Goodell’s sign, the softening of the cervical tip, is primarily caused by:

Supine hypotensive syndromeoccurs in late pregnancy when the gravid uteruscompresses the inferior vena cavawhile lying supine, reducing venous returnand decreasing cardiac output. This leads to maternal hypotension, dizziness, pallor, and tachycardia. Normal maternal cardiac output in pregnancy increases by 30–50% (from 4.5 L/min to 6–7 L/min).

Rationale for correct answer

2.Supine hypotensive syndrome results from compression of the inferior vena cava by the enlarged uterus, especially in the third trimester. This reduces venous return, lowers preload, and decreases cardiac output, causing dizziness when lying flat. Symptoms resolve when the woman turns to the left lateral position.

Rationale for incorrect answers

1.Increased cardiac output occurs in pregnancy due to increased blood volume and stroke volume, peaking at 30–50% above baseline. This increase improves tissue perfusion and does not cause dizziness when supine. Instead, reduced output from vena cava compression explains the symptom.

3.Physiological anemia in pregnancy results from plasma volume expansion exceeding red cell mass increase, leading to lower hematocrit values (normal pregnancy hemoglobin 11–12 g/dL, hematocrit 32–34%). It causes fatigue and pallor, not positional dizziness specific to lying supine.

4.Hyperventilation occurs due to progesterone-mediated respiratory drive increase, leading to mild respiratory alkalosis (PaCO₂ 28–32 mmHg, normal pregnancy pH 7.40–7.45). This causes dyspnea but not dizziness limited to supine position.

Take home points

• Supine hypotensive syndrome results from gravid uterine compression of the inferior vena cava.

• Symptoms include dizziness, pallor, hypotension, and tachycardia when lying flat.

• Turning to the left lateral position relieves symptoms by restoring venous return.

• Physiological anemia and hyperventilation are normal pregnancy changes but do not explain positional dizziness.

Relaxinis a peptide hormonesecreted mainly by the corpus luteum, decidua, and placenta during pregnancy. It increases collagen remodelingand connective tissue elasticity, promoting relaxation of pelvic ligaments and increased joint mobility to facilitate childbirth. Relaxin levels peak in the first trimester and again near term. Normal effects also include softening of the cervix and inhibition of uterine contractions to maintain early pregnancy.

Rationale for correct answer

3.Relaxin causes relaxation and softening of pelvic ligaments and joints, especially the pubic symphysis and sacroiliac joints. This increases pelvic mobility and prepares the birth canal for labor. It also contributes to cervical ripening through collagen breakdown and connective tissue remodeling.

Rationale for incorrect answers

1.Oxytocin stimulates uterine smooth muscle contractions during labor and milk ejection from the breast. It does not influence ligament relaxation or pelvic joint mobility.

2.Prolactin is primarily involved in mammary gland development and initiation of lactation. It has no role in pelvic ligament relaxation or connective tissue changes in pregnancy.

4.Cortisol regulates metabolism and has a role in fetal lung maturation, but it does not act on pelvic ligaments or joints. Its effects are primarily catabolic and immunomodulatory, not structural relaxation.

Take home points

• Relaxin softens pelvic ligaments and joints to facilitate delivery.

• It is secreted by the corpus luteum, decidua, and placenta.

• Cervical ripening and inhibition of uterine contractions are additional effects.

• Oxytocin, prolactin, and cortisol have different physiological roles unrelated to ligament relaxation.