Obstetrics and Gynecology - A.M. Hromova 2000

Operative Obstetrics
Operations Preparing the Birth Canal
Amniotomy

Amniotomy is the artificial rupture of the fetal membranes. The types of amniotomy include:

a) early amniotomy—performed During the first stage of labor when the cervix is dilated up to 7 cm;

b) timely amniotomy—performed when cervical dilation reaches 7 cm or more;

c) delayed amniotomy—performed after full cervical dilation when the Amniotic Fluid has not yet discharged.

Indications for amniotomy:

1. Delayed rupture of the fetal membranes due to excessively dense membranes.

2. Flat amniotic sac, as it fails to perform its function as a hydraulic wedge, inhibits labor progress, and may cause premature placental abruption.

3. Uterine inertia (performing amniotomy enhances the effectiveness of labor stimulation).

4. Polyhydramnios—an overdistended Uterus leads to weak labor activity.

5. Low-lying Placenta—amniotomy halts further placental detachment.

6. Delayed delivery of the second twin in a Multiple Pregnancy.

7. Severe forms of Late gestosis—amniotomy reduces intrauterine pressure and accelerates the labor process, which is crucial for normalizing hemodynamics.

8. Rupture of the fetal membranes is a mandatory prerequisite for the application of Obstetric Forceps.

Surgical technique: After disinfecting the external genitalia with antiseptic solutions, the index and middle fingers are inserted into the Vagina to rupture the membranes of the taut amniotic sac during a contraction. If this maneuver is unsuccessful, the membranes are ruptured using tenaculum forceps or sponge forceps. This is performed either under visual control (using vaginal specula) or digital control (the instrument is guided along the fingers to rupture the membranes safely). The hand inside the vagina restrains the flow of amniotic fluid to prevent umbilical cord prolapse or the premature descent of small fetal parts.