preg fertility test

basis of tests

• hCG is a hormone pro by trophoblast of fertilized ovum

• lvls rise v rapidly, doubles every 2 days aft implantation

• peak lvl betw 6-8wk

• decreases over next 10wks

• detected in ruine 1-2wks aft fertilization

type of pregnancy tests (2)

1. home pregnancy test

2. blood test for hCG

home pregnancy test

• detect presence of hCG in urine

• 97% or higher accuracy, but can have flase +ve/ -ve

• use monoclonal/ polyclonal AB in enzyme immunoassay —> surface ab binds to solid surface & another ab is linked to an enzyme

• if hCG present, complex is formed w AB, hCG get sandwiched betw surface AB & AB linked to enzymes

• enzyme react w chromogen to prod distinctive colour

whole process of test

1. urine sample applied to bottom of stick

2. any hCG present binds to the first anti hCG AB

3. at the test region, it contains immobilized anti hCG AB which binds to alternative sites on hCG to trap it

4. the enzyme attached to 1st AB changes colour as evidence of a +ve test

5. unbound AB progresses further up the stick to the control region to bind to the 3rd type of AB

6. the attached enzyme causes a colour change only as proof to show that the AB is working

blood test for hCG

• most sensitive

• can detect pregnancy earlier than urine test

• can distinguish normal pregnancies frm impending miscarriages/ ectopic pregnancies

• 97-100% accuracy

reasons for false +ve (2)

1. miscarriage/ birth within 8wks

2. medications → menotropins for injection

reasons for false -ve (1)

1. test too soon —> on/ before 1st day of missed period

other rsns for inaccuracies (4)

1. ovarian cyst

2. ectopic pregnancy

3. refrigerated urine that wasnt warmed to room temp before testing

4. soap residue in household containers used to collect urine

how to avoid inaccuracies (3)

1. wait at least 1 wk aft date of expected period before testing

2. test urine sample immediately aft collection

3. store urine in refrigerator & allow it to warm to room temp before testing & dont shake it

procedure for home pregnancy test

1. use first urine in morn unless kit indicates otherwise

2. remove stick/ cassette right before use

3. apply urine to device

• hold stick in urine stream for indicated time

• urinate into cassette well

• collect urine in cup & drip strip/ use a dropper

4. lay device on flat surface

5. wait for reco time ~1-5mins bfr reading results

6. max waiting time improves sensitivity

7. discard device

evaluation of outcome

+ = pt assume preg & call dr

— = pt make sure test correctly used

• test agn in 1 wk if menstruation hvnt occur

• if 2nd result -ve & menses havent begin = contact physician

infertility

medical inability to conceive after 1 year of unsuccessful attempts in women under the age of 35 and after 6months in women over 35

physiology of female reproductive cycle

— ovum remain viable for 12-24h post ovulation

— sperm live for up to 5 days aft intercourse

Optimal day for sex: 2 day bfr ovulation, day of ovulation, day after ovulation, within 24h of LH surge

1. Day 1-12

• Low lvl of circulating oestrogen & progesterone

• Hypothalamus secrete gonadotropin releasing hormone (GnRH)

• Anterior pituitary gland release follicle stimulating hormone FSH & low lvl of luteinizing hormone LH

• Follicles develop within ovary

• Dominant follicle matures while others regress

2. Day 14/ 15 (mid cycle)

• LH surge

• Final maturation of dominant follicle

3. Ovulation

• Dominant follicle rupture and release ovum

• Occurs 20-48h after LH surge 

female fertility tests

• predict/ detect ovulation time

• good for women who have difficulty getting preg/ fertile women who wnna be aware of ovulation period

• not a reliable mean of birth control alone

types of fertility tests (3)

1. basal thermometer

2. urine test

3. saliva test

basal thermometer

• use basal body temp to detect ovulation

• resting temp is below normal of 37

• aft ovulation temp rises by 0.2 closer to 37

disadv (4)

1. recording & interpreting bbt might be difficult

2. reading mercury thermometer might be difficult

3. post ovulation increase is small

4. accuracy can be affected by —> emotion, movement, infections.

• must avoid eating, drinking, talking, smoking until test is completed

procedure (3)

1. be consistent with method of taking bbt

2. take readings at the same time everyday, with at least 5h of sleep

3. plot bbt graph, rise in bbt = ovulation occurred

how to avoid inaccuracies (3)

1. dont move dur test

2. discontinue test if have infections, begin test agn on 1st day of cycle after resolving infection

3. dont eat/ drink/ talk/ smoke within 30mins of testing

urine tests

• predict ovulation time using urine

• use monoclonal ab specific to LH to detect LH surge (diff in colour/ colour intensity)

• intensity of colour proportional to LH lvl of urine

• LH surge happen 24-36h before ovulation

exclusions for self testing (2)

1. false positives caused by —> menotropins, menopause, PCOS, pregnancy

2. pt who j discontinued oral contraceptives —> causes delayed ovulation by 1-2 cycles, start testing aft 2 natural cycles

usage guidelines

1. start testing 2-3 days bfr ovulation is expected/ for 1st month test for 20days starting on 6th day aft start of menstruation

2. fllw manufacturer instruction on timing of urine collection

• usually it is early morn collection

• if not 1st morn urine, restrict fluid intake for at least 4h before testing & avoid urinating until test time

3. method of collection

• if meant to pass thru urine stream

  • hold stick in urine stream for specific time/ collect urine in cup or with use of dip stick

• if not meant to pass thru urine stream

  • collect urine in cup and apply urine to test well via dropper. test immediately after collection

4. if immediate testing not possible

• refrigerate sample for directed length of time

• warm sample to room temp for 20-30mins bfr testing

• avoid re dispersing any sediments

• read result aft 3-5mins

5. interpretation of results

• 1st significant inc in colour intensity = LH surge occurred & ovulation occur within 1-2 days

• clearblue fertility monitor → higher reading = 1-5 days before peak fertility, peak reading = 2 day bfr ovulation

saliva test

• predict ovulation using saliva

• 2 types

types (2)

1. fertility microscope

2. salivary electrolyte monitor

fertility microscope

• examine dried saliva frm pt

• pattern is affected by saliva electrolyte conc, influenced by hormonal changes before, dur, aft ovulation

• fertile period = fern leaf pattern, 3-4days bfr ovulation & persists 2-3days aft ovulation

• non fertile period = dotted/ bubble like pattern

usage guidelines (8)

1. wash & dry hands

2. place saliva on slide area of microscope eyepiece

3. dry saliva for 5-7mins

4. observe patter

5. compare fertile & non fertile pattern

6. clean slide aft use w cotton swab soaked in water/ alcohol

7. dont wash/ soak eyepiece

8. combine w other fertility test to improve accuracy

adv (3)

1. compliance

2. identify larger window

3. potentially reusable

disadv (3)

1. pattern identification is subjective

2. must do daily testing

3. more expensive

salivary electrolyte monitor

• affected by smoking/ alc/ anticholinergic meds/ food

• avoid collecting sample 2h of smoking/ eating/ drinking/ brushing teeth