benefit of this change is reducing confusion among medical laymen, who may not realize that the term "spontaneous abortion" refers to a naturally occurring medical phenomenon and not the intentional termination of pregnancy.