Pregnancy Basic Concepts


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Pregnancy Basic Concepts

  1. 1. Pregnancy: Basic Concepts Anna Mae Smith, MPAS, PA-C Associate Professor
  2. 2. Instructions for an Optimal Pregnancy <ul><li>Begin planning well before pregnancy occurs. </li></ul><ul><ul><li>don’t wait for pregnancy to occur </li></ul></ul><ul><ul><li>rubella testing at least 3 months prior to pregnancy </li></ul></ul><ul><ul><li>stop taking Ocs 3 months prior to pregnancy </li></ul></ul>
  3. 3. <ul><li>Review the medical and family history risk factors. </li></ul><ul><ul><li>arrange genetic counseling or testing before pregnancy if any of the following is possible or has occurred in either family: </li></ul></ul><ul><ul><ul><li>Tay-Sachs </li></ul></ul></ul><ul><ul><ul><li>congenital abnormalities </li></ul></ul></ul><ul><ul><ul><li>Down’s syndrome </li></ul></ul></ul><ul><ul><ul><li>hereditary anemia </li></ul></ul></ul><ul><ul><ul><li>sicklecell anemia </li></ul></ul></ul><ul><ul><li>testing for AIDS is recommended for all women before they become pregnant </li></ul></ul>
  4. 4. <ul><li>Plan ahead if you have a serious medical condition </li></ul><ul><ul><ul><li>diabetes </li></ul></ul></ul><ul><ul><ul><li>epilepsy </li></ul></ul></ul><ul><ul><ul><li>take prescription medications for any reason </li></ul></ul></ul><ul><ul><li>Talk to your clinician BEFORE stopping birth control. </li></ul></ul><ul><ul><ul><li>medications may need to be changed </li></ul></ul></ul><ul><ul><ul><li>be sure overall medical condition is under good control </li></ul></ul></ul><ul><li>Take a vitamin that includes folic acid 0.4 mg daily; begin several months before you plan to be pregnant. </li></ul>
  5. 5. <ul><li>Avoid exposure to potentially toxic agents including: </li></ul><ul><ul><li>alcohol, smoking, excessive caffeine </li></ul></ul><ul><ul><li>x-ray of the abdominal area </li></ul></ul><ul><ul><li>illegal drug use </li></ul></ul><ul><ul><li>megadose vitamins (or mega-anything-else!) </li></ul></ul><ul><li>Do not take any medications until you have discussed with your clinician the possible effects on pregnancy. </li></ul><ul><ul><li>prescription medications </li></ul></ul><ul><ul><li>over-the-counter medications </li></ul></ul>
  6. 6. <ul><li>Make a healthy diet a top priority. </li></ul><ul><ul><li>A restricted diet or weight loss can be dangerous for your fetus. </li></ul></ul><ul><ul><li>Do not eat raw meat or fish. </li></ul></ul><ul><ul><li>Avoid unpasteurized dairy products. </li></ul></ul><ul><li>Aim for fitness, but with moderation. </li></ul><ul><ul><li>Daily exercise is a good idea. </li></ul></ul><ul><ul><li>Some activities may not be wise during pregnancy: </li></ul></ul><ul><ul><ul><li>prolonged aerobic activities </li></ul></ul></ul><ul><ul><ul><ul><li>long-distance running </li></ul></ul></ul></ul><ul><ul><ul><li>sports that may cause injuries </li></ul></ul></ul><ul><ul><ul><ul><li>horseback riding </li></ul></ul></ul></ul><ul><ul><ul><ul><li>skiing </li></ul></ul></ul></ul>
  7. 7. <ul><li>Minimize your risk of STD exposure. </li></ul><ul><ul><li>avoid intercourse </li></ul></ul><ul><ul><li>use condoms </li></ul></ul><ul><ul><li>STDS can cause serious or lethal fetal complications: </li></ul></ul><ul><ul><ul><li>herpes </li></ul></ul></ul><ul><ul><ul><li>gonorrhea </li></ul></ul></ul><ul><ul><ul><li>chlamydia </li></ul></ul></ul><ul><li>Avoid body temperature elevation. </li></ul><ul><ul><li>Do not use a hot tub or sauna. </li></ul></ul><ul><ul><li>Try to avoid exposure to contagious viral illnesses such as influenza. </li></ul></ul>
  8. 8. <ul><li>Avoid contact with cat fecal matter. </li></ul><ul><ul><li>Toxoplasma infection - dangerous for fetus </li></ul></ul><ul><ul><ul><li>wear gloves when gardening </li></ul></ul></ul><ul><ul><ul><li>have someone else empty the kitty litter </li></ul></ul></ul><ul><li>Have a pregnancy test and see your clinician as soon as possible if you think you are pregnant. </li></ul><ul><ul><li>pregnancy dates most accurate if you have an exam within 2 weeks after missing your menstrual period </li></ul></ul><ul><ul><li>early pregnancy diagnosis is especially important if you plan to have prenatal genetic testing. </li></ul></ul>
  9. 9. <ul><li>Watch for the danger signs of possible pregnancy complications. </li></ul><ul><ul><li>most likely to cause symptoms within the first month or two of pregnancy: </li></ul></ul><ul><ul><ul><li>spontaneous abortion (miscarriage) </li></ul></ul></ul><ul><ul><ul><li>ectopic (tubal) pregnancy </li></ul></ul></ul><ul><ul><li>contact your clinician immediately if you have danger signs </li></ul></ul><ul><ul><li>danger signs </li></ul></ul><ul><ul><ul><li>abnormal bleeding </li></ul></ul></ul><ul><ul><ul><li>cramping </li></ul></ul></ul><ul><ul><ul><li>abdominal pain </li></ul></ul></ul>
  10. 10. Goals of Pregnancy Diagnosis <ul><li>Determine whether or not the woman is pregnant. </li></ul><ul><li>Identify possible problems that require further evaluation and/or emergency intervention </li></ul><ul><ul><li>ectopic gestation </li></ul></ul><ul><ul><li>threatened abortion </li></ul></ul><ul><li>Assess gestation length accurately (in weeks). </li></ul><ul><li>Help the patient make and implement her own plans for prenatal care or abortion. </li></ul>
  11. 11. Pregnancy Evaluation <ul><li>review of pertinent history and symptoms </li></ul><ul><ul><li>most common sign - an overdue menstrual period </li></ul></ul><ul><ul><li>determine LMP and PMP - provides accurate estimate of gestational age </li></ul></ul><ul><ul><li>determine date when pregnancy symptoms began: </li></ul></ul><ul><ul><ul><li>1-2 weeks after fertilization </li></ul></ul></ul><ul><ul><ul><ul><li>breast tenderness </li></ul></ul></ul></ul><ul><ul><ul><ul><li>nipple sensitivity </li></ul></ul></ul></ul><ul><ul><ul><li>2 weeks after fertilization </li></ul></ul></ul><ul><ul><ul><ul><li>fatigue </li></ul></ul></ul></ul><ul><ul><ul><ul><li>nausea </li></ul></ul></ul></ul><ul><ul><ul><ul><li>urinary frequency </li></ul></ul></ul></ul>
  12. 12. <ul><li>laboratory test to detect human chorionic gonadotropin (HCG) </li></ul><ul><li>pelvic exam </li></ul><ul><ul><li>confirms pregnancy test results </li></ul></ul><ul><ul><li>correlate uterine enlargement with menstrual dates </li></ul></ul><ul><ul><ul><li>consider possible reasons for the discrepancy </li></ul></ul></ul><ul><ul><ul><li>ultrasound may be helpful </li></ul></ul></ul><ul><ul><li>early signs of pregnancy (within 2-3 weeks after fertilization): </li></ul></ul><ul><ul><ul><li>cervical softening </li></ul></ul></ul><ul><ul><ul><li>blurring of the cervico-uterine angle </li></ul></ul></ul><ul><ul><ul><li>uterine softening </li></ul></ul></ul>
  13. 13. Uterus Smaller Than Expected <ul><li>fertilization later than dates suggest </li></ul><ul><li>ectopic pregnancy </li></ul><ul><li>incomplete or missed, spontaneous abortion </li></ul><ul><li>error in pregnancy test </li></ul>
  14. 14. Uterus Larger Than Expected <ul><li>fertilization earlier than dates suggest </li></ul><ul><li>uterine leiomyomata (fibroids) </li></ul><ul><li>twin gestation </li></ul><ul><li>uterine anomaly </li></ul><ul><li>hydatidiform mole </li></ul>
  15. 16. HCG Levels During Pregnancy <ul><li>Normal pregnancy </li></ul><ul><ul><li>detected in serum at low levels as early as 7-9d after ovulation, very soon after implantation occurs </li></ul></ul><ul><ul><li>first 3-4 weeks after fertilization </li></ul></ul><ul><ul><ul><li>HCG level in normal pregnancy doubles ~2d </li></ul></ul></ul><ul><ul><ul><li>serum HCG level reaches 50-250 mIU/ml by time of first missed menstrual period </li></ul></ul></ul><ul><ul><li>peaks ~60-70d after fertilization, then decreases </li></ul></ul>
  16. 17. <ul><li>Abnormal pregnancies - HCG levels often abnormal </li></ul><ul><ul><li>elevated - multiple pregnancies </li></ul></ul><ul><ul><li>extremely high (million mIU/ml) - molar pregnancy (hydatidiform mole) </li></ul></ul><ul><ul><li>abnormally low - </li></ul></ul><ul><ul><ul><li>spontaneous abortion </li></ul></ul></ul><ul><ul><ul><li>ectopic pregnancy </li></ul></ul></ul><ul><ul><ul><li>normal pregnancy that is earlier in gestation than menstrual dates suggest </li></ul></ul></ul>
  17. 18. HCG Levels After Pregnancy <ul><li>initial decrease is quite rapid </li></ul><ul><ul><li>HCG levels after 2 weeks - < 1% of the level at the time the pregnancy was terminated </li></ul></ul><ul><li>after full-term delivery </li></ul><ul><ul><li><50mIU within 2 wks </li></ul></ul><ul><ul><li>undetectable after 3-4 wks </li></ul></ul>
  18. 19. <ul><li>after first trimester abortion </li></ul><ul><ul><li>initial HCG levels much higher </li></ul></ul><ul><ul><ul><li>may be as high as 150,000 mIU at 8-10 wks gestation </li></ul></ul></ul><ul><ul><li>may still be as high as 1,500 mIU at 2 wks post-AB - all pregnancy tests still positive </li></ul></ul><ul><ul><li>HCG may be detectable by sensitive tests 40 d after 1st trimester AB </li></ul></ul><ul><ul><li>consider serial quantitative HCGs- </li></ul></ul><ul><ul><ul><li>continuing IUP </li></ul></ul></ul><ul><ul><ul><li>retained placenta fragments </li></ul></ul></ul><ul><ul><ul><li>ectopic pregnancy </li></ul></ul></ul><ul><ul><li>HCG level should decline with half-time of disappearance of no more than 24-48 hours </li></ul></ul>
  19. 20. Positive Evidence of Pregnancy <ul><li>demonstration of the fetal heart </li></ul><ul><ul><li>transvaginal U/S - 4-6.5 wks after conception </li></ul></ul><ul><ul><li>transabdominal U/S - 8 wks (menstrual age) </li></ul></ul><ul><ul><li>doppler - 10-12 wks </li></ul></ul><ul><ul><li>fetoscope - 17-19 wks </li></ul></ul><ul><li>appreciation of fetal movement - after 19 wks gestation </li></ul>
  20. 21. <ul><li>visualization of the fetus </li></ul><ul><ul><li>normal IUP by U/S - 5-6 wks of amenorrhea - appears as ring or circular structure within the uterus - gestational sac </li></ul></ul><ul><ul><li>by 8 wks of amenorrhea - fetal echoes within sac - measurement of crown-rump length </li></ul></ul><ul><ul><li>blighted ovum = loss of definition of gestational sac or absence of fetus by 7-8 wks of amenorrhea </li></ul></ul><ul><ul><li>by 11 wks of amenorrhea - gestational sac not distinctly visible, cardiac activity identified </li></ul></ul><ul><ul><li>by 16 wks of gestation, fetus can usually be seen on x-ray films </li></ul></ul>
  21. 22. Probable Evidence of Pregnancy <ul><li>enlargement of the abdomen </li></ul><ul><ul><li>12 wks uterus is palpated abdominally </li></ul></ul><ul><li>uterine changes </li></ul><ul><ul><li>changes from pear-shape to globular contour </li></ul></ul><ul><ul><li>Hegar sign = palpable softening of the lowest part of the corpus at ~6 wks </li></ul></ul><ul><ul><li>McDonald sign = when the uterine body and cervix can easily be flexed against one another </li></ul></ul>
  22. 23. <ul><li>cervical changes </li></ul><ul><ul><li>Goodell sign = softening of the cervix, by beginning of 2nd month </li></ul></ul><ul><ul><li>Chadwick sign = mucous membranes of the vulva, vagina, and cervix become congested and have blue-violet hue, between 6th & 8th wks </li></ul></ul><ul><li>palpation of the fetus - ballottement </li></ul><ul><li>Braxton-Hicks contractions </li></ul><ul><ul><li>near the end of the 1st trimester </li></ul></ul><ul><ul><li>painless and irregular contractions </li></ul></ul><ul><li>positive pregnancy test </li></ul>
  23. 24. Presumptive Evidence of Pregnancy <ul><li>cessation of menses </li></ul><ul><ul><li>8% of pregnant women have a small amount of bleeding on or before 40th day - implantation </li></ul></ul><ul><li>breast changes </li></ul><ul><ul><li>heavy sensation </li></ul></ul><ul><ul><li>tingling and soreness </li></ul></ul><ul><li>vaginal mucosa and skin changes </li></ul><ul><ul><li>blue-violet hue of vulva and vagina </li></ul></ul><ul><ul><li>increased pigmentation - linea nigra, chloasma </li></ul></ul><ul><ul><li>appearance of abdominal striae </li></ul></ul>
  24. 25. <ul><li>nausea </li></ul><ul><ul><li>1/2 of pregnant women </li></ul></ul><ul><ul><li>between weeks 2 & 12 of pregnancy </li></ul></ul><ul><ul><li>subsides 6-8 wks later </li></ul></ul><ul><ul><li>occasionally persists throughout pregnancy </li></ul></ul><ul><ul><li>only rarely first occurs after 1st trimester </li></ul></ul><ul><ul><li>most severe upon awakening; tends to lessen as day progresses </li></ul></ul><ul><ul><li>simple treatments </li></ul></ul><ul><ul><ul><li>crackers before arising </li></ul></ul></ul><ul><ul><ul><li>frequent snacks </li></ul></ul></ul><ul><ul><ul><li>avoidance of foods that prompt nausea </li></ul></ul></ul><ul><ul><li>medication occasionally required </li></ul></ul>
  25. 26. <ul><li>bladder irritability </li></ul><ul><ul><li>early in pregnancy, enlarging uterus puts pressure on bladder </li></ul></ul><ul><ul><li>increased urinary frequency </li></ul></ul><ul><ul><li>usually resolves by 2nd trimester </li></ul></ul><ul><ul><li>returns late in pregnancy when fetal head descends into the pelvis </li></ul></ul>
  26. 27. <ul><li>fatigue </li></ul><ul><ul><li>common, sometimes severe </li></ul></ul><ul><ul><li>often out of proportion to what would be expected </li></ul></ul><ul><ul><li>usually resolves by week 20 </li></ul></ul><ul><li>perception of fetal movement </li></ul><ul><ul><li>multipara - between weeks 16 & 18 - aware of “fluttering” => fetal movement => quickening </li></ul></ul><ul><ul><li>primipara - several weeks later than above </li></ul></ul>
  27. 28. Differential Diagnosis of Pregnancy <ul><li>leiomyomas </li></ul><ul><li>ovarian cysts </li></ul><ul><li>hematometra </li></ul><ul><li>pseudocyesis (imaginary pregnancy) </li></ul><ul><ul><li>most often occurs in women nearing menopause </li></ul></ul><ul><ul><li>also occurs in young women who have a strong, unfulfilled desire for pregnancy </li></ul></ul>
  28. 29. Fetoplacental Unit <ul><li>largely controls the endocrine events of the pregnancy </li></ul><ul><li>input from </li></ul><ul><ul><li>fetus => most active and controlling role in its growth and maturation and probably also parturition </li></ul></ul><ul><ul><ul><li>fetal adrenal gland </li></ul></ul></ul><ul><ul><li>placenta </li></ul></ul><ul><ul><li>mother </li></ul></ul>
  29. 30. Fetal Adrenal Gland <ul><li>major endocrine component of fetus </li></ul><ul><li>larger than fetal kidney in midpregnancy </li></ul><ul><li>consists of </li></ul><ul><ul><li>outer, definitive or adult zone </li></ul></ul><ul><ul><ul><li>secretes </li></ul></ul></ul><ul><ul><ul><ul><li>glucocorticoids </li></ul></ul></ul></ul><ul><ul><ul><ul><li>mineralocorticoids </li></ul></ul></ul></ul>
  30. 31. <ul><ul><ul><li>later develops into the 3 components of adult adrenal cortex </li></ul></ul></ul><ul><ul><ul><ul><li>zona fasciculata </li></ul></ul></ul></ul><ul><ul><ul><ul><li>zona glomerulosa </li></ul></ul></ul></ul><ul><ul><ul><ul><li>zona reticularis </li></ul></ul></ul></ul><ul><ul><li>inner, fetal zone </li></ul></ul><ul><ul><ul><li>constitutes 80% of fetal gland </li></ul></ul></ul><ul><ul><ul><li>primarily secretes androgens during fetal life </li></ul></ul></ul><ul><ul><ul><li>involutes following delivery </li></ul></ul></ul><ul><ul><ul><li>completely disappears by end of 1st year of life </li></ul></ul></ul><ul><ul><li>fetal adrenal medulla </li></ul></ul><ul><ul><ul><li>synthesizes and stores catecholamines </li></ul></ul></ul><ul><ul><ul><li>poorly developed </li></ul></ul></ul><ul><ul><ul><li>role during fetal growth and maturation is not known </li></ul></ul></ul>
  31. 32. Placenta <ul><li>Produces both steroid and peptide hormones </li></ul><ul><ul><li>amounts vary with gestational age </li></ul></ul><ul><li>precursors for progesterone synthesis come from the maternal circulation </li></ul><ul><li>placenta lacks the enzyme 17alpha-hydroxylase </li></ul><ul><ul><li>cannot directly convert progesterone to estrogen </li></ul></ul><ul><ul><li>must use androgens from fetal adrenal </li></ul></ul>
  32. 33. Peptide Hormones <ul><li>Human Chorionic Gonadotropin (hCG) </li></ul><ul><ul><li>secreted by trophoblastic cells of the placenta </li></ul></ul><ul><ul><li>maintains pregnancy </li></ul></ul><ul><ul><li>consists of 2 subunits: alpha and beta </li></ul></ul><ul><ul><li>alpha subunit is shared with </li></ul></ul><ul><ul><ul><li>luteinizing hormone (LH) </li></ul></ul></ul><ul><ul><ul><li>thyroid-stimulating hormone (TSH) </li></ul></ul></ul><ul><ul><li>begins to rise 8 d after ovulation (9 d after midcycle LH peak) </li></ul></ul>
  33. 34. <ul><ul><li>hCG levels peak at 60-90 d and then decline to a moderate, more constant level </li></ul></ul><ul><ul><li>first 6-8 wks of pregnancy </li></ul></ul><ul><ul><ul><li>maintains corpus luteum </li></ul></ul></ul><ul><ul><ul><li>ensures continued progesterone output until progesterone production shifts to the placenta </li></ul></ul></ul><ul><ul><li>it may also </li></ul></ul><ul><ul><ul><li>regulate steroid biosynthesis in the placenta and the fetal adrenal gland </li></ul></ul></ul><ul><ul><ul><li>simulate testosterone production in the fetal testicle </li></ul></ul></ul><ul><ul><ul><li>not verified: immune suppression </li></ul></ul></ul>
  34. 35. <ul><li>Human Placental Lactogen (hPL) </li></ul><ul><ul><li>originates in the placenta </li></ul></ul><ul><ul><ul><li>antagonizes the cellular action of insulin </li></ul></ul></ul><ul><ul><ul><li>decreases glucose utilization </li></ul></ul></ul><ul><ul><ul><li>may play a role in shifting glucose availability toward the fetus </li></ul></ul></ul><ul><ul><li>maternal serum concentrations parallel placental weight - rises throughout gestation to maximum levels in last 4 weeks </li></ul></ul><ul><ul><li>accounts for 10% of all placental protein production </li></ul></ul><ul><ul><li>low values found with: </li></ul></ul><ul><ul><ul><li>threatened abortion </li></ul></ul></ul><ul><ul><ul><li>IUGR </li></ul></ul></ul>
  35. 36. <ul><li>Prolactin </li></ul><ul><ul><li>peptide from the anterior pituitary </li></ul></ul><ul><ul><li>normal nonpregnant levels are ~10 ng/ml </li></ul></ul><ul><ul><li>during pregnancy, levels rise in response to increasing maternal estrogen output that stimulates the anterior pituitary lactotrophs </li></ul></ul><ul><ul><li>decidua is a secondary source, but contributes little to the plasma pool </li></ul></ul><ul><ul><li>amniotic fluid levels exceed those in the circulation </li></ul></ul>
  36. 37. <ul><ul><li>main effects of prolactin </li></ul></ul><ul><ul><ul><li>stimulation of milk production </li></ul></ul></ul><ul><ul><ul><li>in second half of pregnancy, prolactin from fetal pituitary may stimulate fetal adrenal growth </li></ul></ul></ul><ul><ul><ul><li>may also play a role in fluid and electrolyte shifts across the fetal membranes </li></ul></ul></ul>
  37. 38. Steroid Hormones <ul><li>Progesterone </li></ul><ul><ul><li>most important human progestogen </li></ul></ul><ul><ul><ul><li>in luteal phase, induces secretory changes in the endometrium </li></ul></ul></ul><ul><ul><ul><li>in pregnancy, higher levels induce decidual changes </li></ul></ul></ul><ul><ul><li>sources of progesterone </li></ul></ul><ul><ul><ul><li>up to 6-7th week of pregnancy, major source is the ovary => essential for continuation of the pregnancy </li></ul></ul></ul><ul><ul><ul><li>thereafter, the placenta </li></ul></ul></ul>
  38. 39. <ul><ul><li>other actions of progesterone </li></ul></ul><ul><ul><ul><li>prevents uterine contractions </li></ul></ul></ul><ul><ul><ul><li>may also induce some immune tolerance for the products of conception </li></ul></ul></ul><ul><ul><li>the fetus inactivates progesterone by </li></ul></ul><ul><ul><ul><li>transformation to corticosteroids </li></ul></ul></ul><ul><ul><ul><li>by hydroxylation </li></ul></ul></ul><ul><ul><ul><li>conjugation to inert excretory products </li></ul></ul></ul><ul><ul><li>placenta can convert the inert material back to progesterone </li></ul></ul><ul><li>Estrogens </li></ul><ul><ul><li>Both fetus and placenta are involved in the biosynthesis of estrone, estradiol, estriol </li></ul></ul>
  39. 40. <ul><ul><li>Estriol is most abundant estrogen in human pregnancy </li></ul></ul><ul><ul><li>Sudden decline of estriol in maternal circulation may indicate fetal compromise </li></ul></ul><ul><ul><li>Anencephalic fetuses </li></ul></ul><ul><ul><ul><li>lack a hypothalamus and have hypoplastic anterior pituitary and adrenal glands </li></ul></ul></ul><ul><ul><ul><li>estriol production is only ~10% of normal </li></ul></ul></ul><ul><ul><li>estriol determinations have been used as a means of monitoring fetal well-being, however present use is limited </li></ul></ul><ul><ul><li>estriol measurements have generally been replaced by biophysical assessments </li></ul></ul>
  40. 41. <ul><li>Androgens </li></ul><ul><ul><li>originate mainly in the fetal zone of the fetal adrenal cortex </li></ul></ul><ul><ul><li>secretion is stimulated by ACTH and hCG </li></ul></ul><ul><ul><li>fetal adrenal favors production of DHEA over testosterone and androstenedione, and it sulfurylates almost all steroids </li></ul></ul><ul><ul><li>fetal androgens enter the placental circulation and serve as precursors for estradiol and estriol </li></ul></ul><ul><ul><li>fetal testis also secretes androgens, particularly testosterone which is converted within target cells to dihydrotestosterone => required for the development of the male external genitalia. Main tropic stimulus = hCG </li></ul></ul>
  41. 42. <ul><li>Glucocorticoids </li></ul><ul><ul><li>cortisol derived from circulating cholesterol </li></ul></ul><ul><ul><li>maternal plasma cortisol concentrations rise throughtout pregnancy </li></ul></ul><ul><ul><li>the diurnal rhythm of cortisol secretion persists </li></ul></ul><ul><ul><li>metabolized by both fetal adrenal and the placenta </li></ul></ul><ul><ul><li>cortisol is important in the maturation of the lungs </li></ul></ul><ul><ul><ul><li>promotes differentiation of type II alveolar cells </li></ul></ul></ul><ul><ul><ul><li>promotes the biosynthesis and release of surfactant into the alveoli (surfactant decreases the force required to inflate the lungs) </li></ul></ul></ul>
  42. 43. Summary of Pregnancy Hormones <ul><li>HCG </li></ul><ul><ul><li>First hormonal signal of pregnancy. </li></ul></ul><ul><ul><li>Functions to maintain the ovarian corpus luteum. </li></ul></ul><ul><li>Progesterone </li></ul><ul><ul><li>Supplied primarily by the corpus luteum. </li></ul></ul><ul><ul><li>Suppresses uterine contractility </li></ul></ul><ul><ul><li>Is important for breast development in preparation for lactation. </li></ul></ul><ul><ul><li>Required to maintain the pregnancy. </li></ul></ul>
  43. 44. <ul><li>Estrogens </li></ul><ul><ul><li>Supports growth and maintenance of the uterus </li></ul></ul><ul><ul><li>Cooperates with progesterone to promote breast development. </li></ul></ul><ul><li>Relaxin </li></ul><ul><ul><li>may have a role in cervical ripening </li></ul></ul><ul><li>Oxytocin </li></ul><ul><ul><li>causes uterine contractions </li></ul></ul><ul><ul><li>role in initiating labor is unclear </li></ul></ul><ul><ul><li>administered oxytocin can induce labor only at or near term </li></ul></ul>
  44. 45. <ul><li>Placental lactogen (hPL) </li></ul><ul><ul><li>Regulates maternal metabolism, favoring use of maternal resources to benefit the fetus. </li></ul></ul><ul><li>Alpha-fetoprotein (AFP) </li></ul><ul><ul><li>Produced by the fetal liver. </li></ul></ul><ul><ul><li>Tends to be elevated in pregnancies supporting fetuses with neural tube defects (spina bifida) and is lowered in cases of Down’s syndrome. </li></ul></ul><ul><li>Prolactin </li></ul><ul><ul><li>Stimulates milk production during lactation. </li></ul></ul><ul><li>Prostaglandins </li></ul><ul><ul><li>major role in the initiation and control of labor </li></ul></ul>
  45. 46. Physical Changes in Pregnancy <ul><li>skin </li></ul><ul><ul><li>increased vascularity </li></ul></ul><ul><ul><li>increased pigmentation of face (chloasma), areola, abdomen (linea nigra), and genitalia </li></ul></ul><ul><ul><li>striae of breasts and abdomen </li></ul></ul><ul><li>head </li></ul><ul><ul><li>mild changes in scalp </li></ul></ul><ul><ul><li>excessive oiliness or dryness </li></ul></ul>
  46. 49. <ul><li>eyes </li></ul><ul><ul><li>vessel dilation in sclera </li></ul></ul><ul><li>mouth </li></ul><ul><ul><li>edematous, friable gums </li></ul></ul><ul><li>chest/cardiovascular </li></ul><ul><ul><li>increased respiratory effort and rate </li></ul></ul><ul><ul><li>progressive elevation of the diaphragm </li></ul></ul><ul><ul><li>hand/pedal edema by 3rd trimester </li></ul></ul><ul><li>breasts </li></ul><ul><ul><li>increased fullness, tenderness, and enlargement </li></ul></ul><ul><ul><li>excretion of colostrum - common by 3rd trimester </li></ul></ul>
  47. 50. <ul><li>heart </li></ul><ul><ul><li>exaggerated heart sounds </li></ul></ul><ul><ul><li>particularly functional murmurs in systole </li></ul></ul><ul><li>abdomen </li></ul><ul><ul><li>distention secondary to flatus and increased uterine size </li></ul></ul><ul><ul><li>diminished bowel sounds as peristaltic movements are slowed </li></ul></ul><ul><ul><li>enlarging uterus, which displaces abdominal organs </li></ul></ul>
  48. 51. <ul><li>genitalia/reproductive </li></ul><ul><ul><li>external </li></ul></ul><ul><ul><ul><li>increased pigmentation </li></ul></ul></ul><ul><ul><ul><li>pubic hair may lengthen </li></ul></ul></ul><ul><ul><ul><li>near term, pelvic congestion and overall swelling of labia majora are common </li></ul></ul></ul><ul><ul><ul><li>vulvar varicosities </li></ul></ul></ul><ul><ul><li>vagina </li></ul></ul><ul><ul><ul><li>increased pelvic congestion and hypertrophy </li></ul></ul></ul><ul><ul><ul><li>rugation of vaginal mucosa is prominent </li></ul></ul></ul><ul><ul><li>cervix </li></ul></ul><ul><ul><ul><li>positive Chadwick’s sign (bluish/purple color) </li></ul></ul></ul><ul><ul><ul><li>may soften, dilate, and efface close to term </li></ul></ul></ul><ul><ul><ul><li>positive Goodell’s sign may be noted </li></ul></ul></ul>
  49. 52. <ul><ul><li>uterus </li></ul></ul><ul><ul><ul><li>positive Hegar’s sign (softening of the lower uterine segment) by 6 wks gestation </li></ul></ul></ul><ul><ul><ul><li>uterine enlargement occurs in linear fashion = 1 cm per week </li></ul></ul></ul><ul><ul><ul><li>12 wks - fundus at symphysis pubis </li></ul></ul></ul><ul><ul><ul><li>16 wks - fundus midway between the symphysis and the umbilicus </li></ul></ul></ul><ul><ul><ul><li>36th wk - fundus is just below the ensiform cartilage </li></ul></ul></ul><ul><ul><ul><li>lightening - fundal height drops slightly near term </li></ul></ul></ul><ul><ul><ul><li>maintains a globular/ovoid shape throughout pregnancy </li></ul></ul></ul>
  50. 53. <ul><ul><li>adnexa </li></ul></ul><ul><ul><ul><li>discomfort may be noted with exam due to stretching of the round ligaments throughout pregnancy </li></ul></ul></ul><ul><ul><ul><li>ovaries are not palpable once the uterus fills the pelvic cavity at 12-14 wks gestation </li></ul></ul></ul><ul><ul><li>urinary </li></ul></ul><ul><ul><ul><li>bladder may be palpable </li></ul></ul></ul><ul><ul><ul><li>incontinence is common, particularly with multiparity </li></ul></ul></ul><ul><ul><li>rectal </li></ul></ul><ul><ul><ul><li>increased vascular congestion with resulting hemorrhoids often noted </li></ul></ul></ul>
  51. 54. <ul><li>musculoskeletal </li></ul><ul><ul><li>increased relaxation of pelvic structures </li></ul></ul><ul><ul><li>lordosis </li></ul></ul><ul><ul><li>sciatica (common) </li></ul></ul><ul><li>endocrine </li></ul><ul><ul><li>mildly enlarged thyroid </li></ul></ul><ul><ul><li>diffusely enlarged thyroid nodularity or increased firmness is abnormal </li></ul></ul>
  52. 55. Physiological Changes of Pregnancy <ul><li>50% increase in plasma volume </li></ul><ul><ul><li>decreased Hct </li></ul></ul><ul><ul><li>physiological anemia </li></ul></ul><ul><ul><li>increased oxygen carrying capacity of RBCs compensates for volume expansion </li></ul></ul><ul><li>40% increase in cardiac output </li></ul><ul><ul><li>increase in stroke volume </li></ul></ul><ul><ul><li>increase in heart rate </li></ul></ul>
  53. 56. <ul><li>fall in peripheral resistance </li></ul><ul><li>intravascular pressure </li></ul><ul><ul><li>systolic pressure falls only slightly </li></ul></ul><ul><ul><li>diastolic pressure decreases markedly </li></ul></ul><ul><ul><li>BPs highest sitting, somewhat lower lying down, and lower still on one side </li></ul></ul><ul><li>mechanical circulatory effects of the gravid uterus </li></ul><ul><ul><li>displaces and compresses various abdominal structures </li></ul></ul><ul><ul><ul><li>iliac veins </li></ul></ul></ul><ul><ul><ul><li>inferior vena cava </li></ul></ul></ul>
  54. 57. <ul><ul><li>supine position accentuates venous compression => fall in venous return and decrease in CO </li></ul></ul><ul><ul><li>“ supine hypotensive syndrome” </li></ul></ul><ul><ul><ul><li>significant fall in BP </li></ul></ul></ul><ul><ul><ul><li>sxs of nausea, dizziness, even syncope </li></ul></ul></ul><ul><ul><ul><li>bradycardia instead of tachycardia </li></ul></ul></ul><ul><ul><li>venous compression elevates pressure in veins draining legs and pelvic organs </li></ul></ul><ul><ul><ul><li>varicose veins in legs and vulva </li></ul></ul></ul><ul><ul><ul><li>hemorrhoids </li></ul></ul></ul>
  55. 58. <ul><ul><li>late pregnancy can also partially compress aorta and its branches </li></ul></ul><ul><ul><ul><li>Poseiro effect => aortic compression accentuated during uterine contractions => fetal distress when patient is in supine position </li></ul></ul></ul><ul><ul><ul><li>clinically suspected when femoral pulse not palpable </li></ul></ul></ul><ul><li>regional blood flow </li></ul><ul><ul><li>blood flow to most regions of body increases and plateaus early </li></ul></ul><ul><ul><li>exceptions (blood flow increases with gestational age) </li></ul></ul><ul><ul><ul><li>uterus </li></ul></ul></ul><ul><ul><ul><li>skin => elimination of heat </li></ul></ul></ul><ul><ul><ul><li>kidneys => elimination of waste material </li></ul></ul></ul>
  56. 59. <ul><li>total body oxygen consumption increases about 15-20% </li></ul><ul><ul><li>1/2 of this increase is accounted for by the uterus and its contents </li></ul></ul><ul><ul><li>the remainder is mainly accounted for by increased maternal renal and cardiac work </li></ul></ul><ul><li>renal plasma flow and the glomerular filtration rate (GFR) increase early in pregnancy and plateau at ~40% above nonpregnant levels </li></ul>
  57. 60. <ul><ul><li>BUN values are lower due to increased glomerular filtration rate </li></ul></ul><ul><ul><ul><li>in PIH, values increase to non-pregnant levels due to pathological arterial spasm and vasoconstriction </li></ul></ul></ul><ul><ul><li>creatinine values are lower due to increased glomerular filtration rte </li></ul></ul><ul><ul><ul><li>in PIH, values increase to nonpregnant levels due to pathological arterial spasm and vasoconstriction </li></ul></ul></ul><ul><li>renin-angiotensinsystem plasma concentrations are elevated of: </li></ul><ul><ul><ul><li>renin </li></ul></ul></ul><ul><ul><ul><li>renin substrate </li></ul></ul></ul><ul><ul><ul><li>angiotensin I </li></ul></ul></ul><ul><ul><ul><li>angiotensin II </li></ul></ul></ul>
  58. 61. <ul><li>platelets may decrease with severe preeclampsia </li></ul><ul><li>alkaline phosphatase may double - increases due to placental involvement </li></ul><ul><li>cholesterol levels not accurately reflected in pregnancy </li></ul><ul><li>serum iron levels decrease due to increased iron demands during pregnancy </li></ul><ul><li>total iron binding capacity (TIBC) increases </li></ul><ul><ul><li>estrogen increases ability for iron to bind to transferrin, which regulates transport in the body </li></ul></ul>
  59. 62. <ul><li>insulin effects and glucose metabolism </li></ul><ul><ul><li>insulin response to glucose stimulation is augmented </li></ul></ul><ul><ul><li>by 10th wk of normal pregnancy and to term </li></ul></ul><ul><ul><ul><li>fasting concentrations of insulin are elevated </li></ul></ul></ul><ul><ul><ul><li>glucose is reduced </li></ul></ul></ul><ul><ul><li>until midgestation => improved IV GTT (OGTT unchanged) </li></ul></ul><ul><ul><ul><li>anabolic actions of insulin potentiated during first half of pregnancy </li></ul></ul></ul><ul><ul><li>after early pregnancy </li></ul></ul><ul><ul><ul><li>insulin resistance emerges => glucose tolerance impaired </li></ul></ul></ul><ul><ul><ul><li>prolonged elevation of glucose after meals </li></ul></ul></ul><ul><ul><ul><li>FBS still reduced </li></ul></ul></ul>
  60. 63. <ul><li>thyroid panel </li></ul><ul><ul><li>triiodothyronine (T 3 ) decreases due to increase of thyroid binding blobulins by estrogen </li></ul></ul><ul><ul><li>thyroxine (T 4 ) increases: </li></ul></ul><ul><ul><ul><li>basal metabolic rate increases by 25% </li></ul></ul></ul><ul><ul><ul><li>increased thyroid binding globulins </li></ul></ul></ul><ul><ul><li>TSH - most sensitive indicator for hypothyroid/hyperthyroid states in pregnancy </li></ul></ul><ul><li>uric acid values are lower due to increased glomerular filtration rate </li></ul><ul><ul><li>PIH- values increase to nonpregnant levels </li></ul></ul>
  61. 64. <ul><li>urinalysis </li></ul><ul><ul><li>albumin </li></ul></ul><ul><ul><ul><li>elevations seen in preeclampsia and UTIs </li></ul></ul></ul><ul><ul><li>chloride may slightly increase due to increased glomerular filtration rate </li></ul></ul><ul><ul><li>creatinine elevated due to increased glomerular filtration rate </li></ul></ul><ul><ul><li>ketones same </li></ul></ul><ul><ul><ul><li>presence may indicate dehydration </li></ul></ul></ul><ul><ul><ul><li>starvation states </li></ul></ul></ul><ul><ul><ul><li>ketoacidosis in IDDM </li></ul></ul></ul>
  62. 65. <ul><ul><li>glucose elevated due to increased glomerular filtration rate </li></ul></ul><ul><ul><li>WBCs same </li></ul></ul><ul><ul><ul><li>often vaginal contamination </li></ul></ul></ul><ul><ul><ul><li>UTI if other indicators </li></ul></ul></ul><ul><ul><li>RBCs same </li></ul></ul><ul><ul><ul><li>may be due to violent exercise, kidney trauma, systemic or renal disease </li></ul></ul></ul><ul><ul><li>bacteria </li></ul></ul><ul><ul><ul><li>nonpregnant - >100,000 colonies/mL = infection </li></ul></ul></ul><ul><ul><ul><li>pregnant - >10,000 colonies/mL = infection </li></ul></ul></ul>