Most forceps have a pair of fenestrated blades with a cephalic and pelvic curve between the heel and toes (at the distal end) of the blades. The heel continues as a shank which ends in the handle. The handles of the two blades sit together so that they could be held by one hand and are kept in place by a lock on the shank. The cephalic curve is constructed to grasp the fetal head - with the toes of the blades over the maxilla or malar eminences while the length of the blade grasps the sides of the head from the malar area along the side of the head in front of the ear and the parietal bones in front of the occiput. This bimalar-biparietal application exerts uniform pressure on the head. In this position the shank is over the flexion point and thus allowing the correct direction of pull. If the posterior fontanelle is further backwards the blades can be slightly disengaged, lifted upwards and locked so that the downward pull will cause the flexion. The pelvic curve fits the pelvis and is minimal in those forceps used for rotation as in cases with malposition, for example, Kielland's forceps.
Prior to application of forceps the blades should be assembled to check whether they fit together as a pair. The handle which lies on the left hand is the left blade and in cases of direct or LOA positions, it is inserted first negotiating the pelvic and cephalic curve with a curved movement of the blade between the fetal head and the operator's hand kept along the left vaginal wall. The right blade is held by the right hand and is applied between the left hand that protects the vagina and the head by negotiating the cephalic and pelvic curve. If the blades were applied correctly, the handles should lie horizontally and lock easily. The three ESSENTIAL points of, sagittal suture in the midline (i.e. no asynclitism), occiput 3 to 4 cm above the shank (i.e. traction will be along the flexion point) and not more than one finger space between the head and the heel of the blade (i.e. optimal application with uniform pressure on the head from beyond the malar to the parietal area) should be checked prior to traction (Fig. 24.9). Traction is in the direction of the pelvic curve and is synchronized with contractions and maternal bearing-down efforts. An episiotomy is usually needed when the head is crowning at the vulva. The direction of traction is upwards as the head is born by extension.
Before Keilland's forceps are used, it is essential to identify abdominally the side of the baby's back and the occiput on vaginal examination. The forceps are applied with the 'knobs' facing towards the baby's occiput. The anterior or posterior blade may be applied first directly depending on the preference of the obstetrician. The anterior blade can be positioned by direct, reverse or classical and wandering method. In the wandering method the anterior blade is placed over the face and then moved to lie on the side of the fetal head. The posterior blade can be applied directly. The blades are locked and asynclitism corrected by sliding the shanks on each other till the sliding locks come to the same level. If there is no asynclitism the sagittal suture of the fetus will lie equidistant from the two blades of the forceps. If the blades cannot be locked easily the application of the forceps should be checked and reapplied.
An abnormal position (e.g. occipito-transverse) is corrected by rotating the handles of the forceps blades towards the baby's back and then directing the fetal occiput to the anterior position to emerge underneath the symphysis pubis. When the application is correct with the shank 2-3 cm below the occiput the head is flexed with the traction. An excessive twisting force should not be used. Rotational forceps and vacuum deliveries for malposition are best done by an experienced person or under supervision.
Forceps have been used with less frequency due to a greater incidence of maternal vaginal and perineal lacerations including 3rd and 4th degree tears compared with vacuum deliveries. Transientfacial and scalp abrasions are notuncommon butclears in a few days. Paralysis of the VII nerve is rare and it usually resolves within days or weeks. Cephalhaematomas and fracture of the skull are rare and depressed fracture may need elevation by surgery.
Was this article helpful?
The first trimester is very important for the mother and the baby. For most women it is common to find out about their pregnancy after they have missed their menstrual cycle. Since, not all women note their menstrual cycle and dates of intercourse, it may cause slight confusion about the exact date of conception. That is why most women find out that they are pregnant only after one month of pregnancy.