Placenta Previa
Definition
The placenta is an organ that provides oxygen and nutrition to a
baby in the womb. It also removes wastes from the baby. Placenta previa is when this
organ covers part or all of the cervix that the baby must pass through to be born.
Causes
The cause is not known. It may be due to problems with how the
placenta implants due to injury to the lining of the uterus and scarring from:
Multiple prior pregnancies
Prior placenta previa
Prior cesarean delivery (C-section)
Surgery to the lining of the uterus or to remove uterine fibroids
Fertility treatments
Risk Factors
Things that may raise the risk of this problem are:
- Prior cesarean delivery
- Prior abortion
- Being pregnant with a male fetus
- Smoking or cocaine use in the mother
Symptoms
Symptoms differ from person to person. It depends on how much of
the cervix is covered. The main sign is painless bleeding from the birth canal. It can
range from light to heavy. It most often happens after 20 weeks of pregnancy, usually
after sex.
Diagnosis
The doctor will ask about symptoms and health history. An
ultrasound will be done. This can confirm the
diagnosis.
Treatment
The goal of treatment is to manage the bleeding and give the baby
time to grow. How this is done will depend on the amount of bleeding a person has and
how many weeks of pregnancy have passed. Options are:
Monitoring the placenta for changes
Pelvic rest—not having sex or using tampons
Medicines to put off labor and give the fetus time to grow
A C-section will be needed to deliver the baby if the placenta
covers the cervix, there is heavy bleeding during labor, or other health problems
happen.
Prevention
There are no known ways to prevent this health problem.
Resources
The American Congress of Obstetricians and Gynecologists
http://www.acog.org
Family Doctor—American Academy of Family Physicians
http://familydoctor.org
Canadian Resources
Health Canada
https://www.canada.ca
Women's Health Matters
http://www.womenshealthmatters.ca
References
Placenta previa. American Pregnancy Association website.
Available at:
https://americanpregnancy.org/healthy-pregnancy/pregnancy-complications/placenta-previa.
Accessed May 9, 2022.
Placenta previa. EBSCO DynaMed website. Available at:
https://www.dynamed.com/condition/placenta-previa. Accessed May 9, 2022.
Pregnancy complications. Office on Women's Health website.
Available at:
https://www.womenshealth.gov/pregnancy/youre-pregnant-now-what/pregnancy-complications.
Accessed May 9, 2022.