A 28-year-old G2P1 woman from Delhi attends her second antenatal visit at 24 weeks of gestation. Her first pregnancy ended with a spontaneous vaginal delivery of a healthy 3.2 kg baby 2 years ago. Current vital signs are: BP 118/76 mmHg, HR 82/min. Haemoglobin is 11.4 g/dL. Urine routine shows no proteinuria. On abdominal examination, the fundal height is 24 cm. She reports no complaints. According to the antenatal care package guidelines, which of the following investigations should be performed at this visit?

Explanation

## Antenatal Care Package at 24 Weeks Gestation ### Gestational Age-Specific Investigations The antenatal care package in India follows a structured approach with investigations timed to specific gestational ages: | Gestational Age | Key Investigations & Interventions | |---|---| | **8–12 weeks (First visit)** | Blood grouping, Rh typing, Hb, blood pressure, weight, height, counselling | | **16–18 weeks** | Quad screen / triple screen (if available); ultrasound for dating & anomalies | | **20–24 weeks** | **OGTT for GDM screening**; repeat Hb; ultrasound (anatomy scan) | | **28 weeks** | Repeat Hb; Rh-negative women: anti-D prophylaxis (500 IU IM) | | **36 weeks** | Repeat Hb; NST; ultrasound for presentation & amniotic fluid | | **40 weeks** | NST; ultrasound if indicated | ### Rationale for OGTT at 24 Weeks **Key Point:** Gestational diabetes mellitus (GDM) screening via OGTT (75 g or 100 g) is performed at **20–24 weeks** because: 1. **Physiological insulin resistance peaks** in the second trimester 2. **Early detection** allows intervention (diet, exercise, insulin if needed) to reduce adverse outcomes 3. **Timing optimizes fetal outcomes** — early treatment reduces macrosomia, neonatal hypoglycaemia, and maternal complications **High-Yield:** The **OGTT is the gold standard** for GDM screening in India. A 75 g OGTT with fasting, 1-hour, and 2-hour glucose levels is the WHO-recommended approach. Diagnosis: fasting ≥92 mg/dL, 1-hour ≥180 mg/dL, or 2-hour ≥153 mg/dL (any one abnormal = GDM). ### Clinical Assessment of This Patient - **Haemoglobin 11.4 g/dL:** Acceptable at 24 weeks (normal ≥11 g/dL in second trimester); no urgent repeat needed until 28 weeks - **Blood pressure 118/76 mmHg:** Normal; no proteinuria; no signs of preeclampsia - **Fundal height 24 cm:** Appropriate for 24 weeks (fundal height in cm ≈ gestational age in weeks after 20 weeks) - **No symptoms:** Asymptomatic; no indication for urgent investigations ### Why Other Options Are Incorrect - **Repeat blood grouping & Rh typing:** Done only at the first visit (8–12 weeks); no indication to repeat at 24 weeks - **Amniocentesis:** Not indicated; patient is <35 years, has no risk factors, and no abnormal screening markers. Amniocentesis is offered only for specific indications (advanced maternal age, abnormal screening, family history) - **Doppler ultrasound of umbilical artery:** Performed in the third trimester (after 28 weeks) or if there is evidence of intrauterine growth restriction (IUGR), maternal hypertension, or other complications. Not routine at 24 weeks in a low-risk pregnancy **Clinical Pearl:** This is a low-risk, multiparous woman with a normal first pregnancy outcome. Routine screening for GDM is the priority at 24 weeks; no additional high-risk investigations are warranted at this visit.