Pregnancy

Pregnancy Milestones and Measurements

• Development Stages: Zygote → Blastocyst → Embryo → Fetus
• Calculating Due Date (Naegele’s Rule): Subtract three months from the first day of the last menstrual period (LMP), then add seven days (total pregnancy duration: 40 weeks or 280 days).
• Ultrasound Accuracy:
  • First Trimester: Crown-rump length (margin of error: ±7 days)
  • Second Trimester: Multiple fetal measurements (margin of error: ±10-14 days)

Uterine Growth & Landmarks

• Non-pregnant Uterus: Size of a lemon
• 8 Weeks: Comparable to an orange
• 10 Weeks: Size of a baseball, fetal heart tones (FHT) may be detected via Doppler
• 12 Weeks: Reaches just above symphysis pubis, about the size of a grapefruit (Doppler FHT detectable)
• 16 Weeks: Midway between symphysis pubis and umbilicus
• 16-18 Weeks: Quickening (first fetal movements felt)
• 20 Weeks: Fundus at umbilicus (FHT detectable via stethoscope)
• 20-36 Weeks: Fundal height typically matches gestational weeks in centimeters (±1 cm)
• At Term: Fundal height drops as the baby engages in the pelvis

Concern: If the uterus measures smaller than expected, consider intrauterine growth restriction (IUGR).

Risk Factors for Ectopic Pregnancy

• History of:
  • Salpingitis (inflammation of the fallopian tubes)
  • Previous ectopic pregnancy
  • Tubal surgery or damage
  • Pelvic inflammatory disease (PID) or prior cervicitis
  • Infertility or assisted reproductive techniques (e.g., IVF)
• Other contributing factors:
  • Cigarette smoking
  • Progestin-only contraception
  • Current intrauterine device (IUD) use
  • Tubal ligation failure

Diagnosis Considerations:

• If hCG > 1500 but ultrasound does not confirm an intrauterine pregnancy, suspect ectopic.
• Treatment options: Methotrexate (medical management) or surgical intervention if necessary.

Dietary Requirements

• Pregnancy: Increase intake by 300 kcal/day
• Breastfeeding: Requires an additional 500 kcal/day
• Calcium: 1000-1500 mg/day to support bone health
• Folic Acid: 0.4-1 mg/day (found in leafy greens and fortified cereals) to aid in fetal development

Healthy Weight Gain During Pregnancy

BMI Category	BMI Range	Recommended Weight Gain (lbs)
Underweight	Less than 18.5	28 – 40
Normal Weight	18.5 – 24.9	25 – 35
Overweight	25.0 – 29.9	15 – 25
Obese	30 or higher	11 – 20

Twin pregnancy: Higher recommended weight gain (37–54 lbs).Postpartum weight loss: Expect to shed 20–30 lbs within the first few weeks.Food precautions: Avoid soft cheeses, raw or undercooked meats, and unpasteurized milk.Seafood caution: Refrain from consuming raw shellfish or oysters due to the risk of Vibrio vulnificus infection.Deli meats warning: Cold cuts, uncooked hot dogs, and deli meats pose a risk of Listeria monocytogenes contamination.Caffeine intake: Limit to an 8 oz cup of regular coffee.Weight gain pattern: The majority of weight is gained in the third trimester, averaging 1–2 lbs per week.

Asymptomatic bacteriuria

Always requires treatment (3 days if asymptomatic, 7 days if symptomatic).First-line antibiotics:

• Nitrofurantoin (Macrobid) – BID for 5–7 days
• Amoxicillin/Clavulanate (Augmentin) – BID for 3–7 days
• Amoxicillin – BID for 3–7 days
• Cephalexin – BID for 3–7 days

Medication precautions: Avoid nitrofurantoin and sulfa-based drugs near term, during labor, and postpartum.Neonatal risk: Increased hyperbilirubinemia, leading to kernicterus.Pregnancy consideration: A urinary tract infection (UTI) during pregnancy is classified as a complicated UTI.

Indicators of Pregnancy

Definitive (Positive) Signs

• Fetal palpation by a healthcare professional
• Ultrasound confirmation of fetal presence
• Detection of fetal heart tones:
  • Doppler: 10–12 weeks
  • Fetoscope/Stethoscope: 20+ weeks

Likely (Probable) Signs

• Goodell’s Sign (4 weeks): Cervical softening
• Chadwick’s Sign (6–8 weeks): Bluish discoloration of the cervix and vagina
• Hegar’s Sign (6–8 weeks): Softening of the uterine isthmus
• Uterine enlargement
• Ballottement: A bouncing sensation of the fetus when pushed, felt through vaginal examination
• Positive urine hCG (may also indicate molar pregnancy or ovarian cancer)

Possible (Presumptive) Signs

• Missed periods (amenorrhea)
• Nausea and vomiting
• Breast tenderness and changes
• Fatigue
• Frequent urination
• Slightly elevated basal body temperature
• Quickening (16 weeks): First sensation of fetal movement by the mother

Miscellaneous Insights

• Zika Virus: Associated with cleft palate; highest risk occurs during the first trimester.
• Prenatal Visit Schedule:
  • Every 4 weeks up to 28 weeks
  • Every 2 weeks from 28 to 36 weeks
  • Weekly visits from 36 weeks until delivery
• Placental Drug Transfer:
  • Substances <500 daltons can cross the placenta
  • Molecules >1000 daltons typically cannot pass
• Asthma in Pregnancy:
  • Increased risk of bronchospasms between 36 and 40 weeks

Laboratory Tests During Pregnancy

• Urinalysis: Performed at every prenatal visit
• Alkaline Phosphatase: Always elevated due to fetal bone development
• Leukocytosis with Neutrophilia: A normal physiological response
• Alpha-Fetoprotein (AFP) Screening (16-20 weeks):
  • Low AFP: Further evaluation with a triple screen to assess for Down syndrome
  • High AFP: Rule out neural tube defects or multiple gestation with an ultrasound
• Triple Screen Test: Measures AFP, beta hCG, and estriol
• Quad Screen Test: Adds inhibin A to the triple screen, improving detection of Down syndrome
• Amniocentesis: Gold standard for diagnosing genetic disorders via fetal chromosome/DNA analysis (1 in 400 risk of fetal loss)
• Genetic Carrier Screening:
  • Tay-Sachs Disease: Common in Ashkenazi Jewish populations
  • Cystic Fibrosis: More prevalent among Caucasians
  • Sickle Cell Trait: Primarily affects individuals of African descent

Prenatal Lab Schedule

• First Prenatal Visit:
  • Confirm pregnancy with hCG
  • Screen for Pap smear, gonorrhea/chlamydia
  • Check rubella, varicella, rubeola immunity
  • Test for syphilis, HIV, HBsAg (consider HCV screening)
  • CBC, blood type, antibody screen
  • TSH if thyroid disease is being treated
• 16-20 Weeks:
  • Quad Marker/Screen for chromosomal and neural tube abnormalities
• 24-28 Weeks:
  • Gestational diabetes screening
• 28-32 Weeks:
  • Repeat STI screening
  • Administer RhoGAM if the mother is Rh-negative
• 32-36 Weeks:
  • Assess fetal position
  • Monitor fetal well-being with kick counts
• 35-37 Weeks:
  • Group B Streptococcus (GBS) culture
  • If positive: Administer Penicillin G (5 million units IV, then 2.5-3 million units every 4 hours until delivery)
• 40-42 Weeks:
  • Vaginal examination to evaluate cervical ripeness before labor induction if necessary

Physiological Adaptations in Pregnancy

• Cardiovascular Changes:
  • Heart shifts forward and to the left
  • Heart rate increases by 15-20 BPM
  • Heart sounds become more pronounced; S3 is common, and S2 splitting may be noticeable
  • Systolic ejection murmur (Grade II/IV) over pulmonary and tricuspid areas
  • Cardiac output rises by 30-50% (↑ preload), while systemic vascular resistance and blood pressure decrease (↓ afterload)
  • Plasma volume expands by 50%, leading to physiological anemia
  • Uterine compression of the inferior vena cava can cause orthostatic hypotension
  • Hypercoagulable state, increasing the risk of clot formation
• Respiratory System:
  • Basal rales present but clear with coughing
  • FEV1 remains unchanged, but total lung capacity decreases
• Gastrointestinal Changes:
  • Constipation and heartburn due to hormonal effects and pressure on the digestive tract
• Skin and Pigmentation:
  • Increased melanocyte-stimulating hormone causes:
    • Linea nigra – dark line extending down the abdomen
    • Darkening of the nipples and areolas
  • Chloasma (melasma): Blotchy hyperpigmentation on forehead, cheeks, nose, and upper lip
    • More common in individuals with darker skin
    • Linked to elevated estrogen levels
  • Striae gravidarum (stretch marks)
• Hair and Nails:
  • Telogen effluvium (postpartum hair loss) due to hormonal fluctuations
• Renal System:
  • Kidney size increases
  • GFR rises due to increased cardiac output and renal perfusion
• Vascular and Circulatory Effects:
  • Nasal congestion and nosebleeds (epistaxis) from increased blood flow
  • Varicose veins due to vascular relaxation and increased venous pressure
  • Peripheral edema from fluid retention and circulatory changes

Pregnancy History Overview

• Total Pregnancies (Gravida)
• Full-Term Births
• Preterm Deliveries
• Pregnancy Losses (Miscarriages/Abortions)
• Living Children

Medication Safety in Pregnancy

Note: The traditional FDA pregnancy categories (A, B, C, D, X) have been phased out since 2015 in favor of the Pregnancy and Lactation Labeling Rule (PLLR), which provides detailed narrative sections. However, the older categories remain helpful for study purposes and are still referenced in many clinical resources.

• Category A – Proven Safe
  • Vitamin A, Levothyroxine
• Category B – Generally Safe
  • Penicillins, Cephalosporins, Macrolides, Acetaminophen, Pulmicort, Maalox, Colace
  • Methyldopa (Monitor LFTs—discontinue if jaundice, abnormal LFTs, or unexplained fever)
  • Calcium Channel Blockers (Procardia), Beta-Blockers (Labetalol), Insulin
• Category C – Likely Safe
  • Sulfonamides (avoid in the third trimester), Clarithromycin
  • NSAIDs (risk of premature ductus arteriosus closure)
• Category D – Potential Risk
  • ACE Inhibitors, ARBs, Quinolones, Tetracyclines, Tegretol, Depakote
  • Fluoxetine, Paroxetine
• Category X – Unsafe
  • Accutane, Thalidomide, Statins, Proscar, Misoprostol, Evista
• Teratogenic Risks
  • Alcohol – Fetal Alcohol Syndrome (FAS)
  • Aminoglycosides – Hearing loss
  • Smoking – Intrauterine Growth Restriction (IUGR)
  • Cocaine – Increased risk of stroke (CVA)
  • Isotretinoin (Accutane) – Severe birth defects
  • Lithium – Congenital heart defects
  • Gestational Diabetes – Large for Gestational Age (LGA), neural tube defects

Miscellaneous Pregnancy Insights

• Toxoplasmosis Risk – Avoid cat litter and raw or undercooked meat.
• Harmful Substances – Smoking (linked to intrauterine growth restriction) and alcohol should be avoided.
• Heat Exposure – Refrain from using hot tubs, saunas, or prolonged exposure to high temperatures.
• Heartburn Causes – Progesterone and calcium channel blockers (CCBs) relax the esophageal sphincter, contributing to acid reflux.
• Uterine Involution – Postpartum contractions last 2-3 days. A soft, boggy uterus with excessive bleeding indicates uterine atony (poor contraction). Full involution takes about six weeks, with breastfeeding accelerating the process.
• Edwards Syndrome (Trisomy 18) – A genetic condition associated with severe developmental abnormalities.

Condition	Cause	Signs & Symptoms	Diagnostics	Treatment	Concerns
Placental Abruption (Abruptio Placentae)		Late third-trimester pregnancy with sudden-onset vaginal bleeding, painful contractions, and a firm, rigid uterus. Up to 20% may not have visible bleeding.	CBC, PT/PTT, blood typing & crossmatching, Rh testing, ultrasound	Immediate delivery of the fetus; severe cases can lead to maternal hemorrhage.	Increased risk with hypertension, preeclampsia, cocaine use, or prior history of placental abruption.
Placenta Previa		Painless vaginal bleeding in the late second or third trimester, often worsened by intercourse. Soft, non-tender uterus.		Bed rest, magnesium sulfate for cramping. Mild cases may resolve with reimplantation. No vaginal or rectal exams. If cervical dilation or hemorrhage occurs, delivery via C-section.	Higher risk in those with a history of C-sections, multiple pregnancies, older age, smoking, fibroids, or cocaine use.
Preeclampsia	Unknown; risk factors include first pregnancy, multiple pregnancies, age >35, obesity, prior history, hypertension, or kidney disease.	Sudden-onset recurrent headaches, blurred vision, scotomas, facial/hand edema, and rapid weight gain in late third trimester (>34 weeks). New-onset right upper quadrant pain, nausea, vomiting. Blood pressure >140/90 with proteinuria (1+ on dipstick), oliguria. If seizures occur, it progresses to Eclampsia.	Diagnostic criteria: Triad of hypertension, proteinuria, and edema. BP >140/90 after 20 weeks. Proteinuria >0.3g/24hr. Facial/hand swelling.	Delivery (can occur up to four weeks postpartum).	Hypertension before 20 weeks is considered chronic hypertension, not preeclampsia.
HELLP Syndrome (Hemolysis, Elevated Liver Enzymes, Low Platelets)	Rare but severe complication of preeclampsia/eclampsia.	Sudden onset of preeclampsia symptoms with severe worsening.	Elevated AST, ALT, LDH, total bilirubin >1.2, platelets <100,000, decreased hemoglobin/hematocrit.		More common in multiparous women over 25.
Rh Incompatibility	Rh-negative mother carrying an Rh-positive fetus.	If untreated, the maternal immune system develops antibodies against Rh-positive blood, leading to fetal hemolysis in subsequent pregnancies.	Coombs test: Indirect detects maternal Rh antibodies; direct detects antibodies in the infant.	RhoGAM (anti-D immune globulin) prevents maternal sensitization. Given at 28 weeks and within 72 hours postpartum.	Failure to administer RhoGAM can lead to hemolytic disease in future pregnancies.
Gestational Diabetes		Increased risk of neural tube defects, congenital heart disease, macrosomia (large baby), birth trauma (shoulder dystocia), preeclampsia, polyhydramnios, and neonatal hypoglycemia. Risk factors include obesity, family history, ethnicity (Asian, Native American, Black, Hispanic, Pacific Islander), previous large infant (>9 lbs.), and maternal age >35.	Screening: Early screening for high-risk individuals; routine screening at 24-28 weeks. If diabetes is diagnosed in the first trimester, it is classified as Type 2 Diabetes. Postpartum testing at 6-12 weeks and every 3 years. Diagnostic criteria: One-step method: 75g OGTT – fasting >92, 1-hour >180, 2-hour >153. Two-step method: 50g OGTT (non-fasting), if 1-hour >140, proceed to 100g OGTT. Fasting >95, 1-hour >180, 2-hour >155, 3-hour >140. Target glucose: Preprandial ≤95, 1-hour <140, 2-hour <120. A1C goal: 6.0-6.5%.	Lifestyle modifications, insulin, glyburide, or metformin if needed.	Increased risk of Type 2 Diabetes later in life.