Postpartum hemorrhage, or heavy bleeding after delivery, is the most common serious complication of childbirth worldwide. It accounts for roughly 27% of all maternal deaths globally, making it the single leading cause of maternal mortality. But the picture of “common” complications depends on whether you’re talking about life-threatening emergencies or the full range of things that can go wrong during and after delivery. Perineal tearing, for instance, happens far more frequently than hemorrhage, while postpartum depression affects up to one in five new mothers.
Postpartum Hemorrhage: The Leading Serious Complication
Postpartum hemorrhage is defined as blood loss exceeding 500 mL after a vaginal delivery or 1,000 mL after a cesarean birth, both within the first 24 hours. It happens when the uterus doesn’t contract firmly enough after the placenta detaches, leaving open blood vessels at the site where the placenta was attached. Less commonly, it results from tears in the cervix or vaginal tissue, or from blood clotting problems.
What makes hemorrhage so dangerous is speed. A person can lose a life-threatening amount of blood in minutes, and visual estimates of blood loss frequently underestimate the true volume. This is especially concerning in settings where access to emergency care is limited or delayed. The WHO released data in 2025 confirming that hemorrhage, mostly occurring during or just after childbirth, remains responsible for nearly a third of all maternal deaths globally.
Medical teams routinely take steps to prevent hemorrhage during the final stage of labor, after the baby is born but before the placenta is delivered. This “active management” approach includes giving a medication that helps the uterus contract, controlled traction on the umbilical cord, and early cord clamping. Evidence from Cochrane reviews suggests this approach probably reduces the rate of significant blood loss (500 mL or more) by about two-thirds compared to simply waiting for the placenta to deliver on its own. For severe hemorrhage (1,000 mL or more), roughly one fewer case occurs for every 66 women who receive active management.
Perineal Tearing During Vaginal Delivery
If you count all complications rather than just life-threatening ones, perineal tearing is by far the most frequent. The vast majority of women who deliver vaginally experience some degree of tearing in the tissue between the vaginal opening and the anus. Most tears are classified as first or second degree, meaning they involve the skin and underlying muscle but don’t reach the anal sphincter. These typically heal within a few weeks with basic care.
More severe tears, classified as third or fourth degree, extend into or through the ring of muscle that controls the anus. These occur in roughly 4% to 11% of vaginal deliveries in the United States. A third-degree tear involves part or all of the anal sphincter muscle, while a fourth-degree tear goes all the way through to the rectal lining. These require surgical repair and carry a longer recovery timeline, with potential for lasting issues like pain during intercourse or difficulty controlling gas and bowel movements.
Postpartum Infections
Infections after delivery take several forms. The most common is mastitis, an infection of breast tissue, affecting roughly 5% of postpartum women. Urinary tract infections follow at about 3%, and uterine infections (where the lining of the uterus becomes inflamed) occur in about 2% of deliveries. Wound infections at the site of a cesarean incision or perineal repair affect nearly 2%.
How you deliver significantly changes your infection risk. A large retrospective study comparing planned cesarean sections with planned vaginal deliveries found that 15% of women in the cesarean group developed a postpartum infection, compared to 10% in the vaginal delivery group. That 50% increase in relative risk is one reason cesarean deliveries are generally reserved for situations where they offer a clear medical benefit.
Preeclampsia and High Blood Pressure
Hypertensive disorders, including preeclampsia, are the second leading cause of maternal death worldwide, contributing to about 16% of maternal mortality. Preeclampsia involves dangerously high blood pressure combined with signs of organ damage, typically affecting the kidneys or liver. Most people associate it with pregnancy, but it can develop for the first time after delivery, appearing anywhere from 48 hours to 6 weeks postpartum.
Prevalence estimates vary widely, from less than 1% to over 25% of pregnancies depending on the population studied and how broadly the condition is defined. Warning signs include severe headaches, vision changes, upper abdominal pain, and sudden swelling in the face or hands. Postpartum preeclampsia is particularly dangerous because many women aren’t expecting new symptoms after delivery and may dismiss early warning signs.
Postpartum Depression
Postpartum depression is one of the most common adverse outcomes of pregnancy overall. Globally, it affects between 10% and 20% of new mothers. In the United States, the prevalence has roughly doubled over the past decade, rising from about 9% in 2010 to 19% in 2021, according to a study published in JAMA Network Open.
Unlike the temporary mood swings and tearfulness that many women experience in the first week or two after delivery, postpartum depression persists and interferes with daily functioning. It can include intense sadness, anxiety, difficulty bonding with the baby, changes in sleep and appetite beyond what’s expected with a newborn, and in severe cases, thoughts of self-harm. The condition is highly treatable, but the doubling in prevalence over a single decade suggests that many people either lack access to screening or face barriers to care.
Who Faces Higher Risk
Two factors that consistently increase the odds of complications across the board are maternal age and body weight. The relationship between age and adverse outcomes follows a U-shaped curve: risks are elevated for younger mothers (under 20) and rise again after the mid-30s. Women over 40 face roughly 1.7 times the risk of very preterm birth compared to women aged 20 to 34, along with higher rates of gestational diabetes.
Body weight plays a similarly graded role. Women who are underweight before pregnancy have the highest rate of preterm birth at 9.6%, while those with a normal BMI have a rate of about 6.8%. The risk then climbs steadily with increasing weight: women with severe obesity face a preterm delivery rate of 8.6% and nearly three times the odds of extremely early preterm birth compared to normal-weight women. Higher BMI also correlates with larger babies, which increases the likelihood of difficult deliveries and perineal tearing.
These risk factors are worth knowing not because they’re always modifiable, but because they influence the level of monitoring you can expect during pregnancy and delivery. Higher-risk pregnancies typically involve more frequent check-ups, earlier screening for blood pressure problems and gestational diabetes, and delivery planning that accounts for the increased chance of complications.