Pregnancy loss is the spontaneous end of a pregnancy before the fetus can survive independently. The medical community categorizes these losses using specific timeframes based on gestational age. This classification is necessary because the underlying causes, physical management, and emotional care differ significantly depending on the timing. The two primary categories of pregnancy loss are defined by a benchmark in fetal development, separating events that occur in earlier stages from those that happen later.
Early Pregnancy Loss (Miscarriage)
Early pregnancy loss, commonly called a miscarriage, is the spontaneous loss of a pregnancy before the 20th week of gestation. This event is frequent, occurring in 10 to 20 percent of known pregnancies. The vast majority of these losses, about 80 percent, take place during the first trimester (up to the 13th week).
The predominant cause is an abnormality in the developing embryo’s chromosomes. These genetic issues account for 50 to 65 percent of all miscarriages and usually occur by chance during fertilization or early cell division. They are not typically inherited from the parents.
Other contributing factors include structural abnormalities of the uterus, hormonal imbalances, or uncontrolled maternal health conditions such as diabetes or thyroid disorders. Physical symptoms often involve vaginal bleeding and pelvic cramping. Although medical professionals may use the technical term spontaneous abortion, miscarriage is the preferred term in general discussion.
Late Pregnancy Loss (Stillbirth)
Late pregnancy loss, known as stillbirth, refers to the death of a fetus that occurs at or after the 20th completed week of gestation. Stillbirth is less common than early loss, affecting approximately 1 in 160 births in the United States. This type of loss is further categorized based on gestational age: early stillbirth (20 to 27 weeks), late stillbirth (28 to 36 weeks), and term stillbirth (at or after 37 weeks).
The causes of stillbirth differ distinctly from early loss, shifting away from genetic errors to issues involving the placenta, the umbilical cord, and maternal or fetal health. Problems with the placenta, the organ responsible for delivering oxygen and nutrients, are implicated in up to one-quarter of stillbirths. This includes conditions like placental abruption, where the placenta separates prematurely from the uterine wall, which is a factor in 10 to 20 percent of cases.
Maternal health conditions, such as chronic or pregnancy-induced high blood pressure, preeclampsia, and uncontrolled diabetes, also significantly increase the risk. Complications with the umbilical cord, such as knotting or prolapse, can restrict the flow of blood and oxygen, accounting for up to 10 percent of stillbirths. Fetal growth restriction and certain non-chromosomal birth defects are also causes, though a definitive cause is not found in a substantial number of cases, sometimes up to 76 percent globally.
Defining the Critical Differences
The fundamental difference between early and late pregnancy loss is the 20-week gestational age benchmark, which serves as the medical boundary for classification. Losses before this point are miscarriages; those at or after 20 weeks are stillbirths. This distinction is based on the fetus’s potential for survival outside the womb.
The underlying causes, or etiology, also differ significantly. Early losses are predominantly driven by genetic or chromosomal abnormalities in the embryo, representing a failure of development in the earliest stages. In contrast, late losses are more often linked to issues that arise later in the pregnancy, such as placental insufficiency, maternal complications like hypertension, or structural problems with the fetus or umbilical cord.
Medical management and diagnosis reflect these differences in timing and cause. Following an early loss, diagnostic efforts may focus on genetic testing of expelled tissue to identify a chromosomal cause, which often provides closure for parents regarding future pregnancies. For stillbirth, a more comprehensive medical workup is typically performed, including a thorough examination of the placenta, an autopsy of the fetus, and extensive testing of the mother to pinpoint a potentially preventable cause.
Emotional Recovery and Support Resources
The emotional impact of a pregnancy loss is profound, regardless of whether it is an early or late loss, and the grieving process has no set timeline. Parents often experience intense feelings of sadness, guilt, anger, and confusion, which can lead to anxiety and depression. Acknowledging that this grief is complex and can be accompanied by emotional trauma is an important step in the healing process.
Seeking professional guidance from a mental health professional who specializes in grief and trauma related to reproductive loss can provide valuable tools for coping. Many parents find comfort and validation by connecting with others who have shared similar experiences. Organizations like Postpartum Support International (PSI) and The Compassionate Friends (TCF) offer helplines, free virtual support groups, and peer mentor programs, providing a supportive environment for parents to speak openly about their loss and work toward emotional recovery.