Table Of Contents
Placenta previa
Placenta previa is a common condition in which the placenta lies in the lower segment of the uterus. The placenta may avulse from the uterine wall as the lower segment begins to stretch at 28 weeks, classically resulting in painless bleeding PV. Diagnosis is through sonography. A vaginal exam SHOULD NOT be done with a suspected low-lying placenta as it can precipitate life-threatening hemorrhage!
Types of placenta previa
| Classification | Type | Description |
|---|---|---|
| Type I | “Low implantation” | Lower margin dips into the lower segment of the uterus. It is within reach of the examining finger |
| Type IIA | “Marginal anterior” | Placenta is anterior within 2cm of internal os when closed but does not cover it |
| Type IIB | “Marginal posterior” | Placenta is posterior within 2cm of internal os when closed but does not cover it |
| Type III | “Partial” | Placenta covers the internal os when closed but not when fully dilated |
| Type IV | “Complete” | Placenta covers the os even when the cervix is fully dilated |
- Risk factors
- Previous placenta previa
- Multiple gestation
- Assisted Reproductive Technology (ART)
- Previous uterine surgery, insult, or injury e.g Caesarean delivery
- Previous or recurrent abortion
- Signs and symptoms
- Painless uterine bleeding
- Bright red blood
- Starts light then becomes heavier
- Signs and symptoms of shock with heavy bleeding
- Soft and non-tender uterus
- Usually normal fetal heart rate
- Painless uterine bleeding
Treatment of placenta previa
| Gestational age | Treatment |
|---|---|
| Preterm and stable (< 37 weeks) | Admit for observation, Deliver at 37 -38 weeks |
| Treatment if stable, low-lying and marginal os > 2cm (Type I) | Vaginal deliver |
| Treatment if marginal os < 2cm (Type II – IV) | Elective casesarean section |
| Treatment if non-reassuring fetal status and unstable | Emergency caesarean delivery |
- Complications of placenta previa
- Preterm delivery
- Preterm Prelabor Rupture of Membranes
- Intrauterine Growth Restriction
- Malpresentation (commonly a transverse lie due to concurrent congenital uterine anomalies)
- Vasa previa
- Congenital anomalies
