Labor

How do Braxton-Hicks contractions clinically differ from true labor pains?

Braxton-Hicks are irregular, non-rhythmic, do NOT cause cervical dilation, and are relieved by ambulation/rest. True labor pains are regular, progressive, and cause cervical change.

What are the four stages of labor?

1st: Onset of labor to full (10cm) cervical dilation.2nd: Full dilation to delivery of the baby.3rd: Delivery of the baby to delivery of the placenta.4th: The first two hours postpartum (monitoring phase).

What is the "Rule of 5ths" for assessing fetal head engagement abdominally?

If more than 2/5 of the fetal head is palpable abdominally, it is NOT engaged. Engagement occurs when the widest part passes the pelvic inlet (typically at Station 0).

Why are the maternal Ischial Spines critical obstetric landmarks?

1. They mark Station 0 (midpelvis) to assess fetal descent.2. They are the landmark for a pudendal nerve block (the nerve passes inferior and medial/anteroinferior, NOT posterior, to the spine).

Compare the primary shapes of the Gynecoid and Android pelvis regarding labor outcomes.

Gynecoid: Round/oval, most common, and most favorable for labor.Android: Heart-shaped; predisposes to deep transverse arrest and Occipito-Posterior (OP) position.

What is the most favorable fetal position and presenting diameter for a spontaneous vaginal delivery?

Position: Occipito-Anterior (OA).Diameter: Suboccipito-bregmatic (9.5 cm), which occurs when the fetal head is well-flexed.

Identify the "Denominator" (presenting reference point) for Vertex, Face, and Breech presentations.

Vertex: Occiput.Face: Mentum (chin).Breech: Sacrum.

What are the 5 parameters of the original Bishop Score?

1. Dilation2. Effacement (Length)3. Station4. Consistency (Firm/Soft)5. Position (Posterior/Anterior).

According to the mnemonic "Most High CAPUT", what are the absolute contraindications to labor induction?

Macrosomia, Hydrocephalus, Contracted pelvis/Cervical CA, Active genital herpes, Placenta/Vasa previa, Uterine scar (classical C-section), and Transverse lie.

What are the dangerous side effects of intravenous Oxytocin (Syntocinon) infusion?

Uterine tachysystole/hyperstimulation, Hypotension (relaxes vascular smooth muscle), and Hyponatremia/Water retention (due to its structural similarity to ADH).

What is the primary physiological mechanism for placental separation during the 3rd stage of labor?

The reduction in the surface area of the placental site as the myometrium shrinks following the delivery of the baby.

What are the three components of "Active Management of the Third Stage"?

1. IM injection of a uterotonic (e.g., 10 IU Oxytocin).2. Delayed cord clamping (1-3 minutes).3. Controlled cord traction.

Why is Methergine (Methylergometrine) strictly contraindicated in patients with preeclampsia or hypertension?

It causes sustained uterine contractions and vasoconstriction, which can trigger acute hypertension, stroke, or myocardial infarction (MI).

A routine examination of the umbilical cord reveals a Single Umbilical Artery (SUA). What is the clinical significance?

It is an indicator of an increased incidence of fetal congenital anomalies (renal, cardiac, GI). (Note: It is NOT specifically linked to maternal diabetes).

What is the initial maneuver for resolving Shoulder Dystocia, and what action is strictly contraindicated?

First maneuver: McRoberts position (hyperflexion of maternal legs to flatten the lumbar spine).Contraindicated: Vigorous fundal pressure (can cause uterine rupture or brachial plexus injury).

According to past papers, what is the most common cause of non-engagement of the fetal head at term in a primigravida?

Cephalopelvic Disproportion (CPD). (Note: IUGR does NOT cause non-engagement; small babies engage easily).

What are the 7 Cardinal Movements of labor in a vertex presentation?

Engagement → Descent → Flexion → Internal Rotation → Extension → Restitution → External Rotation → Expulsion.

What is "Restitution" during the delivery of the fetal head?

After the head is delivered via extension, it untwists and rotates to become perpendicular to the shoulder's axis to realign with the body.