anatomy and physiology of pregnancy

Pregnancy is a normal physiologic process . . .. . . not a disease!

Bluish or purplish coloration of the vaginal mucosa and cervix (Chadwick’s sign-a dark blue to purplish-red congested appearance of the vaginal mucosa )

Palpation of Braxton-Hicks contractions Outlining the fetus manually Endocrine tests of pregnancy

Identification of the fetal heart beat separately and distinctly from that of the mother (10-12 w)

Perception of fetal movements by the examiner (18-20 w)

Visualization of pregnancy on ultrasound

Fetal recognition on X-ray

Non Pregnant Non Pregnant UterusUterus

Pregnant UterusPregnant Uterus

MuscularMuscular

StructurStructuree

Almost Solid Almost Solid Relatively thin – Relatively thin – walled (≤ 1.5 cm)walled (≤ 1.5 cm)

WeightWeight ≈ ≈ 70 gm70 gm Approx. 1100 gm Approx. 1100 gm by the end of by the end of pregnancypregnancy

VolumeVolume ≤ ≤ 10 ml10 ml ≈ ≈ 5 L by the end 5 L by the end of pregnancyof pregnancy

First few weeks, original peer shaped organ

As pregnancy advances, corpus & fundus assumes a more globular form.

By 12 weeks, the uterus becomes almost spherical .

Subsequently, uterus increases rapidly in length than in width & assumes an ovoid shape.

With ascent of uterus from pelvis, it usually undergoes Dextrorotation (caused by the rectosigmoid colon on the left side)

Breast: tenderness, fullness, tingling enlargement, nipple and areola hyperpigmentation, Montgomery’s tubercles, colostrum (16 w)

Darcening of nipples, areola, axillae, vulva Facial melasma=chloasma Linea Nigra Striae gravidarum Palmar erythema (Caucasian, African-American)

Pigmentation: It is due to suprarenal changes, it usually begins to appear after the 4th month. The pigmentation may appear anywhere but the commonest sites are:

1. Linea nigra: which is a line of pigmentation between the umbilicus and the symphysis pubis.

2. Increased pigmentation of the nipple as primary areola and appearance of the secondary areola.

Vascular spider

Minute, red elevations on the skin

common on the face, neck, upper chest,

and arms, with radicles branching out

from a central lesion. The condition is often

designated as nevus, angioma, or telangiectasia. Palmar erythema .

The two conditions are of no clinical significance and disappear in most women shortly after pregnancy (estrogen)

Change in posture Waddling walk Back Pain Slight relaxation and increased mobility

of the pelvic joints Diastasis recti abdominis

Uterine enlargement 12 weeks – At Symphysis 16 weeks – Midway between

symphysis and umbilicus 20 weeks – At the umbilicus 36 weeks - Near xyphoid process

Gestational Gestational Age weeks)Age weeks)

Ultrasound Ultrasound MeasurementsMeasurements

Range of Range of AccuracyAccuracy

< 8< 8 Sac sizeSac size ++ 10 days 10 days

8-128-12 CRLCRL ++ 7 days 7 days

12-1512-15 CRL, BPDCRL, BPD ++ 14 days 14 days

15-2015-20 BPD, HC, FL, ACBPD, HC, FL, AC ++ 10 days 10 days

20-2820-28 BPD, HC, FL, ACBPD, HC, FL, AC ++ 2 weeks 2 weeks

> 28> 28 BPD, HC, FL, ACBPD, HC, FL, AC ++ 3 weeks 3 weeks

Serious illnesses Hospitalizations Surgery Drug allergies or unusual reactions Meds since LMP

Maternal› Diabetes› CAD› Pre-eclampsia› Preterm delivery› Cancers (breast,

ovarian, colon)› Depression,

bipolarity› Twins› Anesthesia reactions

Maternal or Paternal› Birth defects› Mental retardation› Bleeding disorders› Chromosomal

abnormalities (e.g. Down Syndrome)

Temperature Blood

pressure Respirations Radial pulse

Elevated BP suggests the presence of preeclampsia.

Elevated BP may be defined as a persistently greater than 140 systolic or 90 diastolic. Usually, if one is elevated, both are elevated.

Elevated temperature suggests the possible presence of infection.

Many pregnant women normally have oral temperatures of as much as 99+. These mild elevations can also be an early sign of infection.

While a pregnant pulse of up to 100 BPM or greater may be normal, rapid pulse may also indicate hypovolemia.

Height Weight BMI (Body mass index )

› BMI Categories: › Underweight = <18.5 › Normal weight = 18.5-24.9 › Overweight = 25-29.9 › Obesity = BMI of 30 or greater

The obstetric conjugate extends from the middle of the sacral promontory to the posterior superior margin of the pubic symphysis. This is the most important diameter of the pelvic inlet.

The diagonal conjugate extends from the subpubic angle to the middle of the sacral promontory and can be measured clinically to estimate the obstetric conjugate.

The transverse diameter, between the ischial spines, is a measurement of the dimensions of the pelvic cavity

Subpubic arch

Bituberous (transverse) diameter

Inferior pubic rami

What to expect during the course of prenatal care

Risk factors encountered

Nutrition Exercise Work Sexual activity

Travel, seat belts Smoking cessation Avoidance of drugs

and alcohol Warning signs Where to go or call

in case of problems Prenatal vitamins

1. Using two hands and compressing the maternal abdomen, a sense of fetal direction is obtained (vertical or transverse).

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