Lectures 9 & 10 - Pregnancy I & II Flashcards
What is the gestational period?
From conception to birth: normally 266 days (9 months or 38 weeks) BUT we calculate gestation from the last menstrual period (2 weeks before ovulation/fertilization), it is 40 weeks (9.5 months or 280 days)
What are the 3 trimesters of pregnancy?
- 1st – First 12-14 weeks
- 2nd – Week 12-14 to week 24-28
- 3rd – Week 24-28 to week 37-42
3 types of deliveries with regards to timing? When is delivery optimal?
- Preterm: any delivery before 37 weeks
- Term: delivery between 37-42 weeks:
a. Early term: 37-38 6/7 weeks
b. ***Full term: 39-40 6/7 weeks
c. Late term: 41-41 6/7 - Postterm: delivery after 42 weeks
What is gravidity?
Number of times a woman has been pregnant including current pregnancy, if applicable
What is parity? What to note?
Describes the outcomes of those pregnancies: number of term deliveries, number of preterm deliveries, number of abortions (spontaneous or induced), number of living children
NOTE: count twins as just one pregnancy
3 methods of pregnancy detection?
- Urine or blood ß-hCG (human chorionic gonadotropin)
- Ultrasound identification (4-5 wks)
- Fetal cardiac activity by doppler (5.5-6 wks)
How should hCG levels fluctuate in early pregnancy?
Should double every 48 hours in early pregnancy
Where does hCG come from? Purpose? What to note?
Secreted by the placenta and maintains the corpus luteum which produces progesterone essential for maintaining pregnancy
NOTE: During the 2nd and 3rd trimester, the placenta secretes its own estriol and progesterone and the corpus luteum degenerates
What physiological changes does pregnancy cause?
Almost every organ system is affected by pregnancy to accommodate the maternal/fetal environment and allow for delivery: cardiovascular, pulmonary, gastrointestinal, renal, hematological, endocrine, and anatomical changes (everything gets squished)
4 cardiovascular changes in pregnancy?
- Increase in plasma volume by 50% in preparation for blood loss of delivery, causing a systolic murmur in 90-95% of pregnant women
- Red blood cell (RBC) volume increases by 20-30%,
1 + 2 => decrease in hematocrit known as physiologic or dilutional anemia of pregnancy (not true anemia) => resulting decreased blood viscosity improves flow through placenta (decreased resistance)
- Cardiac output (CO) increases by 30-50% due to increased BV, decreased afterload, and elevated HR in late pregnancy => causes increased uterine blood flow (12% of CO by late pregnancy instead of 1-2%!)
- Systemic vascular resistance decreases causing a decrease in systolic (by 5-10 mm Hg) and diastolic (by 10-15 mm Hg) blood pressure in the first two trimesters due to a decreased responsiveness to hormones that constrict vasculature
How to calculate hematocrit?
RBC volume/plasma volume
Does BP return to pre-pregnancy levels by term?
YUP (by 12 weeks postpartum)
Effect of progesterone on smooth muscle of the uterus and BVs?
Relaxation
3 pulmonary changes in pregnancy?
- Oxygen consumption increases by 15-20%
- Tidal volume increases by 30-40% causing an increase in minute ventilation (RR relatively normal) due to the
respiratory centers being more sensitive to CO2 (decreased in CO2 in pregnancy compensated by kidneys, pH still in normal range) - Total lung capacity decreases by 5% due to elevated diaphragm => 50-70% of women experience dyspnea of pregnancy
3 endocrine changes in pregnancy?
Almost every hormone is affected:
- Hyperestrogenic state produced mainly by the placenta and necessary for fetal well being => increased risk of blood clots (DVT, PE) due to hypercoagulable state (and sometimes forced immobility)
- Diabetogenic state due to increased blood sugar due to increased insulin resistance
- Progesterone causes smooth muscle relaxation, which is necessary to relax the uterus
What happens during delivery aka parturition?
- Fetal hormone secretion stimulates placenta to release large amounts of estrogen => prepares myometrium for oxytocin (posterior pituitary) and prostaglandins (uterine) by upregulating receptors
- Oxytocin from fetus initiates cervical dilation and uterine prostaglandin secretion
- Cervical dilation stimulates release of maternal oxytocin (Ferguson reflex) => uterine contractions and positive feedback
What are the 3 stages of labor? Timing for each?
- First stage: dilation of the cervix to 10 cm and effacement (thinning of the cervix) => longest stage: 6-12 hours
- Second stage: time from full dilation to delivery of the fetus => bout an hour
- Third stage: delivery of the placenta (about 30 min after birth)
During what labor stage is there a bleeding risk? Why?
Third stage because of placental delivery causing the break of many blood vessels
List reasons for Cesarean deliveries in order of prevalence.
- Labor arrest
- Malpresentation
- Non-reassuring fetal tracing
- Multiple gestation
- Maternal-fetal complications
- Other obstetric indications
- Macrosomia
- Preeclampsia
- Maternal request
Rate of C-section in the US?
30% (10-15% is the goal)
2 early gestation pathologies?
- Miscarriage
2. Ectopic pregnancy
3 late gestation pathologies?
- HT problems
- Gestational diabetes
- Placental abnormalities
What is a miscarriage?
Spontaneous abortion with pregnancy loss before 20 weeks gestation
When are miscarriages most common?
1st trimester spontaneous abortions are extremely common, 2nd trimester rare
4 possible causes of miscarriages?
- Fetal chromosomal anomalies, anembryonic implantation (blighted ovum)
- Teratogen exposure
- Endocrine abnormalities (low progesterone, hypothyroidism)
- Space in uterus: leiomyomas (fibroids), uterine malformation etc.
4 risk factors for miscarriages?
- Advanced maternal age
- Previous miscarriage (especially consecutive)
- Maternal smoking
- Intrauterine trauma (previous medical procedures)
Clinical presentation of miscarriage?
- Vaginal bleeding
- Pelvic pain
- Open cervical os
- Expulsion of fetal content
Is vaginal bleeding normal during pregnancy?
YUP
2 types of miscarriages?
- Complete abortion: all fetal material expelled, usually in early pregnancy
- Incomplete abortion: retention of products of conception with increased infection (endometritis) risk if untreated
What is a threatened abortion? Treatment?
Vaginal bleeding with closed cervical os
No treatment other than observation but may be nothing because vaginal bleeding is normal during pregnancy
How to clinically manage miscarriages? What to note?
- Ultrasonography helpful to monitor fetal cardiac activity, gestational sac, yolk sac
- Examination of expelled contents, but difficult to distinguish complete from incomplete abortions
- Removal of retained tissue:
- Dilatation and curettage (D&C) = dilate cervix and scrape uterus (definitive treatment)
- Medical treatment with misoprostol: cervix dilation, uterine contractions (but D&C might still be needed)
- Expectant management: wait and look out for symptoms of endometritis
NOTE: #3 is the same for induced abortions
Incidence of ectopic pregnancies? Why is it rising?
1-2 in 100 pregnancies
Because incidence of pelvic inflammatory disease (risk factor) is rising
List 7 locations for ectopic pregnancies in order of prevalence.
- Ampulla
- Isthmus
- Fimbriae
- Ovarian
- Abdominal
- Interstitial
- Cervical
What are the risk factors for ectopic pregnancy?
Factors that disrupt the fallopian tube and causes scaring or decreased peristalsis:
- Pelvic inflammatory disease: causes scarring in reproductive tract
- Prior tubal surgeries: ligation
- Endometriosis
- Intrauterine device: creates harsh intrauterine environment
- Smoking: interferes with motility
- In vitro fertilization
Symptoms of ectopic pregnancy?
- Abdominal or pelvic pain
- Missed menses (or known pregnancy)
- Vaginal bleeding
- If ruptured and bleeding, patient may show signs of hemodynamic instability (tachycardia, hypotension etc.) => emergency!
Clinical presentation of ectopic presentation during exam?
- Abdominal/pelvic tenderness
- Palpable adnexal mass
- Or no abnormality at all