Q. I delivered prematurely at 32 weeks last year. I am now 5 months pregnant. My obstetrician did a vaginal scan and told me that the cervix was 2.3 cm in length. He said that I had a short cervix. As the risk of premature birth is high, he suggested that I should have a stitch around the cervix. What is a short cervix? Is the cervical stitch safe? What can be done to prevent me from having another premature birth?
During pregnancy, the cervix is firm, long, and closed until late in the last trimester when it gets softer and shorter (efface), and opens up (dilate) as you prepare to give birth. The cervix can be accurately measured by vaginal ultrasound. The average cervical length varies from 3.5cm to 5cm. Your cervix is 2.3 cm long and is thus considered short.
Studies have shown that premature delivery is related to short cervices. The shorter the cervix, the higher the risk. Measurement of cervical length at 20 to 24 weeks gestation has been considered a good marker for premature birth. One study has found that premature birth would occur in one out of five women whose cervical length is less than 2.2 cm at mid-trimester.
Since you have a history of premature birth and a cervical length of 2.3cm, it is generally recommended that a cervical stitch (cervical cerclage) be done to avert a premature labour.
Cerclage is a procedure in which a band of strong thread is stitched around the cervix to reinforce and help hold it closed. It's usually performed under a short general or epidural anaesthesia. You have to rest for a few days at home as you may have slight staining or bleeding and/or mild cramping. Sexual intimacy should be avoided until after delivery to prevent infection. Vaginal discharge is usually increased and may continue for the rest of the pregnancy.
The procedure is usually safe with very minimal complications. Possible risks include:
· Accidental puncturing of the amniotic membranes(water bag)
· Infection of the cervix leading to intrauterine infection and premature birth
· The cervix may form scar tissue after cerclage and fail to dilate during labour
· Cervical tears may occur if labour happens before the thread is removed
Recent studies have found that cerclage is effective in the prevention of premature birth in women with short cervices.
To detect cervical infection, tests for urinary and vaginal infection and blood tests will be done.
You may be given antibiotics to prevent infection and drugs to stop uterine contractions.
Your level of activity should be reduced and you should refrain from exercise and intercourse and take frequent breaks.
Progesterone tablets (oral or vaginal) may be prescribed and steroid injections given to help your baby's lungs develop more quickly.
Your cervix will be checked regularly until the stitch is removed at around 37-38 weeks of pregnancy for normal labour to set in.
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