MIDWIFERY I: MATERNAL SYSTEMIC RESPONSE TO LABOR

Cardiovascular System: Cardiac output—increases about 12 - 31% in the 1st stage. -Increases about 50% in the second stage. Rationale: Because 300 to 500 ml of blood loss is squeezed from the uterus into maternal circulation with each contraction. Heart rate—increases slightly BP—systolic increases in 1st stage -Systolic and Diastolic increase in 2nd stage. -Rises with each contraction. -May rise further with pushing. - Anxiety and pain may also increase the blood pressure. Supine hypotensive syndrome- decreased blood pressure when in supine position due to the vessels being compressed by the fetal weight.

Fluid and Electrolyte Imbalance: -Increase in renin, plasma renin activity, and angiotensinogen. -Edema may occur at base of bladder due to pressure of fetal head. -Perspires profusely Rationale: Because of the muscular activity of labor, the mother’s temperature increases. Nursing intervention: > Initiate intravenous fluid such as lactated ringer.

Respiratory System: Respiratory Rate—increases Increase in oxygen demand and consumption. - As long as the respiratory center is not depressed by medication, the increased respiratory rate continues with oxygen consumption almost double the normal amount Mild respiratory acidosis usually occurs by time of birth. Hyperventilation may decrease the level of carbon dioxide in the mother’s blood. If the mother develops hypoxia or acidosis, the fetus may be compromised.

Renal System: When engagement occurs, the bladder, now an abdominal organ, is pushed forward and upward----Distended bladder-may impede fetal descent--Pressure from the presenting part, during contraction may cause edema of the tissues because of impaired blood and lymph drainage. Urinary flow is decreased---especially when the woman is in supine------->uterus compresses the ureters Health teaching: Encourage the client to void. Nephrology findings—slight proteinuria may occur; polyuria; GFR increased due to increased CO.

GI System: Gastric Motility/Peristalsis and Absorption—decreased Gastric emptying is prolonged. Gastric volume remains increased. Gastric contents increase in acidity NOTE: The client in labor should not eat solid food because there is always a possibility of an obstetrical emergency requiring surgery and eating solid food would increase the risk of aspirating vomitus. Dry lips and mouth as a result of mouth breathing.

Immune System & other Values: WBC—increase sometimes up to 25,000/mm during labor and stays elevated during the early postpartum period. Temp—may slightly increase especially if mom is dehydrated Blood glucose—decreases

Integumentary system The vagina and perineum have a great ability to stretch. The degree of stretching varies with each client; however, minute tears may occur in the vagina or perineum during delivery of the baby.

Musculoskeletal System: The marked increase in muscle activity during labor is accompanied by increased body temperature, diaphoresis, fatigue and some proteinuria(1+). The relaxation of pelvic joints caused by the influence of relaxin may result in backache. Leg cramps may also be experience.

Pain: In the first stage: arises from dilatation of cervix, stretching of lower uterine segment, pressure, and hypoxia of uterine muscle cells during contractions. In the second stage: arises from hypoxia of contracting uterine muscle cells, distention of the vagina and perineum, and pressure. In the third stage: arises from contractions and dilatation of cervix as placenta is expelled.