What to do about Morbidly Adherent Placenta or MAP

Many of us know that doctors recommend against having a c-section if there is no medical reason. We also know that obstetricians are trying really hard to decrease the overall number of c-sections performed, which has shot up to about a third of all deliveries in the United States. Many people don’t know why doctors are so insistent in trying to reduce the number of c-sections. Mainly, they are trying to reduce the complications that happen as a result of this major surgery. One of the most significant complications occurs not in the present pregnancy, but in the next one: Morbidly Adherent Placenta or MAP. Its incidence has been increasing over the last century. In 1928, MAP occurred in about 1 in 20,000 live births. In 2002, it occurred in about 1 in 500. The risk of the mother dying as a result of MAP may be as high as 7% and possibly higher in low-resource settings.

MAP is a catch-all term that refers to placentas that implant deeper into the layers of the uterine wall than normal.  MAP can cause big problems at delivery. Because the placenta has such tremendous blood flow- it has been supplying the growing babe for the whole pregnancy after all- removing the deeply implanted placenta can cause massive hemorrhage.  One of the most important steps in treating MAP is to be prepared and diagnose it before delivery. Check out the below infographic on the differences between deliveries where MAP was diagnosed during the pregnancy versus at the time of delivery. Obviously, we should do everything we can to not only prevent MAP, but also to find it before delivery and plan ahead.

Now on to the ways in which MAP can be treated. The standard of care is delivery by planned cesarean hysterectomy at 34 to 35 weeks gestation. This means delivering the baby by c-section and then doing surgery to remove the whole uterus with the placenta in place. This may be the safest approach, but recently, many researchers have been exploring “conservative management” in which the surgeons attempt to leave the uterus, either because it seems safer than a hysterectomy in that particular case or in an attempt to preserve fertility. Below is a chart listing the various approaches to treating MAP and the rates of hysterectomy, or needing to remove the entire uterus for each one. These rates come from small studies that tried the various procedures on only a small number of women, so the estimates may not be very accurate.

The other important consideration is side effects. Up to 42% of women undergoing some of these treatments experienced massive blood loss, blood clotting disorders, infections of the uterus, or systemic infections.

At this point, the long-term outcomes of conservative management of MAP are unknown. There is an estimated 29% risk of repeat accreta in the next pregnancy. Other possible outcomes can be uterine scarring that can disrupt periods, and there is one case of the uterus rupturing open in a subsequent pregnancy.  While conservative management may be attempted in the right scenarios, it’s important for the clinical team to be ready to switch gears to hysterectomy if needed and to have clear endpoints to indicate when switching to hysterectomy is needed.