Expert: Catherine Beier MS CBE - 12/28/2011

Question
I'm 37 weeks, I was checked last week for Beta Strep. That came out positive. Whats the percentage that the baby can become infected with this? I didn't have it with my first two babies, is it normal to get it with this pregnancy and not the other ones? Last week at 36 weeks, they did a cervix check. I was 1-2 cm, 50% effaced and -2 station. They checked me this week (different doctor) he said I was the same but my cervix is funneling. Its closed on top but opened at the bottom. What does that mean? The Doc last week was the in his 3rd year and the Doc this week was in his first year. The Docs I see are in their resident program for the hospital. How could the checks be different? Does this mean that labor is still a while away? Thank you

Answer
Hello Rachael,


Beta strep is a natural, normal bacteria found in approximately 30% of pregnant women.  It is transient in nature, meaning that while you swabbed positive for it at this time, you could swab negative for it next week if checked again. So, yes, it's very common to be negative with some pregnancies and positive with others. Because of its transient nature, it's common to swab negative but actually be positive when giving birth, or to swab positive during pregnancy and be negative for it during labor. Of the 4 million babies born yearly in the United States, approximately only 1,200 will contract early onset GBS disease, meaning the rates of transmission and active infection during labor are quite low. See http://www.givingbirthnaturally.com/group-b-streptococcus.html for more detailed information and references.


To explain the concept of funneling, you must first understand the structure of the cervix.  Think of it as the neck of a turtleneck sweater.  It has openings on both sides.  The lower portion is the outer opening that leads into the vagina, called the external os.  The upper portion leads into the uterus where the baby is located and is called the internal os.  

So, when the doctor spoke of "funneling", he meant that the external os (the bottom portion) is dilated 1-2 cm and is "funneling" open toward the internal os, but that the internal os (the top portion) remains closed.  This is completely natural and normal and how cervical dilatation typically occurs. When the internal os is also open, the bag of waters or even the baby's head through the bag of waters can be felt.  

It's not that the checks were different but that the second doctor gave you more information than the first.  Most do not bother to state more than just the degree of dilatation (1-2 cm) even if funneling is present, as it's just quicker and easier to say a number than to explain what it really means.


As to whether labor is close or far away, only your baby knows that.  Cervical dilation and effacement before the onset of labor are not reliable indicators of when true labor will begin.  It could be hours or weeks away.  All that can be determined from early dilatation and effacement is that more progress has been made in advance of labor, meaning that there's less left that has to happen once true labor begins, which can mean a shorter overall labor time once it does begin.  See http://www.givingbirthnaturally.com/cervix-dilation.html and http://www.givingbirthnaturally.com/cervix-effacement.html for more information.