Pregnancy Overview & Hormones PDF

**[Pregnancy Overview & Hormones]** The Events of Pregnancy - Fertilized ovum called a zygote - Implantation - Within two weeks of fertilization - Fetus at eight weeks - Fetal period - Gestation duration... - 40 weeks - Trimesters - Critical periods S...

**[Pregnancy Overview & Hormones]** The Events of Pregnancy - Fertilized ovum called a zygote - Implantation - Within two weeks of fertilization - Fetus at eight weeks - Fetal period - Gestation duration... - 40 weeks - Trimesters - Critical periods Stages of Embryonic and Fetal Development - Anatomic and physiological changes - First trimester - \_\_mood swings\_\_\_\_ - \_\_morning sickness\_\_\_\_\_\_\_\_\_ - Perspiration increases - Fetus enlarges and puts pressure on urinary bladder - "Critical period" as fetal organ systems develop - CNS and heart developing - Healthy behaviors Critical periods of organ system development - Critical period - Rapid cell division and growth for a given organ system - Cellular activity for given systems can vary from a couple of days to several months...importance?? - \_Susceptible to nutrient deficiencies, toxins, and traumas \_\_\_\_\_\_ - Neural tube defects - Process for embryonic tissue formation is disturbed causing neural tube to remain open - Typically occurs on day 28 Anatomic and physiological changes - 1^st^ Trimester - At the end of trimester, the fetus is about 4 inches long and weighs about 1 ounce - The eyes and ears have begun to form and small buds that eventually develop into arms and legs are apparent - By the end of 4 weeks, the heart is beating - Second trimester... - Body adjusts to hormone levels - Thus, less fatigue and nausea - Enlarging fetus promotes back pain - \_\_Center of balance changes \_\_\_\_\_\_ - Joints become less stable - Reflux develops as uterus and fetus are displaced - Breasts continue to swell - Edema develops - Second trimester - All major organ systems have begun developing - By the end of 6 months, the fetus averages 14 to 16 in and nearly 3 lbs. - Fetus can begin to hear mother's voice and respond to stimuli - The brain undergoes substantial development during 5^th^ month as nervous tissue acquires its specialized functions - Third trimester... - Fetus respiratory system is last to develop - Fetus enlarges and crowds out maternal organs - Urge to urinate increases - Fatigue ensues - Braxton-Hicks contractions might develop - Irregular uterine contractions that are typically not intense but cause discomfort - Induced by increased physical activity The Placenta - Placenta - Previous nutritional habits crucial - \_Supply depot and waste-removal system\_\_\_\_\_\_ - Two bloods never mix - Metabolically active organ - Umbilical cord - Amniotic sac Role of Hormones - Initially, hormones are released by the \_\_\_Corpus luteum\_\_\_\_\_\_\_, under the influence of human chorionic gonadotropin (hCG) - hCG created by placental cells - Later, the placenta is responsible for production of hormones - Human chorionic gonadotropin (hCG) - Can first be measured in the blood 8 to 9 days after ovulation, shortly after the blastocyst implants in the endometrium - Hormone detected by pregnancy kits - Maintains corpus luteum until placenta develops - Corpus luteum grows to twice its size in ovary in the first month of pregnancy - Stimulates production of estrogen and progesterone - \_reaches a maximum at about 8-12 weeks of pregnancy\_\_\_\_\_\_ - Decreased to low levels secretion by 16 to 20 weeks and maintains this level - Hcg(cont) - The corpus luteum involutes slowly after the 13th to 17th week of gestation - After about 3 months, the placenta begins to regulate sex hormones - Thought to be hormone responsible for nausea and vomiting - Estrogens (estradiol, estrone, estriol) - Proliferative function on most reproductive organs - Rebuild the endometrial lining after menstruation - First secreted from corpus luteum for first 12 weeks, then from placenta - Aid in enlargement of uterus for fetal growth - Aid in enlargement of breasts and growth of ductal structures for lactation - Relax pelvic ligaments - Help regulate progesterone levels during pregnancy - Progesterone - Secreted from corpus luteum for first 12 weeks, then from placenta - Increases secretions of fallopian tubes and uterus to provide nutritive environment for developing blastocyst - Prevents menstruation by maintaining endometrium decidual cells during pregnancy - Relaxes smooth muscle of the uterus to prevent contractions early in pregnancy - Progesterone (cont) - Relaxes smooth muscle of GI tract - \_\_\_Slows peristalsis \_\_\_\_\_\_\_\_\_ - Benefit? - Helps estrogen prepare breasts for lactation, but also helps prevent lactation until after birth - Also, responsible for headaches, blurred vision, and heartburn - Hormonal Changes During Pregnancy Role of additional hormones - Relaxin - Secreted by corpus luteum and placenta and controlled by hCG - Released early in pregnancy to limit uterine contractions - Softens cervix at time of delivery - Was thought to make joints in the body flexible, but this is only confirmed in animals - Prolactin - Secreted by anterior pituitary gland at end of pregnancy - Coincides with reduction in estrogens and progesterone - Stimulates milk production in mammary glands - Role of additional hormones (cont'd) - Oxytocin - Released from posterior pituitary gland - Secreted near end of pregnancy - \_\_Stimulates uterine contraction\_\_\_\_\_\_\_\_\_\_ - Stimulates milk ejection or letdown after birth in response to feeding baby - Human Chorionic Somatomammotropin (Human Placental Lactogen) - Secreted by placenta starting \~5^th^ week of pregnancy - Secreted at highest rate compared to all pregnancy hormones - Functions are unknown, but observations tell us - Possible Involvement in breast development and lactation - Promotion of growth - Similar to growth hormone - Causes decreased insulin sensitivity and utilization of glucose in the mother - Makes more glucose available to the fetus - Promotes release of fatty acids from adipose for use as substrate by mother **[Weight Gain in Pregnancy]** How Much Weight Should a Woman Gain During Pregnancy? - Women must gain weight during pregnancy - Ideal weight-gain pattern - \_\_Nearly all lean tissue\_\_\_\_\_\_ - \_\_\_Essential fat weight\_\_\_\_\_\_\_\_\_ - Benefits of appropriate weight gain Weight loss after pregnancy - Most women retain a few pounds Negative Effects of Abnormal Weight - \_Underweight mothers tend to have low-birthweight babies (\< 5.5 lbs)\_\_ - Low-birthweight babies are associated with lower adults IQs, short stature, and chronic diseases - Babies born to obese mothers are more likely to have heart defects and neural tube defects - Obese women are at a higher risk for developing high blood pressure or diabetes during pregnancy - Thus, obese women are urged to achieve a healthy weight before pregnancy - Hence, frequent weight assessments Maternal Weight and Birth Weight - Maternal weight from 1987-2003: - Strong correlation with birth weight - Maternal weight of 200 lbs. + - Increased from 17% to 34% - \_Birth weight is greatest predictor of infant health\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_ Obesity - Obesity in general population associated with metabolic syndrome - Central obesity - Insulin resistance - Hypertension - Glucose intolerance - Elevated cholesterol and triglycerides - Obesity: Reduced insulin sensitivity during pregnancy Hypertension and Preeclampsia - Hypertension - Chronic vs. gestational hypertension - Risks for mother and fetus - Preeclampsia - Characterized by high blood pressure and protein in urine - Advancement to eclampsia Obesity in Pregnancy - MetS-like complications: gestational hypertension and pre-eclampsia - Obese 2.5 and 1.6 times more likely to get gestational hypertension and pre-eclampsia, respectively - Even higher in obese women with poorly controlled gestational diabetes - Morbidly-obese 3.2 and 1.6 times more likely to get gestational hypertension and pre-eclampsia Pre-eclampsia - \_\_Characterized by HTN & protein in urine (proteinuria)\_\_\_\_\_ - Also known as Toxemia - Occurs in 8% of pregnancies - Cause is unknown, but occurs only in pregnant women - Could be related to the placenta failing to implant properly in the lining of the uterus; preventing arteries from dilating as they should, restricting blood flow and leading to a host of other problems - No known cure (other than having the baby) Pre-eclampsia: Signs & Symptoms - Principle Signs: - Proteinuria (protein in urine) - Hypertension due to vasoconstriction - Other signs & symptoms include: - Edema - Rapid weight gain - Low oxygen tissue extraction leading to low O~2~ consumption - HELLP syndrome (20% of women with severe pre-eclampsia) - **H**emolysis (breakdown of RBC) **E**levated **L**iver enzymes, and **L**ow **P**latelets - Rapid progression of Pre-eclampsia may not show such symptoms. Pre-eclampsia - \_High risk for multiple gestations, women under age 20, pre-existing HTN, & diabetes\_\_\_\_\_\_\_ - Occurs after 20 weeks gestation - Usually detected early with adequate prenatal care Obesity - Additional risks of obesity: - Difficulties conceiving - Increased risk of early and recurrent miscarriage - Increased congenital anomalies, esp. neural tube defects and heart defects - Neural tube defects: - Maternal obesity doubles the risk of neural tube defects - Birth defects of the brain or spinal cord - Spina Bifida and anencephaly (usually still-born) - Reduced visualization of fetal ultrasound measures makes it difficult to assess heart and craniospinal structures Spina Bifida - Types of Spina Bifida 3 in 1,000 births 1\. Spina Bifida Occulta -- an abnormality is confined to the vertebrae only and is due to an unclosed posterior vertebral arch. 2\. Spina Bifida Cystica -- A more severe type of spina bifida that has two classifications. - Occulta - Approximately 40% of all Americans may have spina bifida occulta, but because they experience little or no symptoms, very few of them ever know that they have it. - Cystica - Meningocele -- Where the meninges protrude through the defect. (4%) - Myelomeningocele -- Elements of the cord also protrude through the defect, resulting in severe neural deficits. (96%) - 1 out of 1,000 births Obesity in pregnancy - Associated with more incidence of conditions previously thought to be due to aging: - sleep apnea - nonalcoholic fatty liver disease - chronic renal and cardiac dysfunction Fetal effects - Baby health: the factor most strongly association with unexplained fetal death was increased pre-pregnancy weight - Risk increased with gestational age - Fetal macrosomia (\>4000g) (\~8.8 lbs) - 13.3% and 14.6% incidence in obese and morbidly obese groups (8.3% in nonobese) - \_\_Large for gestational age is positively related to obesity in adolescence and adulthood \_\_\_\_\_\_\_\_\_\_\_\_\_\_\_ - Transgenerational Obesity - Increased obesity in adults accounts for 33% of the increase in T2D - 50-90% of adolescents with T2D have a BMI \>27 - 25% obese children aged 4-10 have impaired glucose tolerance - Does the diabesity epidemic begin in utero with fetal overgrowth??? - Controversial - Appears that high-fat or high-sugar diets, low-protein diets, and various toxins may trigger the inheritance of particular conditions in offspring **[Pregnancy & Physiological Changes]** - Numerous changes occur with the systems of the body during pregnancy - A major reason for these changes is to meet the needs of the fetus - Building blocks for fetal growth - Nature's stress test - \_CVD in pregnancy leading cause of maternal death\_\_\_\_\_ - Exercise professionals must be cognizant of these changes and how they may influence exercise testing and prescription **Metabolism During Pregnancy** - BMR increases by \~15% - Latter half of pregnancy - Anabolic processes enhanced - Increase in core temperature - Increased secretion of sex hormones - Thyroxine, adrenocortical hormones - Increased muscular activity - \_\_\_Weight gain\_\_\_\_\_\_\_\_\_\_ - Increase nutrient needs - Especially 3^rd^ trimester BMR and exercise - Cardiovascular Changes - Blood volume increases in first trimester - 40-50% by the 36^th^ week (peak) - Estrogens - Maintains blood pressure and retains sodium and water - Aldosterone (↑ Na reabsorb) - Blood volume increase is due to increase in both, RBC count and plasma volume - Increased erythropoiesis - Assuming proper nutrition Changes in Blood during Pregnancy - Direct association between plasma volume expansion and fetal growth - Reduced plasma volume is correlated with pre-ecclampsia - Plasma volume increases much more than RBCs causing hemodilution (low hemoglobin level) - \_\_\_"Physiological anemia"\_\_= 11 g/dl, no negative effect unless levels get lower - RBC increase is dependent upon normal nutrition and sufficient iron levels - Blood composition - Cholesterol levels increase - Proteins become more available - Cardiac Output Cardiac Output: Increases during the first 8 months - Increases by 40-50%% 1. \_Placental circulation\_\_\_\_\_\_\_\_\_ 2. \_\_Increased BMR\_\_\_\_\_\_\_\_\_\_ - Maternal heart demonstrates hypertrophy Cardiovascular Changes during Pregnancy - Blood pressure: 3. In early to mid-pregnancy systolic and diastolic Bp↓ - Lowest point (5-10 mmHG) during second trimester 4. In late pregnancy (3^rd^ trimester) systolic and diastolic Bp↑ back to baseline levels 5. In overweight and obese females, blood pressure is higher compared to females with a healthy BMI Respiratory changes during pregnancy - Thoracic cage expands 5-7% 6. **Relaxation of ligaments attaching ribs (relaxin)** 7. Increases in inspiratory capacity - Elevated position of diaphragm - Ventilation increases 8. Pulmonary resistance decreases 50%, tidal volume increases 9. Carbon dioxide increases; acts as a direct respiratory stimulant 10. Alveoli become more efficient Respiratory system - Dyspnea during pregnancy 11. Common complaint - 60-70% of patients - late first or early second trimester 12. Likely due to various factors - reduced PaCO2 levels - Mild respiratory alkalosis - awareness of increased tidal volume of pregnancy - Hypersecretion of airway mucosa 13. Most pronounced in the upper airways, especially third semester 14. Estrogens responsible - Nasal obstruction, sneezing episodes, and vocal changes occur 15. Worsen when lying down - Nasal obstruction can lead to snoring and sleep apnea - Preferential mouth breathing - Placental gas exchange - **Diffusion of Oxygen Through the Placental Membrane** - Dissolved O2 passes into the fetal blood by *simple diffusion* - *\_\_Chronic villi\_\_\_\_\_\_*exchange with maternal blood - Gas exchange exist between mother's oxygen rich blood and fetal blood - Driven by an oxygen pressure gradient from the mother's blood to the fetus's blood. Maternal PO~2~ \> than fetal PO^2^ **Placenta - oxygen transport** - Nutritional Needs - Increased Need for Nutrients - Energy 16. Needs vary with progression of pregnancy - Carbohydrate 17. \>175g/day - Protein 18. DRI for pregnancy 19. Supplements discouraged - Fat 20. Essential fatty acids Increased Need for Nutrients - Folate 21. Neural tube defects (NTD) - Anencephaly - Spina bifida 22. Enrichment of grain products - Vitamin B~12~ 23. Assists folate with manufacture of new cells 24. Meat, eggs, milk, and milk products - Choline - Vitamin D and calcium 25. Calcium absorption doubles during pregnancy 26. Vitamin D plays vital role in calcium absorption - Iron 27. Iron needs of fetus take priority 28. Iron supplements **[Exercise Testing in Pregnancy]** Testing and special considerations - During much of the 1900s, women were urged to reduce physical activity during pregnancy and stop all together (including work) late in pregnancy - Exercise was thought to induce premature birth by stimulating uterine contractions - Ingride Kristiansen, famous marathon runner, ran throughout her pregnancy and delivered a healthy baby. - Five months after delivery she ran a 2:27 marathon - American College of Obstetricians and Gynecologists (ACOG) recommendations - 1985 - "...exercise moderately for only 15 minutes at a time, keeping the heart rate below 140 bpm." Guidelines caused an outcry!!! - 1994 - "...No data indicating that pregnant women should limit exercise intensity. "...regular, moderate exercise is sufficient to derive health benefits. "...women should listen to their body and not exercise when fatigued and do not exercise until exhaustion - 2002 - "...recreational and competitive athletes with healthy pregnancies can stay active during pregnancy while modify exercise habits as medically indicated. Information on strenuous exercise and pregnancy is scarce!!! Fetal Responses to exercise - Minimum to moderate increase in heart by 10-30 bpm - Strenuous exercise during 3^rd^ trimester may lead to reduced birth weight - \_Although no negative growth effects\_\_\_ Exercise in pregnancy - A pregnant women should avoid exercise to exhaustion and should not exercise when feeling excessively fatigued - In general, exercises involving high-impact and quick changes in direction should be avoided. - Strenuous exercise - Should be avoided at all cost during the first trimester - Exercise in pregnancy **The concerns of exercise during pregnancy are:** - Increased fetal core temperature to a dangerous level - Reduced blood flow to uterus leading to poor oxygen delivery - Low birth weight - \~50% decrease may damage fetus - No strong evidence - Birth weight is decreased in pregnant exercisers (0.66 lbs) - No known negative health effects... - **\_Probably due to slightly less CHO delivery to fetus \_\_\_\_\_\_\_\_\_\_\_\_\_\_** Contraindications for Exercise during Pregnancy **RELATIVE** - Severe anemia - Unevaluated maternal cardiac dysrhythmia - Chronic bronchitis - Poorly controlled Type 1 diabetes mellitus - Extreme morbid obesity - Extreme underweight - History of extremely sedentary lifestyle - Intrauterine growth restriction in current pregnancy - Poorly controlled hypertension - Orthopedic limitations - Poorly controlled seizure disorder - Poorly controlled hyperthyroidism - Heavy smoker **ABSOLUTE** - Hemodynamically significant heart disease - Restrictive lung disease - Incompetent cervix/cerclage - Multiple gestation at risk for premature labor - Persistent second or third trimester bleeding - Placenta previa after 26 wk of gestation - Premature labor during the current pregnancy - Ruptured membranes - Preeclampsia/pregnancy-induced hypertension Pre-testing evaluation - PARmed-X for Pregnancy - Completed by health care provider prior to exercise testing - All pregnant women should complete the PARmed-X prior to performing exercise while pregnant Maximal exercise testing - Should only be performed with physician supervision AFTER medical evaluation - Exercise testing should be limited during pregnancy - Risk vs. Benefit - Especially in sedentary individuals - Maximal strength testing should NOT be performed - Essentially, the risks of exercise testing outweigh the benefits - Exercise considerations - Increase in abdominal weight gain shifts the point of gravity - Lordosis - 60% experience back pain - Should not challenge balance ability - Prolonged motionless postures such as standing or yoga and the supine position should be avoided....Why and examples! - \_HTN due to reduced venous return \_\_\_\_\_\_\_\_\_\_ - Increases likelihood of varicose veins - Especially after 12 weeks Exercise considerations - Temperature regulation is crucial - Especially during first trimester - \_\_\_Hydration & environmental factors \_\_\_\_\_\_\_\_\_\_ - Pregnant women should: - Stay well-hydrated - Wear loose-fitting clothes - Avoid high heat and humidity - Exposure to sources of heat (hot tubs, saunas, fever) related to neural tube defects - Exercise considerations - If previously sedentary, pregnant women might tolerate exercise better at the start of the 2^nd^ trimester - Severe fatigue, nausea, and vomiting - Women who are pregnant should avoid contact sports - Also, activities/sports that may cause a loss of balance or trauma to the mother or fetus - E.g. Soccer, basketball - Exercise at altitudes above 6,000 ft should be avoid - Vaginal bleeding - The Valsalva maneuver should be avoided Exercise considerations **Reasons exercise should be terminated immediately and a medical follow-up should occur:** - Vaginal bleeding - Dyspnea before exertion - Dizziness - Headache - Chest pain - Muscle weakness - Calf pain or swelling - Amniotic fluid leakage - Post-Partum considerations - Evidence shows that women's participation in exercises diminishes after childbirth. - After a healthy birth, exercise can be safely performed within a few days - After cesarean birth, a physician should indicate when it is safe - Nursing women should ensure proper hydration. Otherwise, exercise does not negatively affect lactate - If possible, nursing prior to exercise is optimal to avoid discomfort **[Exercise Prescription in Pregnancy]** - Benefits of exercise during pregnancy - \_Reduces back pain\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_ - May decrease risk of gestational diabetes, preeclampsia, and cesarean delivery - \_\_\_promotes healthy weight gain\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_ - \_\_improves overall fitness\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_ - \_cardiovascular endurance, muscular endurance \_\_\_\_\_\_\_\_\_\_\_\_\_\_ - Eases constipation - Decreased risk of urinary incontinence - Prevention/improvement of depressive symptoms - Helps mother lose weight after the baby is born - Exercise should be modified according to the woman's symptoms, discomforts, and abilities during pregnancy - Benefits of exercise during pregnancy **Healthy Weight Gain** - Remember, being overweight during pregnancy increases risk of gestational diabetes, hypertension, and preeclampsia - Exercise moderates weight gain during pregnancy - Exercisers are still able to gain a healthy weight - Birth weight is related to maternal weight gain - Behavioral benefit - Pregnant exercisers are more likely to continue exercise post-partum - Benefits of exercise during pregnancy **Metabolic Benefits** - Moderate aerobic exercise helps prevent eclampsia - Also, aerobic exercise reduced cholesterol levels - Associated with lower risk of gestational diabetes and preeclampsia - Gestational diabetes - Exercise can lower maternal glucose levels - Benefits of exercise after pregnancy **Cardiovascular Benefits** - Exercise increases blood volume, cardiac output, and number of blood vessels - Helps to reduce uncomfortable swelling - \_\_Improved circulation\_\_\_\_\_\_\_\_\_\_\_\_\_ - Oxygen-binding capacity of hemoglobin is improved - Thus, exercise improves oxygen delivery to maternal and fetal tissues - Benefits of exercise after pregnancy **Resistance Training (RT)** - RT performed in a safe manner has no adverse effects for the mother or baby - RT performed with aerobic exercise is most beneficial - Muscular endurance is maintain/improved making ADL's easier for the mom - Those who performed RT reported less pain and soreness - Also, those who performed RT required less medication and had a less complicated delivery - \_\_Less cesarean births\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_ - ACSM: Aerobic exercise Recommendations for pregnant women - For a healthy pregnancy and previously active women, recommendations are very similar as those for adults. - If previously inactive, she should progress towards these recommendations. - Aerobic exercise for pregnant women **Intensity** - Moderate intensity exercise is recommended for women with a prepregnancy body mass index (BMI) \