Placenta Previa

Update: We went to the doctor yesterday and he verified that everything looks perfect as far as the baby goes. They are measuring right where he wanted them to be, and everything looks great. He said the not so fun news for us is that we do have placenta previa (like I had guessed). He called it an inferior placenta previa, which means that only the tip (end) of the placenta is covering the cervix and not the entire thing. So we do have a good chance that as the uterus expands that it will pull up and hopefully get out of the way. He did say though that if the placenta remains low then our only option really is to have a c-section around 36-37 weeks so we won't have added risks of tearing and bleeding as my body naturally dilates to get ready for labor.

We will schedule an appointment for another ultrasound next month and see if there are any changes. We were told we don't have to worry too much about bleeding or other effects caused by placenta previa until around week 28, and that's only if the placenta hasn't moved at all... so basically after 2 ultrasounds if it still hasn't moved then we will have to be monitored a lot closer and worry about those complications. Until then we just relax and hope the placenta moves up. :)

For those of you interested in what placenta previa this is the information that I have found about it.

Low Lying Placenta at the 18-20 week Ultrasound Examination

Normally the placenta is situated in the upper part of the uterus (womb) or along the front or back wall, well clear of the birth canal (cervix) see figure 1.

In 5% of pregnancies at 18-20 weeks, the placenta is situated low in the uterus either close to, or covering the cervix (see figure 2). As pregnancy progresses however, the lower part of the uterus grows such that the placenta eventually becomes clear of the cervix. In fact, in 95% of cases the placenta will be clear of the birth canal by 37 weeks of pregnancy.

Therefore if you are informed at your 18-20 week scan that the placenta is low, do not be alarmed, you can continue normal activities as usual. A repeat ultrasound should however be arranged at around 26-34 weeks of pregnancy to determine if the placenta has moved away from the cervix.

In a small number (5%) of pregnancies, the placenta remains low after 28 weeks. This is called placenta praevia (refer figure 3). A placenta which is previa may cause vaginal bleeding in later pregnancy. Also in some patients with Placenta Previa the baby may need to be delivered by Caesarean section. So in this situation extra care and monitoring of your baby and the placenta may be required. Your specialist will discuss with you the best way to manage this situation and advise you of any precautions.

A normally situated placenta

Figure1. The placenta is situated at the top of the uterus well clear of the neck of the womb (cervix).

A low placenta at 18 weeks

Figure 2. The placenta is situated low in the uterus. In 95% of patients however the placenta "moves up" in later pregnancy.

Placenta Praevia

Figure 3. The placenta covers the birth canal (cervix). of the womb (cervix)