When you become pregnant, a placenta will form in your uterus. The placenta provides the baby with oxygen and nutrients and is connected to your baby via the umbilical cord. Placenta is often referred to as afterbirth. Once your baby is born, the placenta
will be expelled soon after.
If your placenta implants very low in your uterus, and either partially or entirely covers your cervix (the opening to the birth canal), you have a condition called placenta previa. Obstetrician/gynecologist
Katherine Bachman, MD, describes the condition.
Placenta previa is a condition where the placenta implants very low in the uterus and often covers, either partially or entirely, the cervix or the opening from the uterus to the outside.
Placenta previa can be a serious condition. It's important to let the patient know that they have a previa so that they're aware of things that they want to avoid. In particular, you put them on pelvic rest, limit the amount of physical activity. We don't want to put anybody on bedrest 'cause that can increase the risk for blood clot but just to be smart in terms of their activity and maybe modify the type of physical activities that they do to kind of decrease any stress in the cervical region or where that placenta is. The majority of placenta previas will resolve by the end of third trimester so it may make somebody a little anxious at the beginning to know that and when we're talking about restrictions, they get little uncomfortable thinking that there's a problem when in many cases, it turns out not to be a problem. But the biggest concern with this condition is the amount of bleeding that somebody could present with if that placenta starts to separate from the cervix.
You likely won’t know you have placenta previa. It’s usually discovered when you have your second trimester ultrasound. Bleeding is the most common symptom. Dr. Bachman explains what you can expect.
Symptoms of placenta previa are typically bleeding, usually in the second and third trimester. Most women won't know they have a previa. It's found incidentally when they have their second trimester ultrasound. Typically, women will have a routine anatomy scan around 18 to 20 weeks, average is about 20 weeks. Often time, the placenta previa's diagnosed at that time. They notice the placenta's implanting lower by the cervix or covering the cervix. But the good news, the majority of those will become, or move out-of-the-way by late in the third trimester. So just because it's diagnosed incidentally on the ultrasound doesn't mean it's going to be there at the time of delivery. But most women will present, in terms of symptoms, will present second or third trimester with bleeding. Usually it's painless bleeding but bleeding itself from a previa will cause contractions, and so some women may present with contraction pain and possibly signs of preterm labor when in fact, it's actually a previa.
Doctors aren’t sure what causes placenta previa. Dr. Bachman explains that your risk may be increased under certain conditions.
What puts a woman at increased risk for placenta previa?
There are multiple risk factors for placenta previa. There's a whole list of them, probably at least 10, but the most common ones are the more pregnancies you have, each subsequent pregnancy, you're at greater risk for placenta previa. If you've had prior uterine surgery, so women who've had a prior C-section, anybody who's had prior surgery to remove a fibroid, anything that interrupts or disrupts the endometrial lining. Women who've had recurrent miscarriages, even spontaneous losses, they're at increased risk for placenta previa. In today's day and age, with technology and advanced reproductive, or assisted reproductive technologies such as IVF, we are seeing increased risk of placenta previa in those pregnancies as well. Smoking is a huge risk factor for placenta previa, as well as cocaine use. I think those are probably the major risk factors or the major conditions we see associated with a risk for placenta previa.
Placenta previa occurs in about 1 in 200 pregnancies. Severe bleeding sometimes occurs with the condition, which can put both mom and baby at risk of dying. That’s why your doctor likely will prescribe bed rest or reducing your activities, and pelvic
rest (no sex, tampons, or douching). Other treatment options which your doctor may consider include:
