Maternity and Neonatology Exam 2 Review: Comprehensive Study Guide

Terminology and Calculations for Gestational Dating

In the clinical management of pregnancy, several key abbreviations are utilized to define the timeline of the pregnancy. The acronym LMP refers to the Last Menstrual Period, specifically marking the first day of that period. WgA stands for Weeks of Gestation, representing the current progress of the pregnancy in weekly increments. EDD refers to the Estimated Delivery Date, which is the foundational target for clinical preparation.

To calculate these dates, healthcare providers use specific formulas. The primary method is Naegele's Rule, which provides the calculated EDD by adding 7 to the day of the LMP and subtracting 3 from the month. To determine the current weeks of gestation, one must calculate the total sum of all days elapsed since the LMP up to the current date and then divide that total by 7. The total duration of a standard pregnancy is categorized in several ways: it lasts for 10 lunar months, 9 calendar months, a total of $280\,\text{days}$, or exactly $40\,\text{weeks}$.

Categories of Pregnancy Signs and Initial Diagnosis

The diagnosis of pregnancy is categorized into three distinct levels of evidence: presumptive, objective, and confirmatory. Presumptive data are those expressed by the patient, consisting of subjective symptoms. Objective data include physical signs observed by a clinician or lab results, such as Chloasma, Ballottement (referred to as "paloteo" in the transcript), and the measurement of HCG serum levels. Confirmatory data provide definitive proof of a viable pregnancy and include the detection of Fetal Heart Rate (FCF), Sonography, and X-rays.

Specific definitions include Chloasma, which is characterized by dark hyperpigmentation appearing on the cheeks and forehead. Ballottement ("paloteo") involves the palpation of a lump or mass within the pelvic area. HCG Serum refers to the Human Chorionic Gonadotropin hormone levels found in the blood. The normal Fetal Heart Rate (FCF) range is between $110-160\,\text{lpm}$ (beats per minute), with $140\,\text{lpm}$ serving as the standard index.

Anatomical and Hormonal Changes in Reproductive Organs

During pregnancy, the reproductive system undergoes significant transformations marked by specific clinical signs. The Chadwick Sign is the development of a bluish or violet coloration of the cervix. The Goodel Sign is defined as the softening of the cervix. The Heegar Sign involves the softening of the uterine isthmus, which is the lower portion of the uterus.

Regarding the ovaries, ovulation ceases entirely during pregnancy. The corpus luteum remains active for approximately $6-7\,\text{weeks}$ and secretes the hormone relaxin. The uterus prepares itself for conception using estrogen and progesterone; its primary function at the end of gestation is to expel the fetus, placenta, and membranes, typically occurring between weeks 37 and 42. Within the cervix, a mucous plug (tapón mucoso) is formed, and the tissue becomes sensitive, bleeding with relative ease. Ligaments throughout the body stretch due to distention, and joints soften to accommodate the growing pregnancy.

Maternal Physiological Adaptations and Systemic Effects

Pregnancy impacts every major body system. On the skin, women may develop striae gravidarum and experience the separation of the rectus muscles. The cardiovascular system sees an increase in pulse by $10-15\,\text{lpm}$, and plasma volume increases significantly between weeks 10 and 20 of gestation (WgA). Despite these changes, there are typically no changes observable on an EKG. In the respiratory system, patients may experience physiological dyspnea. The urinary system undergoes ureter dilation (particularly on the right side), which can cause edema and infection because it prevents urine from flowing correctly.

Uterine activity includes Braxton Hicks contractions, which are described as unpredictable, short contractions occurring from week 20 onwards. Prostaglandins play a vital role in dilating blood vessels. Progesterone is essential for the maintenance of the pregnancy; if levels are not sufficiently elevated, there is a significant risk of miscarriage. In the gastrointestinal system, increased progesterone levels lead to constipation and a decrease in peristalsis. The musculoskeletal system is affected by lordosis, calf pain, and leg cramps often attributed to levels of calcium and phosphorus.

Hematological and Biochemical Baseline Values during Pregnancy

Blood pressure typically decreases initially and then rises during the third trimester. It is critical to note that placing a patient in a supine position can trigger supine hypotension. Hematological changes include a plasma increase during the first semester and a decrease in hemoglobin between weeks 24 and 32 (WgA). Platelets may decrease slightly, while White Blood Cells (WBC) generally increase. Leukocytes serve to phagocytize viruses and bacteria.

The standard laboratory values for a pregnant patient include Hemoglobin within a range of $12-15\,g/dl$. Platelet counts should be between $150,000-400,000/mm^3$. The White Blood Cell (WBC) count is normally $4,500-11,500/mm^3$, though in pregnant women, a count up to $15,000/mm^3$ is considered normal. Electrolyte balances should show Sodium at $135-145\,mg/dl$ and Potassium at $3.5-5.0\,mEq/l$. If potassium levels drop too low, there is a risk of heart arrhythmias. Fasting glucose should remain between $70-100\,mg/dl$.

Metabolic Adjustments, Nutrition, and Weight Management

Metabolic changes involve shifts in carbohydrate processing, leading to mild hypoglycemia when fasting and postprandial hyperglycemia. There is also a state of hyperinsulinemia. Between $10-15\%$ of pregnant women develop gestational diabetes. A normal Body Mass Index (BMI) for pregnancy is considered to be between $18.5-24.9$. Nutritional recommendations suggest a daily protein intake of $71\,g$, which is essential for the growth of the placenta, uterus, mammary glands, and the fetus. Electrolytes like Sodium and Potassium decrease in serum concentration, while Calcium and Magnesium are vital for bone and muscle health. Additionally, the glomerular filtration rate increases during this period.

Psychologically, patients may experience ambivalence and emotional lability. Estrogen and progesterone significantly affect both mood and stress levels. Proper nutrition, specifically a diet rich in fiber, can help prevent fatigue and depression. Deficiencies in iron, folic acid, and vitamin B12 can negatively impact cognitive functions and emotional stability.

The Physiology and Mechanics of the Labor Process

Labor is the physiological process that concludes with the birth of the baby and the delivery of the placenta. This process can last up to 18 hours after the rupture of the membranes (water breaking). Several factors trigger the onset of labor, including the detachment of the mucous plug, the discharge of amniotic fluid, the maturation of the placenta, fetal cortisol levels, and the onset of contractions. The mechanical aspects of birth are often categorized by the "5 Ps":

1. Passage: This refers to the types of pelvis. These include the Gynecoid (the most adequate for childbirth), Anthropoid, Android, and Altipeloides.

2. Passenger: This includes the fetus and the placenta.

3. Powers: These are the contractions and the resulting cervical dilation to $10\,cm$. This also involves effacement (thinning) measured from $0-100\%$. These powers facilitate fetal descent and rotation, as well as maintaining balance and hemostasis. External fetal monitors are used to evaluate the frequency, duration, and intensity of these contractions.

4. Psyche: The emotional state of the mother, including her confidence, stress levels, anxiety, and expectations.

5. Position: The lithotomy position is mentioned, which historically was popularized by King Louis XVI of France because he wished to watch his children being born.

Clinical Management of the Four Stages of Parturition

Pain during labor stems from four primary causes: the stretching of the cervix, distention of the lower uterine segment, stretching of the uterine ligaments, and pressure exerted on the utero-vaginal nerve ganglia. The process of labor is divided into four distinct stages. The first stage is Dilatation ($1-10\,cm$), which contains an active phase (6 cm dilations occurring every $3-5\,\text{min}$) and a transition phase (8 cm dilations occurring every $1-3\,\text{min}$). The second stage is Pushing (Parto), characterized by $10\,cm$ of dilation, crowning, and pushing. The third stage is the expulsion of the placenta and membranes, which features the maternal face (the side attached to the uterus that produces bleeding) and the fetal face. The fourth stage involves recovery and the stabilization of vital signs (SV).

Fetal Orientation: Attitude, Situation, Position, and Presentation

The orientation of the fetus is described using four specific terms. Attitude refers to the relationship that different parts of the fetus have with one another. Situation describes the relationship between the longitudinal axis of the fetus and the longitudinal axis of the mother's uterus; this can be Longitudinal, Transverse, or Oblique. Position describes the relationship of the fetal back (dorso) with either the left or right side of the maternal pelvis, categorized as Anterior, Posterior, Left (Izquierda), or Right (Derecha). Presentation refers to the part of the fetal ovoid that makes contact with the superior narrows of the maternal pelvis, such as Cephalic, Breech (Nalgas/Podálica), or Shoulder (Hombro).

Legal Regulations and Healthcare Protocols in Maternity

In Puerto Rico, several laws and administrative orders govern maternity care. Law 156 of August 10, 2006, mandates that women have the right to accompaniment during labor and birth. Law 79 of March 13, 2004, prohibits the unsolicited supply of formula. Law 87 consolidates all existing lactation laws in Puerto Rico. Administrative Order 336 requires that every health professional must be knowledgeable about breastfeeding (lactation).

Upon entering the labor room, standard protocols include a medical order, a review of health history and vital signs (VS), a physical examination, and an emotional assessment. Clinical focus remains on identifying the fetal position and presentation, ensuring fetal well-being, and monitoring the progression of the labor process.