Surgery relating to pregnancy

In more recent years, excellent literature for the laity has been published on all phases of obstetrics, parturition (birth), and postnatal (postpartum) care. A complete treatise of ob­stetrics is not within the scope of this book; however, certain obstetrical procedures involve surgical methods.

Episiotomy is an incision at the back or side of the vaginal opening through the skin and muscle layers, performed at the time of delivery by the obstetrician to allow sufficient opening for passage of the baby. This prevents tearing of the tissues as the passageway is stretched by the infant’s descent. Such incision is most often to be recommended for the first delivery, and for each successive delivery if the tissues have not been relaxed by a previous delivery without episiotomy. This minor operation at the time of childbirth prevents surface tears, but more im­portant is the fact that the muscles supporting the perineum are not torn and stretched, the result of which may be cystocele and/or recto- cele (see below). Frequently, however, episiot­omy may not be practical at the time of delivery. Injured or incised tissues are surgically recon­structed into normal anatomical position after the delivery is completed.

Perineal tears may occur at the time of de­livery when episiotomy to enlarge the delivery opening has not been performed. Tears of the deeper structures may go unnoticed at the time but surface tears of the vaginal lining and the skin are repaired surgically just after delivery.

Cervical tears may result when the delivery through the birth canal is rapid and the usual dilatation of the cervix is not completed as the baby passes this portion of the birth canal. These may be repaired operatively at the time of de­livery completion, and if not repaired, may heal with some cervical deformity. Old healed lacera­tions may necessitate an operation for correc­tion, by vaginal approach—the operation known as trachelorrhaphy.

Forceps delivery from the birth canal is employed more frequently today in hospital de­liveries, to expedite the delivery process or when there is difficulty in delivery progression. With this obstetrical maneuver the large curved in­strument is placed about the baby’s head to guide it from the birth canal. This may be used in either the cephalic (head first) delivery or the less common breech (feet first) delivery.

Retained placenta is the condition where the afterbirth does not spontaneously deliver after the birth of the infant. The placenta is a vascular organ which develops with the enlarg­ing fetus and lies attached to the uterine lining for blood component exchanges between the maternal and infant blood. At full term it reaches the weight of about lYz pounds. The birth of the placenta usually follows the birth of the baby in 1 to 10 minutes. Rarely this does not occur and the afterbirth has to be removed manually from the uterus by approach through the vagina. If only a fragment should remain, there may be prolonged postpartum (after-birth) bleeding and curettement of the uterus may become necessary.

Cesarean section

Cesarean section is delivery of a child by operation through the abdomen, also known as delivery by hysterotomy. There are very def­inite indications for the selection of this method of delivery. In most instances, delivery through the natural birth canal is to be preferred and is safer for both mother and child. Under some conditions, however, delivery by abdominal operation must be performed.

In the condition called placenta praevia, where the placenta overlies the cervical opening, marked bleeding may occur as the contractions of labor and dilatation of the cervix begin. With progression of labor there is increase in the bleeding. Delivery by cesarean operation may be imperative to spare life.

When the placenta begins to separate from its uterine attachments before the infant has been born, the condition is known as abruptio pla­centa. In this instance there is loss of blood and the infant may suffer from lack of oxygena­tion, as the placenta is the only source of oxy­gen. Urgent cesarean section is often the infant’s only chance of survival.

Cesarean section may be indicated in other cases where urgent delivery is necessary. In prolapse of the umbilical cord the cord pre­sents through the cervical opening ahead of the presenting part of the infant; as the uterine con­tractions force the infant downward the cord becomes compressed and its blood supply pinched off. Labor must be stopped and the infant delivered by the abdominal route.

When there is a disparity in the size of the infant’s head (the largest part of the infant, in comparison with the maternal birth canal), so that the head cannot pass, this is called cephalo- pelvic (head-pelvis) disproportion. This may be discovered by x-ray picture and elective cesarean section performed. But more often a trial of labor is undertaken, and if normal prog­ress does not ensue, cesarean section is indi­cated.

Less common reasons for delivery by hys­terotomy may be certain tumors and scars ob­structing the birth canal and concurrent dis­eases of other systems which designate this method as the least risk to the mother and/or the infant.

Previous cesarean section may indicate this method of delivery for all subsequent deliveries. Repeat section is usually indicated in all cases where the first was for cephalopelvic dispropor­tion and when there have been two to three or more previous hysterotomies. Some surgeons and obstetricians believe that, once delivered by section, the patient should have section for all deliveries, because the scarred incision in the uterus may give rise to a weakened area in the wall which could perforate with the contractions of labor. More and more, however, the natural birth canal is used after a solitary cesarean birth.

The methods of cesarean section are several but differ only in detail, as far as the patient is concerned. All entail an incision through the lower abdominal wall and then incision through the uterine wall, from where the infant and the afterbirth are delivered. Preoperative prepara­tion and choice of anesthetic must be calculated carefully. Here two lives are under considera­tion and drugs given to the mother may also enter the infant’s body. If too much sedation or prolonged anesthesia is used, the infant may have difficulty in its initial respirations. Fre­quently local anesthesia is used for the dissec­tion through the abdominal wall and then gen­eral anesthesia employed just before opening the uterus. In other cases, spinal anesthesia may be the method of choice, or general anesthesia with rapid induction may be used.

Incomplete Pregnancies. Abortion is the term which designates the disruption of preg­nancy during the first five months. Miscarriage is the term applied to the delivery of a dead fetus during the sixth or seventh months. Stillbirth means the birth of a dead baby. Delivery of a live child before maturity is called premature birth. Spontaneous abortions may occur with complete emptying of the uterus, known as com­plete abortion. When the uterus does not totally evacuate its contents it is known as in­complete abortion. In this case the D & C (scraping of the uterine lining) may be neces­sary. Spontaneous abortions are manifested with cramping and bleeding after a missed menstrual period. Obstetricians classify abortions as threat­ened, impending, and inevitable.

Ectopic pregnancy is another abnormality of pregnancy which falls into the category of surgery. In this instance the fertilized ovum did not descend into the uterine cavity for implanta­tion. When the pregnancy begins to develop in the tube, it is called a tubal pregnancy. The embryo grows within the tube, but this structure is not capable of the full expansion necessary for full-term pregnancy enlargement. Symptoms may ensue that cause recognition of the condi­tion so that surgical intervention may be under­taken. More frequently there is rupture of the tube with internal pelvic hemorrhage. Surgical intervention is imperative and usually entails salpingectomy (removal of tube) with its in­cluded early pregnancy.