From the Guidelines
No, missed abortion is not the same as spontaneous abortion, as they represent different stages and manifestations of early pregnancy loss (EPL) 1. The term "Early Pregnancy Loss (EPL)" is a general term endorsed by OB-Gyn communities to describe a pregnancy that may or will not progress, is in the process of expulsion, or has incompletely or completely passed 1. Missed abortion, also referred to as missed miscarriage, is a type of EPL where the embryo or fetus has died in the uterus but the body has not recognized the pregnancy loss, so the tissue is not expelled naturally. In contrast, spontaneous abortion (commonly called miscarriage) is the natural loss of a pregnancy before 20 weeks where the body actively expels the pregnancy tissue, typically accompanied by bleeding, cramping, and tissue passage. Key differences between the two include the presence or absence of fetal cardiac activity, the location of the gestational sac, and whether the pregnancy tissue is being expelled or retained 1. Management options for missed abortion include expectant management, medication management with misoprostol, or surgical evacuation through dilation and curettage (D&C), highlighting the importance of distinguishing between these concepts to guide appropriate clinical care 1. Some important terms to use when describing these scenarios include "Concerning for", "Diagnostic of", "In progress", "Incomplete", and "Completed" EPL, as outlined in the recent consensus conference recommendations 1. Understanding these distinctions is crucial for providing accurate diagnoses, appropriate management, and sensitive patient care in the context of early pregnancy loss. The preferred terms and modifiers can help standardize communication among healthcare providers and improve patient clarity, with "miscarriage" being a preferred term by patients and "spontaneous abortion in progress (SAB)" considered synonymous with miscarriage 1.
From the Research
Definition and Categorization
- Missed abortion is a type of spontaneous abortion, which is categorized as threatened, inevitable, incomplete, complete, or missed 2, 3.
- Spontaneous abortion refers to the loss of a pregnancy without outside intervention before 20 weeks' gestation 3, 4.
- Missed abortion is defined as an in utero death of the embryo or fetus before the 20th week of gestation with retained conception products 2.
Comparison of Missed Abortion and Spontaneous Abortion
- Missed abortion is a subtype of spontaneous abortion, and both terms are often used in the context of early pregnancy loss 2, 3, 4.
- The key difference between missed abortion and other types of spontaneous abortion is that the embryo or fetus has died, but the pregnancy has not been expelled from the uterus 2, 5.
- The management and treatment of missed abortion and spontaneous abortion may differ, with medical therapy using misoprostol being a common approach for missed abortion 2, 3.
Clinical Implications
- The diagnosis and management of missed abortion and spontaneous abortion require careful evaluation and consideration of the patient's individual circumstances 3, 5.
- Ultrasonography and other diagnostic tests may be used to confirm the diagnosis and rule out other conditions, such as ectopic pregnancy 3, 5.
- Patients with a history of missed abortion or spontaneous abortion may be at risk for subsequent pregnancy complications, but the evidence suggests that the reproductive performance and fertility of these patients are not significantly affected 6.