I know that some people reading this may not know what IC and a TAC are so I thought I would give a brief description:
Cervical incompetence is a medical condition in which a pregnant woman’s cervix begins to dilate (widen) and efface (thin) before her pregnancy has reached term. Internal os opening more than 1 cm is abnormal and cervical length less than 2 cm is considered diagnostic. Cervical incompetence may cause miscarriage or preterm birth during the second and third trimesters.
In a woman with cervical incompetence, dilation and effacement of the cervix may occur without pain or uterine contractions. In a normal pregnancy, dilation and effacement occurs in response to uterine contractions. Cervical incompetence occurs because of weakness of the cervix, which is made to open by the growing pressure in the uterus as pregnancy progresses. If the responses are not halted, rupture of the membranes and birth of a premature baby can result.
According to statistics provided by the Mayo Clinic, cervical incompetence is relatively rare in the United States, occurring in only 1–2% of all pregnancies, but it is thought to cause as many as 20—25% of miscarriages in the second trimester.
Risk factors for premature birth or stillbirth due to cervical incompetence include:
- diagnosis of cervical incompetence in a previous pregnancy,
- previous preterm premature rupture of membranes,
- history of conization (cervical biopsy),
- diethylstilbestrol exposure, which can cause anatomical defects, and
- uterine anomalies.
Repeated procedures (such as mechanical dilation, especially during late pregnancy) appear to create a risk.Additionally, any significant trauma to the cervix can weaken the tissues involved. There are also women who are born with a weak cervix so they have no known risks or issues with their cervix yet still have IC.
A Transabdominal Cerclage (TAC) is a full-blown abdominal surgery. The surgeon places the woman under general anesthesia in pre-pregnancy or have a spinal if pregnant and makes a bikini cut at the bottom of the abdomen (just like in a C-section). They then carefully move the bladder (which is in the way of the cervix). Spacers are placed in the cervix to make sure the mersilene band is not fitted too tightly however during pregnancy, the cervix is swollen, so they tie the band as tightly as possible. After delivery, the swelling goes down and leaves a functional cervical canal. The band is then tied around the very top of the cervix, just below the internal os. If it is placed correctly, there is enough room left for all normal functions of the cervix (enough room for semen, menstrual blood, fertility treatments, even enough room to have a D&C if that is necessary). The band simply prevents the cervix from dilating beyond its normal state. The TAC is always meant to be permanent, and can be used through multiple pregnancies without being redone. Also, a TAC can be placed laparoscopically, either by hand or by DaVinci robot.