The signs of pregnancy are classified into three groups:

1. Presumptive

2. Probable

3. Positive

Presumptive Signs:

These are signs that suggest pregnancy but are not definitive.

1. Amenorrhea: Absence of menstruation. While a strong indicator, it can also be caused by factors like contraception, environmental changes, illness, or emotional disturbances.

2. Breast Changes: Many women experience tingling, prickling, enlargement, and tenderness of the breasts.

3. Morning Sickness (Nausea and Vomiting): Occurs in 30-50% of pregnant women, typically between weeks 4 and 14. Often subsides by the end of the first trimester.

4. Increased Frequency of Urination: The growing uterus puts pressure on the bladder, especially before 12 weeks. This symptom tends to decrease once the uterus rises out of the pelvis.

5. Skin Changes:

   • Striae Gravidarum: Stretch marks appearing around the 16th week on the abdomen, thighs, and breasts.

   • Chloasma (Mask of Pregnancy): Darkened patches of skin on the face.

   • Linea Nigra: A darkened line appearing above and below the umbilicus.

   • Darkening of Areolas: Primary areolas darken, and secondary areolas may form. These changes are caused by melanin hormone produced by the anterior pituitary gland.

6. Quickening: The first fetal movements felt by the mother, usually around 18-20 weeks for first-time pregnancies (primigravida) and 16-18 weeks for women who have been pregnant before (multigravida).

7. Fatigue: Common due to increased blood production, lower blood sugar, decreased blood pressure (influenced by progesterone), sleep disturbances, and nausea.

8. Mood Changes: Physical stress, metabolic changes, fatigue, and hormonal fluctuations (progesterone and estrogen) can lead to mood swings.

Probable Signs:

These signs are more indicative of pregnancy but still not conclusive.

1. Hegar’s Sign: Detectable between weeks 6 and 12. A softening of the isthmus (lower uterine segment) is felt during a bimanual examination (one hand on the abdomen, two fingers in the vagina).

2. Jacquemier’s Sign: Bluish discoloration of the vaginal walls, noticeable from the 8th week onwards, due to pelvic congestion.

3. Osiander’s Sign: Increased pulsation felt on the lateral vaginal fornices from the 8th week onwards, due to increased vascularity.

4. Softening of the Cervix (Goodell’s Sign): The cervix softens from the 8th week onwards, feeling like the lower lip compared to the tip of the nose in a non-pregnant state.

5. Uterine Soufflé: A soft blowing sound heard on abdominal auscultation from the 16th week, due to increased uterine vascularity.

6. Abdominal Enlargement: Rapid and progressive uterine enlargement from the 16th week, distinguishable from other causes like gas, a full bladder, fibroids, or ascites.

7. Braxton Hicks Contractions: Painless contractions beginning from the 16th week, felt during abdominal palpation, occurring approximately every 15 minutes.

8. Internal Ballottement: A sharp tap on the uterus above the cervix causes the fetus to float upward and then sink back down, felt by fingers in the vagina between weeks 16 and 28.

9. Presence of hCG (Human Chorionic Gonadotropin): Detectable in blood as early as 9 days after conception and in urine around 14 days after conception. Also present in conditions like hydatidiform mole.

Positive Signs:

These signs definitively confirm pregnancy.

1. Fetal Heart Sounds: The fetal heart begins beating around the 24th week after conception. It can be heard with a Doppler device as early as 10 weeks and with a fetoscope by 24 weeks. The normal fetal heart rate is 120-160 beats per minute.

2. Ultrasound Scanning of the Fetus: The gestation sac can be visualized as early as the 4th week, an embryo by the 4th week, and fetal body parts by the 10th week.

3. Palpation of the Entire Fetus: A trained examiner can feel the head, back, and upper and lower body parts.

4. Palpation of Fetal Movement: Skilled healthcare providers can feel fetal movements after the 24th week.

5. X-ray: Identifies the complete fetal skeleton as early as the 12th week, but not recommended due to radiation risks to the fetus.

6. Actual Delivery of the Baby: The conclusive evidence of pregnancy.

Differential Diagnosis

Abdominal enlargement can be caused by conditions other than pregnancy. These include:

1. Ovarian Cysts: Cause swelling distinguishable from the uterus, and pregnancy tests will be negative.

2. Fibroids: Noncancerous uterine growths that can cause a hard mass, but pregnancy tests will be negative.

3. Distended Urinary Bladder: Due to urine retention, relieved by catheterization, with no other pregnancy signs.

4. Pseudocyesis (False Pregnancy): Mimics pregnancy symptoms, including amenorrhea, but pregnancy signs are absent, and tests are negative. Often occurs in women with a strong desire to conceive or high anxiety related to pregnancy.