Placenta Previa Seen at the 20 Week Ultrasound
One of the most common problems spotted at the 20 week ultrasound is placenta previa. Placenta previa is where the placenta is nearby, or actually covering some or all of the cervix. It’s a potentially dangerous condition because if the placenta covers the cervix, it blocks baby’s way out, requiring a cesarean section to deliver the baby. And more seriously, as the cervix dilates towards the end of pregnancy, the placenta can be torn and bleed, which can be life-threatening to mom and baby.
Complete or partial placenta previa, where the placenta covers at least a quarter, or even all of the cervix, occurs in around 1 in 200 pregnancies, and requires careful monitoring by your doctor.
And more common is a marginal placenta previa, where the placenta is close by, or touching the cervix, but not actually covering it.
At 20 weeks, when the placenta is relatively large compared to the size of the uterus, many women appear to have placenta previa. The ultrasound technician will note the position of the placenta, so your doctor is aware and can discuss it with you. The doctor will probably tell you to avoid intercourse, heavy lifting, and strenuous activity. Your husband will be thrilled that he has to do the vacuuming instead of sex.
Several moms I know, including me, had marginal placenta previa at 20 weeks. At my next obstetrician appointment, the doctor explained what it was. The position of the placenta is largely random, but there are risk factors to placenta previa, including previous cesarean sections, a history of placenta previa, and it’s more common in older moms. Apparently, smoking or using cocaine also increases the risk, my doctor told me, raising one eyebrow. What? I’ve never smoked and the only kind of coke I know comes in a red can with a swirl on it.
The good news is that for most women who have marginal placenta previa at 20 weeks, as your uterus grows, the placenta gets further from the cervix and you’ll likely be given the all-clear to get back to normal activities by 24-28 weeks. Your doctor will schedule another ultrasound to check the position of the placenta at that time. If the placenta is now clear of the cervix, then vaccuming, etcetera are back on.
I had another ultrasound at 25 weeks, and like 90% of moms with marginal placenta previa at 20 weeks, my placenta was in a normal position, and the rest of my pregnancy went smoothly, except for having to think of other excuses to not vacuum.
If you are pregnant, and experience any vaginal bleeding, get checked by a doctor asap. If you have been told you have, or may have placenta previa, it is important to let the doctor who examines you know, as they will need to take extra precautions when they examine you to avoid causing any damage to your placenta.