The leading cause of death during childbirth worldwide is severe bleeding, which accounts for roughly 27% of all maternal deaths. It’s followed by indirect causes like pre-existing medical conditions (23%) and high blood pressure disorders such as preeclampsia (16%). Together, these three categories make up the majority of deaths, though infections, blood clots, and rare emergencies like amniotic fluid embolism also play significant roles. More than 80% of these deaths are considered preventable with timely medical care.
Severe Bleeding
Hemorrhage is the single most common killer, and most of it happens after delivery rather than during labor. A loss of 1,000 mL of blood or more within 24 hours of birth is the clinical threshold, roughly equivalent to a full wine bottle. The most frequent cause is the uterus failing to contract firmly after the placenta detaches, leaving open blood vessels that bleed freely. Less commonly, tears in the cervix or vaginal tissue, a placenta that doesn’t fully separate, or a uterus that ruptures along a previous cesarean scar can trigger catastrophic bleeding.
What makes hemorrhage so dangerous is the speed at which things can deteriorate. Rapid blood loss drops blood pressure, which starves organs of oxygen. Within minutes, the kidneys can begin to shut down, the blood’s clotting system can collapse (causing bleeding to worsen everywhere at once), and the lungs can fill with fluid. In settings without access to blood transfusions or surgical intervention, this cascade is often fatal before transfer to a hospital is even possible.
Preeclampsia and High Blood Pressure
Preeclampsia typically appears in the third trimester as a sudden rise in blood pressure along with signs that the kidneys are under stress. It can progress rapidly to seizures (called eclampsia), stroke, liver rupture, or multi-organ failure. The underlying problem starts with the placenta: poor blood flow between the placenta and the uterine wall triggers a bodywide inflammatory response that damages blood vessel walls, raises blood pressure, and impairs the liver, kidneys, and brain.
Women with preeclampsia also face a threefold higher risk of a condition called peripartum cardiomyopathy, where the heart muscle weakens and can no longer pump effectively. In a 20-year population study, about 8% of women who developed this heart condition died, and 14% ultimately needed a heart transplant, a mechanical heart pump, or died. Even among women whose hearts recovered, 13% experienced a second decline in heart function within a few years. Preeclampsia’s damage extends well beyond delivery: women who survive it carry roughly double the long-term risk of heart disease and stroke compared to women with uncomplicated pregnancies.
Infection and Sepsis
Infections that lead to maternal death most often begin in the uterus after delivery, when the raw surface left by the detached placenta is exposed to bacteria. The most dangerous pathogen is group A streptococcus, the same bacterium responsible for strep throat, which can invade the bloodstream and trigger overwhelming sepsis within hours. In the second trimester, gut bacteria that ascend through the cervix are a more common culprit, while viral infections like influenza and HIV contribute significantly in lower-income countries.
One reason sepsis kills during and after childbirth is that pregnancy itself masks the warning signs. A pregnant woman’s heart rate is naturally faster and her immune responses are altered, so the usual red flags for infection, like an elevated heart rate or mild fever, can look like normal pregnancy physiology. By the time sepsis becomes obvious, organ damage may already be underway. Survival depends heavily on starting treatment within the first hour of suspected infection, a window that’s easy to miss when symptoms blend into the background of normal postpartum recovery.
Amniotic Fluid Embolism
Amniotic fluid embolism is rare, occurring in roughly 2 to 8 out of every 100,000 deliveries, but it is one of the most sudden and lethal emergencies in obstetrics. It accounts for 7.5% to 10% of maternal deaths in the United States. The name is somewhat misleading: rather than a simple blockage like a blood clot in the lungs, the condition appears to be an intense immune reaction. Fetal cells or other material from the amniotic fluid enter the mother’s bloodstream and trigger a response resembling severe anaphylaxis, with activation of the immune complement system and widespread inflammation.
The result is a near-simultaneous cardiovascular collapse. The heart’s pumping ability is suppressed by the inflammatory response, blood pressure plummets, and the clotting system activates uncontrollably, consuming clotting factors and causing both clots and uncontrolled bleeding at the same time. Because the onset is so abrupt, often occurring during labor or within minutes of delivery, even in a fully staffed hospital the window to intervene is extremely narrow.
Pre-Existing Health Conditions
Nearly one in four maternal deaths globally falls into the category of “indirect” causes, meaning the death results from a medical condition that existed before pregnancy or developed during it but wasn’t directly caused by an obstetric complication. Heart disease is the most prominent example. Pregnancy increases blood volume by about 50% and forces the heart to work significantly harder, which can push an already compromised heart into failure. Diabetes, kidney disease, autoimmune conditions, and infections like malaria or tuberculosis can all become life-threatening under the added physiological demands of pregnancy and labor.
Cardiovascular conditions have become an increasingly recognized driver of maternal deaths in high-income countries, where hemorrhage and infection are more effectively managed. A weakened heart muscle during or just after pregnancy (peripartum cardiomyopathy) occurs in about 1 in 5,000 deliveries, with risk factors including obesity, high blood pressure during pregnancy, and carrying multiples.
Who Faces the Highest Risk
Maternal death rates in the United States reveal stark disparities. The overall rate in 2024 was 17.9 deaths per 100,000 live births, but that figure obscures enormous differences by race and age. Between 2007 and 2016, Black women died at a rate of 40.8 per 100,000 births, 3.2 times the rate for white women. American Indian and Alaska Native women died at 2.3 times the white rate. These gaps widen dramatically with age: among women 30 and older, Black and Indigenous women died at four to five times the rate of white women in the same age group.
Education and income do not erase the disparity. Black women with a college degree or higher died at 5.2 times the rate of white women with the same level of education, and at 1.6 times the rate of white women who never finished high school. This pattern points to systemic factors, including differences in how symptoms are assessed and treated, chronic stress from discrimination, and unequal access to high-quality obstetric care, rather than individual health behaviors alone.
Age is an independent risk factor for all women. Maternal mortality climbs steadily after age 30, driven in part by higher rates of chronic conditions like hypertension and diabetes, but also by the greater physiological strain pregnancy places on an older cardiovascular system.
Why Most Deaths Are Preventable
The CDC estimates that more than 80% of pregnancy-related deaths in the United States could be prevented. The causes of death are well understood, and effective treatments exist for nearly all of them. Hemorrhage can be managed with medications that help the uterus contract, blood transfusions, and surgery. Preeclampsia can be controlled with blood pressure management and timely delivery. Sepsis responds to early antibiotics. The gap between what medicine can do and what actually happens comes down to delays: delays in recognizing warning signs, delays in escalating care, and delays rooted in the uneven distribution of skilled obstetric providers and well-equipped hospitals.
Globally, about 75% of all maternal deaths stem from just five causes: severe bleeding, infection, preeclampsia, complications during delivery, and unsafe abortion. In every case, the difference between survival and death is most often the speed and quality of the medical response, which is why maternal mortality remains highest in regions with the least access to emergency obstetric care.