1. Diagnosis of pregnancy in the first and second trimester

Question 1

How is the duration of pregnancy calculated?

Answer 1

- The duration of pregnancy has traditionally been calculated by the
clinicians in terms of:
- 10 lunar months or 
- 9 calendar months and 7 days or 
- 280 days or 
- 40 weeks, 

= calculated
from the first day of the last menstrual period. This is called menstrual or gestational age.

• The reproductive period of a woman begins at menarche and ends in menopause. It usually extends from
  13–45 years. While biological variations may occur in different geographical areas, pregnancy is rare below
  12 years and beyond 50 years.

Question 2

How is the true gestation period calculated?

Answer 2

• fertilization usually occurs 14 days prior to the expected missed period
• and in a previously normal
  cycle of 28 days duration, it is about 14 days after the first day of the period.

Thus, the true gestation period is to be calculated by subtracting 14 days from 280 days, i.e. 266 days. This is called fertilization or
ovulatory age and is widely used by the embryologist.

Question 3

How is pregnancy diagnosed in the first trimetser?

Answer 3

SUBJECTIVE SYMPTOMS
Amenorrhea
Morning sickness
Frequent Micturition
Breast discomfort
Fatigue

OBJECTIVE SIGNS
Breast changes
Per abdomen
Pelvic changes

Question 4

What are some subjective symptoms in the 1st trimester?

Answer 4

AMENORRHEA:
Amenorrhea during the reproductive period in an otherwise healthy individual having previous normal periods is likely due to pregnancy unless proved otherwise.

However, cyclic bleeding may occur up to 12 weeks of pregnancy, until the decidual space is obliterated by the fusion of decidua vera
with decidua capsularis.

Such bleeding is usually scanty, lasting for a shorter duration than her usual
and roughly corresponds with the date of the expected period.

This is termed the placental sign.

This type of bleeding should not be confused with the commonly met pathological bleeding, i.e. threatened
abortion. Pregnancy, however, may occur in women who are previously amenorrheic — during lactation and puberty.

MORNING SICKNESS (NAUSEA AND VOMITING):
- is inconsistently present in about 70% cases, more often in the first pregnancy than in the subsequent one. It usually appears soon following the missed period and rarely lasts beyond 16 weeks. Its intensity varies from nausea on rising from the bed to loss of appetite
or even vomiting. But it usually does not affect the health status of the mother

FREQUENCY OF MUCTURITION:
Frequency of micturition is quite troublesome symptom during 8–12th week of pregnancy. It is due to
(1) resting of the bulky uterus on the fundus of the bladder because of exaggerated anteverted position of the uterus
(2) congestion of the bladder mucosa and
(3) change in maternal osmoregulation causing
increased thirst and polyuria. As the uterus straightens up after the 12th week, the symptom disappears.

BREAST DISCOMFORT:
Breast discomfort in the form of feeling of fullness and ‘pricking sensation’ is evident as early as
6–8th week specially in primigravidae.

FATIGUE:
Fatigue is a frequent symptom which may occur early in pregnancy.

Question 5

What are some objective signs in the 1st trimester?

Answer 5

BREAST CHANGES
-Breast changes are valuable only in primigravidae, as in multiparae, the breasts
are enlarged and often contain milk for years. The breast changes are evident between 6 and 8 weeks. There is enlargement with vascular engorgement evidenced by the delicate veins visible under the skin
- The nipple and the areola (primary) become more pigmented especially in dark women. Montgomery’s
tubercles are prominent. Thick yellowish secretion (colostrum) can be expressed as early as 12th week.

PER ABDOMEN
- Uterus remains a pelvic organ until 12th week, it may be just felt per abdomen as
a suprapubic bulge.

PELVIC CHANGES
- The pelvic changes are diverse and appear at different periods. Collectively, these
may be informative in arriving at a diagnosis of pregnancy

• Jacquemier’s or Chadwick’s sign
• Vaginal sign: Osiander’s sign
• Cervical signs: Goodell’s sign
• Uterine signs

Question 6

What is the Jacquemier’s or Chadwick’s sign?

Answer 6

Jacquemier’s or Chadwick’s sign:

It is the dusky hue of the vestibule and anterior vaginal wall visible at about the 8th week of pregnancy.

The discoloration is due to local vascular congestion.

Question 7

What are the different vaginal signs? What is Oslander’s sign?

Answer 7

Vaginal sign:

(a) Apart from the bluish discoloration of the anterior vaginal wall
(b) The walls become softened and

(c) Copious non-irritating mucoid discharge appears at
6th week

(d) There is increased pulsation, felt through the lateral fornices at 8th week called Osiander’s sign.

Question 8

What are the cervical signs? What is Goodell’s sign?

Answer 8

(a) Cervix becomes soft as early as 6th week (Goodell’s sign), a little earlier in
multiparae.

The pregnant cervix feels like the lips of the mouth, while in the non-pregnant state, like that of tip of the nose.

(b) On speculum examination, the bluish discoloration of the cervix
is visible. It is due to increased vascularity

Question 9

What are the uterine signs?

Answer 9

(a) Size, shape and consistency — The uterus is enlarged to the size of a hen’s egg at 6th week, size of a cricket ball at the 8th week, and size of a fetal head by the 12th week. The pyriform shape of the non-pregnant uterus becomes globular by 12 weeks.

There may be asymmetrical
enlargement of the uterus if there is lateral implantation. This is called Piskacek’s sign where one half is more firm than the other half.

As pregnancy advances, symmetry is restored. The pregnant uterus feels soft and elastic.

(b) Hegar’s sign
(c) Palmer’s sign

Question 10

What is Hegar’s sign?

Answer 10

Hegar’s sign:
It is present in two-thirds of cases. It can be demonstrated between 6 and 10 weeks, a little earlier in multiparae.

This sign is based on the fact that:
(1) upper part of the body
of the uterus is enlarged by the growing fetus
(2) lower part of the body is empty and extremely
soft and
(3) the cervix is comparatively firm. Because of variation in consistency, on bimanual
examination (two fingers in the anterior fornix and the abdominal fingers behind the uterus), the abdominal and vaginal fingers seem to appose below the body of the uterus

Examination must be gentle to avoid the risk of abortion.

Question 11

What is Palmer’s sign?

Answer 11

Palmer’s sign:

Regular and rhythmic uterine contraction can be elicited during the bimanual
examination as early as 4–8 weeks. Palmer in 1949, first described it and it is a valuable sign when
elicited

Question 12

How is the uterine test performed?

Answer 12

To elicit the test, the uterus is cupped between the internal fingers and the external fingers for about
2–3 minutes.

During contraction, the uterus becomes firm and well defined but during relaxation, becomes soft and ill defined.

While the contraction phase lasts for about 30 seconds, with increasing duration of pregnancy, the relaxation phase increases.

After 10th week, the relaxation phase
is so much increased that the test is difficult to perform.

Question 13

What is the principle for immunological tests used in the diagnosis of pregnancy?

Answer 13

Principle:

Pregnancy tests depend on the detection of the antigen (hCG) present in the maternal urine or serum with antibodies either polyclonal or monoclonal available commercially.

Question 14

How are the immunological tests used to diagnose pregnancy classified?

Answer 14

A. Immunoassays without radioisotopes

B. Immunoassays with radioisotopes

Question 15

What are agglutination inhibition tests?

Answer 15

: A. Immunoassays without radioisotopes

Agglutination inhibition tests — Using latex (LAI). The materials for these tests are supplied in kits containing
all the reagents needed to do a test.

• Principle of agglutination inhibition tests: One drop of urine is mixed with one drop of a solution that contains
  hCG antibody. If hCG is not present in the urine sample (e.g. the woman is not pregnant), the antibody remains free.
  -Now one drop of another solution that contains latex particles coated with hCG is added. Agglutination of the
  latex particles can be observed easily this time.
• Therefore, the pregnancy test is negative if there is agglutination.
  On the other hand, if hCG were present in the urine sample (e.g. woman was pregnant), it would bind the available
  antibody. There would be no further agglutination when the solution containing hCG coated latex particles was
  added. Therefore, pregnancy test is positive if there is no agglutination (schematic presentation above).

PREGNANT =
urine (containing hCG) + hCG antiserum = neutralization of teh antibody + hCG coated latex particles -> no visible agglutination

NON-PREGNANT =
Urine (no hCG0 + hCG antiserum = hCG antibosy not neutralized + hCG coated latex particles -> visible agglutination

Question 16

What are Direct agglutination tests (hCG direct test)?

Answer 16

: A. Immunoassays without radioisotopes

•  Direct agglutination test (hCG direct test) — Latex particles coated with anti-hCG monoclonal antibodies
  are mixed with urine.
• An agglutination reaction indicates a positive result when the urine sample contains hCG.
• Absence of agglutination (urine without hCG) indicates a negative one. The sensitivity is 0.2 IU hCG/mL.

Question 17

What are Fluoroimmunoassays (FIA)?

Answer 17

: A. Immunoassays without radioisotopes

It is a highly precise sandwich assay. It uses a second antibody tagged
with a fluorescent label. The fluorescence emitted is proportional to the amount of hCG. It can detect hCG
as low as 1 mIU/mL. FIA takes 2–3 hours. It is used to detect hCG and for follow up hCG concentrations.

Question 18

What are Radioimmunoassays (RIA)?

Answer 18

B. Immunoassays with radioisotopes

• It uses I125 ido hCG antibodies. It is more sensitive and can detect
  β subunit of hCG up to 0.002 IU/mL in the serum.

It can detect pregnancy as early as 8–9 days after
ovulation (day of blastocyst implantation).

Radio receptor assay gives highest sensitivity of 0.001 IU/mL in the serum.

RIAs are quantitative, so can be used for determining the doubling time of hCG (ectopic pregnancy monitoring). RIAs require 3–4 hours to perform.

Question 19

What are Immunoradiometric assays (IRMA)?

Answer 19

B. Immunoassays with radioisotopes

It uses sandwich principle to detect whole hCG molecule.

IRMAs use I125 labeled hCG and require only 30 minutes. It can detect hCG as low as 0.05 mIU/mL.

Selection of time: Diagnosis of pregnancy by detecting hCG in maternal serum or urine can be made
by 8 to 11 days after conception. The test is not reliable after 12 weeks.

Question 20

What are the other uses of pregnancy tests?

Answer 20

Apart from the diagnosis of uterine pregnancy, the tests are employed in the diagnosis of:

• ectopic pregnancy
• to monitor pregnancy following in vitro fertilization and embryo transfer
• to follow up cases of hydatidiform mole and choriocarcinoma.

Test accuracy ranges from 98.6 – 99%.

Non-pregnant level is
below 1 mIU/mL.

Limitations: Test accuracy is affected due to
presence of 
(i) hemoglobin 
(ii) albumin 
(iii) LH
(iv) immunological diseases.

Question 21

What are the advantages of immunological tests in diagnosing pregnancy?

Answer 21

They are advantageous over biological methods because of their speed,
simplicity, accuracy, and less cost.

Biological tests
were based on the classic discovery of Aschheim
and Zondek in 1927. All these tests are of historical
interest.

Question 22

How is ultrasonography used in diagnosing pregnancy?

Answer 22

• Intradecidual gestational
  sac (GS) is identified as early as 29 to 35 days of
  gestation
• Fetal viability and gestational age is determined by detecting the following structures by transvaginal ultrasonography.
• Gestational sac and yolk sac by 5 menstrual weeks;
• Fetal pole and cardiac activity — 6 weeks; Embryonic movements by 7 weeks.
• Fetal gestational age is best determined
  by measuring the CRL between 7 and 12 weeks (variation ± 5 days).
• Doppler effect of ultrasound can
  pick up the fetal heart rate reliably by 10th week.
• The instrument is small, handy and cheap.
• The gestational sac (true) must be differentiated from pseudogestational sac.

Question 23

What are the pregnancy symptoms observed in the second trimester?

Answer 23

The subjective symptoms — such as nausea, vomiting and frequency of micturition usually subside, while amenorrhea continues.

The new features that appear are:

 “Quickening” (feeling of life) denotes the perception of active fetal movements by the women.

It is usually felt about the 18th week, about 2 weeks earlier in multiparae.

Its appearance is an
useful guide to calculate the expected date of delivery with reasonable accuracy

 Progressive enlargement of the lower abdomen by the growing uterus.

Question 24

What are some changes observed in the general examination?

Answer 24

 Chloasma: Pigmentation over the forehead and cheek may appear at about the 24th week.

 Breast changes:
(a) Breasts are more enlarged with prominent veins under the skin
(b) Secondary areola specially demarcated in primigravidae, usually appears at about 20th week
(c) Montgomery’s tubercles are prominent and extend to the secondary areola
(d) Colostrum
becomes thick and yellowish by 16th week
(e) Variable degree of striae may be visible with
advancing weeks.

Question 25

What methods are used in the abdominal examination of the patient in the 2nd trimester?

Answer 25

• inspection
• Palpation
• Auscultation

Question 26

What can be observed during the inspection of a patient in the 2nd trimester?

Answer 26

(1) Linear pigmented zone (linea nigra) extending from the symphysis pubis to ensiform cartilage may be visible as early as 20th week
(2) Striae (both pink and white) of varying degree are visible in the lower abdomen, more towards the flanks

Question 27

What can be observed during the palpation of a patient in the 2nd trimester?

Answer 27

Fundal heightis increased with progressive
enlargement of the uterus.

Approximate duration of
pregnancy can be ascertained by noting the height of the uterus in relation to different levels in the abdomen. The
following formula is an useful guide for the purpose:

The height of the uterus is midway between the
symphysis pubis and umbilicus at 16th week; at the level of the umbilicus at 24th week and at the junction of the lower
third and upper two-thirds of the distance between the
umbilicus and ensiform cartilage at 28th week.

 The uterus feels soft and elastic and becomes ovoid
in shape.
 Braxton-Hicks contractions are evident, the
features of which have been mentioned in p. 54.
 Palpation of fetal parts can be felt distinctly by 20th
week. The findings are of value not only to diagnose
pregnancy but also to identify the presentation and
position of the fetus in later weeks.
 Active fetal movements can be felt at intervals by
placing the hand over the uterus as early as 20th week. It not only gives positive evidence of pregnancy but of a live fetus. The intensity varies
from a faint flutter in early months to stronger movements in later months.
 External ballottement is usually elicited as early as the 20th week when the fetus is relatively smaller
than the volume of the amniotic fluid. It is difficult to elicit in obese patients and in cases with scanty liquor amnii. It is best elicited in breech presentation with the head at the fundus.

Question 28

What can be observed during the auscultation of a patient in the 2nd trimester?

Answer 28

Fetal heart sound (FHS) is the most conclusive clinical sign of pregnancy.

With an ordinary
stethoscope, it can be detected between 18–20 weeks.

The sounds resemble the tick of a watch
under a pillow. Its location varies with the position of the fetus. The rate varies from 110–160 beats
per minute.

Two other sounds are confused with fetal heart sounds. Those are:

• Uterine souffle
• Funic or fetal souffle
• Uterine souffle is a soft blowing and systolic murmur heard low down at the sides of the uterus, best on the
  left side.
  The sound is synchronous with the maternal pulse and is due to increase in blood flow through the dilated uterine vessels. It can be heard in big uterine fibroid.
• Funic or fetal souffl e is due to the rush of blood through the umbilical arteries. It is a soft, blowing murmur
  synchronous with the fetal heart sounds.

Question 29

What can be observed during the vaginal examination of a patient in the 2nd trimester?

Answer 29

 The bluish discoloration of the vulva, vagina and cervix is much more evident, so also softening of the cervix.

 Internal ballottement can be elicited between 16–28th weeks. The fetus is too
small before the 16th week and too large to displace after the 28th week. However, the test may not be elicited in cases with scanty liquor amnii, or when the fetus is transversely placed.

Question 30

What imaging studies can be performed to diagnose pregnancy in the 2nd trimester?

Answer 30

• Sonography:

Routine sonography at 18–20 weeks permits a detailed survey of fetal anatomy, placental localization and the integrity of the cervical canal.

Gestational age is determined by measuring the biparietal diameter (BPD), head circumference (HC), abdominal circumference (AC) and femur length
(FL).

It is most accurate when done between 12 and 20 weeks (variation ± 8 days).

BPD is measured at
the level of the thalami and cavum septum pellucidum.

BPD is measured from outer edge of the skull
to the inner edge of the opposite side

Fetal organ anatomy is surveyed to detect any malformation.

Fetal viability is determined by realtime ultrasound.

Absence of fetal cardiac motion confirms fetal death.

Magnetic Resonance Imaging (MRI): MRI can be used for fetal anatomy survey, biometry and
evaluation of complex malformations.

Radiologic evidence of fetal skeletal shadow may be visible as early as 16th week