Miscarriage, also known in medical terms as a spontaneous abortion, is an end to pregnancy resulting in the loss and expulsion of an embryo or fetus from the womb before it can survive independently.

[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.

Some medical authors advocated a change to the use of miscarriage instead of spontaneous abortion because they argued this would be more respectful and help ease a distressing experience.

[29] In 2005 the European Society for Human Reproduction and Embryology (ESHRE) published a paper aiming to facilitate a revision of nomenclature used to describe early pregnancy events.

[30] Most affected women and family members refer to miscarriage as the loss of a baby, rather than an embryo or fetus, and healthcare providers are expected to respect and use the language that the person chooses.

[32] Signs of a miscarriage include vaginal spotting, abdominal pain, cramping, fluid, blood clots, and tissue passing from the vagina.

[55] Some of these risks include endocrine, genetic, uterine, or hormonal abnormalities, reproductive tract infections, and tissue rejection caused by an autoimmune disorder.

[67] Second-trimester losses may be due to maternal factors such as uterine malformation, growths in the uterus (fibroids), or cervical problems.

[50] Miscarriage caused by invasive prenatal diagnosis (chorionic villus sampling (CVS) and amniocentesis) is rare (about 1%).

Women with endometriosis report a 76%[86] to 298%[87] increase in miscarriages versus their non-afflicted peers, the range affected by the severity of their disease.

A condition called luteal phase defect (LPD) is a failure of the uterine lining to be fully prepared for pregnancy.

[47] Infections can increase the risk of a miscarriage: rubella (German measles), cytomegalovirus, bacterial vaginosis, HIV, chlamydia, gonorrhoea, syphilis, and malaria.

In the case of an autoimmune-induced miscarriage, the woman's body attacks the growing fetus or prevents normal pregnancy progression.

[97] Immunohistochemical studies on decidual basalis and chorionic villi found that the imbalance of the immunological environment could be associated with recurrent pregnancy loss.

[98] Fifteen per cent of women who have experienced three or more recurring miscarriages have some anatomical defect that prevents the pregnancy from being carried for the entire term.

Those chemicals that are implicated in increasing the risk for miscarriage are DDT, lead,[104] formaldehyde, arsenic, benzene and ethylene oxide.

In dental offices where nitrous oxide is used with the absence of anaesthetic gas scavenging equipment, there is a greater risk of miscarriage.

[45] Some risk factors can be minimized by avoiding the following: Women who miscarry early in their pregnancy usually do not require any subsequent medical treatment but they can benefit from support and counseling.

[38][123] Most early miscarriages will be completed on their own; in other cases, medication treatment or aspiration of the products of conception can be used to remove the remaining tissue.

Significant distress can often be managed by the ability of the clinician to clearly explain terms without suggesting that the woman or couple are somehow to blame.

[131] Studies looking at the methods of anaesthesia for surgical management of incomplete miscarriage have not shown that any adaptation from normal practice is beneficial.

[133] Self-induced abortion performed by a woman or non-medical personnel can be dangerous and is still a cause of maternal mortality in some countries.

[145] In Western cultures since the 1980s,[145] medical providers assume that experiencing a miscarriage "is a major loss for all pregnant women".

Parents may be advised to wait even longer if they have experienced late miscarriage or molar pregnancy, or are undergoing tests.

Medical professionals are advised to take previous loss of a pregnancy into account when assessing risks for postnatal depression following the birth of a subsequent infant.

[157] The precise rate is not known because a large number of miscarriages occur before pregnancies become established and before the woman is aware she is pregnant.

[145] The dominant attitude in the mid-century was that a miscarriage, although temporarily distressing, was a blessing in disguise for the family and that another pregnancy and a healthier baby would soon follow, especially if women trusted physicians and reduced their anxieties.

[145] Beginning in the 1980s, miscarriage in the US was primarily framed in terms of the individual woman's emotional reaction, especially her grief over a tragic outcome.

[145][158] In places where induced abortion is illegal or carries a social stigma, suspicion may surround miscarriage, complicating an already sensitive issue.

[160][161][162] Miscarriage occurs in all animals that experience pregnancy, though in such contexts it is more commonly referred to as a spontaneous abortion (the two terms are synonymous).