Click here to view next page of this article

 

Vacuum Extraction

The definitions, indications, and prerequisites for vacuum extraction of the fetus are the same as for forceps deliveries. Contraindications include face or breech presentation and cephalopelvic disproportion; relative contraindications include prematurity, macrosomia, fetal coagulation defects, and scalp puncture (after pH sampling).

Devices available for clinical use include a rigid metal cup (Malmstr6m), a silicone cup (Kobayashi), and several different disposable plastic cups. Proper placement over the sagittal suture, avoiding the fontanelles, facilitates flexion and descent when traction is applied. Care should be taken that there is no maternal soft tissue interposed between the cup and the fetal head. As with forceps deliveries.

There are data that suggest a benefit to vacuum extraction over forceps. Successful vaginal delivery rates appear to be higher with vacuum extraction, and maternal and fetal trauma and the need for anesthesia are decreased. There is evidence that rectal incontinence and nonneurologic weakening of the sphincter are more common with forceps than vacuum deliveries. Increased hyperbilirubinemia and scalp trauma.

Advances in anesthetic technique, blood transfusion, and antibiotics have made cesarean delivery safer, with a maternal mortality of 5-14 in 100,000 live births after adjusting for coexisting complications. Nonetheless, abdominal delivery results in a 1.5- to 7-fold increase in maternal mortality and a significant increase in morbidity, including endometritis, hemorrhage, thromboembolic events, and urinary tract infection. With more than 4 million deliveries occurring in the United States and a cesarean delivery.

Classification of Forceps Deliveries According to Station and Rotation

Type of Procedure

Classification

 

Outlet forceps

1) Scalp visible at introitus without labial separation

2) Fetal skull has reached the pelvic floor

3) Sagittal suture is in anteroposterior diameter or right or left occiput anterior or posterior position

4) Fetal head is at or on perineum

5) Rotation does not exceed 45 degrees

Low forceps

Leading point of fetal skull is at station $+2 cm and not on the pelvic floor

a. Rotation #45 degrees (left or right occiput anterior to occiput

anterior or left or right occiput posterior to occiput posterior

b. Rotation >45 degrees

Mid forceps

Station above +2 cm but head engaged

High forceps

Not included in classification

 

American College of Obstetricians and Gynecologists. Operative vaginal delivery. ACOG Technical Bulletin 196. Washington, DC: ACOG, August 1994

The assessment of fetal maturity is important in determining the timing of repeat cesarean birth. Amniocentesis should be performed before elective cesarean delivery unless the woman presents in spontaneous labor or the gestational age is 39 weeks or more (normal menstrual cycles and no immediate antecedent oral contraceptive use), supported by one of the following criteria: 1) fetal heart tones for 20 weeks by fetoscope or 30 weeks by Doppler ultrasonography, 2) 36 weeks.

Low transverse incisions should be routinely used in cesarean deliveries; low vertical incisions are reserved for placenta previa, transverse lie, selected multifetal gestations, and premature breech, particularly with an undeveloped lower uterine segment. Classical cesarean deliveries are rarely performed. A single dose of prophylactic antibiotics at the time of cord clamping.

Vaginal Birth After Cesarean Birth

Early in this century, the adage "once a cesarean, always a cesarean" was promulgated by those who noticed a high incidence of uterine rupture (12%) in women with a prior classical uterine incision. In such cases, uterine rupture occurred during or even before the onset of labor and often led to catastrophic results for mother and infant. Numerous recent studies have shown the rate of uterine separation of a single low transverse incision to be as low as 0.5-1% in women attempting vaginal birth.