Pregnancy loss is a deeply personal and emotionally challenging experience, yet medical professionals categorize these common outcomes primarily based on the timing of the pregnancy, establishing two distinct categories. This gestational timing determines the medical terminology, the likely underlying causes, and the necessary physical and emotional care pathways. The distinction centers on whether the event occurs before or after the point of fetal viability, typically defined by a specific week of gestation. Understanding this framework clarifies the clinical approach and the scientific differences between the two forms of loss.
Defining Early Pregnancy Loss (Miscarriage)
Early pregnancy loss, commonly known as a miscarriage, refers to a termination of pregnancy that occurs before the 20th week of gestation. This event is formally termed a spontaneous abortion, classified clinically as O03. It is the most frequent form of pregnancy loss, often occurring so early that a person may not realize they were pregnant.
The majority of miscarriages happen within the first trimester, before 13 weeks of pregnancy. Clinicians use several terms to describe the specific presentation. A “threatened” miscarriage involves bleeding and cramping while the cervix remains closed and the pregnancy continues. Conversely, a “missed” miscarriage describes a situation where the embryo or fetus has stopped developing, but the tissue has not yet been expelled from the uterus.
An “incomplete” miscarriage means that some, but not all, of the pregnancy tissue has passed, often requiring medical intervention. Early pregnancy failure, sometimes referred to as a “blighted ovum,” occurs when a gestational sac develops, but no embryo forms inside it. These classifications help guide healthcare providers in determining the most appropriate management plan.
Defining Late Pregnancy Loss (Stillbirth)
Late pregnancy loss, medically referred to as a stillbirth, is defined as the death of a fetus occurring at or after 20 completed weeks of gestation. In some jurisdictions, stillbirth may also be defined by a minimum weight threshold, such as 350 to 400 grams, if the exact gestational age is unknown. This event is classified clinically under the code P95, denoting fetal death.
Stillbirths are further categorized based on when the loss occurs. An early stillbirth takes place between 20 and 27 weeks of gestation. A late stillbirth is defined as a loss occurring between 28 and 36 weeks. A loss at 37 weeks or later is considered a term stillbirth, which is the least common occurrence.
Another distinction is whether the death occurred before or during the process of birth. Antepartum stillbirth refers to fetal death that happens before the onset of labor. Intrapartum stillbirth, also known as a death during labor, occurs after labor has begun but before the delivery is complete. This clinical differentiation helps in the investigation of the cause and guiding future pregnancy planning.
Distinguishing Factors: Causes and Risk Profiles
The underlying causes for early and late pregnancy losses show a fundamental distinction related to the stage of development. Early pregnancy loss, or miscarriage, is overwhelmingly attributed to random genetic errors. Approximately half to two-thirds of first-trimester miscarriages are due to chromosomal abnormalities, such as an incorrect chromosome count. These errors are random events that prevent the embryo from developing properly and are typically non-recurrent.
The primary cause of stillbirth, however, often relates to the conditions and environment supporting the fetus. Issues with the placenta, the organ responsible for delivering oxygen and nutrients, are frequent findings. These placental problems can include placental abruption, where the placenta prematurely separates from the uterine wall, or placental insufficiency, which restricts fetal growth.
Maternal health conditions are a greater risk factor for stillbirth than for miscarriage. Uncontrolled chronic conditions such as high blood pressure, diabetes, and thyroid disorders can compromise the intrauterine environment. Infections and umbilical cord accidents, where blood flow is restricted, are common findings. While miscarriage is attributed to a flaw in the initial genetic blueprint, stillbirth is more often linked to issues with the pregnancy’s support system or complications arising from maternal health.
Medical Care and Emotional Support Following Loss
The medical management following a pregnancy loss is guided by the gestational timing and the specific circumstances. For early pregnancy loss, or miscarriage, there are three management options. Expectant management involves waiting for the body to naturally expel the pregnancy tissue, which can take several weeks. Medical management uses medication, such as misoprostol, to induce the process and encourage the uterus to contract.
If tissue remains or if bleeding is heavy, dilation and curettage (D&C) may be performed to remove the tissue from the uterus. This method is common for missed or incomplete miscarriages. The management of a stillbirth, due to the advanced gestational age, requires the induction of labor to deliver the fetus and the placenta.
Following a stillbirth, a comprehensive investigation, including a post-mortem examination, is recommended to determine the cause and inform future pregnancy risk. Both types of loss require focused emotional support, although the needs may differ. Resources specific to perinatal loss, including counseling and support groups, are important for parents navigating the complex grief associated with the death of a child, regardless of the gestational age.