Mirena Intrauterine Contraceptive Device

Last updated 20.09.12

 

Definition

-  Long term hormone (progestogen) releasing intrauterine contraceptive device

 

Mirena

 

 

-  Insertion

-  Removal

-  Lost strings

 

Features

-  Levonogestrel (progestogen)

-  52mg total

-  20mcg released per 24hrs, reduced to 10mcg per 24hrs after 5yrs

-  5 yrs of contraception then replaced

-  Device inserted into uterus

-  0.2% failure rate 1yr (Pearl index 0.21%)

-  0.7% at 5yrs

-  Easily reversed

-  80% women conceive by 12months of removal

-  Safe in breast feeding, does not effect milk production

-  Subsidised in Australia

-  $30 on PBS

-  May be used in nuliparous women but usually requires analgesia

 

Mechanism

-  Inhibits endometrial synthesis of oestrogen receptors (anti-proliferative effect)

-  Thickening of cervical mucus preventing sperm passage

-  +/- inhibition of ovulation

-  Weak foreign body reaction

 

Indications

-  Contraception

-  May alleviate dysmenorrhoea

-  Menorrhagia

-  Including Perimenopausal

-  Less effective if submucosal fibroids

-  HRT

-  Progestogenic component

-  Prevention of endometrial hyperplasia during oestrogen therapy

 

Contraindications

-  Pregnancy

-  Current or recurrent PID

-  UTI

-  Post partum endometritis

-  Cervicitis

-  Cervical dysplasia

-  Uterine or cervical Ca

-  Progestogen dependant tumours

-  Undiagnosed abnormal bleeding

-  Congenital or acquired uterine anomaly

-  Acute liver disease or tumour

-  Precautions

-  First episode whilst on Mirena of migraine

-  Severe headache

-  Jaundice

-  Severe HTN

-  Stroke, AMI

-  Breast Ca

 

Side Effects/Complications

-  Irregular bleeding: shorter or longer

-  Initial spotting in first few months, progressive decrease

-  Menstrual loss generally reduced

-  May progress to oligomenorrheoa or amenorrhoea

-  17% pts amenorrhoea 3months+

-  After 6 weeks DDx pregnancy

-  Ectopic pregnancy

-  Absolute risk lower than wo Mirena

-  Increased risk if become pregnant whilst using Mirena

-  0.1% per yr

-  Pregnancy

-  Recommend removal of Mirena which may result in spontaneous miscarriage

-  If not easily removed recommend TOP

-  If pregnancy continued may have virilising effects but no evidence of birth defects

-  Expulsion

-  5yr rate 2.2-5.8%

-  Partial or complete

-  Presents w bleeding &/or pain, increased length of or lost threads

-  Uterine perforation

-  Incidence 0.01-0.1%

-  Usually at time of insertion

-  Icreased risk post partum, breast feeding or fixed retroverted uterus

-  Presents with pain &/or bleeding

-  Enlarged functional follicles

-  Delayed follicular atresia

-  Difficult to DDx ovarian cysts

-  12% patients

-  Usually symptomatic but may have pelvic pain +/- dyspareunia

-  Most resolve spontaneously 2-3 months

-  Consider ongoing US R/V +/- surgical R/V

 

 

 

Mirena Insertion

 

Definition

-  Insertion of Mirena contraceptive IUD

 

Features

-  May be inserted post partum up to 48hrs but not between 2/7 & 4/52 because of increased expulsion rates

-  Inserted

-  Within 7 days from 1st day LMP

-  Immediately post D&C or TOP (1st trimester)

-  6 weeks post partum

 

Equipment

- Sterile gauze

- Chlorhexidine prep

-  +/- LA: lidocaine 1%

-  10ml syrine

-  25G needle

-  Speculum

-  Lubricant

-  Sterile gloves

-  +/- MCS swabs for Chlamydia

-  Hagar size 3, 4 & 5 (Mirena = 5mm in diameter)

-  Mirena

- Tenaculum

-  +/- pipelle (if inserting for menorrhagia)

 

Procedure

-  Ensure Pap smear up to date

-  +/- prior pelvic US for uterine anomalies

-  Insert up to day 7 post LMP

-  Consider NSAIDs 1hr prior to procedure

-  Bimaual exam to exclude PID & determine orientation of uterus

-  Speculum exam

-  +/- MCS swab

- Prepare cervix with Chlorhexidine

- Grasp anterior lip of cervix with tenaculum to stabilise

-  +/- 0.5-1ml Lidocaine into anterior lip of cervix +/- into cervical os

-  Sound uterus

-  Anything abnormal or concerned --> pelvic US

-  Typically 7-9cm = normal

-  If >9cm not suitable contraceptive method as increased expulsion rates

-  Prepare Mirena

-  Release threads at end

-  Load Mirena by holding slider & pulling threads

-  Avoid sustained compression so that device maintains memory of T shape

-  Secure threads

-  Set flage to depth of sound

-  Some methods use +1cm or -1cm

-  Insert Mirena until flange 1-1.5cm from external os

-  Release slider to 1st position: opens Mirena arms

-  +/- wait 30seconds for device to deploy fully into T shape

-  Advance device so that flange abuts internal os (Mirena to fundus)

-  Release slider to 2nd position

-  Automatically releases threads

-  Ensure threads are loose

-  Remove device

-  Careful not to pull out Mirena via threads

-  Cut threads to leave 2-3cm outside cervix

-  Remove speculum

-  Woman to palpate threads to confirm feeling & location

-  R/V 4-8 weeks

-  Consider early F/U to confirm locaton

 

 

 

Mirena Removal

 

Definition

-    Removal of Mirena IUD

 

Features

-   

 

Indications

-  Mirena in situ for 5yrs

-  Partial expulsion

 

Equipment

- Speculum

-  Forceps

 

Procedure

-  Grasp Mirena threads with foreps

-  Gentle traction on threads

 

 

 

Lost Threads

 

Definition

-  Suspected expulsed Mirena by loss of cervical threads

 

Features

-  Must DDx current pregnancy

-  Women should be instructed how to examine for strings each month

 

Causes

-  Partial or complete expulsion

-  Retraction of threads into cervix or uterus

 

Ix

-  Beta HCG: DDx pregnancy

-  Speculum Exam

-  Gently probe for threads

-  Pelvic US

-  Presence or absence of Mirena

-  Fundal position of Mirena

-  +/- X-ray if US not available

 

Mx

-  If not visible on spec then progress to imaging

-  Reinsertion as necessary

 

 

 

References

 

Mirena: Intrauterine Levonorgestrel Delivery System, Bayer

Pic