Frequently Asked Questions About Pregnancy (cont'd)
Dr. Abraham-Hebert answers more pregnancy questions:
Q: What happens to the pelvic area during later pregnancy?
A: Dr. Abraham-Hebert: During the last four weeks of pregnancy, beginning at around 36 weeks and sometimes even a little bit earlier, many doctors will start checking the mother's cervix. During this time, the cervix will shorten or efface and it will start dilating, or opening. These things progress slowly until actual labor hits.
When labor begins, the dilation and the effacement progress much more rapidly. The cervix will dilate from 1 centimeter all the way to 10 centimeters. That's how we actually measure cervical dilation. Ten centimeters is where the cervix is at the point of delivery.
Around the same time the cervix will efface, or shorten, usually from a length of 3.5 centimeters all the way to where you can't feel any more cervical length.
Q: While the cervix is effacing and dilating, what is the uterus doing to expel the baby?
A: Dr. Abraham-Hebert: The rhythmic, powerful uterine contractions cause the cervical changes. Cervical change doesn't usually happen without uterine contractions.
The contractions are a physical tightening of the entire uterus. All those uterine smooth muscles work together in concert to squeeze the infant out as well as when the mother pushes. Of course the mother has to push to actually get the baby out, but the uterus itself is expelling the baby with the uterine contractions.
Q: What accounts for the pain with labor and delivery?
A: Dr. Abraham-Hebert: Labor pains are due to the uterus muscle squeezing and contracting. When muscles contract, it's very painful. Menstrual cramps are actually uterine contractions on a very smaller scale.
There are also chemicals produced in the body, the prostaglandins, that actually cause pain, and these are released during labor.
Q: What factors might lead to a Caesarean-section delivery?
A: Dr. Abraham-Hebert: Some of the factors that cause or contribute to a C-section would be slow progression of labor or no progression of labor. There's a certain speed to labor that is normal. We usually try to adhere to that to keep it safe for the mom and the baby.
What happens in many cases is that the pelvic bones are just not large enough to allow the passage of a certain size baby. If that's the case, the cervix may open to a certain number, say, to 4 to 5 centimeters, and just stop and stay at that number for two hours.
Usually a first-time mom who is experiencing good, strong labor contractions with no progress for several hours would be a candidate for a C-section. Another case would be if the cervix dilated to 10 centimeters and the mom was pushing for a certain amount of time without the baby appearing, we'd assume that the baby's just not going to be able to come out through the pelvic outlet. We allow a shorter amount of time for somebody without an epidural.
But there are two big reasons that C-sections happen. One big one would be where the fetal heartbeat would drop suddenly and stay down rather than recovering after a contraction. That would be an emergency and we would have to get the baby out.
The other situation would be if the fetal heart tracing just does not look normal regardless of the resuscitation that we're doing — oxygen and position change or putting some fluid back up inside the uterus. If things are just not looking healthy or safe for the baby or the mother, that would necessitate a C-section.
