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Key messages

  • The anterolateral thigh is the preferred site for intramuscular (IM) injection.
  • Never give an IM injection in the buttocks.
  • Ensure needle of appropriate length and gauge is used.
  • Nursing and medical staff must be familiar with the principles of the administration of medications to an infant.

Please note that all guidance is currently under review and some may be out of date. We recommend that you also refer to more contemporaneous evidence in the interim.

Intramuscular (IM) injections in neonates may be required to administer medications or vaccines.

The anterolateral thigh is the preferred site for IM injection in infants under 12 months of age. Medications are injected into the bulkiest part of the vastus lateralis thigh muscle, which is the junction of the upper and middle thirds of this muscle.

Nursing and medical staff must be familiar with the principles of the administration of medications to an infant. These principles include:

  • observation of standard precautions
  • aseptic techniques
  • correct drug/dose/time/route/patient practices.

Equipment required

Equipment: required for IM injection includes:

  • IM medication ampoule
  • large-bore needle for withdrawing medication from ampoule
  • 1 mL or 2 mL syringe
  • 23 gauge 25 mm needle or 25 gauge 16 mm needle for preterm babies two months or younger (see table below)
  • antiseptic swab if used must be allowed to dry before injection given
  • cotton wool swab
  • gloves for standard precautions.

Recommended needle size, length and angle for administering vaccines


Needle type

Angle of needle insertion

Preterm babies (< 37 weeks' gestation) up to two months of age and/or very small infants 23 or 25 gauge,* 16 mm
in length
90° to skin plane
Infant, child or adult for IM vaccine 23 or 25 gauge, 25 mm
in length
90° to skin plane
Subcutaneous injection in all infants 25 or 26 gauge, 16 mm
in length
45° to skin plane

* If using a narrow 25 gauge needle for an IM vaccination, ensure vaccine is injected slowly over a count of five seconds to avoid injection pain and muscle trauma.

Needle length

The use of short needles for administering IM vaccines may lead to inadvertent SC injection and increase the risk of significant local adverse events, particularly with aluminium-adjuvanted vaccines (for example, hepatitis B, DTPa, DTPa-combination or dT vaccines).

Refer to the Australian Immunisation Handbook 10th edition 2013.


Follow this procedure when administering IM injections to newborns:

  1. Make sure there is a written medication order on the medication chart.
  2. Check the correct drug/dose/time/interval/route/patient.
  3. Draw the medication up into the syringe using the large bore needle.
  4. Change to the 23 g 25 mm needle or 25 g 16 mm needle.
  5. Be aware that a second staff member to help position the infant on his/her back on an appropriate surface may be required.
  6. Administer sucrose.
  7. Undo the infant’s nappy to locate the junction of the upper and middle thirds of the vastus lateralis thigh muscle.
  8. Place your forearm across the infant’s pelvis and secure the thigh between your thumb and forefinger if you are the clinician performing the injection.
  9. Position the limb to relax the muscle.
  10. Pierce the skin at an angle of 90 degrees to the skin. Provided an injection angle of > 70 per cent is used, the needle should reach the muscle layer. The following figures of the thigh show the recommended injection site.
Figure 1: Anatomical markers, immunisation
Figure 1: Anatomical markers used to identify the vastus lateralis injection site (X) on the anterolateral thigh

Source: Australian Immunisation Handbook 10th Edition 2013 used by permission of the Australian Government.

  1. As there are no large blood vessels in the recommended sites, aspiration before injection of vaccines (pulling back on the syringe plunger after needle insertion but before injection) is not necessary.
  2. Slowly inject the medication for even distribution and to minimise the infant's discomfort.
  3. Remove the needle.
  4. Check the injection site for bleeding and apply cotton wool ball if necessary. Observe the site for local inflammation.
  5. Dispose of the needles and syringe into a labelled puncture proof container to prevent needle stick injury or reuse.
  6. Document the administration of the IM injection on the medication chart and/or child health record (where appropriate).

Practice points

Issue to note regarding administration of IM injections:

  • Avoid subcutaneous and intramuscular injections when intravenous administration is a suitable alternative option. Note: Vitamin K is preferably given intramuscularly as soon as possible after birth as endogenous endorphins are present at high levels at the time of birth.
  • Alcohol and other disinfecting agents must be allowed to evaporate before injection of medication to reduce inactivation of live vaccinations and irritation at injection site.
  • If an injection site is cleaned using a 70 per cent alcohol / 2 per cent chlorhexidine swab it must be swabbed for 30 seconds and allowed to air dry completely.
  • Current best clinical practice is not to swab an injection site (intramuscular (IM), subcutaneous (s/c) and immunisation) with a 70 per cent alcohol / 2 per cent chlorhexidine swab, if the site is visibly clean.
  • If the site is soiled in any way the clinician should clean the site with soap and water (as outlined by the World Health Organization).
  • Never give an IM injection in the buttocks. Using the vastus lateralis muscle avoids the risk of sciatic nerve damage from gluteal injection. Also, the vastus lateralis muscle has a larger muscle mass than the gluteal region and therefore has reduced risk of severe local reactions. The deltoid in infants is not sufficiently bulky to absorb IM medications adequately. The vastus lateralis muscle avoids the thicker layer of subcutaneous fat on the anterior thigh.
  • Make sure that infants do not move during the IM injection. This is very important. However, excessive restraint can increase the infant’s fear and can result in increased muscle tension.
  • The infant can be held in the ‘cuddle’ or semi-recumbent position on the lap of the parent/caregiver/health professional.
  • Breastfeed the infant at time of injection if appropriate.
  • Oral sucrose may be given for relief of distress with parental consent.
  • The volume of the IM injection should not be more than 1 mL.

When two IM injections are being administered, give one medication into the right thigh and the other into the left thigh. There is currently insufficient evidence to support simultaneous injections by two providers demonstrating a difference in pain response.

Get in touch

Centre of Clinical Excellence - Women and Children
Safer Care Victoria

Version history

First published: June 2017

Last web update: October 2018

Review by: June 2020


Page last updated: 17 Feb 2021

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