Miscarriage is the body’s process of ending a pregnancy that isn’t developing normally, and it happens far more often than most people realize. Roughly 10 to 20 percent of known pregnancies end in miscarriage, with the vast majority occurring in the first trimester. The process involves a cascade of hormonal shifts, uterine contractions, and bleeding that can unfold over hours or stretch across weeks, depending on the circumstances.
Why Most Miscarriages Happen
The single biggest cause is a chromosomal problem in the embryo. Between 40 and 76 percent of first-trimester miscarriages are linked to chromosomal abnormalities, with one large study of over 7,000 cases finding the rate at about 67 percent. These errors happen randomly during fertilization or the earliest cell divisions: an extra copy of a chromosome (trisomy), a missing one, or entire extra sets of chromosomes. The embryo simply can’t develop further, and the pregnancy stops progressing.
This is important to understand because it means most miscarriages are not caused by anything the pregnant person did or didn’t do. Exercise, stress, sex, and most foods don’t cause chromosomal errors. The risk does climb with age, though, because egg quality declines over time. For people in their twenties, the miscarriage rate is roughly 9 to 17 percent. At 35, it rises to about 20 percent. At 40, it’s around 40 percent, and by 45 it reaches approximately 80 percent.
How Risk Changes Week by Week
The risk of miscarriage drops sharply as the pregnancy progresses. At six weeks of gestation, the risk is about 9.4 percent. By seven weeks, it falls to 4.2 percent. At eight weeks, it’s just 1.5 percent and continues to decrease from there. Between weeks 14 and 19, the rate is only 1 to 5 percent. This is why many people feel a wave of relief after hearing a heartbeat or reaching the second trimester: the odds shift dramatically in their favor.
The Hormonal Chain Reaction
A healthy pregnancy depends on progesterone, a hormone produced first by a structure in the ovary called the corpus luteum and later by the placenta. Progesterone keeps the uterine lining thick, blood-rich, and stable enough to support the embryo. When a pregnancy fails, progesterone levels drop. That withdrawal triggers the uterine lining to break down and shed, much like what happens during a menstrual period, only heavier. This breakdown is what produces the bleeding and cramping associated with miscarriage.
At the same time, the pregnancy hormone hCG begins to fall. How quickly it returns to zero depends on how far along the pregnancy was. A very early loss, when hCG levels are still low, may resolve within days. If levels were in the thousands or tens of thousands, it can take several weeks for hCG to become undetectable. Once it does, the menstrual cycle and ovulation typically resume.
What the Body Goes Through Physically
When a miscarriage happens on its own, the experience typically involves bleeding and cramping that are heavier than a normal period. Most people pass the pregnancy tissue within two weeks of the diagnosis, though the most intense part usually concentrates into a window of two to four hours once heavy cramping and bleeding begin. After that, light spotting or bleeding can continue for up to a month.
The tissue itself may look like large blood clots, or it may appear white or gray. It does not look like a baby. The process can be painful, and pain relief is commonly prescribed to help manage the discomfort. One important warning sign to watch for: soaking through more than two large pads per hour for two or more hours is considered dangerously heavy bleeding and needs immediate medical attention.
The Different Types of Miscarriage
Not every miscarriage unfolds the same way, and the clinical terms you might hear describe where things stand in the process.
- Threatened miscarriage: Bleeding occurs before 20 weeks, but the cervix remains closed. Some threatened miscarriages resolve and the pregnancy continues.
- Inevitable miscarriage: Bleeding is accompanied by the cervix opening. At this point, the pregnancy cannot continue.
- Incomplete miscarriage: Some pregnancy tissue has been expelled, but some remains inside the uterus.
- Missed miscarriage: The embryo or fetus has stopped developing, but the body hasn’t recognized it yet. There’s no bleeding, no cramping, and no tissue passage. This type is often discovered during a routine ultrasound.
A missed miscarriage can be especially disorienting because there are no outward signs. You may still feel pregnant, and symptoms like nausea may linger because hCG takes time to fall. Eventually the body will begin the process of passing the tissue, but that delay can take weeks.
How Miscarriage Is Managed
Once a miscarriage is confirmed, there are three general paths: waiting for the body to complete the process naturally, using medication to help it along, or having a brief surgical procedure.
Expectant management (waiting) works for many people, especially with early losses. The body typically passes the tissue within two weeks, though it isn’t always predictable.
Medication management uses drugs that cause the uterus to contract and empty. The most effective approach combines two medications taken in sequence, 24 to 48 hours apart, which completes the miscarriage about 84 percent of the time with a single round. When only one of the two medications is available, success rates are lower, in the range of 67 to 71 percent. The physical experience with medication is similar to a natural miscarriage: several hours of heavy cramping and bleeding, followed by a gradual taper.
A surgical procedure called a D&C (dilation and curettage) is a short outpatient procedure in which the cervix is gently opened and the uterine contents are removed. Some cramping and bleeding occur during and after, but the process is faster and more predictable than the other options. It’s often recommended for incomplete miscarriages where tissue remains, or when bleeding is heavy.
Physical and Hormonal Recovery
The body recovers faster than many people expect. Once hCG returns to zero, ovulation and menstruation typically resume within four to six weeks. Physically, bleeding tapers off over days to weeks, and energy levels gradually return to normal. Some people are surprised to learn they can become pregnant again within that very first cycle after a loss, before even having a period.
Emotional recovery is a different timeline entirely and varies enormously from person to person. Grief, guilt, relief, numbness, and anger are all common and normal responses, sometimes experienced simultaneously. There is no correct way to feel after a miscarriage.
When Miscarriage Keeps Happening
A single miscarriage, while painful, is very common and doesn’t usually indicate an underlying problem. Recurrent pregnancy loss is defined as two or more failed clinical pregnancies, and that’s the threshold at which further evaluation is typically recommended. Testing may look for blood clotting disorders, hormonal imbalances, uterine structural issues, or chromosomal factors in either partner. In many cases, a cause is identified and can be treated, improving the odds for a future pregnancy.