Can you outline the WHO‑recommended antenatal care visits, specifying which ultrasound scan is performed at each visit, its purpose, preparation requirements, and the objectives of each visit?

WHO-Recommended Antenatal Care Visit Schedule and Ultrasound Protocols

The WHO recommends a minimum of 8 antenatal care contacts throughout pregnancy, with one ultrasound scan before 24 weeks of gestation as part of routine care 1, 2.

The 8-Contact ANC Schedule Framework

The current WHO model represents a significant shift from the traditional 4-visit approach, increasing contact frequency to improve pregnancy outcomes. This 8-contact model has been shown to reduce unnecessary caesarean sections by 50% when properly implemented 2.

Timing of the Eight Contacts

While the evidence provided doesn't specify exact gestational ages for each of the 8 contacts, the framework emphasizes:

• First contact should occur within the first 12 weeks (first trimester) - this is critically important, as attending the first ANC contact within 12 weeks increases compliance with the full 8-contact schedule by more than 6-fold 3
• At least 3 contacts should occur during the third trimester to optimize outcomes 4
• Maximum gap between any visits should not exceed 21 days - gaps longer than 3 weeks are associated with nearly 3 times higher risk of preterm birth 4
• Care should continue until delivery - discontinuing care before the third trimester increases preterm birth risk by more than 12-fold 4

Ultrasound Scanning Protocol

When and Why

One ultrasound scan before 24 weeks of gestation is recommended as part of routine antenatal care 5, 6. This early obstetric ultrasound serves multiple purposes:

• Accurate dating of pregnancy
• Detection of multiple pregnancies
• Identification of major fetal abnormalities
• Assessment of placental location
• Risk stratification for referral needs

Current Reality vs. Recommendation

The utilization of early obstetric ultrasound remains suboptimal in many settings, with rates around 63% in sub-Saharan Africa 5, falling short of WHO recommendations.

Preparation for Ultrasound

The evidence doesn't specify particular preparation requirements for routine obstetric ultrasound, though standard practice typically involves:

• Full bladder for first-trimester scans (improves visualization)
• No special preparation needed for second-trimester scans
• Comfortable clothing for abdominal access

Why Scans May Take Time

Ultrasound examinations require:

• Adequate training of personnel (midwives can be trained to perform basic obstetric ultrasound) 7
• Proper equipment and electricity supply 7
• Thorough systematic examination of fetal anatomy
• Documentation and interpretation
• Potential need for repeat views if fetal position is suboptimal

Objectives of Each ANC Contact

Core Components Across All Visits

Every antenatal contact should include 8, 1:

Clinical Interventions:

• Blood pressure measurement
• Fetal heart rate assessment
• Symphysis-fundal height measurement
• Fetal presentation assessment (later visits)
• Maternal weight monitoring

Screening and Diagnostic Procedures:

• Syphilis screening (most commonly recommended screening intervention) 8
• Anemia screening (most commonly recommended screening intervention) 8
• Urine testing for proteinuria and bacteriuria
• Blood group and Rh status determination
• HIV testing and counseling

Health Education and Promotion:

• Nutrition counseling and supplement distribution (iron, folic acid, calcium)
• Birth preparedness and complication readiness
• Danger signs recognition
• Breastfeeding promotion
• Family planning counseling

Progressive Focus Through Pregnancy

Early pregnancy contacts (first trimester):

• Establish accurate gestational age
• Complete baseline screening tests
• Initiate nutritional supplementation
• Assess risk factors
• Perform ultrasound scan before 24 weeks

Mid-pregnancy contacts (second trimester):

• Monitor fetal growth
• Assess maternal well-being
• Reinforce health education
• Address any complications identified

Late pregnancy contacts (third trimester - minimum 3 visits):

• Assess fetal presentation
• Monitor for pre-eclampsia
• Finalize birth plan
• Ensure facility delivery arrangements
• Screen for Group B Streptococcus (where applicable)

Key Implementation Strategies

Service Delivery Models

Midwife-led continuity of care is recommended throughout the antenatal, intrapartum, and postnatal periods 1. This approach:

• Improves quality of care
• Increases service utilization
• Can incorporate task-shifting for specific ANC components
• Allows for both group and individual care models

Women-Held Case Notes

Providing women with their own case notes to carry between visits is recommended 1 to:

• Improve continuity of care
• Facilitate emergency referrals
• Empower women in their care
• Ensure information availability at delivery

Duration and Intensity Targets

Aim for more than 2.25 total hours of care during pregnancy and more than 0.75 hours during the third trimester 4. These thresholds are associated with:

• Reduced preterm birth rates
• Better pregnancy outcomes
• Improved patient engagement

Critical Pitfalls to Avoid

The Referral System Gap

A major caveat: Simply screening for pregnancy risks through ultrasound or other means does not automatically improve outcomes if the referral hospital system is not prepared to receive and appropriately manage referred patients 6. The First Look Study demonstrated that routine ultrasound in rural settings did not improve mortality outcomes when referral systems were inadequate.

Compliance Barriers

Only 23.4% of women achieve full compliance with the 8-contact schedule 3. Factors that improve compliance include:

• Early first contact (within 12 weeks)
• Insurance coverage
• Urban residence
• Partner employment
• Adequate health education

Resource Constraints

Scaling up ultrasound and the 8-contact model requires 7:

• Trained personnel (preservice and on-the-job training)
• Adequate infrastructure and electricity
• Community sensitization to address misconceptions
• Political will and resource allocation
• Standardized training materials

The 8-contact model with integrated ultrasound screening represents evidence-based best practice, but successful implementation demands simultaneous strengthening of referral systems, community engagement, and healthcare infrastructure 6, 7.