Maternal Physiology Flashcards
During pregnancy, cardiac output increases by ___ [%].
30-50%
During pregnancy, maximum cardiac output is reached ___ [age of gestation]
Between 20 and 24 weeks’ gestation and maintained until delivery
The increase in cardiac output is first due to an increase in ___ and is then maintained by an increase in ___ as the ___ decreases to near prepregnancy levels by the end of the third trimester
Stroke volume
Heart rate
Stroke volume
Systemic vascular resistance decreases during pregnancy, resulting in a fall in arterial blood pressure. This decrease is most likely due to elevated ___ [hormone], leading to smooth muscle relaxation.
Progesterone
There is a decrease in systolic blood pressure of ___ [mmHg] and in diastolic blood pressure of ___ [mmHg] that nadirs at week ___ [age of gestation]
5-10 mm Hg
10-15 mm Hg
24
There is an increase of 30-40% in tidal volume during pregnancy despite the fact that the total lung capacity is [1: decreased / increased] by 5% due to the elevation of the diaphragm. This increase in tidal volume [2: decreases / increases] the expiratory reserve volume by about 20%.
Decreased total lung capacity
Decreased expiratory reserve volume
PaCO2 decreases to approximately 30 mm Hg by ___ weeks’ gestation from 40 mm Hg during prepregnancy.
20 weeks’
Nausea and vomiting occur in more than ___ % of pregnancies
70%
Nausea and vomiting have been attributed to the elevation in ___, ___, and ___. They may also be due to ___ and can be treated with frequent snacking.
Estrogen
Progesterone
hCG
Hypoglycemia
The nausea and vomiting typically resolve by ___ weeks’ gestation
14-16 weeks’
A severe form of morning sickness associated with weight loss (>/= 5% of prepregnancy weight) and ketosis
Hyperemesis gravidarum
During pregnancy, the stomach has [1: reduced / prolonged] gastric emptying times and the gastroesophageal sphincter has [2: decreased / increased] tone. The large bowel also has [3: decreased / increased] motility.
Prolonged gastric emptying times Decreased esophageal tone Decreased motility (leading to increased water absorption and constipation)
The glomerular filtration rate increases by ___ % early in pregnancy and is maintained until delivery. As a result of increased GFR, blood urea nitrogen and creatinine decrease by about ___ %.
50%, 25%
Although the plasma volume increases by (1) % in pregnancy, the RBC volume increases by only (2) %, which leads to a decrease in the (3), or dilutional anemia.
50%
20-30%
Hematocrit
The WBC count increases during pregnancy to a mean of 10.5 million/mL with a range of ___ million.
6-16 million
During labor, stress may cause the WBC count to rise to over ___ million/mL.
20 million/mL
Changes in clotting and bleeding times in pregnancy
No change
A drop in the platelet count below ___ million/mL over a short time is not normal and should be investigated promptly
100 million/mL
In pregnancy, there are elevations in the levels of fibrinogen and factors:
VII to X
Pregnancy is a hyperestrogenic state. The increased estrogen is produced primarily by the ___.
Placenta (with the ovaries contributing to a lesser degree)
The ___ [1] subunit of hCG is identical to the ___ [1] subunits of luteinizing hormone (LH), follicle-stimulating hormone (FSH), and thyroid-stimulating hormone (TSH), whereas the ___ [2] subunits differ.
Alpha subunit
Beta subunit
Levels of hCG double approximately every ___ hours during early pregnancy, reaching a peak at approximately ___ weeks. A nadir is reached by approximate ___ weeks.
48 hours
10-12 weeks
16 weeks
The placenta produces ___ [1], which acts to maintain the corpus luteum in early pregnancy. The corpus luteum produces ___ [2], which maintains the endometrium. Eventually, the placenta takes over ___ [2] production and the corpus luteum degrades into the corpus albicans. ___ [2] levels increase over the course of pregnancy.
hCG
Progesterone
Also known as human chorionic somatomammotropin (hCS)
Induces lipolysis with a concomitant increase in circulating free fatty acids
Also acts as an insulin antagonist, along with various other placental hormones, thereby having a diabetogenic effect
Human placental lactogen
Changes in thyroid hormone changes early in pregnancy (T3, T4, TSH)
Slight increase in T3 and T4 and a slight decrease in TSH early in pregnancy
(Overall, however, pregnancy is considered a euthyroid state)
Numerous changes occur in the skin, including spider angiomata and palmar erythema secondary to increased ___ levels and hyperpigmentation of the nipples, umbilicus, abdominal midline (the linea nigra), perineum, and face (melasma or chloasma) secondary to increased levels of the ___.
Estrogen
Melanocyte-stimulating hormones and the steroid hormones
Pregnancy is also associated with ___, which results from compression of the median nerve.
Carpal tunnel syndrome
The caloric requirement is increased by ___ kcal/day during pregnancy and by ___ kcal/day when breastfeeding.
300 kcal/day
500 kcal/day
Most patients should gain ___ during pregnancy. Overweight women are advised to gain less, ___; underweight women are advised to gain more, ___.
20-30 lbs
15-25 lbs
28-40 lbs
Intraocular pressure [decreases / increases] during pregnancy
Decreases (due to increased vitreous outflow)
Maternal adrenal glands secrete more aldosterone as early as:
15 weeks
Maternal plasma prolactin increase markedly during normal pregnancy, and concentrations are usually ___ [fold] greater at term–about ___ ng/mL, compared with those of nonpregnant women
Ten-fold
150 ng/mL
The pituitary gland increases by ___ [%] in pregnancy
135%
Effect of retained bile salts on the skin of pregnant women
Pruritus gravidarum
In pregnancy, gallbladder action is impaired because progesterone inhibits:
CCK-mediated smooth muscle contraction
Effect of pregnancy on liver size and hepatic blood flow
No effect on liver size
Increased hepatic blood flow
Focal, highly vascular swelling of the gums that regresses spontaneously after delivery
Epulis of pregnancy
In pregnancy, which ureter is more dilated?
Right ureter
During pregnancy, albumin excretion ranges from [mg/day]:
5-30 mg/day
Serum creatinine levels are decreased during pregnancy. Values above ___ suggest underlying renal disease and prompt investigation
0.9 mg/dL
To compensate for the respiratory alkalosis in pregnancy, serum bicarbonate levels decrease by:
4-5 mmol/L
Because of the dilatation of ureters during pregnancy, it is recommended that elective pyelography be deferred until how many weeks’ postpartum?
12 weeks
Estimated maternal blood loss in a cesarean section or vaginal delivery of twins
1,000 mL
Estimated maternal blood loss in a spontaneous vaginal delivery of a singleton
500-600 mL
This hormone is secreted primarily by the stomach in response to hunger. It cooperates with leptin in energy homeostasis modulation. It is also expressed in placenta and likely has a role in fetal growth and cell proliferation.
Ghrelin
On blood glucose levels: Pregnancy is characterized by mild fasting ___, postprandial hyperglycemia, and ___
Mild fasting hypoglycemia
Postprandial hyperglycemia
This hormone opposes the effects of PTH and vitamin D and protects the maternal skeleton during times of calcium stress
Calcitonin
By approximately ___ weeks, the placenta is the principal source of growth hormone secretion
17 weeks
Early in the first trimester, levels of thyroxine-binding globulin [decrease / increase].
Increase (reach their zenith at about 20 weeks, and stabilize at approximately double baseline values for the remainder of pregnancy)
There is marked [decrease / increase] in aldosterone secretion in pregnancy
Increase
The main hormone responsible for hyperglycemia in pregnancy
Human placental lactogen
In pregnancy, the respiratory rate is essentially unchanged, but tidal volume and resting minute ventilation ___ [decrease / increase] significantly as pregnancy advances
Increased tidal volumes: 660 mL to 800 mL
Increased resting minute ventilation: 10.7 L to 14.1 L
