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Abdominal Examination in Pregnant Women: 1st, 2nd & 3rd Trimester
Overview: Why It Changes Every Trimester
The gravid abdomen changes dramatically across pregnancy. The uterus grows from a pelvic organ to one occupying most of the abdominal cavity, displacing the bowel, compressing the inferior vena cava, and altering organ positions. The examination approach, what you look for, and what you can find all shift with gestational age.
Preparation (All Trimesters)
Before you start:
- Ask the patient to empty her bladder (a full bladder mimics a mass and causes discomfort)
- Warm your hands before palpation
- Expose the abdomen from the pubic symphysis to the xiphisternum
- Ask about pain before touching
Positioning:
| Gestation | Position |
|---|
| < 28 weeks (1st & 2nd trimester) | Supine, head of bed raised 15-30° |
| > 28 weeks (3rd trimester) | Left lateral tilt / left lateral position |
Why left lateral after 28 weeks? The enlarged uterus compresses the inferior vena cava (IVC) when the patient lies flat, reducing venous return to the heart and causing dizziness, hypotension, or even syncope (supine hypotensive syndrome). Tilting left moves the uterus off the IVC.
STEP 1: INSPECTION
Look from the end of the bed first. Inspect for:
Abdominal skin signs (normal findings):
| Sign | Description | Significance |
|---|
| Linea nigra | Vertical hyperpigmented line from pubis to umbilicus (or xiphoid) | Normal; due to elevated MSH in pregnancy |
| Striae gravidarum (stretch marks) | Striae rubra = red/pink (new); Striae alba = white/silver (old) | Normal; due to rapid skin stretching |
| Umbilical eversion | Umbilicus becomes flattened or protrudes outward | Normal in later pregnancy as uterus enlarges |
Size and shape:
- Is the uterus visible above the pelvis?
- Is the abdomen symmetrical?
- Note any scars (previous caesarean section - Pfannenstiel scar at suprapubic area)
STEP 2: UTERINE SIZE AND FUNDAL HEIGHT
This is the single most important measurement at every prenatal visit. The uterine fundus rises predictably through pregnancy.
Fundal Height Landmarks
Fig. 1 - Fundal growth at various weeks of gestation (Textbook of Family Medicine, 9e)
| Gestational Age | Fundal Height Location |
|---|
| 8-10 weeks | Just above pubic symphysis (felt on bimanual, not abdominally) |
| 12 weeks | At the pubic symphysis (just palpable above it abdominally) |
| 16 weeks | Midway between pubic symphysis and umbilicus |
| 20 weeks | At the umbilicus |
| 24 weeks | ~4 cm above umbilicus |
| 28 weeks | ~8 cm above umbilicus |
| 36 weeks | At the xiphoid process / lower costal margin |
| 40 weeks | Slightly lower than 36 weeks (lightening/engagement) |
Symphyseal-Fundal Height (SFH) Measurement
After 20 weeks, the SFH in centimetres should equal the gestational age in weeks (±2 cm).
How to measure:
- Start just inferior to the xiphisternum, using the ulnar border of your left hand
- Locate the fundus (firm upper border of the uterus)
- Place one end of the tape measure at the upper border of the pubic symphysis
- Measure to the fundus in centimetres
- Place tape facing down, only read numbers once in position (avoids measurement bias)
Abnormal SFH:
- Larger than expected: multiple gestation, polyhydramnios, uterine fibroids, LGA fetus
- Smaller than expected: oligohydramnios, fetal growth restriction (FGR), fetal demise, incorrect dates
TRIMESTER BY TRIMESTER BREAKDOWN
🔵 FIRST TRIMESTER (Weeks 1-13)
What you can do abdominally:
- The uterus is still a pelvic organ - it cannot be palpated abdominally before 12 weeks
- At 12 weeks, the fundus just reaches the pubic symphysis and may be barely felt
- Before 12 weeks: uterine size is assessed by bimanual pelvic examination
- Fetal heart tones with Doppler may be heard from ~10-12 weeks (variable)
Abdominal findings at 12 weeks:
- Little to no visible abdominal distension
- Uterine fundus palpable just at or above pubic symphysis
- No fetal parts palpable yet
- Auscultation: Doppler FHT may be detectable (150-170 bpm)
Key focuses:
- Confirm uterine size matches dates
- Rule out masses (ovarian cysts, ectopic - though usually not palpable)
- Check for suprapubic tenderness
🟡 SECOND TRIMESTER (Weeks 14-27)
What you can do:
- Fundus is now above the pelvis and palpable abdominally
- At 20 weeks: fundus at umbilicus - a reliable landmark
- SFH measurement begins at 20 weeks
- Fetal heart tones audible with Pinard stethoscope from ~20 weeks; Doppler from ~14 weeks
Palpation technique:
- Light palpation of all 9 abdominal regions first (screen for non-obstetric tenderness - appendicitis, cholecystitis, etc.)
- Uterine palpation - identify upper and lateral edges; assess for tenderness
- At 20+ weeks: measure SFH with tape measure
Abdominal findings at 20-24 weeks:
- Clearly palpable uterus at and above the umbilicus
- Uterus is smooth and non-tender
- Fetal parts not yet clearly distinguishable by palpation
Important: IVC compression becomes a consideration from ~20 weeks onwards but is critical from 28 weeks.
🔴 THIRD TRIMESTER (Weeks 28-40)
This is where the most detailed abdominal examination is performed - including fetal lie, presentation, position, engagement, and fetal heart auscultation.
Positioning: Left lateral tilt is mandatory.
STEP 3: LEOPOLD'S MANEUVERS
Used from ~28-30 weeks onward, when the fetus is large enough to palpate.
Purpose: Determine fetal lie, presentation, position, and engagement.
Before performing - ask: Has the patient emptied her bladder? Warm your hands.
The Four Leopold Maneuvers
Fig. 2 - The four Leopold maneuvers (ROSEN's Emergency Medicine)
Fig. 3 - Leopold's maneuvers A-D (Textbook of Family Medicine, 9e)
MANEUVER 1 - Fundal Grip ("What is in the fundus?")
Position: Face the patient's head. Place both hands on upper abdomen, cupping the fundus.
| Finding | What it means |
|---|
| Firm, hard, round, ballotable mass | Fetal head (cephalic pole) in fundus = breech presentation |
| Soft, irregular, less mobile (moves with trunk) | Fetal buttocks in fundus = vertex/cephalic presentation |
| No discrete pole felt laterally | Transverse lie |
Determines: Fetal lie and what pole is in the fundus
MANEUVER 2 - Lateral/Umbilical Grip ("Where is the fetal back?")
Position: Face the patient's head. Place both hands on the lateral sides of the uterus. Apply steady, gentle pressure with one hand while the other "palpates" the opposite side.
| Finding | What it means |
|---|
| Smooth, firm, continuous resistance on one side | Fetal back on that side |
| Irregular, knobby, small parts felt on the other side | Fetal limbs (arms and legs) |
Determines: Fetal position (e.g., back on the left = LOA/LOT/LOP)
MANEUVER 3 - Pawlik's Grip ("What is the presenting part?")
Position: Face the patient's head. Use one hand (usually right hand) to grasp the lower abdomen just above the pubic symphysis between the thumb and fingers.
| Finding | What it means |
|---|
| Firm, hard, round, ballotable mass | Fetal head presenting (vertex) |
| Soft, irregular, cannot ballot | Breech presenting |
| Cannot grasp a distinct part | Head may be deeply engaged |
Determines: Presenting part and whether it is engaged (engaged = cannot be moved/balloted)
MANEUVER 4 - Deep Pelvic Grip ("Is the head flexed? What is the attitude?")
Position: Turn to face the patient's feet. Place both hands on the lower abdomen, fingers pointing toward the pelvis, and palpate deeply downward.
| Finding | What it means |
|---|
| Cephalic prominence on the same side as the fetal back | Head is extended (deflexed) - brow or face presentation |
| Cephalic prominence on the opposite side from the fetal back | Head is well flexed (normal vertex) |
| Hands converge easily | Head is engaged |
| Hands diverge (one sinks deeper) | Head is not yet engaged |
Determines: Degree of head flexion (attitude) and engagement
STEP 4: FETAL HEART AUSCULTATION
Normal fetal heart rate: 110-160 bpm
Where to listen depends on fetal position (sounds best through the fetal back):
- LOA (Left Occiput Anterior): Left lower quadrant
- ROA (Right Occiput Anterior): Right lower quadrant
- Breech: Above the umbilicus
Tools:
- Pinard stethoscope - from 20 weeks
- Doppler (Sonicaid) - from 10-14 weeks
STEP 5: ASSESSING ENGAGEMENT
Engagement = the widest diameter of the fetal head has passed through the pelvic inlet.
Clinical assessment (fifths palpable):
| Fifths of head palpable above pubic symphysis | Clinical status |
|---|
| 5/5 | Head completely above pelvis (not engaged) |
| 4/5 | Head just entering pelvis |
| 3/5 | Partially engaged |
| 2/5 | Engaged |
| 1/5 | Deep in pelvis |
| 0/5 | Not palpable abdominally (fully engaged) |
In primigravidas, engagement normally occurs at 36-38 weeks. In multigravidas, it may not occur until labor begins.
FETAL STATIONS (Vaginal Examination Reference)
Fig. 4 - Fetal stations. Level of ischial spines = 0 station (ROSEN's Emergency Medicine)
The ischial spines are the reference point for station:
- Negative stations (-5 to -1): Head above the ischial spines (not engaged)
- Station 0: Head at the level of the ischial spines (engaged)
- Positive stations (+1 to +5): Head below the ischial spines (descending)
QUICK REFERENCE SUMMARY TABLE
| 1st Trimester (< 13 wks) | 2nd Trimester (14-27 wks) | 3rd Trimester (28-40 wks) |
|---|
| Position patient | Supine, 15-30° elevation | Supine, 15-30° elevation | Left lateral tilt (>28 wks) |
| Uterus palpable abdominally? | No (until 12 wks) | Yes (above pelvis) | Yes (large, prominent) |
| Fundal height landmark | At pubic symphysis (12 wks) | Umbilicus at 20 wks; SFH starts | SFH = gestational age (weeks) |
| SFH measurement | Not yet | From 20 weeks | Yes, every visit |
| Fetal parts palpable? | No | No (until ~28 wks) | Yes |
| Leopold's maneuvers | No | Not reliable until 28+ wks | Yes (main assessment) |
| Fetal heart (Doppler) | From 10-12 wks (variable) | Yes (Doppler reliable) | Yes (Doppler or Pinard) |
| IVC compression risk | No | Moderate (>20 wks) | High (>28 wks) |
| Key concern | Confirm dates, rule out ectopic | Growth, placenta position | Lie, presentation, engagement |
ABNORMAL FINDINGS AT A GLANCE
| Finding | Possible Causes |
|---|
| SFH > gestational age + 2 cm | Multiple gestation, polyhydramnios, macrosomia, fibroids |
| SFH < gestational age - 2 cm | IUGR/FGR, oligohydramnios, incorrect dates |
| Uterine tenderness | Placental abruption, preterm labor, chorioamnionitis, round ligament pain |
| Breech presentation at >36 weeks | Requires obstetric review, ECV assessment |
| Transverse lie | Requires obstetric review; can't deliver vaginally |
| No fetal heart tones | Fetal distress, fetal demise - urgent ultrasound |
| Head not engaged at term (primigravida) | Cephalopelvic disproportion, low-lying placenta |
Sources: ROSEN's Emergency Medicine Concepts and Clinical Practice; Textbook of Family Medicine, 9e;
Geeky Medics Obstetric Examination Guide;
Medmastery Abdominal Exam in Pregnancy
Here is a video walkthrough of the full obstetric abdominal examination for visual learning: