The PregnanT-study: Pregnancy Outcomes After TVT and Other Mid-urethral Sling (MUS) Procedures

Stress urinary incontinence (SUI) is defined as involuntary leakage of urine on effort, or exertion, or on sneezing or coughing or laughing. This is the commonest form of incontinence in women affecting one in three over the age of 18 years with significant impact on their quality of life.

The Tension-free vaginal tape (TVT) was introduced in 1996 and has become one of the most widely used incontinence operations worldwide. In 2001, Delorme described a new mid-urethral sling using an outside-in transobturator approach, where the tape is inserted through the skin and the obturator foramen into the vagina (TOT). DeLeval developed a similar approach in 2003, where the tape is inserted inside-out from the vagina through the obturator foramen and the skin (TVT-O). TVT, TOT and TVT-O are collectively known as mid-urethral sling (MUS) operations.

Mid-urethral sling (MUS) operations can be performed as minimal invasive surgery in local anesthesia with short operative time and minimal surgical dissection. This type of surgery is now considered to be the standard surgical management for both SUI and mixed urinary incontinence (MUI) in which there is a predominant stress component. The short- and long term results are comparable to the Burch colposuspension and have been well documented.

Surgical treatment of SUI and MUI is generally recommended after the completion of childbearing for several reasons, one reason being that numerous studies have demonstrated pregnancy and delivery to be risk factors for SUI. Furthermore, in women treated with MUS, a new pregnancy and delivery might, in theory, change the position of the tape leading to the recurrence of incontinence symptoms. Women treated with MUS, who have recurrence of their SUI and MUI, also have a poorer outcome if given a second procedure (either a MUS or a bulking agent).

There is very limited knowledge about the consequences of a pregnancy in women who have undergone a mid-urethral sling operation, and only a few case reports exist in the literature. There is currently no consensus on either the management of a subsequent pregnancy or the mode of delivery after MUS surgery. Some clinical experts have claimed that vaginal delivery, where the baby's head exerts pressure on the anterior vaginal wall, may cause the tape to dislocate with potential injury to the bladder and urethra15. During the last decade, there has been a marked increase in the number of mid-urethral sling operations. This increase is probably due to the excellent short and long-term results, with less morbidity and a shorter hospital stay compared to colposuspension (the previous "gold standard" for SUI). It may therefore be expected in the future that more women of fertile age will request surgical treatment of SUI before the completion of their childbearing.