Flashcards in Pregnancy - HY Deck (64):
Role of hCG:
Stimulates the production of progesterone (PG) by the corpus luteum (ie maintains corpus luteum function).
hCG can be assayed in MATERNAL BLOOD at day ... or MATERNAL URINE at day ... using a radioimmunoassay with antibodies directed against the β-subunit of hCG.
MATERNAL BLOOD --> Day 8.
MATERNAL URINE --> Day 10.
Quantitative hCG dating of pregnancy:
During weeks 1-6 of a normal pregnancy, hCG levels will increase by about 70% every 48h:
0-2 weeks --> 0-250.
2-4 weeks --> 100-5.000.
1-2 months --> 4.000-200.000.
2-3 months --> 8.000-100.000.
2nd trimester --> 4.000-75.000.
3rd trimester --> 1.000-5.000.
Other tests using hCG:
1. Low hCG levels may predict a spontaneous abortion or indicate an ectopic pregnancy.
2. Elevated hCG leves may indicate a multiple pregnancy, hydatidiform mole, or gestational trophoblastic neoplasia.
What is the human placental lactogen (hPL)?
A protein hormone produced by the placenta --> Induces lipolysis, thereby elevating FFA in the MOTHER.
hPL is considered ...?
The GH of the latter half of pregnancy.
hPL can be assayed in ...?
Maternal blood at week 6.
hPL levels vary with ...?
Placental mass --> May indicate a multiple pregnancy.
--> Rapidly disappear after delivery.
Prolactin (PRL) is a ...?
Protein hormone produced by the:
1. Maternal hypophysis.
2. Fetal hypophysis.
3. Decidual tissue of the uterus.
PRL can be assayed ...?
In maternal BLOOD throughout the pregnancy or later in amniotic fluid.
Near term, PRL levels ...?
Rise to MAX of about 100ng/mL (normal non pregnant levels 8-25).
PG is a ...?
Steroid hormone --> Produced by the corpus luteum until WEEK 8 and THEN BY THE PLACENTA until birth.
PG prepares the endometrium for ...?
Implantation (nidation) and maintains the endometrium.
PG is used by the ...?
FETAL ADRENAL CORTEX as a precursor for corticosteroid + mineralocorticoid synthesis.
PG is also used by the ...?
Fetal testes as a precursor for testosterone synthesis.
Estrone, estradiol, and estriol - These hormones are produced ...?
By complex series of steps involving the:
1. Maternal liver.
3. Fetal adrenal gland.
4. Fetal liver.
E-E-E synthesis - Steps:
1. CH from the maternal liver is converted to pregnenolone by the placenta.
2. Pregnenolone is converted to pregnenolone sulfate.
3. Pregnenolone sulfate is converted to DHEA-SO4 by the fetal adrenal gland.
4. DHEA-SO4 is converted to estrone and estradiol by the placenta.
5. DHEA-SO4 is also converted to 16a-hydroxy DHEA-SO4 by the fetal liver.
6. 16a-hydroxy DHEA-SO4 is converted to estriol by the placenta.
Estrone is a ...?
Fairly weak estrogen.
Estradiol is a ...?
The most potent estrogen.
Estriol is a ...?
Very weak estrogen but is produced in very high amounts during pregnancy.
Estriol can be assayed in maternal BLOOD + maternal URINE:
Maternal blood --> Shows a distinct diurnal variation with peak amounts early in the morning.
Maternal urine --> 24h urine sample shows no diurnal variation.
Significant amount of estriol are produced at month ...?
Month 3 and continue to rise until birth.
Maternal urinary levels of estriol have long been recognized as a ...?
Reliable index of fetal-placental function --> Because estriol production depends on a normal functioning fetal adrenal cortex, fetal liver, placenta.
The estimated date of confinement (EDC) is based on the assumption ...?
That a woman has a 28d cycle with ovulation on day 14-15.
In general, the duration of the pregnancy is ... days, ... weeks, from the 1st day of the last menstrual period.
280 days, 40 weeks.
A common method for determining the EDC (Naegele's rule) is to ...?
Count back 3 months from the 1st day of the last menstrual period and then add 1 year + 7d.
At days ...-..., a positive pregnancy test is obtained by hCG assay.
Pregnancy milestones - At week 12, ...?
The uterine fundus is palpable at the PUBIC syphysis.
--> Doppler fetal heart rate is first audible.
Pregnancy milestones - At weeks 14-18, ...?
AMNIOCENTESIS is performed when suspicion of fetal chromosomal abnormalities exists.
Pregnancy milestones - At week 16, ...?
Uterine fundus is palpable midway between the pubic symphysis and umbilicus.
Pregnancy milestones - At weeks 16-18, ...?
First fetal movements occur (quickening) in a woman's second or higher pregnancy.
Pregnancy milestones - At weeks 17-20, ...?
Fetal heart rate is audible with the fetoscope.
Pregnancy milestones - At week 18, ...?
Female and male external genitalia can be distinguished with U/S (ie sex determination).
Pregnancy milestones - At weeks 18-20, ...?
First fetal movements occur (quickening) in a woman's first pregnancy.
Pregnancy milestones - At week 20, ...?
Uterine fundus is palpable at the umbilicus.
Pregnancy milestones - At weeks 25-27, ...?
Lungs become capable of respiration.
Pregnancy milestones - At week 27, the fetus weighs about ...?
Pregnancy milestones - End of 2nd trimester:
Pupillary light reflex is present.
Descent of the fetal head to the pelvic inlet (called lightening) occurs.
The fetus at term weighs about ...?
Prenatal diagnosis is indicated in about ...% of all pregnancies.
4 prenatal diagnostic procedures:
3. Chorionic villus biopsy.
4. Percutaneous umbilical blood sampling (PUBS).
US is commonly used to:
1. Date a pregnancy.
2. Diagnose multiple pregnancy.
3. Assess fetal growth.
4. Determine placenta location.
5. Determine position and lie of the fetus.
6. Detect certain congenital anomalies.
7. Monitor the needle/catheter insertion during amniocentesis and chorionic villus biopsy.
In obstetric US, ...-...mHz are used for good tissue differentiation.
Amniocentesis is a ...?
Transabdominal sampling of amniotic fluid + fetal cells.
Amniocentesis is performed at weeks ...-... .
Amniocentesis is indicated for the following situations:
1. Woman >35.
2. Previous child with chr. anomaly.
3. One parent is a known carrier of a translocation/inversion.
4. One or both parents are known carriers of an XR or AR trait, or there is a history of neural tube defects.
Amniocentesis - The sample obtained is used in the following studies:
1. AFP assay to diagnose NTDs.
2. Spectrophotometric assay of bilirubin --> Hemolytic disease of the newborn.
3. L/S ratio and phosphatidylglycerol assay --> Lung maturity.
4. DNA analysis.
Chorionic villus biopsy is a ...?
Transabdominal or transcervical sampling of the chorionic villi to obtain a large amount of fetal cells for DNA analysis.
Chorionic villous biopsy is performed at weeks ...-...?
6-11. MUCH EARLIER than amniocentesis.
Percutaneous umbilical blood sampling (PUBS) is a ...?
Sampling of fetal blood from the umbilical cord.
Fetal distress during labor is defined in terms of ...?
Fetal hypoxia and measured by changes in either FETAL HEART RATE or FETAL scalp capillary pH.
The normal baseline FHR is ...-... beats per min.
Fetal hypoxia causes a ... in FHR.
Decrease in FHR --> FHR
The normal fetal scalp capillary pH is ...-... .
--> Fetal hypoxia causes a decrease in pH, that is, a pH
The APGAR score assesses 5 characteristics:
The APGAR score is used to ...?
Determine which infants need resuscitation.
The APGAR score is calculated at ... and again at ... after birth.
1min and again at 5min after birth.
To obtain an APGAR score, one scores 0, 1, or 2 for the five characteristics and adds them together:
0-3 --> Life-threatening situation.
4-6 --> Indicates temperature and ventilation support is needed.
7-10 --> Normal situation.
Extends from immediately after delivery of the baby until the reproductive tract returns to the non pregnant state in approx. 4-6weeks.
Puerperium - Important events that occur are:
1. Involution of the uterus.
2. Afterpains due to uterine contractions.
3. Uterine discharge (lochia).
4. In non lactating women, menstrual flow returns within 6-8 weeks post partum, and ovulation returns 2-4weeks post partum.
5. In lactating women, ovulation may return within 10 weeks post partum.
6. Birth control protection afforded by lactation is assured for only 6 weeks, after which time pregnancy is possible.
Lactation during pregnancy:
1. hPL, PRL, PG, estrogens, cortisol, insulin stimulate the growth of LACTIFEROUS ducts and proliferation of epithelial cells to form ALVEOLI.
2. Alveoli secrete COLOSTRUM.
Lactation after delivery of the baby:
1. Lactation is initiated by a decrease in PG and estrogens, along with the release of PRL from the adenohypophysis.
2. This initiates MILK PRODUCTION.
Lactation during suckling:
1. A stimulus from the breast inhibits the release of PRL-inhibiting factor from the HYPOTHALAMUS --> Surge in PRL, which increases milk production.
2. In addition, stimulation of the nipples during suckling causes a surge of oxytocin, which causes the expulsion of accumulated milk ("milk letdown") by stimulating myoepithelial cells.