Pregnancy can be diagnosed based on clinical symptoms, physical signs, and laboratory investigations.
1. Presumptive Signs of Pregnancy (Subjective Symptoms)
These are symptoms experienced by the woman, but they are not definitive as they can occur in other conditions.
- Amenorrhea (Absence of Menstruation)
- Most common early sign in a woman with regular cycles.
- Usually occurs after conception.
- Morning Sickness (Nausea & Vomiting)
- Common between 6–12 weeks due to increased hCG levels.
- Frequency of Micturition (Frequent Urination)
- Due to pressure of the growing uterus on the bladder in early pregnancy.
- Breast Changes
- Tenderness, enlargement, & tingling due to hormonal effects.
- Darkening of the areola and Montgomery’s tubercles become prominent.
- Quickening (Fetal Movements Perceived by Mother)
- Felt around 18–20 weeks in primigravida.
- Felt around 16–18 weeks in multigravida.
- Fatigue & Drowsiness
- Common in early pregnancy due to hormonal changes.
2. Probable Signs of Pregnancy (Objective Signs)
These are examined by the clinician but are still not definitive.
- Abdominal Enlargement
- Uterus becomes palpable above the pubic symphysis by 12 weeks.
- Uterine Changes:
- Hegar’s Sign (Softening of the Isthmus) → Felt on bimanual examination around 6–10 weeks.
- Goodell’s Sign (Softening of Cervix) → Seen around 6 weeks.
- Chadwick’s Sign (Bluish Discoloration of Cervix & Vagina) → Due to increased vascularity.
- Piskacek’s Sign (Asymmetrical Uterine Enlargement) → Seen in unilateral implantation.
- Palmer’s Sign (Regular Rhythmic Uterine Contractions) → Felt during bimanual examination at 6–8 weeks.
- Braxton Hicks Contractions (Irregular Uterine Contractions)
- Felt by 20 weeks as painless contractions.
- Ballottement (Internal & External)
- Fetus rebounds when tapped per vagina.
- Positive by 16–20 weeks.
- Pulsation of Uterine Arteries (Osiander’s Sign)
- Increased vascular pulsations in fornices at 8 weeks.
- Detects hCG in urine or blood.
3. Positive Signs of Pregnancy (Definitive Signs)
These confirm the presence of a fetus and are 100% diagnostic.
- Fetal Heart Sounds (FHS)
- Detected by Doppler at 10–12 weeks.
- Detected by stethoscope at 18–20 weeks.
- Normal fetal heart rate: 120–160 bpm.
- Fetal Movements Felt by Examiner
- Can be palpated by 18–20 weeks.
- Fetal Parts Palpated
- Can be felt on abdominal examination after 20 weeks.
- Ultrasound Confirmation
- Gestational sac visible by 4–5 weeks.
- Fetal pole & heartbeat visible by 6–7 weeks.
4. Laboratory Diagnosis of Pregnancy
Pregnancy Test (hCG Detection)
- hCG (Human Chorionic Gonadotropin) is secreted by the trophoblast after implantation.
- Detectable in:
- Blood (Serum hCG) by 8–10 days post-conception.
- Urine (Home Pregnancy Test) by 4 weeks of amenorrhea.
Types of hCG Tests:
- Urine Pregnancy Test (UPT)
- Uses hCG-coated latex particles.
- Positive: No agglutination (hCG neutralized).
- Negative: Visible agglutination (hCG not present).
- Serum Beta-hCG Test (Quantitative hCG Test)
- Most sensitive & specific test.
- Used to diagnose ectopic pregnancy, molar pregnancy.
- Radioimmunoassay (RIA) & ELISA
- Detects hCG at very low levels.
Ultrasound in Pregnancy Diagnosis
|
Gestational Age |
Ultrasound Finding |
|
4–5 Weeks |
Gestational Sac visible |
|
6–7 Weeks |
Fetal Pole & Heartbeat |
|
8 Weeks |
Embryo with movements |
|
12 Weeks |
Fully formed fetus |
|
20 Weeks |
Detailed anomaly scan |
Clinical Methods of Estimating Gestational Age
1. Naegele’s Rule (Calculation of Expected Due Date - EDD)
- Formula: EDD=(LMP+9months)+7daysEDD = (LMP + 9 months) + 7 days
- Example: If LMP = 1st January, then
- Add 9 months → 1st October
- Add 7 days → EDD = 8th October
2. Symphysis-Fundal Height (SFH) Measurement
- 12 weeks: Uterus at symphysis pubis
- 16 weeks: Midway between symphysis & umbilicus
- 20 weeks: At umbilicus
- 36 weeks: At xiphoid process
3. Quickening (Fetal Movements Perceived by Mother)
- Primigravida: Felt at 18–20 weeks.
- Multigravida: Felt at 16–18 weeks.
Summary of Pregnancy Diagnosis
|
Sign Type |
Examples |
|
Presumptive (Subjective) |
Amenorrhea, Nausea, Quickening |
|
Probable (Objective) |
Abdominal enlargement, Chadwick’s sign, Pregnancy
test |
|
Positive (Definitive) |
Fetal heart sounds, Ultrasound confirmation |