Diagnosis Of Pregnancy Flashcards
(26 cards)
What are the benefits of diagnosing pregnancy early?
Lifestyle habits (e.g. alcohol consumption, smoking, taking certain medications, etc) may influence the
wellbeing of the fetus and child
Medical procedures such as x-rays may have been planned and they should be deferred if pregnancy is confirmed
Certain drugs (e.g. some antihypertensives, epilepsy and diabetes treatment) may have to be altered in pregnancy
what are the main diagnostic tools in diagnosing pregnancy?
- History & physical examination,
- Laboratory evaluation and
- Ultrasonography
how do you calculate EDD?
Done according to Naegele’ s formula
Add 9 to months and 7 to days to the 1st day of the LNMP
Alternatively, subtract 3 months from 1st day of the LNMP and then add 7 to get the
EDD e.g. a pregnancy with LNMP 16.08.17 will have EDD of 23.05.18
The former method is commonly used
what are the expected subjective symptoms during the first trimester of pregnancy?
- Amenorrhoea: During the reproductive period in a healthy woman having previous normal periods,
amenorrhoea is likely to be due to pregnancy unless proved otherwise
Exclude pregnancy first prior to determining other causes of amenorrhoea
Note: Pregnancy may also occur in women who were previously amenorrhoeic – during lactation & puberty. - Morning sickness (nausea & vomiting) (emesis gravidarum)
One of the commonest symptoms in early pregnancy.
Common more often in 1st pregnancy than subsequent ones
Usually appears soon after the missed period and rarely lasts beyond 16 weeks.
Its intensity varies from nausea on rising from bed to loss of appetite or even vomiting
Aetiology is unknown but it is thought to possibly be due to rising levels of HCG produced by the
trophoblast in 1st trimester - Frequency of micturition – troublesome symptom between 8 & 12 weeks. It is due to:
Resting of bulky uterus on the fundus of the bladder due to the exaggerated anteverted position of the uterus
Congestion of the bladder mucosa
Change in maternal osmoregulation causing increased thirst & polyuria
As the uterus straightens up after 12th week, the symptoms disappear - Breast discomfort/ fatique – may feel full & have pricking sensation commonly between 6 & 8 weeks. More in
primigravidas - Extreme tiredness – infrequent symptom which may occur in early pregnancy.
Lasts for 12 – 14 weeks and then resolves in the majority - Food cravings and pica (ingestion of peculiar substances e.g. soil)
- Appetites and eating habits often change in early pregnancy
what is placental sign?
Cyclic bleeding may occur up to 12wks of preg, until decidual space is obliterated by fusion of decidua vera with
decidua capsularis. Such bleeding is scanty, lasting for a shorter duration than usual & roughly corresponds with
date of expected period. This is termed as placental sign.
what are the expected objective symptoms during the first trimester of pregnancy?
- Breast changes:
Valuable only in primigravidas. The changes are evident between 6 and 8 weeks
Enlargement with vascular engorgement evidenced by delicate veins visible
under skin
Breasts enlarge with nipple and areolar becoming more pigmented
Sebaceous glands in the areola develop hypertrophy to form Montgomery’ s tubercles - Per abdomen – uterus remains a pelvic organ until 12th week, it may be just felt per abdomen as a suprapubic
bulge - Pelvic changes – are diverse and appear at different periods e.g. cervix becomes soft as early as 6th week and
uterus size is enlarged
Jacquemier’s or Chadwick’s sign
Jacquemier’s or Chadwick’s sign: dusky hue / bluish discoloration of vestibule and anterior vaginal wall
visible at about 8th week of pregnancy, due to local vascular congestion.
what vaginal signs are diagnostic of pregnancy?
Vaginal sign:
1) Walls become softened and
2) Copious non-irritating mucoid discharge appears at 6th week
3) Increased pulsation, felt through the lateral fornices at 8th week called Osiander’s sign
Osiander’s sign
3) Increased pulsation, felt through the lateral fornices at 8th week called Osiander’s sign.
what cervical signs are diagnostic of pregnancy?
Cervical signs:
1) Goodell’s sign- Softening of cervix occurring as early as 6th week, but a little earlier in multiparae.
Cervix feels like lips of mouth, while its , like that of tip of the nose in non-pregnant state
2) Bluish discoloration of the cervix is visible on speculum exam, due to increased vascularity
Goodell’s sign
Goodell’s sign- Softening of cervix occurring as early as 6th week, but a little earlier in multiparae.
Cervix feels like lips of mouth, while its , like that of tip of the nose in non-pregnant state
what uterine signs are diagnostic of pregnancy?
Size, shape and consistency- uterus is enlarged progressively, becomes globular shaped by 12 weeks
other than the pyriform shape of the non-pregnant uterus and feels soft as well as elastic.
Asymmetrical enlargement of the uterus is noted if there is lateral implantation, called Piskacek’s
sign (where one half is more firm than the other half but symmetry is restored as preg advances)
Hegar’s sign: demonstrated between 6–10 weeks, or a little earlier in multiparae. Present in 2
/3 of
cases. It’s based on the fact that:
Growing fetus enlarges the upper part of the body of the uterus
Lower part of the body is empty and extremely soft and cervix is
comparatively firm.
Due to that variation in consistency, on bimanual exam (2 fingers in
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.
Palmer’s sign: Regular and rhythmic uterine contraction can be elicited
during bimanual examination as early as 4–8 weeks.
Piskacek’s sign
Asymmetrical enlargement of the uterus is noted if there is lateral implantation, called Piskacek’s
sign (where one half is more firm than the other half but symmetry is restored as preg advances)
Hegar’s sign
Hegar’s sign: demonstrated between 6–10 weeks, or a little earlier in multiparae. Present in 2
/3 of
cases. It’s based on the fact that:
Growing fetus enlarges the upper part of the body of the uterus
Lower part of the body is empty and extremely soft and cervix is
comparatively firm.
Due to that variation in consistency, on bimanual exam (2 fingers in
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
Palmer’s sign
Palmer’s sign: Regular and rhythmic uterine contraction can be elicited
during bimanual examination as early as 4–8 weeks.
outline the Immunoassays without radioisotopes in diagnosis of pregnancy
- Agglutination inhibition tests
Principle of agglutination inhibition tests:
One drop of urine is mixed with one drop of a sol that contains hCG antibody.
If hCG is not present in urine sample (e.g. woman is not
pregnant), Ab 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, preg. test is -ve if there is agglutination - Direct agglutination test (hCG direct test) - Latex
particles coated with anti-hCG monoclonal antibodies are
mixed with urine. Direct test
An agglutination reaction indicates a +ve result- urine
sample has hCG.
Absence of agglutination (urine without hCG) indicates a -ve one. Sensitivity is 0.2 IU hCG/Ml - Enzyme-linked immunosorbent assay (EL-ISA)
One monoclonal antibody binds hCG in urine and serum.
A 2nd antibody linked with enzyme alkaline phosphatase is used to ‘sandwich’ the bound hCG.
After binding, color change detected.
More sensitive and specific.
ELISA can detect hCG in serum up to 1–2 mIU/mL and as early as 5 days before the 1st missed period.
Home pregnancy test kits available - Fluoroimmunoassay (FIA) - Highly precise sandwich assay.
Uses a 2nd antibody tagged with a fluorescent label.
Fluorescence emitted is proportional to the amount of hCG.
Can detect hCG as low as 1 mIU/mL.
FIA takes 2–3 hours. Used to detect hCG and for follow up hCG concentrations.
outline the Immunoassays with radioisotopes in diagnosis of pregnancy
- Radioimmunoassay (RIA) - use I
125 ido hCG antibodies.
More sensitive and can detect β subunit of hCG up to 0.002 IU/mL in the serum.
Detect pregnancy as early as 8–9 days after ovulation (day of blastocyst implantation).
Gives highest sensitivity of 0.001 IU/mL in the serum.
It’s a quantitative test used for determining the doubling time of hCG (ectopic pregnancy monitoring).
RIAs require 3–4 hours to perform. - Immunoradiometric assay (IRMA) - uses sandwich principle to detect whole hCG molecule.
Uses
125I labelled hCG and require only 30 minutes.
Detect hCG as low as 0.05 mIU/mL. - Fluoroimmunoassay (FIA)
imaging in first trimester to diagnose pregnancy
- Ultrasonography: Gestational ring at 5th week
Identify intradecidual gestational sac (GS) as early as 29 to 35 days of
gestation.
Transvaginal U/S determine Fetal viability and gestational age by detecting the following structures
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 U/S can pick up the FHR reliably by 10th wk.
Gestational sac (true) must be differentiated from pseudogestational sac
subjective symptoms in 2nd trimester
Subjective symptoms
Nausea, vomiting & frequency of micturition usually subside while amenorhhoea continues
New features that appear include:
a. Quickening (feeling of life) – perception of active fetal movements by the woman. It is usually felt about 18
weeks, about 2 weeks earlier in multiparous women. Useful guide to calculate the EDD with reasonable accuracy
b. Progressive enlargement – of the lower abdomen by the growing uterus
what does gen exam in 2nd trimester show?
a) Chloasma – pigmentation of the forehead & cheek may appear at about 24 weeks
b) Breast changes – e.g. breasts more enlarged; colostrum becoming more thick & yellowish by week 16
Enlarged breasts with prominent veins under the skin
Secondary areola specially demarcated in primigravidae, usually by 20th week
Prominent Montgomery’s tubercles and extend to the secondary areola
Colostrum becomes thick and yellowish by 16th week
Variable degree of striae may be visible with advancing weeks
Abd exam in pregnancy shows:
Inspection –
Linea nigra - Linear pigmented zone extending from symphysis pubis to ensiform cartilage,
seen by 20th
week
Striae (both pink and white)- varying degree in the lower abdomen, more towards the flanks
Palpation –
Fundal height - increase progressively with uterine enlargement.
Approximate duration of pregnancy can be ascertained by noting height of uterus in relation to different levels in
the abdomen.
HOF is
o Midway between symphysis pubis and umbilicus at 16th week;
o At level of umbilicus at 24th week and
o At the junction of the lower third and upper two-third of distance between the umbilicus and ensiform
cartilage at 28th week
Uterus feels soft and elastic and becomes ovoid in shape.
Braxton-Hicks contractions are evident. These are spontaneous irregular, infrequent, spasmodic and
painless contractions without any effect on dilatation of the cervix and pt. is not conscious about the
contractions. Intrauterine pressure remains < 8 mm Hg
Palpation of fetal parts - distinctly by 20th week. Findings are valuable to diagnose pregnancy and identify
the presentation and position of the fetus in later weeks.
Active fetal movets at irregular intervals- as early as 20th wk.
External ballottement- as early as 20th week. Elicited when
fetus is relatively smaller than vol. of amniotic fluid. Hard to
elicit in obese pts. and in cases with scanty liquor amnii but
best elicited in breech presentation with head at the
fundus.
Auscultation
Fetal heart sound (FHS)- Conclusive clinical sign of pregnancy, detected betwn 18-20wks with a stethoscope
sounds resemble the ticks of a watch under a pillow
Location varies with position of fetus
Rate ranges between 110 – 160 beats per minute
Distinguish the FHS from the maternal pulse
Uterine soufflé- soft blowing and systolic murmur heard low down at sides of the uterus, best on the left side
due to increased blood flow through the dilated uterine vessels.
Sound is synchronous with maternal pulse
Can be heard in big uterine fibroid.
Funic or fetal soufflé- soft, blowing murmur synchronous with the FHS due to rush of bld via umbilical arteries
investigations in 2nd trimester
1) Sonography – routine u/s at 18 – 20 weeks permits detailed
Survey of fetal anatomy,
Placental localization and integrity of cervical canal
Gestational age is determined by measuring Biparietal diameter (BPD- measured from outer edge of skull to
inner edge of opposite side), head circumference (HC), abdominal circumference (AC) & femur length (FL)
It is most accurate when done between 12 & 20 weeks (variation +/- 8 days)
Fetal organ anatomy is surveyed to detect any malformation
Fetal viability is also determined. Absence of fetal cardiac motion confirm fetal death
2) Magnetic Resonance Imaging (MRI): used for fetal anatomy survey, biometry and evaluation of complex
malformations.
3) Radiologic evidence of fetal skeletal shadow may be visible as early as 16th week
symptoms seen in 3rd trimester
Symptoms
1. Amenorrhoea persists
2. Enlargement of the abdomen is progressive and may produce some mechanical discomfort to the patient e.g.
palpitation or dyspnea following exertion
3. Lightening – at about 38 weeks, a sense of relief of pressure symptoms is obtained due to engagement of the
presenting part especially in PGs
4. Frequency of micturition reappears
5. Fetal movements are more pronounced
signs seen in 3rd trimester
- Cutaneous changes are more prominent with increased pigmentation and striae
gravidarum (arising from tearing of the elastic fibres of the dermis) - Stretch marks are found on the abdominal wall, outer thighs, breasts and upper
arms - Uterine shape changed from cylindrical to spherical beyond 36 weeks
- Fundal height – distance between the umbilicus and ensiform cartilage is
divided into three equal parts:
At 32 weeks- fundal height corresponds to the junction of upper and middle third,
At 36th week - up to the level of ensiform cartilage
At 40th week- comes down to 32 week due to level of engagement of the presenting part.
To determine whether height of the uterus corresponds to 32 weeks or 40 weeks, test, engagement.
Pregnancy is of 32 weeks if head is floating, but of 40 weeks head is engaged.
Symphysis fundal height (SFH) is measured with a tape. Distance between the upper border of the fundus
and upper border of the symphysis pubis
After 24 weeks, the SFH in cm corresponds to the gestational age +/- 2 cm up to 36 weeks. - Braxton-Hicks contractions are more evident.
- Fetal movements are easily felt.
- Much easier palpation of fetal parts & their identification. Lie, presentation & position of fetus are determined.
- FHS is heard distinctly- in areas corresponding to presentation and position of the fetus
Not be audible in maternal obesity, polyhydramnios, occipitoposterior position & certainly in IUD
