2.1 Prenatal Visit Cadence, Milestone Screening & Fundal Height

Routine prenatal care is a preventive clinical model designed to promote optimal maternal-fetal health, identify emerging obstetric complications before they become life-threatening, and provide anticipatory guidance. Certified nurse-midwives maintain a holistic approach while executing rigorous, evidence-based surveillance of maternal hemodynamics, fetal growth, and biophysical well-being.

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Schedule of Routine Prenatal Visits

For an uncomplicated, low-risk pregnancy, the standard schedule of prenatal visits is structured as follows:

• Conception to 28 0/7 weeks: Every 4 weeks (monthly)
• 28 0/7 to 36 0/7 weeks: Every 2 weeks (biweekly)
• 36 1/7 weeks to delivery: Every week (weekly)
• Postdates (≥40 0/7 to 41 0/7 weeks): Twice weekly, incorporating biophysical fetal surveillance

Critical Milestone Screenings by Gestational Age

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Objective Physical Assessment Parameters

Blood Pressure Measurement Technique

Accurate blood pressure measurement is essential to distinguish chronic hypertension and gestational hypertension from preeclampsia.

• The patient must be seated comfortably with feet flat on the floor, back supported, for at least 5 minutes prior to measurement.
• The arm must be supported at heart level. Use an appropriately sized cuff: the bladder must encircle at least 80% of the arm circumference and cover 40% of the arm width.
• Determine the diastolic pressure at the disappearance of sound (Korotkoff Phase V).

Routine Urine Dipstick Screening

• Dipstick evaluation of clean-catch urine assesses for proteinuria and glucosuria.
• Clinical Nuance: Routine dipstick protein has a high false-positive and false-negative rate due to maternal hydration variations. A trace or 1+ dipstick in an asymptomatic normotensive woman is common, but a dipstick ≥1+ with elevated blood pressure mandates quantitative confirmation using a urine protein-to-creatinine ratio (UPC ≥0.3) or 24-hour urine collection (≥300 mg protein).

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Uterine Growth Assessment: McDonald's Rule

Fundal height measurement assesses fetal growth trajectory and amniotic fluid volume non-invasively.

Measurement Technique

1. Instruct the patient to empty her bladder completely prior to measurement (a full bladder can artificially elevate fundal height by 2–3 cm).
2. Position the patient supine with a small wedge under the right hip to avoid vena cava compression and supine hypotension syndrome.
3. Place the zero mark of a non-elastic, flexible tape measure at the superior border of the pubic symphysis in the midline.
4. Extend the tape measure smoothly over the contour of the gravid abdomen to the top of the uterine fundus, holding it perpendicular to the maternal spine.

Anatomical Landmarks & McDonald's Concordance

• 12 weeks: Fundus rises out of the pelvis, palpable just above the symphysis pubis.
• 16 weeks: Fundus is palpable midway between the symphysis pubis and the umbilicus.
• 20 weeks: Fundus reaches the level of the umbilicus (typically measures ~20 cm).
• 20 to 36 weeks: Fundal height in centimeters correlates closely with gestational age in weeks within a margin of ±2 cm (McDonald's rule).

Fundal Height Discordance Evaluation (Discrepancy > 2 cm)
├── Fundal Height Lagging (< GA by > 2 cm)
│   ├── Etiologies: Fetal Growth Restriction (FGR), Oligohydramnios, Transverse Lie, Fetal Demise
│   └── Action: Urgent diagnostic ultrasound (fetal biometry + Amniotic Fluid Index [AFI])
└── Fundal Height Leading (> GA by > 2 cm)
    ├── Etiologies: Polyhydramnios, Macrosomia / LGA, Multiple Gestation, Uterine Leiomyomata
    └── Action: Diagnostic ultrasound (fetal biometry + AFI + anatomical re-evaluation)

What Happens at Every Routine Visit

The milestone table above tells you what is added at a given gestational age. Independent of gestational age, a complete routine visit always contains the same core, and examination stems frequently test whether a candidate notices that one element was omitted:

• Blood pressure by the technique described above, compared against the patient's own baseline rather than only against a population threshold.
• Weight, interpreted against the Institute of Medicine gain range for the patient's pre-pregnancy BMI, not against an absolute number.
• Fundal height from 24 weeks onward, plotted serially so that a flattening curve is visible before any single measurement looks abnormal.
• Fetal heart rate, auscultated and documented as a rate and a pattern.
• Presentation, determined by Leopold maneuvers from about 36 weeks, since that is the decision point for external cephalic version referral.
• A focused review of symptoms that is really a warning-sign screen: vaginal bleeding, leaking fluid, regular contractions, decreased fetal movement, severe or persistent headache, visual change, right upper quadrant or epigastric pain, dysuria, and new or worsening swelling of the face and hands.
• Psychosocial screening at the intervals the practice has set — mood, substance use, intimate partner violence, food and housing insecurity — asked in private, with no partner or family member present.
• Anticipatory guidance matched to the interval until the next visit, plus an explicit statement of what to call about and how to reach the practice after hours.

Gestational-Age Terminology

Precision matters here because delivery timing recommendations are written in these terms:

"Term" as a single undifferentiated 37-to-42-week block is obsolete. An elective delivery at 37 weeks is an early-term birth with measurably higher neonatal respiratory morbidity than a full-term birth, which is why elective delivery before 39 0/7 weeks requires a medical indication.

When to Intensify the Schedule

Move a patient off the routine cadence — more frequent visits, added surveillance, or consultation — for chronic or gestational hypertension, pregestational or gestational diabetes requiring medication, fundal-height lag or a growth-restricted fetus, multiple gestation, a prior preterm birth or stillbirth, significant maternal cardiac, renal, or autoimmune disease, or any psychosocial circumstance that makes continuity fragile. The routine schedule is a floor for a low-risk pregnancy, never a ceiling.