Obstetric Examination

Original Author: Minesh Mistry
Last Updated: 13th July 2017
Revisions: 5

The obstetric examination is a type of abdominal examination performed in pregnancy.

It is unique in the fact that the clinician is simultaneously trying to assess the health of two individuals – the mother and the fetus.

In this article, we shall look at how to perform an obstetric examination in an OSCE-style setting.

Introduction

  • Introduce yourself to the patient
  • Wash your hands
  • Explain to the patient what the examination involves and why it is necessary
  • Obtain verbal consent

Preparation

  • Measure the patient’s height and weight
    • In the UK, this is performed at the booking appointment, and is not routinely recommended at subsequent visits
  • Patient should have an empty bladder
  • Expose the abdomen from the xiphisternum to the pubic symphysis
    • Cover above and below where appropriate
  • Ask the patient to lie in the supine position with the head of the bed raised to 15 degrees
  • Prepare your equipment: measuring tape, pinnard stethoscope or doppler transducer, ultrasound gel

General Inspection

  • General wellbeing – at ease or distressed by physical pain.
  • Hands – palpate the radial pulse.
  • Head and neck – melasma, conjunctival pallor, jaundice, oedema.
  • Legs and feet – calf swelling, oedema and varicose veins.

Abdominal Inspection

In the obstetric examination, inspect the abdomen for:

  • Distension compatible with pregnancy
  • Fetal movement (>24 weeks)
  • Surgical scars – previous Caesarean section, laproscopic port scars
  • Skin changes indicative of pregnancy – linea nigra (dark vertical line from umbilicus to the pubis), striae gravidarum (‘stretch marks’), striae albicans (old, silvery-white striae)

Fig 1 – Skin changes in pregnancy. A) Linea nigra. B) Striae gravidarum and albicans.

Palpation

Ask the patient to comment on any tenderness and observe her facial and verbal responses throughout. Note any guarding.

Fundal Height

  • Use the medial edge of the left hand to press down at the xiphisternum, working downwards to locate the fundus.
  • Measure from here to the pubic symphysis in both cm and inches. Turn the measuring tape so that the numbers face the abdomen (to avoid bias in your measurements).
  • Uterus should be palpable after 12 weeks, near the umbilicus at 20 weeks and near the xiphisternum at 36 weeks (these measurements are often slightly different if the woman is tall or short).
  • The distance should be similar to gestational age in weeks (+/- 2 cm).

Lie

  • Facing the patient’s head, place hands on either side of the top of the uterus and gently apply pressure
  • Move the hands and palpate down the abdomen
  • One side will be feel fuller and firmer – this is the back. Fetal limbs may be palpable on the opposing side

Fig 2 – Assessing fetal lie and presentation.

Presentation

  • Palpate the lower uterus (below the umbilicus) to find the presenting part.
  • Firm and round signifies cephalic, soft and/or non-round suggests breech. If breech presentation is suspected, the fetal head can be often be palpated in the upper uterus.
  • Ballot head by pushing it gently from one side to the other.

Liquor Volume

  • Palpate and ballot fluid to approximate volume to determine if there is oligohydraminos/polyhydramnios
  • When assessing the lie, only feeling fetal parts on deep palpation suggests large amounts of fluid

Engagement

  • Fetal engagement refers to whether the presenting part has entered the bony pelvis
  • Note how much of the head is palpable – if the entire head is palpable, the fetus is unengaged.
  • Engagement is measured in 1/5s

Fig 3 – Assessing fetal engagement.

Fetal Auscultation

  • Locate the back of the fotus to listen for the fetal heart, aim to put your instrument between the fetal scapulae to aim toward the heart.
    • Hand-held Doppler machine >16 weeks (trying before this gestation often leads to anxiety if the heart cannot be auscultated).
    • Pinard stethoscope over the anterior shoulder >28 weeks
  • Feel the mother’s pulse at the same time
  • Measure fetal HR for one minute
    • Should be 110-160bpm (>24 weeks)

Completing the Examination

  • Palpate the ankles for oedema and test for hyperreflexia (pre-eclampsia)
  • Thank the patient and allow them to dress in private
  • Wash your hands
  • Summarise findings
  • Perform:
    • Blood pressure
    • Urine dipstick

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