Physiological and Anatomical changes during Pregnancy

Dr. P.G. Jain¹, Dr. S.D. Patil¹, Hemakshi Chaudhari¹, Amol R. Pawar²*, Anita B. Patil²

¹Department of Clinical Pharmacy, R. C. Patel Institute of Pharmaceutical Education and Research,

Shirpur, Dist.: Dhule (M.S.) India 425405.

²Department of Quality Assurance, KVPSS Institute of Pharmaceutical Education, Boradi, Tal-Shirpur,

Dist - Dhule (M.S.) India 425405.

*Corresponding Author E-mail: patilanita541@gmail.com

ABSTRACT:

The body undergoes numerous physiological changes during pregnancy in order to provide an adequate environment for fetal development, meet the increased metabolic demands and prepare for childbirthPregnancy is a natural but altered physiological state resulting in major changes in cardiovascular system, respiratory system, endocrine system, reproductive system and skeletal and bone changes..The body undergoes a number of physiological changes over the course of pregnancy.For both doctors and patients, the cutaneous findings may be most obvious and sometimes alarming. Obstetricians and dermatologists ought to be able to differentiate between normal changes and unhealthy ones. The pregnant mother undergoes essential physiological changes during pregnancy in order to support and accommodate the developing fetus. These modifications start after conception and affect every organ system in the body. This review underlines the major changes that occur during normal pregnancy.

KEYWORDS: Hypercoagulable state, diabetogenic, uterine contractions, physiological changes during pregnancy, physiologic changes.

INTRODUCTION:

Physiological Changes in The female Reproductive System during Pregnancy ^{(1, 2)}

Oestrogen Changes and Progesterone Changes

During one pregnancy, a woman will produce more oestrogen than if not pregnant during her entire lifetime. In pregnancy, during one pregnancy a woman will produce more oestrogen than all oestrogen promotes the flow of maternal blood within the uterus and placenta.

UTERAL, CERVICAL, AND VAGINAL CHANGES:

The uterus provides a nutritive and protective environment after conception, in which the fetus grows and developsIn its nonpregnant state it increases from the size of a small pear to accommodate a full-term baby at 40 weeks gestation.The tissues from which the uterus is produced continue to develop for the first 20 weeks, and it increases in weight from about 50 to 1,000 gm (grams) does not get any heavier after this time, but extends to accommodate the growing baby, placenta, and amniotic fluid.The uterus will have grown to about five times its normal size By the time pregnancy is complete:

In heights from 7.5 to 30 cm (top to bottom)

In width from 5 to 23 cm (side to side),

2.5 to 20 cm in depth (front to back).

CARDIOVASCULAR SYSTEM ^{(1-4, 6, 24-27)}:

· Due to the effects of increased oestrogen and progesterone levels, the occurrence of peripheral vasodilatation and the resulting decrease in systemic vascular resistance (SVR) begins by the 8th week of gestation.

· Peripheral vasodilatations occur.

· Increased stroke frequency and an increase in heart rate of 10-20 beats per minute are contributing to the increased heart performance.

· The physiological changes described above are caused by changes in examination and the ECG below

· The blood pressure in the first two trimesters is lower than normal but returns to normal in the third trimester.

· There is an increased risk of pulmonary oedema if blood volume increases, or pulmonary capillary permeability increases secondary to preeclampsia. The highest risk time when cardiac output is high is the second stage of labour, or immediate postpartum period.

· Cardiac output increases by 20% at week 8, followed by an increase of up to 40% at week 20-28. There is a further increase in cardiac output in labor and then a massive increase immediately after delivery, followed by a return to normal within about an hour.

· Blood pressure (BP) falls as early as seven weeks of gestation.

· Blood volume increases to achieve a average rise of about 20 per cent by mid-third trimester beginning from 6 to 8 weeks of gestation.

· Changes in CO in working and postpartum time

· A high pulse pressure and decreased mean arterial pressure result in the retention of sodium and water by stimulating the renin – angiotensin system. This results in an rise of 40–50 per cent in plasma production. The left end- ventricular volume is increased while the end- volume remains unchanged which contributes to an increase in the fraction of the ejection. Central venous and capillary pulmonary coil pressures remain unchanged.

RESPIRATORY SYSTEM^(1-5,29,30)

· Because of the effect of oestrogen, nasal, oropharyngeal and laryngeal mucosa are capillarily engorbed.

· Tidal volume increases by approximately 200 ml, increasing vital capacity and decreasing residual volume; Splinting of the diaphragm may occur at later stages of pregnancy, with some decrease in tidal volume. Respiratory rate is not significantly altered.

· Increased oxygen consumption (by about 20 percent) and increased metabolism lead to increased demand for oxygen.

· The state of compensated respiratory alkalosis-decreases in arterial pCO2, increases in arterial pO2 and decreases in bicarbonate prevent change in

· Many women complain without hypoxia or explanatory pathology of feeling short of breath during pregnancy. This mechanism is not fully grasped.

· Despite the cerebrospinal displacement of the diaphragm, the diaphragm excursion during breathing rises by 2 cm while the chest wall excursion is decreased. Therefore no shift is observed in loops of the flow rate.

· MV rises by 70–200 percent during work, PaCO2 decreases to 10–15 mmHg and oxygen intake rises by 40–75 percent due to higher metabolic demands. Consumption of MV, TV and oxygen exceeds pre-pregnancy values by 6–8 weeks postpartum.

ENDOCRINE SYSTEM ^{(7,8, 13, 31)}:

Due to both follicular hyperplasia and decreased vascularity, the thyroid gland is swollen. Total levels of T3 and T4 are raised by 50 percent due to the rise of thyroid-binding globulin caused by oestrogen but free levels of T3 and T4 do not alter. The thyroid gland is enlarged by both follicular hyperplasia and increased vascularity. Total levels of T3 and T4 are raised by 50 percent due to the rise in thyroid-binding globulin caused by oestrogen but free levels of T3 and T4 are not increasing. During pregnancy, placecental lactogen and dopamine induce hyperprolactinemia. In the pituitary there is a 30 percent rise in oxytocin stores, which are released during childbirth and just after delivery. During pregnancy, placecental lactogen and dopamine induce hyperprolactinemia. In the pituitary there is a 30 percent rise in oxytocin stores, which are released during childbirth and just after delivery.

Adrenal gland ^(9,10,2):

· The thyroid gland is enlarged by both follicular hyperplasia and increased vascularity. Total levels of T3 and T4 are increased by 50 percent due to the rise in thyroid binding globulin caused by oestrogen but free levels of T3 and T4 do not alter.

· As of both follicular hyperplasia and decreased vascularity the thyroid gland is swollen. Total levels of T3 and T4 are raised by 50 percent due to the rise of thyroid- globulin caused by oestrogen but free levels of T3 and T4 do not alter.Both changes induce a state of pathological hypercortisolism and can be clinically expressed by striae, facial plethora, elevated blood pressure or decreased glucose tolerance.

· Such changes induce physiological hypercortisolism and can be clinically expressed by striae, facial proliferation, increasing blood pressure or decreased glucose tolerance. The average cortisol levels increase by the end of the first trimester and are three times higher at the end of pregnancy than the non-pregnant values.

Pituitary gland ^(11,12):

· Such changes induce physiological hypercortisolism and can be clinically expressed by striae, facial proliferation, increasing blood pressure or decreased glucose tolerance.27 Average levels of cortisol rise towards the end of the first trimester and at the end of pregnancy are three times higher than non- values.

· Follicle-stimulating hormone (FSH) and luteinizing hormone (LH) levels during pregnancy are undetectable due to negative feedback from elevated levels of oestrogen, progesterone and inhibin.

· Owing to adverse feedback from elevated levels of oestrogen, progesterone and inhibin, levels of follicle-stimulating hormone (FSH) and luteinizing hormone (LH) are undetectable during pregnancy.

· The posterior pituitary vasopressin (AVP) contains oxytocin and arginine. Oxytocin levels increase in pregnancy and peak over time.

· Antidiuretic hormone levels (ADH) remain constant but the decrease in sodium concentration during pregnancy causes osmolality to decrease. Therefore osmoreceptors are reset for release of ADH and thirst.

SKELETAL AND BONE CHANGES: ^(14-21,32)

The pelvis is the area located between the spine and the lower extremities. For females, the pelvis is broader and lower than their male equivalent, making it more appropriate for a fetus both during pregnancy and delivery. Increased thoracic curvature, increased cervical curvature, shoulder girdle protraction, hyper-extended knees, and ankle extension Walking is an necessary everyday activity and useful in reducing pregnancy-related adipose tissue weight gain. Walking mechanics, though can be affected as pregnancy, are characterized by maternal changes in shape and size, particularly in the trunk. When pregnancy progresses, the inertial features of the lower trunk segment indicate a far greater rate of increase than the other segments of the body. With rapid changes in mass, and moment of inertia, Kinematics of the trunk section can be altered in everyday activities such as walking. The possibility of altered cinematic is significant, since this can also affect the kinetics and therefore musculoskeletal demands on the trunk segments Static postures have been the subject of most of the trunk mechanical adaptations during pregnancy. A collection of musculo-skeletal effects result in hormonal shifts and weight gains. The lumbar lordosis is intensified with anterior neck flexion and downward displacement of the shoulders to compensate for the change in center of gravity. Collection of musculo-skeletal effects results in hormonal shifts and weight gains. The lumbar lordosis is intensified with anterior neck flexion and downward displacement of the shoulders to compensate for the change in center of gravity. In order to prepare for childbirth, joint laxity is increased due to relaxin, progesterone, and mechanical effects of pregnancy.

· Postural changes include forward head, narrow back, broad elbows, increased lumbar lordosis, hyper-extended knees and pronounced feet.

· The center of gravity moves forward, leading to some disruption in the balance.

· Effective improvements are also characteristic and involve shorter hip flexors, lower back muscles and pectorals.

· Abdominal muscles, spine, and muscle classes at the upper back elongate. That can encourage weakness in the stretch.

· Bones and joints: there is a propensity to decalcification the bones, sublaxing the joints by releasing the hormone due to ligament softening. It is more pronounced in sacroiliac joint and symphysis pubis, which enables stretching at baby delivery time.This is more pronounced in the sacroiliac joint and symphysis pubis, which allows stretching at baby delivery time.

· This is caused by the increase in uterus size and the strain along the abdominal wall. The patient walks back and chest with head and shoulders protruding outwards to cover. This gives a "waddling" gait for the patient.

· In late pregnancy, Foti and associates registered an increased peak anterior pelvic tilt compared with one year post-birth without variations in pelvic rotation in the transverse or coronal axis.No control group has been used, and variations can be attributed to normal human variation with retesting

Nervous system ⁽²⁸⁾:

A reduction in cerebrovascular resistance allows cerebral blood flow to increase. The blood – brain barrier is rapidly permeable. There is an increase in pain tolerance at full term and potentially in pregnancy due to higher levels of plasma endorphins and progesterone. There is dilatation of the epidural venous plexus due to the squeezing of the IVC by the gravid uterus. The epidural fat rises and the amount of epidural free space and spinal cerebrospinal fluid (CSF) decreases.

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