Women Talk: Why do women have cesarean sections?

Katherine, a 26-year-old sales agent, had been seeing me regularly for pre-natal check-ups. It was her first pregnancy, and during one visit she came in looking worried. Upon query, she said that many friends had been warning her that with her height—she was barely 5 feet tall—she would certainly end up with a CS, or a cesarean (caesarean) section. She wanted to know if that was true.

Indeed, there is a preconception that short women will not be able to deliver their babies by NSD (Normal Spontaneous Delivery), or in a normal way. I immediately told Katherine that that is not true at all. I have many patients who are shorter than her who delivered normally in an unremarkable manner. I assured her that small women naturally have smaller babies, and explained further why some women end up with cesarean sections.

Passenger size

The most common reason for a CS is a disparity between the size of the “passenger” (the baby) and the “passageway” (pelvic bone). The baby’s head has to manuever through the mother’s pelvis by assuming some positions, called the cardinal movements of labor. During active labor, the baby’s head, too, normally “molds”—becomes more compact—assuming a smaller diameter for easier accommodation through the passageway.

Logically then, it is a mechanical adaptation: the size of the baby’s head and the size of the pelvic bones. Unless the pelvic bone is really narrow (the obstetrician does an evaluation of this) or the baby is unusually large, there is always room for a trial of labor. That is, we allow women to go into labor and closely observe the effect of uterine contractions on the cervical opening (dilatation), cervical thinning (effacement), and the descent of the baby’s head. An experienced obstetrician knows when to advise further observation of labor, and when to decide on a CS at this point.

Moreover, during labor, the obstetrician will observe the fetal heart pattern vis-á-vis the mother’s contractions using a fetal monitoring device. Anything that causes a slowing down, an increase, or an irregularity in the baby’s heartbeats may be interpreted as “fetal distress,” and the obstetrician will be closely observing the labor, and discuss any problems with the mother.

Presentation

A presentation that is not head-first (cephalic) is also an indication for a CS. When the baby’s buttocks present first, this is called a breech presentation. For first time mothers, the pelvis is deemed “untried,” and there is fear of entrapment of the head after all parts of the baby had been delivered.

Some very skilled obstetricians will do a vaginal breech extraction in women having their second or third child, provided the weight of the present baby is not any larger than the previous ones, and the breech is “frank.” This means the thighs are flexed upon the abdomen, and the lower extremities are extended: think of the baby folded in half. The whole buttock of the baby “plugs” the pelvic rim of the mother.

When the breech is “complete,” which means that the thighs are flexed upon the abdomen, and the smaller extremities are also flexed against the thighs (think of the baby folded in thirds, assuming an inverted letter “N” if you look at it from the side), a CS is the safest way to deliver the baby. This is because when the smaller extremities are folded against the thighs, there are spaces between the small parts and the pelvic bones for the umbilical cord to fall through, into the vagina and out, especially when the bag of waters ruptures. This is called “cord prolapse,” an emergency situation where a CS should be done immediately. For the same reason, when the baby presents with a single foot or both feet (called single or double footling, respectively), we do not attempt a vaginal delivery.

How does one know the baby’s presentation? The obstetrician usually does an internal examination from the 36th week of pregnancy onwards, and the presentation can be determined. A pelvic ultrasound can clear up any doubts.

Another presentation that will warrant a CS will be shoulder presentation. Here, the baby lies transversely in the abdomen of the mother, and may present its back, front, or with either arm. In unusual cases of shoulder presentations, e.g. very small, preterm babies that are no longer alive, a vaginal delivery might be attempted. Sometimes, the baby presents with its face. Provided the chin is anterior, there is room for considering a vaginal delivery. One thing to remember, though, is that face presentations often come with a narrow pelvic bone.

Many times the pregnant woman has medical complications. This includes severe preeclampsia, where the blood pressure shoots up to very high levels, endangering both mother and child. The obstetrician will judiciously decide on a CS. In some cases too, when the placenta is way below and completely obstructs the passageways (a condition called placenta previa), a normal delivery will not be possible.

Normal delivery after CS

Is a normal delivery possible after a CS? Many obstetricians do VBACs (vaginal birth after a cesarean) provided strict criteria are met. The argument is, when the conditions that led to the previous CS are no longer present (e.g. placenta previa, breech presentation) there is always room to consider a normal delivery.

Rupture of the uterus after a previous CS is a constant fear. Champions of VBACs cite medical literature and point out that uterine rupture does not occur in carefully chosen patients. They allow these women to go into labor spontaneously, and watch over them very carefully. Many successful vaginal deliveries have been done after a CS.

A word on “elective” cesarean section—that is, a CS done for no reason other than the mother’s wish: Don’t. A CS is still a major surgical procedure, with its concomitant surgical and anesthetic risks. True, it is a very safe procedure during these times. But compared to a normal vaginal delivery, the risks are still higher. There is more blood loss. If it is labor pains that one is afraid of, there are safe anesthesia procedures (e.g. epidurals) that could help you.

Talk to your obstetrician about what worries you. She will be more than glad to answer your queries. And Katherine? She delivered a 6-pound boy—yes, normally! — BM, GMA News

Dr. Alice M. Sun-Cua is an author and practicing obstetrician-gynecologist at the San Juan de Dios Hospital in Pasay City.