An older cesarean section closure technique may reduce the complications caused by the surgery. Though faster, the technique now used most frequently seems to be responsible for the creation of uterine scars that can affect fertility, cause pelvic pain and abnormal bleeding, and may increase the incidence of placenta accreta.

The US rate of cesarean sections increased dramatically over the past half century from 5% in the 1970s to 32% in 2023. The increase has been driven by a combination of factors including increased maternal age, higher rates of maternal health problems such as obesity and high blood pressure, scheduled cesareans, and an increased rate of labor induction.

While cesareans are necessary in many cases to protect the health of the mother and baby, the marked increase in the procedure has also led to nearly a third of these women suffering from long-term complications.

A growing body of research shows that it may be the cesarean section surgical technique that’s responsible for the long-term complications rather than the procedure itself, noted study author Emmanuel Bujold, MD, MSc, professor in the Department of Obstetrics & Gynecology, Faculty of Medicine at Laval University in Quebec City, Quebec, Canada, and colleagues in the American Journal of Obstetrics & Gynecology (AJOG).

Problems With the Newer Cesarean Technique

For nearly a century, surgeons were taught a method of endometrium-free womb closure, which means suturing similar layers of tissue to each other when suturing the incision. The uterus is made up of three layers: the endometrium, which is the inner layer of the uterus; the myometrium, the thick muscular layer of the uterus; and the outer layer of the uterus, the perimetrium. Endometrium-free cesareans line up each layer with its like so that the scar heals without any defects.

But in the past three decades, as cesareans have increased dramatically, the surgical closure technique changed to cinching the tissue together in a single layer so that the tissues are combined and the endometrial layer is brought to the outside of the uterus. Today, this technique is used in the majority of cesarean sections because it’s faster, creates a smaller incision, and reduces the risk for bleeding. But while the technique has been praised for its efficiency and low short-term risks, in the long term, it can cause pockets or defects in the surgery scar in the uterus.

There are no data to show how often the single-layer method is used now, but Bujold estimated that it is used in 9 out of 10 cesarean sections.

Bujold said that there is good reason to rethink this faster method because, according to the AJOG study, it’s associated with a 5.6-fold to 11-fold increase in clinically substantial uterine scar defects.

Additionally, the newer technique can get endometrial cells into the scar on the outside of the uterus, which can cause endometriosis, resulting in pelvic pain and abnormal bleeding, said Christine Greves, MD, obstetrician-gynecologist at Orlando Health, Orlando, Florida.

The endometrium-free technique becomes more difficult, said Greves, when women have labored for long periods and the uterine lining has thinned such that it’s hard to distinguish the layers. It may also be problematic when an infection has led the layers of tissue to become compromised.

Infertility Associated With Cesarean Complications

Infertility can occur in as many as 4%-19% of women with a uterine scar defect. Poorly healed scars can harbor fluid for long periods, and when patients undergo in vitro fertilization, the non-sterile fluid can destroy the embryo before it can implant in the uterus.

Additionally, scar tissue that develops inside the uterus can make the environment hostile to an embryo transfer by reducing places for the embryo to land and implant, said Greves.

The Most High-Risk Long-Term Complications of Cesareans

Cesarean sections can also cause a serious complication called placenta accreta, which, while rare, has increased in the US as the number of cesareans has increased, said Robert M. Silver, MD, obstetrician-gynecologist in Salt Lake City and a nationally recognized expert in high-risk pregnancies. The condition currently affects 1 in 272 pregnancies compared with 1 in 2500 pregnancies in 1980.

The placenta is supposed to detach after labor and be pushed out of the body. But in patients with placenta accreta, scar tissue from a previous cesarean scar can cause the placenta to become stuck to the uterine scar tissue so that it doesn’t properly detach.

“It’s extremely dangerous because it results in a lot of rapid blood loss, which can quickly become deadly,” said Silver.

The most common treatment for this high-risk complication is a cesarean hysterectomy, which removes the uterus entirely to prevent blood loss. But it is a major surgery and prevents any further pregnancies.

Another serious complication is rupture of the uterus, which is also rare but deadly. It occurs in 1 in 300 of all deliveries and 9 in 300 deliveries in women who have had cesareans. It happens when a defect from a previous cesarean scar bursts under the pressure of labor. The woman will most likely have to have a hysterectomy, and 1 in 20 women will die.

Endometrium-free cesareans are much less likely to cause a scar defect that could split, Bujold said. He started researching the benefits of endometrium-free cesareans when he saw a uterus rupture while tending to a woman in labor. It was an experience that stayed with him for his entire career. And he’s convinced that the endometrium-free technique, which takes only a few minutes longer, can reduce the risk for rupture as well as other complications.

“Too many women are suffering as a result of complications that can be prevented,” said Bujold.