3.1a Physiological Adaptations to Pregnancy Flashcards
Uterus Size, Shape, Position
- Uterine growth during first trimester do to progesterone and estrogen
- Early enlargement includes vascularity, hyperplasia, hypertrophy and development of decidua
- Uterus rises in the abdomen as it grows and rotates to the right (due to rectosigmoid colon)
- Discomfort may occur with ligament tension during growth of uterus
Hegar’s Sign (6 weeks)
- 6 weeks of gestation
- Softening and compressibility of lower uterine segment (Uterine Ishtimus)
12 Weeks of Gestation
- Uterus changes in shape from pear to spherical
- Uterus rises in pelvis to the abdominal cavity
14th Week of Gestation
- This is when pregnancy “shows”
- Uterus can be palpated above the symphysis pubis gradually to the level of the umbilics
20-22 weeks of getstation
- Uterus should be palpable from the xiphoid process at term
Lightning (30-38 weeks)
Fetus begins to descend to the pelvis
Nullipara - Occurs 2 weeks before the onset of labor
Multipara - Occurs at the start of labor
Braxton Hicks Contractions (4th month of pregnancy)
- Intermittent uterine contractions may be felt through the abdominal wall
- Enhances blood flow through the intervillous spaces
- Irregular and painless
- After 28th week they become more definite and usually cease with walking or exercise
Uterine Souffle
- You may hear this sound when auscultating the fetal heart tones
- Similar to a bruit, this sound will be synchronized with mother’s heart beat
Funic Souffle
- Synchronous with fetal heart rate
- Caused by fetal blood coursing through the umbilical cord
Ballottement (16th-18th week)
- Passive movement of unengaged fetus
- Identified by examiner
- Practitioner places finger within the vagina taps upward on the cervix causing the fetus to rise
- The fetus can be felt moving up and down.
Quickening (14-16th Week)
- First recognizable movement of fetus
- Difficult to distinguish from peristalsis
Goodell Sign (Beginning of 6 weeks)
- Softening of the cervical tip due to increased vascularity, slight hypertrophy, and hyperplasia
Friability
- Tissue is easily damaged and can result in slight bleeding after vaginal examination or coitus
- Glands near the external OS proliferate and cervix looks velvety
Operculum
- Mucus fills the endocervical canal resulting in formation of a mucus plug early in pregnancy
- Accuracy of pap tests can also be complicated
Changes in Ovaries
- Ovulation does not occur during pregnancy due to suppression of follicle stimulating hormone (FSH) and luteinizing hormone (LH) by estrogen and progesterone
- Corpus luteum produces estrogen and progesterone for the first 6-10 weeks and then the placenta becomes the primary source of these hormones
- Menstrual periods cease (amenorrhea)
- Periods can be confused with implantation bleeding which occurs 6-12 days after conception
Changes to vagina
- Vaginal mucosa thickens
- Connective tissue loosens
- Hypertrophy of smooth muscle
- Vaginal vault lengthens
Chadwick Sign (6-8th week of pregnancy)
- Increase vascularity results in blue color of vaginal mucosa and cervix
Leukorrhea
- White/Gray mucoid vaginal discharge with musty odor
- Odor due to microbiome changing and secretions become more acidic
- Alterations help prevent bacterial infections in the uterus
Changes to the Breast
- Increased levels of estrogen and progesterone make breasts feel heavier and heightened sensitivity
- Sensitivity varies from tingling to sharp pain
- Nipples become more pigmented and erectile
- Stretch marks may appear
Prolactin
- Produced by anterior pituitary gland
- Stimulates production of colostrum by end of first trimester
Montgomery Tubercles
- Hypertrophy occurs
- Sebaceous glands secrete lubricating anti-infectives to protect the nipple during breast feeding
Lactogenesis Stage 1
- Human placental lactogen stimulates secretion of colostrum
Changes in blood Volume
- Total blood volume increases 40-50%
- Increased blood is protective mechanism
- Meet the blood volume needs of the enlarged uterus
- Hydrates fetal and maternal tissue when the woman assumes an erect or supine position
Cardiac Output
- Increases by 30-50%
Blood Pressure
- Influenced by age, activity level, presence of health problems, circadian rhythm, alcohol consumption, smoking, anxiety, pain, and maternal position
Supine Hypotensive Syndrome (Inferior Vena Cava Compression Syndrome)
- Happens when pregnant women lie on their back during second half of pregnancy
- This compresses the vena cava
- CO reduced by 25-30%
- Can experience falls in blood pressure up to 30 mmHg
- After 5 minutes bradycardia is noticed and CO is reduced by half. Women feel faint
Structural Adaptations
- Cardiac Hypertrophy
- Diaphragm is displaced upward because of enlarged uterus
- Heart is elevated upward
- Apical pulse shifts up and laterally 1-1.5cm
- Maternal heart rate increases at 5 weeks gestation (15-20bmp)
Changes in Blood Components
- RBC mass increases by 20-30%
- Percentage of RBC depends on iron available
- Plasma increase is greater than RBC production
- Decrease in normal hemoglobin and hematocrit values
Anemia That Occurs with Pregnancy
- Vitamin B12 deficiency, folate-deficiency anemia, iron deficiency anemia
- Iron deficiency anemia is the most common
- Iron deficiency anemia can lead to low birth weight, premature birth, preeclampsia, and postpartum hemorrhage
- Signs of anemia include weakness, fatigue, headaches, dizziness, pale or sallow skin, low body temperature, rapid or irregular heartbeat, chest pain, shortness of breath, brittle nails and pica.
- Best way to prevent anemia is proper nutrition
- Iron rich foods include red meat, dark green leafy vegetables, eggs, peanuts, fortified cereals etc
- Folate-Deficiency Anemia can lead to neural tube defects (fetal brain and spinal cord anomalies) including spina bifida and anencephaly