Situation: A 26-year-old woman comes to the Rural Health Unit (RHU) for her first prenatal visit on May 6, 2026. Her last menstrual period (LMP) began on January 28, 2026, and her menstrual cycles have always been regular at 28 days. She has no medical conditions and reports no danger signs. At this visit, the nurse records four findings. Which finding should the nurse refer for further evaluation?

From January 28 to May 6, 2026 is 98 days, so her age of gestation is 14 weeks 0 days. The fundus reaches the symphysis pubis at about 12 weeks and the umbilicus only at about 20 weeks, so a uterus at the umbilicus is much larger than dates and needs ultrasound to look for wrong dates, multiple gestation, or other causes. The other findings are normal for 14 weeks.

Gestational Age Calculation

The interval from January 28 to May 6, 2026 is 98 days. Dividing by 7 gives exactly 14 weeks 0 days. With regular 28-day cycles, this Naegele-based calculation is reliable, placing the pregnancy at the start of the second trimester.

Uterine Growth and Fundal Height

Uterine size follows a fairly predictable pattern in a singleton pregnancy. At 12 weeks, the fundus is just palpable above the symphysis pubis. It does not reach the level of the umbilicus until approximately 20 weeks. A fundus felt at the umbilicus at 14 weeks is therefore advanced by about 6 weeks relative to dates. A uterus that is larger than expected for gestational age requires ultrasound evaluation to distinguish among inaccurate dating, multiple gestation, uterine fibroids, or molar pregnancy. This is the only finding that deviates from the expected clinical picture.

Normal Findings at 14 Weeks

Fetal heart rate by Doppler is typically audible from 10–12 weeks onward and normally ranges from 110 to 160/min. A rate of 152/min is well within normal limits. Blood pressure of 98/60 mmHg is normal in early pregnancy; physiologic vasodilation from progesterone and increased nitric oxide lowers systemic vascular resistance, often producing a slight drop in blood pressure during the first and second trimesters. Weight gain of 1.5 kg above prepregnancy weight at 14 weeks is also acceptable, as total first-trimester gain in a normal-BMI woman is generally 0.5–2 kg.

Finding	Expected at 14 weeks	Interpretation
Fundus at umbilicus	Fundus at symphysis pubis only	Abnormal — size greater than dates; needs ultrasound
Fetal heart rate 152/min	110–160/min	Normal
Blood pressure 98/60 mmHg	Normal to slightly low in early pregnancy	Normal
Weight gain 1.5 kg	0.5–2 kg by 14 weeks	Normal

Clinical Reasoning and Referral

Fundal height assessment is a core component of antenatal surveillance. The CORE randomized trial used McDonald’s rule with referral for ultrasound when fundal height differed from gestational age by 3 cm or more, reflecting the principle that a size–dates discrepancy is a trigger for further imaging rather than an isolated finding to be dismissed. In this case, the discrepancy is far greater than 3 cm, because the uterus is at a landmark expected 6 weeks later. Antenatal care guidelines consistently emphasize that uterine size inconsistent with dates warrants investigation for multiple pregnancy, fetal growth abnormalities, or molar pregnancy. Key point! The nurse should not assume the LMP is wrong without objective confirmation; ultrasound is the appropriate next step to clarify gestational age and rule out pathologic causes of uterine enlargement.