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🩺 Obstetrics Revision — MBBS Final Year

Complete Charts, Tables & Mnemonics

📋 TABLE OF CONTENTS

Normal Obstetric Values
Antenatal Care
Hypertensive Disorders of Pregnancy
Antepartum Hemorrhage (APH)
Abnormal Labor
Postpartum Hemorrhage (PPH)
Obstetric Emergencies
Preterm Labor & PROM
Multiple Pregnancy
Instrumental & Operative Delivery
Neonatal Assessment (APGAR)
High-Yield Mnemonics Master List

1. NORMAL OBSTETRIC VALUES

Parameter	Normal Value
Duration of pregnancy	280 days / 40 weeks / 9 calendar months
Naegele's rule	LMP + 9 months + 7 days
Fundal height at term	36–38 cm
Normal FHR	110–160 bpm
Normal liquor volume	500–1000 mL
AFI normal	8–18 cm
AFI oligohydramnios	< 5 cm
AFI polyhydramnios	> 24 cm (AFI >20 by some criteria)
Normal amniotic fluid	Clear / pale straw
Umbilical cord length	~50 cm
Normal placental weight	~500 g (1/6 of baby weight)
Normal blood loss at vaginal delivery	< 500 mL
Normal blood loss at C-section	< 1000 mL

Fundal Height at Key Weeks (Easily Memorised):

Weeks	Fundal Height Level
12 wks	Just above symphysis pubis
16 wks	Between symphysis & umbilicus
20 wks	At umbilicus
28 wks	28 cm (midway xiphoid–umbilicus)
36 wks	At xiphisternum
40 wks	Drops (head engages) → 34–36 cm

Mnemonic: "20 = Umbilicus, then 1 cm per week"

2. ANTENATAL CARE

Schedule of Antenatal Visits (WHO Recommended)

Visit	Gestation	Purpose
1st	Before 12 wks	Booking visit — bloods, USS dating
2nd	16 wks	Anomaly screening, maternal wellbeing
3rd	20 wks	Anomaly scan
4th	24–28 wks	GDM screen (OGTT), anaemia screen
5th	28 wks	Anti-D if Rh-ve, growth USS
6th	32–34 wks	Growth, presentation
7th	36 wks	Presentation, pelvic assessment
8th–10th	38–40 wks	Surveillance, discuss delivery

Booking Investigations — "BVFHGU"

Blood group & Rh typing
VDRL / Syphilis screen
FBC (Hb, platelets)
Hepatitis B & HIV
Glucose (random)
Urine — routine & culture

Physiological Changes in Pregnancy

System	Change
Blood volume	↑ 45% (plasma more than RBC → dilutional anaemia)
CO	↑ 40–50%
BP	↓ in 1st & 2nd trimester (↑ back to normal at term)
RBC mass	↑ 20–30%
WBC	↑ (up to 15,000 normal)
GFR	↑ 50% → lower serum creatinine
Uterus	60g → 1000g
Progesterone	↑ → ureteral dilatation, GI relaxation

3. HYPERTENSIVE DISORDERS OF PREGNANCY

Classification

Condition	Definition
Gestational HTN	BP ≥140/90 after 20 wks, no proteinuria
Preeclampsia	BP ≥140/90 + proteinuria (≥300 mg/24h or protein:creatinine ≥0.3) after 20 wks
Severe preeclampsia	See HELLP / severe features below
Eclampsia	Seizures in preeclamptic woman (no other cause)
Chronic HTN	BP ≥140/90 before 20 wks
Superimposed PE	Chronic HTN + new proteinuria or worsening features

Severe Features of Preeclampsia — "Dr PUNCHES"

DBP ≥ 110 or SBP ≥ 160 mmHg
Renal — creatinine > 1.1 mg/dL
Pulmonary edema
Urine output < 500 mL/24h
Neurological — severe headache, visual disturbances
Convulsions (= eclampsia)
HELLP syndrome
Epigastric / RUQ pain
Seizure threshold low → MgSO₄

HELLP Syndrome

H – Hemolysis EL – Elevated Liver enzymes LP – Low Platelets (< 100,000/μL)

Lab	HELLP Threshold
Platelets	< 100,000
LDH	> 600 U/L
AST/ALT	> 2× upper limit of normal
Bilirubin	> 1.2 mg/dL
Peripheral smear	Schistocytes (microangiopathic hemolysis)

Risk Factors for Preeclampsia — "NULL-PATH"

Nulliparity (RR 2.9)
Uterine over-distension (twins, polyhydramnios)
Long interval between pregnancies (> 10 yrs)
Low socioeconomic status
Previous preeclampsia (RR 7.2 — highest!)
Age >40
Twins / multiple gestation (RR 2.9)
Hypertension / DM / antiphospholipid antibodies

Management of Preeclampsia

Antihypertensives Safe in Pregnancy — "New Moms Hate Labor"

Nifedipine
Methyldopa
Hydralazine
Labetalol

(Avoid ACE inhibitors, ARBs, thiazides)

Magnesium Sulfate (MgSO₄) — Eclampsia Prophylaxis & Treatment

Parameter	Value
Loading dose	4 g IV over 15–20 min
Maintenance	1–2 g/hr IV
Therapeutic level	4–7 mEq/L
Loss of patellar reflex	7–10 mEq/L
Respiratory depression	> 10 mEq/L
Cardiac arrest	> 15 mEq/L
Antidote	10 mL of 10% Calcium gluconate IV

Delivery Timing in Preeclampsia:

Gestation	Decision
≥ 37 weeks	Deliver promptly
34–37 weeks (severe features)	Deliver
< 34 weeks (severe features)	Corticosteroids → expectant if stable
Contraindications to expectant Mx	Eclampsia, DIC, pulmonary edema, uncontrolled BP, abnormal fetal testing, abruption

4. ANTEPARTUM HEMORRHAGE (APH)

Bleeding from genital tract after 28 weeks gestation (before delivery)

Causes — "P-A-V-U"

Placenta previa
Abruption placentae
Vasa previa
Unexplained (local causes: cervical ectropion, polyp, cancer)

Placenta Previa vs Abruption — HIGH YIELD CHART

Feature	Placenta Previa	Abruption Placentae
Bleeding	Painless, bright red	Painful, dark red
Uterus	Soft, non-tender	Hard, woody, tender
FHR	Usually normal	Fetal distress common
Shock	Proportional to visible blood	Out of proportion to visible blood
Coagulopathy	Rare	Common (DIC)
Presentation	Abnormal (malpresentation)	Normal
Engagement	Absent	May be present
USS	Low-lying placenta	Retroplacental clot (may be normal)
Dx gold standard	Transvaginal USS	Clinical (USS insensitive)
PV exam	CONTRAINDICATED	Cautious

Degrees of Placenta Previa

Grade	Description
Grade I	Placenta in lower segment, edge doesn't reach os
Grade II	Edge reaches internal os
Grade III	Covers internal os partially
Grade IV	Completely covers internal os (central)

Mnemonic: "1-just there, 2-touching, 3-partial, 4-full cover"

5. NORMAL LABOR

Stages of Labor

Stage	From → To	Nullipara	Multipara
1st Stage — Latent	Onset → 4 cm	Up to 20 hrs	Up to 14 hrs
1st Stage — Active	4 cm → Full dilation	≥ 0.5–1 cm/hr	≥ 1 cm/hr
2nd Stage	Full dilation → Delivery	Up to 3 hrs (2 hr without epidural)	Up to 2 hrs (1 hr without epidural)
3rd Stage	Delivery → Placenta	30 minutes	30 minutes

Cardinal Movements of Labor — "Every Damn Internal Rotation Feels Extra Exciting"

Engagement
Descent
Internal rotation (flexion occurs between engagement and IR)
Rotation — External rotation (restitution)
Flexion (maximum)
Extension (delivery of head)
Expulsion

(Standard mnemonic also: "Every Dumb Foolish Intern Eats Extra Eggs" — Engagement, Descent, Flexion, Internal rotation, Extension, External rotation/Restitution, Expulsion)

Bishop Score (Cervical Favorability for Induction)

Parameter	0	1	2	3
Dilation	Closed	1–2 cm	3–4 cm	≥5 cm
Effacement	0–30%	40–50%	60–70%	≥80%
Station	-3	-2	-1/0	+1/+2
Consistency	Firm	Medium	Soft	—
Position	Posterior	Mid	Anterior	—

Score ≥ 8 → Favorable cervix → High success induction
Score ≤ 5 → Unfavorable → Cervical ripening first
Score 6–7 → Intermediate

Mnemonic: "DECSP" — Dilation, Effacement, Consistency, Station, Position

Partograph — Key Alert Lines

Alert line: From 4 cm at rate of 1 cm/hr
Action line: 4 hours to the right of alert line
If progress crosses action line → augmentation/reassess for C-section

6. POSTPARTUM HEMORRHAGE (PPH)

Primary PPH: Blood loss > 500 mL within 24 hrs of vaginal delivery (> 1000 mL for C-section) Secondary PPH: Abnormal bleeding between 24 hrs and 12 weeks postpartum

Causes — 4 T's

T	Cause	Frequency
Tone	Uterine atony	80%
Trauma	Lacerations, hematoma, rupture, inversion	10%
Tissue	Retained placenta / products	5–10%
Thrombin	Coagulopathy (DIC, pre-existing)	1%

Risk Factors — "PARTUM"

Placenta previa / abruption
Augmented labor / assisted delivery
Retained placenta
Twins / overdistension
Uterine fibroids
Multiparity

Management of PPH — "HAEMOSTASIS"

Hask for help
Assess and resuscitate
Establish etiology (4 T's)
Massage the uterus (bimanual compression)
Oxytocin (10 units IM/IV bolus, then infusion)
Surgical options if medical fails
Tranexamic acid (TXA 1g IV)
Analogue — Ergometrine 0.5 mg IM
Surgery — B-Lynch suture, ligation
Interventional radiology (uterine artery embolisation)
Stepwise devascularization → hysterectomy if all else fails

Uterotonic Drugs

Drug	Dose	Route	Notes
Oxytocin	10 IU IM / 20–40 IU in 500 mL NS infusion	IM / IV	1st line
Ergometrine	0.5 mg	IM / IV	CI: HTN, cardiac disease
Syntometrine	Oxytocin 5 IU + Ergometrine 0.5 mg	IM	Active 3rd stage
Carboprost (PGF₂α)	250 mcg IM q15 min (max 8 doses)	IM	CI: asthma
Misoprostol (PGE₁)	600–1000 mcg	PR / SL	Good for low-resource settings
TXA	1 g IV (repeat if needed)	IV	Give within 3 hours

7. OBSTETRIC EMERGENCIES

Shoulder Dystocia — "HELPERR"

Help — call for help
Episiotomy (if needed)
Legs — McRoberts maneuver (flex thighs onto abdomen)
Pressure — suprapubic pressure (Rubin I)
Enter — internal rotational maneuvers (Rubin II, Woods screw)
Remove the posterior arm
Roll the patient (Gaskin/all-fours position)

Cord Prolapse Management

Call for help immediately
Relieve pressure on cord manually (fingers in vagina)
Position: knee-chest or left lateral Trendelenburg
Warm saline-soaked swabs to cord
Keep cord moist, don't handle excessively
Emergency C-section (or assisted delivery if fully dilated)

Uterine Rupture — Signs "CRASH"

Continuous abdominal pain (loss of contraction pattern)
Regression of presenting part
Abdominal tenderness / rigidity
Shock (maternal)
Hearing — fetal heart changes / absent

Eclampsia Management

Secure airway, lateral position
MgSO₄ 4g IV loading dose
Antihypertensives (SBP ≥ 160)
Deliver after stabilization

8. PRETERM LABOR & PROM

Definitions

Term	Definition
Preterm birth	Delivery before 37 completed weeks
Late preterm	34–36+6 weeks
Very preterm	28–31+6 weeks
Extremely preterm	< 28 weeks
PROM	Rupture of membranes before onset of labor
PPROM	Preterm PROM (< 37 weeks)

Tocolytics (Suppress Preterm Labor) — "RAIN"

Ritodrine (β₂ agonist) — now rarely used
Atafosiban (oxytocin antagonist) — first line in UK
Indomethacin (COX inhibitor) — < 32 weeks
Nifedipine (Ca channel blocker) — widely used

Corticosteroids in Preterm Labor

Betamethasone 12 mg IM × 2 doses 24 hrs apart (or Dexamethasone 6 mg IM × 4 doses)
Indicated: 24–34+6 weeks threatening preterm delivery
Benefit: Lung maturation (surfactant), reduces RDS, IVH, NEC

GBS Prophylaxis in Labor

Indications: GBS +ve swab, previous GBS infant, GBS bacteriuria in pregnancy
Penicillin G 5 MU IV, then 2.5 MU q4h until delivery

9. MULTIPLE PREGNANCY

Complications — "HI PAPA"

Hypertension (preeclampsia risk ×3)
IUGR / Growth discordance
Preterm labor (most common complication)
Anemia
Placenta previa
Abruption

Twin-Twin Transfusion Syndrome (TTTS)

Only in monochorionic twins
Donor twin: small, oligohydramnios, anemia
Recipient twin: large, polyhydramnios, polycythemia
Treatment: Fetoscopic laser ablation of communicating vessels

10. OPERATIVE OBSTETRICS

Criteria for Forceps/Vacuum — "FORCEPS"

Full cervical dilation
OS (membranes ruptured)
Resenting part engaged
Consent given
Empty bladder (catheterize)
Personnel — operator skilled
Size and position known (cephalic, position identified)

C-Section Indications — Absolute

Maternal	Fetal
Placenta previa (Grade III/IV)	Transverse lie at term
Previous classical C-section	Cord prolapse
Obstructed labor	Severe fetal distress (immediate)
CPD (cephalopelvic disproportion)	Brow presentation
Active genital herpes

Types of C-Section Uterine Incisions

Type	Description	When Used
LSCS (Lower segment)	Transverse in lower segment	Standard (most common)
Classical	Vertical midline in upper segment	Preterm, anterior placenta, emergency
De Lee (J)	Extension of LSCS	Large baby, malpresentation

Scar rupture risk: Classical >> Lower segment

11. NEONATAL ASSESSMENT

APGAR Score — "APGAR"

Letter	Parameter	0	1	2
A	Appearance (color)	Blue/pale all over	Blue extremities, pink body	Pink all over
P	Pulse (heart rate)	Absent	< 100/min	≥ 100/min
G	Grimace (reflex)	No response	Grimace	Cry / cough / sneeze
A	Activity (muscle tone)	Limp	Some flexion	Active motion
R	Respiration	Absent	Weak / irregular	Strong cry

Score	Interpretation	Action
7–10	Normal	Routine care
4–6	Moderately depressed	Stimulation, O₂
0–3	Severely depressed	Immediate resuscitation

(Assessed at 1 minute and 5 minutes; if < 7 at 5 min, continue every 5 min up to 20 min)

12. HIGH-YIELD MNEMONICS — MASTER LIST

Topic	Mnemonic	Expansion
Booking investigations	BVFHGU	Blood group, VDRL, FBC, Hep B/HIV, Glucose, Urine
Antihypertensives in pregnancy	"New Moms Hate Labor"	Nifedipine, Methyldopa, Hydralazine, Labetalol
HELLP	HELLP	Hemolysis, Elevated Liver enzymes, Low Platelets
PPH causes	4 T's	Tone, Trauma, Tissue, Thrombin
PPH risk factors	PARTUM	Placenta previa, Augmented labor, Retained products, Twins, Uterine fibroids, Multiparity
Shoulder dystocia	HELPERR	Help, Episiotomy, Legs (McRoberts), Pressure (suprapubic), Enter (rotation), Remove arm, Roll
Bishop score	DECSP	Dilation, Effacement, Consistency, Station, Position
Cardinal movements	"Every Damn Foolish Intern Eats Extra Eggs"	Engagement, Descent, Flexion, Internal rotation, Extension, External rotation, Expulsion
Severe preeclampsia features	Dr PUNCHES	DBP↑, Renal, Pulmonary edema, Urine↓, Neuro, Convulsions, HELLP, Epigastric pain, Seizures
Multiple pregnancy complications	HI PAPA	Hypertension, IUGR, Preterm, Anemia, Placenta previa, Abruption
Tocolytics	RAIN	Ritodrine, Atosiban, Indomethacin, Nifedipine
Forceps criteria	FORCEPS	Full dilation, OS ruptured, Presenting part engaged, Consent, Empty bladder, Personnel, Size/position
APH causes	PAVU	Placenta previa, Abruption, Vasa previa, Unexplained
Uterine rupture signs	CRASH	Continuous pain, Regression, Abdominal rigidity, Shock, Heart rate changes
PPH stepwise Rx	HAEMOSTASIS	Help, Assess, Etiology, Massage, Oxytocin, Surgical options, TXA, Analogue (ergometrine), Surgery, Interventional radiology, Stepwise hysterectomy
Fetal heart rate patterns	VEAL CHOP	Variable→Cord compression, Early→Head compression, Accelerations→OK, Late→Placental insufficiency

QUICK-FIRE HIGH YIELD FACTS

Commonest cause of maternal mortality worldwide → Hemorrhage
Commonest cause of PPH → Uterine atony (80%)
Commonest malpresentation → Breech (3–4% at term)
Commonest ectopic site → Ampulla of fallopian tube (70%)
Lie of baby assessed → Ballottement, Leopold's maneuvers
Engagement = largest diameter of head passes through pelvic brim; in Nullipara occurs at 36 wks
Lightening = engagement of head — woman breathes easier
Show = mucus plug dislodgement — early labor sign
Braxton-Hicks = irregular, painless "practice" contractions; not true labor
Ritgen's maneuver = controlled delivery of baby's head (prevent perineal tear)
Active management of 3rd stage = Oxytocin 10 IU IM + controlled cord traction + uterine massage
MgSO₄ antidote = Calcium gluconate 1g IV (10 mL of 10%)
Kleihauer–Betke test = detects fetal cells in maternal blood → quantify feto-maternal hemorrhage → guides anti-D dosage
Apt test = differentiates fetal from maternal blood in vasa previa
De Lee suction used at birth → routine suctioning now NOT recommended for meconium-stained liquor unless baby vigorous (neonatal team resuscitates directly)

CTG INTERPRETATION — "VEAL CHOP"

Fetal Heart Pattern	Cause
Variable decelerations	Cord compression
Early decelerations	Head compression (normal)
Accelerations	Oh! — all is OK (reassuring)
Late decelerations	Placental insufficiency (OMINOUS)

Normal CTG features:

Baseline FHR: 110–160 bpm
Variability: 5–25 bpm
Accelerations: ≥ 2 in 20 min (each ≥ 15 bpm × 15 sec)
Decelerations: None

DIABETES IN PREGNANCY

Parameter	Normal	GDM (OGTT 75g)
Fasting glucose	< 5.1 mmol/L	≥ 5.1
1-hour glucose	< 10.0	≥ 10.0
2-hour glucose	< 8.5	≥ 8.5

Complications of GDM — "MACROSOMIA" (mnemonic for fetal risks)

Macrosomia → shoulder dystocia
Birth trauma
Neonatal hypoglycemia
Respiratory distress
Polycythemia / jaundice

IMPORTANT DRUG CONTRAINDICATIONS IN PREGNANCY

Drug	Reason to Avoid
ACE inhibitors/ARBs	Renal anomalies, oligohydramnios
NSAIDs (after 32 wks)	Premature closure of ductus arteriosus
Tetracyclines	Teeth discoloration, bone effects
Aminoglycosides	Fetal ototoxicity
Warfarin (1st trimester)	Warfarin embryopathy
Methotrexate	Teratogen (abortifacient)
Misoprostol (1st Trimester)	Möbius syndrome risk
Isotretinoin	Severe teratogen — CNS, cardiac defects
Thalidomide	Phocomelia (limb defects)
Fluconazole (high-dose)	Teratogenic

Sources: Creasy & Resnik's Maternal-Fetal Medicine (9th Ed), Berek & Novak's Gynecology, ACOG guidelines.

This covers all the high-yield topics for MBBS Finals Obstetrics. The mnemonic master list and comparison tables are especially useful for last-minute revision before exams. Focus extra attention on preeclampsia management, PPH 4 T's, APGAR scoring, Bishop score, and the VEAL CHOP CTG mnemonic — these come up repeatedly in written papers and clinical vivas.

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