MAHE 2006 Contraceptive
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a)2
b)1
c)5
d) 10
Answer:c) 5 years
Review: Tcu-380A device has approved life span of only 5 years but effective life is atleast 10 years. The Tcu-380A is now the most widely available used IUD distributed in more than 70 countries and one of the most effective methods of contraception ever developed (Schmidt et al, 1994).
Types
Unmedicated or inert
Medicated - copper bearing or hormone releasing
The majority of the IUDs now widely used are copper bearing
Progressing from stones in camels to insert devices, researchers have developed the second and third generation of medicated IUDs which are highly effective, long lasting, have fewer side effects than earlier models.
Actually the first modern IUDs, the Lippes Loop and the Margulies Spiral appeared in the early 1960s. They were made of polyethylene, biologically inert plastic (Zipper et al 1969). The first generation of copper IUDs, which included the Cu-7, the Tcu-200 and the Multiload-250, carried copper wire with a surface area of 200 to 250 mm2. it was thought that these IUDs would have to be replaced every few years therefore newer IUDs were developed including the Tcu-380A, the Tcu-220C, the Nova T, the Multiload-375 and others. IUDs that release a hormone in the uterus were developed in the 1970s (Luukkainen 1994). A smaller, lightweight and flexible T-shaped copper IUD, the Cu-SAFE 300, which can be inserted without a plunger and is designed to move towards the uterine fundus when the uterus contracts (Vankets et al 1995) is also being marketed. Others are frameless IUDs consisting of six copper sleeves on a surgical nylon thread called the FlexiGard 330, Gynefix TM, or Cufix PP 330 (Vankets et al, 1995, WHO 1995).
The hormone releasing LNG-20 IUD may be even more effective than copper IUDs. Also it reduces menstrual bleeding, while copper IUDs may increase it (Luukkainen and Trivonen 1995). The Progestasert which has been marketed since 1976, contains 38 mg of progesterone released at a rate to 65mg per day for one year. The LNG-20 IUD contains 52 mg of levonorgesterel released at a rate if 20 mg per day and lasts at least five years.
The other major types of unmedicated IUDs are flexible stainless steel rings (either round or of the shape of the uterine cavity and made with a single or double coil). These ring have been widely used in China but not elsewhere.
Mechanism of Action:
The precise mechanism of action of copper IUDs is still not certain, probably affect ova and sperm in various ways, most likely the primary action is altering the function or survival of sperms and ova before they can meet (Croxatto et al 1994). They stimulate a pronounced inflammatory reaction or foreign body response in the uterus. The concentration of various types of white blood cells postaglandins and enzymes in uterine- tubal fluids increases markedly (Sagiroglu 1971, WHO 1987). These changes may interfere with transport of sperms in the genital tract and may damage sperms and ova so that fertilization is impossible (WHO 1987). It has been reported that fewer sperms are found in the fallopian tubes in IUD users than in nonusers. Various types of white blood cells probably consume or damage many sperms in the uterus (Sagiroglu 1971). However, the LNG-20 IUD, although also prevent sperm and ova from joining, has a primarily hormonal mode of action, probably working chiefly by thickening cervical mucus so that sperms cannot pass through it (Luukkainon and Toivonen 1995). Prevention of implantation as a result of biochemical and histological changes in the endometrium as a result of biochemical and histological changes in the endometrium play only a minor role, specially in case of Cu ebaring or progesterone releasing IUDs.
Progesterone releasing IUD exerts no protective effect against ectopic pregnancy. Progesterone decreases tubal motility and this may be the reson for the progesterone releasing IUD failing to reduce the frequency of ectopic pregnancies. Rate of ectopic pregnancy with Levonogestrel releasing IUD is very low 0.02/100 women after 5 years of use (WHO 1997).
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