Methods of Obstetrical Examination

PREGNANCY DIAGNOSIS TESTS:

• Principle: Pregnancy tests depend on detection of the antigen Human chorionic gonadotropin (hCG) secreted during early pregnancy by trophoblastic cells  to maintain the corpus luteum that appears in the maternal urine or serum with antibody either polyclonal or monoclonal.
• HCG (doubles every 2 days)reaches peak at approximately 10 weeks.
• Earliest diagnsostic test

Test	Test Sensitivity	Time Taken	Inference	Positive On
Immunological tests (Urine)
Agglutination inhibition test (Latex test)	0.5–1 (IU/mL) (Urine)	2 minutes	Absence of agglutination	2 days after missed period
Direct latex agglutination test	0.2 (IU/mL) (Urine)	2 minutes	Presence of agglutination	2–3 days after missed period
Two-site sandwich immunoassay (membrane ELISA/ card tests)	30–50 mIU/mL (Urine)	4–5 minutes	Color bands in the control as well as in test window	On the 1rst day of the missed period (28th day of cycle)
Various kits in card forms are available			+ Pregnant (Card test)	– Not pregnant (Card test)
Enzyme-linked Immunosorbent Assay (ELISA)	1–2 mIU/mL (Serum)	2–4 hours		5 days before the ! rst missed period
Radioimmunoassay(most sensitive)
(β subunit)	0.002 IU/mL	3-4 hrs		25th day of cycle
Immunoradiometric assay (IRMA)	0.05 mIU/mL (Serum)	30 min		8 days after conception

ANTINATAL VISITS: 

Schedule for antenatal visits in India(12-14) :

• Monthly visits upto 28 weeks.
• Two weekly visit between 28 and 36 weeks.
• Weekly visit from 36 weeks onwards
• As per Indian scenario – minimum 3 visits are essential 20^th, 32^nd  & 36^th weeks

WHO recommends atleast 4 visits :

1. 16 weeks
2. 24-28 weeks
3. 32 weeks
4. 36 weeks

INDICATIONS:

• Diagnose the lie, presentation, position and the attitude of the fetus.
• Used to assess intrauterine growth retardation

POSITION:

• Dorsal position with the thighs slightly flexed.

Inspection:

• Uterine ovoid:longitudinal or transverse or oblique
• Contour of the uterus—fundal notching, convex or flattened anterior wall, cylindrical or spherical shape
• Skin condition of abdomen:ringworm or scabies
• Any incisional scar mark on the abdomen
• Undue enlargement of the uterus

Palpation:

• Height of the uterus
• SFH can be measured

Obstetric grips (Leopold maneuvers):

Fundal grip:

• Whole of the fundal area is palpated
• To find out which pole of the fetus is lying in the fundus
• Breech:broad, soft and irregular mass
• Head: smooth, hard and globular mass

Lateral or umbilical grip:

• To find out the position of the back, limbs and the anterior shoulder
• The position of the anterior shoulder is to be sought for

Pawlik’s grip (Third Leopold):

• Mobility from side to side is tested. 
• In transverse lie, Pawlik’s grip is empty.

Pelvic grip (Fourth Leopold):

• To palpate the part occupying the lower pole of the uterus
• If head :precise presenting area,attitude and engagement should be checked
• Most comfortable for the woman and gives most information

Auscultation:

• Fetal heart sounds (FHS)

Usefulness:

• Differnt presentation if fetus
• Live fetus
• Best audible through the back (left scapular region) in vertex and breech presentation
• Heart sounds are heard through the fetal chest in face presentation

Intensity of the FHS:

Presentation	Location
Cephalic	Below umbilicus
Breech	Around umbilicus
Occipitoanterior position	Middle of spinoumbilical line of same side
Occipitolateral position	Laterally
Occipitoposterior position	Mother’s flank on the same side

ESTIMATION OF GESTATIONAL AGE & EDD:

PATIENT’S STATEMENT:

Date of fruitful coitus:

• Accuracy of 50% within 7 days on either side
• 266 days are to be added to the date of the single fruitful coitus to calculate

Naegele’s formula

• Interval of cycles longer: extra days are to be added 
• Interval is shorter:Lesser days  subtracted to get the EDD.

Date of quickening:

• EDD = 22 weeks primigravidae+ 24 weeks in multiparae+date of quickening
• 40 weeks are between LMP and EDD

OTHER METHODS:

• Size of the uterus12 weeks
• Nine calendar months +7 days
• 280 days or 40 weeks
• 10 lunar months
• Palpation of fetal parts:20th week
• Auscultation of FHR18–20 weeks
• Height of the uterus
• Lightening:3 week before EDD
• Size of the fetus
• Ultrasonographic findings
  • Gestation sac — at 5 weeks.
  • Hasse’s formula
    • If the crown heel length is known then the intrauterine age of fetus is calculated as:
    • If CH length is up to 25 cm then IU age = Square root of CH length
    • If the CH length is > 25 cm then IU age = 1/5 of CH length
  • First trimester : Crown — Rump Length (CRL) is most accurate. (Variation ± 5 days).
  • Second trimester : BPD, HC, AC and FL measurement. Most accurate when done between 12 and 20 weeks (variation ± 8 days).
  • Third trimester : Less reliable, variation ± 16 days.

• X-ray: Appearance and density of ossification centers in the upper end of the tibia (38–40 weeks) and lower end of femur (36–37 weeks).

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