Physiological Changes in Pregnancy PDF

Physiological changes in Pregnancy Dr Alpana Asurlekar UM2010 Slides Adapted From Dr Allyson Clelland  Lecture plan Identify the main hormones and endocrine organs that are relevant to reproduction and maintenance of pregnancy. Los:- 1. identify the role of hormones in the pregnancy...

Physiological changes in Pregnancy Dr Alpana Asurlekar UM2010 Slides Adapted From Dr Allyson Clelland  Lecture plan Identify the main hormones and endocrine organs that are relevant to reproduction and maintenance of pregnancy. Los:- 1. identify the role of hormones in the pregnancy 2. explain the changes in hormone levels that occur in the pregnancy 3. identify and explain the role of hormones on other body systems.  Maintenance of pregnancy The first key events of pregnancy are: 1. Maintenance of pregnancy 2. Formation and growth of the placenta Pregnancy hormones are initially released by the corpus luteum after ovulation and the key hormones are: 3. Human Chorionic Gonadotrophin 4. Progesterone 5. Oestrogen Pregnancy hormone levels over pregnancy, starting Placenta will take over production fromat ovulation CL. Human chorionic gonadotrophin and Gonadotrophin Releasing Hormone in pregnancy GnRH increases over 24 weeks. Stimulates placental hCG production Human Chorionic Gonadotropin (hCG) Secreted by developing placenta Maintains CL for 6-7 weeks Prevents menstruation and embryonic loss by maintaining P and E production from the CL Peaks at about 12 weeks before decreasing- possible link with morning sickness Stimulates testosterone production from fetal adrenal medulla for development of external genitalia Take note of the hCG levels in red, unbroken line  Hormonal changes Hormonal changes are amongst the first indicators of pregnancy. Early Pregnancy Factor (EPF) is found in the bloodstream within hours of conception. It is an immunosuppressant and helps to stimulate trophoblast (placental) growth during the peri-implantation period. β-human chorionic (β-hcg) gonadotropin is diagnostic and used along with ultrasound to confirm pregnancy. Maternal menstrual and “pregnancy” hormones change Ovulation Decrease: Increase: Pregnancy maintenanc Gonadotrophin Releasing Hormone Progesterone (P) e (GnRH) Oestrogen (E) Follicle Stimulating Hormone (FSH) human Chorionic Gonadotrophin (hCG) Luteinising Hormone (LH)  Hormonal Changes in the mother Key hormones that change during pregnancy: INCREASE human Placental Lactogen (hPL): interferes with maternal insulin levels to increase serum glucose. Increases maternal fat storage Relaxin: increases flexibility of tendons to allow for fetal growth and birth. Allow relaxation of uterus for growing foetus. Dilates pubic symphysis and cervix for birth passage. Adrenocorticotrophic Hormone (ACTH): stimulates the adrenal cortex- Thyroid Stimulating Hormone (TSH): stimulation of TH: glucose availability and growth Vasopressin: affects constriction of smooth muscle (blood vessels, uterus and mammary gland) Prolactin: inhibition of ovulation, controls movement of salt and water, milk production Thyroid Hormones (TH): involved in increasing maternal basal metabolic rate Changes continued to allow body to support pregnancy Additional factors that increase: Renin: increases kidney function Erythropoietin: increase in blood cell production Vitamin D: increases Ca++ absorption- metabolic demand burden – concern in teenage pregnancy Parathyroid Hormone (PTH): Increases serum levels of Ca++ Glucocorticoids: increase maternal glucose levels  Inhibits Prevents contracti embryonic loss on Roles for Progestero ne in Decidual Nourishment of cell embryo supporting developme Maintenance of nt endometrium Early pregnancy Prevents follicular Inhibition development of FSH Prevents ovulation  Breast Increases gland developm number Progesterone in ent Increases gland size later pregnancy Expansion of uterus Capacity of blood Smooth vessels Muscle Varicose veins  relaxation Constipation as GI tract slows  Regulation of Glucose Modifies the effects of Increase placental lactogen in Insulin and cortisol Control of glucose Increases in Progesterone and lipid affect mammary gland availability development Progesterone promotes prostaglandin precursors required for labour.  Roles of Oestrogen in pregnancy Secreted by placenta (CL first) Input from fetal and maternal androgens (Adrenal glands) Relaxes pelvic ligaments to allow for expansion of uterus and birth (from 2- 3mm to 9mm) Supports proliferation of fetal and maternal tissues: Enlargement of uterus, breasts and external genitalia By Fred the Oyster, CC BY-SA 4.0, https://commons.wikimedia.org/w/index.php? Increases cortisol levels: curid=35384964 cortisol levels increase  Hormonal Changes Relative hormone levels during pregnancy. hCG is detectable at 8d, peaks Hormone levels induce the changes required for at 9 weeks and decreases at 4-5 the maintenance and accommodation of pregnancy months Chorion secretes oestrogen from Hormone levels 3-4 w and progesterone from 6w. Other Relaxin: produced by the CLeffects? then the placenta. ↑ during pregnancy to prepare the body for birth pLactogen: mammary gland preparation, maternal growth 0 birth Pregnancy (weeks) and alters glucose availability hCG Oestrogen Placental Lactogen Relaxin Corticotrophin Releasing Progesterone Prolactin Glucocorticoids Corticotrophin RH Hormone: Cardiovascular system Blood Volume Increases Pregnancy weight gain can be related to Blood plasma increases from 2.6L to fluid retention 3.8L Efficiency of oxygen and nutrient delivery as Increase in Cardiac output mainly demand increases increase in Stroke Volume (SV) and 13-14 weeks. Decreased vascular resistance normal Heart Rate Decreased Blood Pressure Increase in erythropoietin means more red blood cells are made Increased in Blood Cells- EPO Renal blood flow increase 30% to increased creatinine clearance Red Blood cells Increase blood supply to kidney and To prevent blood loss after delivery of foetus skin Hypercoagulability What does this mean? 1. Pregnancy “glow” 2. Increased risk of thrombosis 3. Minimal bleeding when the placenta detaches after labour. 4. Folic acid supplements are required for the first 12 weeks to combat anaemia. Anything else?  Cardiovascular system Oxygen use in a pregnant woman increases by 16% Increase in Cardiac Output means that there is an increase in blood flow to the lungs – Alveolar ventilation is greater Tidal volume increase by 200ml : 500ml to 700ml, means 40% increase without increasing respiratory rate Deeper breaths allows for more efficient gaseous exchange Squashing of lungs is compensated for by deeper breaths. – Uterus height Pregnant women get more O2 not through rapid breathing but by increasing depth of breathing. What does this mean: Tiredness during exertion as deeper breathing requires more energy. Breathlessness during rest is indicative of problems. Eg embolism  Reproductive system Growth of the uterus Hypertrophy and hyperplasia of the uterine tissue Spiral arrangement of muscle fibres in upper part Lower part is only circular arrangement Blood vessels in the uterus are Image from Nursekey. Arrangement of uterine muscle fibres closed during a contraction showing that muscle fibres are not parallel, but that they spiral around the uterus to increase the effect. What dies this mean? 1. Uterus grows with the baby 2. Increased strength during muscular contraction. Contractions not as strong towards the cervix. Why?  The GI Tract Gastrointestinal system Cravings and changes in Varies with trimester. Social influences? food preferences Savoury (1st, protein?), Sweet, (2nd, energy/social?, Salty (3rd: fluid?) Unusual cravings: coal, chalk etc. Pica. Indicative of deficiencies? Increased sensitivity to taste and smell. Textural. Hormonal fluctuations. Tends to settle down by 12 weeks. Nausea Tiredness. Hyperemesis gravidarum lasts longer. May be related to Thyroid Hormone (T4) levels. Cardiac sphincter relaxes Reflux oesophagitis and heart burn, effect of relaxin. Decreased motility and Progesterone relaxes smooth muscle to decrease movement acid secretion (increased through gut, Constipation P) Increase Anti-insulin environment, along with human placental Increased metabolic rate Lactogen (hPL), the effect is - Increased glucose availability for growing foetus. Increased growth and fat deposition (0.5kg and 4kg of protein and fat) Transfer of nutrients across placenta Amino acid- active transport , Glucose- facilitated diffusion Duchess of Cambridge famously had hyperemesis gravidarum during GI system continued Effects of all this change? Constipation due to increased water absorption from slowed gut motility Hospitalisation in severe cases of hyperemesis gravidarum Extra 300 calories required/day in third trimester, generate extra heat. her pregnancies Also require additional extra 6 g protein/day from 14gm/day to 20 gm/day  Renal System Urinary collection system calyces, Progesterone produces smooth muscle renal pelves and ureter markedly relaxation. dilates. Driven by increased Progesterone to Increased blood flow to kidney so clear creatinine Glomerular Filtration rate Not enough time to reabsorb increases Increased Protein and sugar Increase in Aldosterone: increases salt levels in urine compared to non- absorption and therefore water pregnant retention. To increases/ maintain blood Increased water retention volume. What does this mean? 1. Standard levels of proteinuria and glycosuria are different for pregnant and non- pregnant individuals 2. Hospitalisation in severe cases of hyperemesis gravidarum  Anything else? Venous valves malfunction due to increased Varicose veins and oedema weight and BV/BP. Progesterone induced smooth muscle relaxation may also contribute. Immune system of the pregnant mother is Bladder infections and other mild modified. infections Pressure exerted on vein by ↑ BV Leg cramps Development of breast stimulated by Breast development and growth Oestrogen, Progesterone- Prepare mammary gland ducts to increases in number during pregnancy Prolactin is similar in structure to Growth Hormone (GH) responsible for lactation  Maternal responses Fetal requirements Pregnancy is about supporting embryonic and foetal growth. Appropriate maternal responses are needed to the foetal requirements as mentioned:-  Problems with pregnancy- Match the following Gestational Decreased TSH levels. Symptoms similar to Diabetes normal pregnancy: tiredness, mood changes Gestational Hypothyroidism Persistent vomiting, weight loss, tremors. Increased T4(TH) levels as hCG stimulates T4 production. May resolve at 20 weeks. Associated with Hyperemesis Gravidarum Obstetric Pruritis (itching), leakage of bile salts into the cholestasis blood stream. More common with multiple pregnancies. Gestational transient Thirst, hunger. Increased sugar in the blood thyrotoxicosis stream, not enough insulin produced. If any question please write to [email protected]