Levonorgestrel, Pharmacokinetics, Efficacy and Safety 53In another study, patient satisfaction was evaluated in 78 women who had
the LNG-IUD inserted for menstrual disorders. 12% of the women had the
IUD prematurely removed, with the major reason being pain and heavy
bleeding. However, the majority of women were satisfied with the IUD. 78%
of the women reported improvement in their periods, and 84% reported
improvement in menstrual discomfort. 72% of the women reported they would
use the LNG-IUD again, 73% would recommend it to their peers and the
overall satisfaction rate was 76% [111].
Although the systemic absorption of LNG in IUD form is much less
compared to oral LNG containing contraceptives, it can occasionally be
associated with some undesirable side effects such as ovarian cysts, acne,
weight gain, depression and decreased libido. Three meta-analyses have
reported systemic side effects of the LNG-IUD. These identified a significant
increase in headaches and breast tenderness and a fivefold (but not significant)
increase in acne [112-114].
The LNG-releasing intrauterine system is a safe, effective and acceptable
form of contraception and has a multitude of non-contraceptive benefits. Most
of the side effects are minor and tolerable.
Other side effects encountered with different progestins varies depending
on their androgenic or mineralocorticoid activity. Undesirable side effects due
to androgenic activity include acne and seborrhea, weight gain, blood pressure
increase, and an increase in the low-density lipoprotein (LDL) to high-density
lipoprotein (HDL) ratio. Acne is one of the side effects observed when an
androgenic molecule such as LNG is used in higher doses.
A headache is observed due to hyperestrogenism in combination pills
where estrogen is predominant. Alopecia may be another effect of systemic
absorption of LNG in women using this device, although the exact mechanism
is unknown. Alopecia has been cited as an adverse effect of progestin OC
[115] and has also been reported with progestin implants with incidence rates
of 1.1% [116] to 11.8% [117]. The LNG-IUD product information includes
hair loss as an “uncommon” side effect. The incidence is quoted at 0.1–1%.
The analysis of IMMP cohort suggests that the incidence is likely to be
between 0.18% and 0.33% [118]. The etiology of hair loss with LNG-IUD and
implants has not been explained but may result from a lower circulating
estrogen level in some women [119]. Although alopecia is rare (0.1–<1.0%), it
definitely is psychologically upsetting for women [120].
Cardiovascular effect: Most of the OCP have progestins derived from
testosterone, and their main side effects are due to their androgenic or
corticosteroid properties. Natural progesterone and some of its derivatives,