Accurate U/S Anomaly (DAO) Scan in Karachi at Dr. Essa Lab

U/S Anomaly (DAO) at Dr. Essa Lab

The U/S Anomaly (DAO) scan, clinically referred to as the Detailed Anomaly Obstetrical scan or Level II obstetric ultrasound, is one of the most critical diagnostic imaging examinations performed during pregnancy. Available at Dr. Essa Lab in Karachi, Pakistan, this specialized diagnostic procedure uses high-frequency sound waves to generate high-resolution, real-time images of the developing fetus. Unlike ionizing radiation used in X-rays or CT scans, ultrasound technology is entirely non-invasive and safe for both the mother and the developing baby. The primary objective of the U/S Anomaly (DAO) scan is to conduct a systematic, head-to-toe anatomical survey of the fetus, evaluate placental positioning, measure amniotic fluid volume, and assess maternal pelvic structures. This detailed evaluation allows maternal-fetal specialists and radiologists to monitor gestational progress, confirm normal physiological development, and identify congenital structural anomalies early in the second trimester.

At Dr. Essa Lab, the U/S Anomaly (DAO) scan is performed using state-of-the-art diagnostic ultrasound systems equipped with advanced multi-frequency transducers. These systems utilize the piezoelectric effect, where high-frequency sound waves are emitted into the maternal abdomen and bounce off fetal tissues of varying acoustic impedance. The returning echoes are captured by the transducer and processed by sophisticated software to produce highly detailed two-dimensional (2D), three-dimensional (3D), and sometimes four-dimensional (4D) structural images. This imaging modality is crucial for evaluating complex anatomical structures, including the fetal brain ventricles, the four chambers of the heart, the outflow tracts, the renal pelvis, and the spinal column. By choosing Dr. Essa Lab, patients in Karachi benefit from the expertise of highly experienced radiologists and sonologists who follow standardized international protocols to ensure clinical accuracy and peace of mind during this pivotal stage of pregnancy.

Clinical Procedure: What to Expect

Patient Preparation

Proper preparation is essential to ensure the highest image quality during the U/S Anomaly (DAO) scan. Patients are advised to adhere to the following preparation guidelines:

• Gestational Timing: The scan is ideally scheduled between the 18th and 22nd weeks of pregnancy, as fetal structures are sufficiently developed and visible at this stage.
• Hydration and Bladder Preparation: Patients are generally instructed to drink approximately 2 to 3 glasses of water one hour before the appointment and refrain from urinating. A moderately full bladder helps lift the uterus out of the pelvic cavity and pushes the bowel loops away, creating an optimal acoustic window for the ultrasound waves. However, the bladder should not be painfully full.
• Clothing: Wear loose, comfortable, two-piece clothing (such as a salwar kameez or a separate top and skirt) to allow easy access to the lower abdomen.
• Documentation: Bring all previous obstetric ultrasound reports, maternal serum screening results, and the doctor's referral slip to help the radiologist perform a comparative analysis.
• Avoid Topical Products: Do not apply any moisturizing creams, oils, or lotions to the abdomen on the day of the scan, as these substances can interfere with the transmission of ultrasound waves and degrade image quality.

During the Procedure

The U/S Anomaly (DAO) scan is a comfortable, pain-free, and highly interactive procedure. Here is what patients can expect during their visit to Dr. Essa Lab:

• Positioning: The patient will lie comfortably in a supine position (on their back) on an examination table. To prevent supine hypotensive syndrome—which can occur when the heavy uterus compresses the maternal inferior vena cava—the radiologist may place a small wedge or pillow under the right hip to tilt the body slightly to the left.
• Gel Application: A warm, water-soluble acoustic gel is applied to the bare abdomen. This gel eliminates air pockets between the skin and the transducer, facilitating seamless transmission of high-frequency sound waves into the pelvic cavity.
• Scanning Process: The sonologist or radiologist will gently move the transducer across the abdomen, applying mild pressure to obtain clear views of the fetus from various angles. The patient may feel slight pressure but no pain.
• Anatomical Survey: The practitioner systematically measures the fetal head (biparietal diameter and head circumference), abdomen (abdominal circumference), and limbs (femur length) to estimate fetal weight and confirm gestational age. The internal organs, including the brain, heart, spine, kidneys, stomach, and bladder, are meticulously evaluated.
• Duration: The entire procedure typically takes between 30 to 45 minutes, depending on the fetal position, maternal tissue thickness, and fetal activity.
• Safety: Because ultrasound uses mechanical sound waves rather than ionizing radiation, there are no known biological risks or side effects associated with this diagnostic test.

When is a U/S Anomaly (DAO) Performed?

Routine Second-Trimester Screening (18-22 Weeks)

The U/S Anomaly (DAO) scan is universally recommended as a routine screening tool for all pregnant women during the second trimester. This specific window of pregnancy is optimal because the fetal organs have developed sufficiently to be visualized in detail, and there is still an adequate volume of amniotic fluid surrounding the fetus to act as a clear contrast medium. Performing the scan during this period allows for the timely detection of structural anomalies, enabling parents and healthcare providers to make informed decisions regarding prenatal care, delivery planning, and postnatal medical or surgical interventions.

Evaluation of High-Risk Pregnancies

Physicians frequently request a detailed anomaly scan for patients classified as having high-risk pregnancies. High-risk factors include advanced maternal age (35 years or older), a maternal history of chronic medical conditions such as pre-gestational diabetes, chronic hypertension, systemic lupus erythematosus (SLE), or active epilepsy. Additionally, pregnancies achieved through assisted reproductive technologies (ART) or those with a history of recurrent miscarriages are closely monitored using this detailed ultrasound protocol to rule out structural defects or placental insufficiency.

Abnormal Maternal Serum Screening Results

If a patient receives abnormal results from first-trimester screening tests (such as the double marker test) or second-trimester maternal serum screenings (such as the triple or quadruple test), a U/S Anomaly (DAO) scan is immediately indicated. The scan serves as a diagnostic follow-up to visually investigate potential chromosomal abnormalities or neural tube defects. For instance, an elevated alpha-fetoprotein (AFP) level in maternal blood strongly indicates the need for a detailed ultrasound evaluation of the fetal spine and cranium to rule out open neural tube defects like spina bifida.

Family History of Congenital Anomalies

A family history of congenital heart defects, cleft lip or palate, renal disorders, skeletal dysplasias, or genetic syndromes is a primary indication for a U/S Anomaly (DAO) scan. Because many structural anomalies have a hereditary component, the radiologist will pay extra attention to the specific organ systems previously affected in the family. For example, if a previous sibling was born with a congenital heart defect, a detailed fetal echocardiography view is integrated into the anomaly scan to evaluate the four chambers, septal walls, and great vessels of the fetal heart.

Monitoring Suspected Fetal Growth Restriction or Fluid Abnormalities

When clinical examinations, such as symphysis-fundal height measurements, suggest that the baby is small for gestational age, or if previous basic scans indicate abnormal amniotic fluid levels (oligohydramnios or polyhydramnios), a detailed U/S Anomaly (DAO) scan is performed. This scan helps determine if the growth restriction is symmetrical or asymmetrical and checks for underlying structural causes, such as renal abnormalities (which can cause low amniotic fluid) or gastrointestinal obstructions (which can cause excessive amniotic fluid).

What Does a U/S Anomaly (DAO) Detect?

The U/S Anomaly (DAO) scan is designed to detect a wide spectrum of structural, developmental, and physiological abnormalities. Some of the key findings and conditions that this scan can identify include:

• Neural Tube Defects: Conditions such as anencephaly (absence of a major portion of the brain and skull) and spina bifida (incomplete closure of the spine).
• Craniofacial Abnormalities: Cleft lip, cleft palate, microphthalmia (abnormally small eyes), and nasal bone absence or hypoplasia (often associated with Down syndrome).
• Congenital Heart Defects: Ventricular septal defects (VSD), atrial septal defects (ASD), Tetralogy of Fallot, transposition of the great arteries, and hypoplastic left heart syndrome.
• Gastrointestinal Obstructions: Duodenal atresia (indicated by the "double bubble" sign), esophageal atresia, and echogenic bowel.
• Abdominal Wall Defects: Omphalocele and gastroschisis, where abdominal organs herniate outside the fetal body.
• Renal and Urinary Tract Anomalies: Bilateral or unilateral renal agenesis (missing kidneys), multicystic dysplastic kidney disease, infantile polycystic kidney disease, and posterior urethral valves causing bladder outlet obstruction.
• Skeletal Dysplasias: Short-limb dwarfism, osteogenesis imperfecta, clubfoot (talipes equinovarus), polydactyly (extra fingers or toes), and syndactyly (webbed digits).
• Placental Abnormalities: Placenta previa (placenta covering the internal cervical os), low-lying placenta, and signs of abnormal placental attachment (placenta accreta spectrum).
• Umbilical Cord Anomalies: Single umbilical artery (instead of the normal two arteries and one vein) and abnormal cord insertion sites (velamentous or marginal insertion).
• Amniotic Fluid Disorders: Oligohydramnios (insufficient fluid, often linked to renal issues or placental insufficiency) and polyhydramnios (excessive fluid, linked to swallowing difficulties or maternal diabetes).
• Hydrops Fetalis: Abnormal accumulation of fluid in two or more fetal compartments, such as pleural effusion, pericardial effusion, ascites, or skin edema.
• Diaphragmatic Hernia: A defect in the fetal diaphragm allowing abdominal organs to migrate into the chest cavity, compressing the lungs.
• Cerebral Ventriculomegaly: Dilation of the lateral ventricles of the brain, which may indicate hydrocephalus.
• Dandy-Walker Malformation: A congenital brain malformation involving the cerebellum and the fluid-filled spaces around it.
• Holoprosencephaly: A failure of the forebrain to divide properly into two hemispheres.
• Sacrococcygeal Teratoma: A tumor arising from the coccyx, detectable as a mass at the base of the fetal spine.
• Choroid Plexus Cysts: Small fluid-filled spaces in the brain that, while often benign, can sometimes be associated with chromosomal trisomies.
• Echogenic Intracardiac Focus (EIF): A small bright spot seen in the fetal heart, which can be a normal variant or a soft marker for chromosomal abnormalities.
• Short Femur Length: A potential marker for skeletal dysplasia or fetal growth restriction.
• Cervical Incompetence: Measurement of maternal cervical length to assess the risk of preterm labor.

Turnaround Time and Report Access at Dr. Essa Lab

At Dr. Essa Lab, we understand that waiting for prenatal test results can be an anxious time for expectant parents. Therefore, we prioritize both clinical accuracy and rapid reporting. Following your U/S Anomaly (DAO) scan, the performing radiologist or sonologist will carefully review and analyze all recorded measurements, anatomical images, and Doppler waveforms. A preliminary verbal overview is often shared with the patient immediately after the procedure.

The finalized, comprehensive diagnostic report—complete with high-resolution printed images of the fetal anatomy—is typically ready within a few hours of the scan. Dr. Essa Lab offers a seamless digital reporting experience. Patients receive an SMS notification containing a direct link to download their electronic report as soon as it is verified by the consultant radiologist. Reports can also be accessed securely through the official Dr. Essa Lab online portal or mobile application, allowing patients to easily share the findings with their obstetrician or gynecologist without needing to make an extra trip to the lab.

U/S Anomaly (DAO) Findings Overview

Structure / Parameter Evaluated	Normal Findings	Possible Abnormal Findings
Fetal Cranium & Brain	Intact skull bones; normal lateral ventricles (<10 mm); visible midline falx, cavum septum pellucidum, and cerebellum.	Ventriculomegaly; anencephaly; lemon or banana sign (associated with spina bifida); choroid plexus cysts.
Spine & Vertebrae	Regular alignment of vertebrae from cervical to sacral regions; intact overlying skin line.	Spina bifida (aperta or occulta); hemivertebrae; sacrococcygeal teratoma.
Fetal Face & Profile	Intact upper lip and palate; presence of nasal bone; symmetrical orbits.	Cleft lip; cleft palate; absent nasal bone; micrognathia (receding chin).
Heart & Great Vessels	Symmetrical four-chamber view; normal axis; crossing of aorta and pulmonary artery; normal heart rate (110-160 bpm).	Ventricular septal defect (VSD); hypoplastic left heart; transposition of great arteries; ectopia cordis.
Diaphragm & Lungs	Intact diaphragm separating chest and abdomen; homogeneous lung tissue.	Congenital diaphragmatic hernia; congenital pulmonary airway malformation (CPAM); pleural effusion.
Gastrointestinal System	Visible fluid-filled stomach bubble in the left upper quadrant; normal bowel echogenicity.	Absent stomach bubble (esophageal atresia); double bubble sign (duodenal atresia); echogenic bowel; gastroschisis.
Urinary Tract & Kidneys	Two kidneys present in renal fossae; normal renal pelvis size (<4 mm); visible fluid-filled bladder.	Renal agenesis; hydronephrosis; multicystic dysplastic kidneys; keyhole sign (bladder outlet obstruction).
Limbs & Extremities	Three segments visible in all four limbs; normal mineralization; five digits on each hand and foot.	Skeletal dysplasia (short limbs); clubfoot; polydactyly; syndactyly; clinodactyly.
Placenta & Cord	Placenta clear of the internal cervical os; three-vessel umbilical cord (two arteries, one vein).	Placenta previa; low-lying placenta; single umbilical artery (SUA); marginal or velamentous cord insertion.
Amniotic Fluid	Normal amniotic fluid volume (AFI between 5 and 25 cm).	Oligohydramnios (AFI <5 cm); polyhydramnios (AFI >25 cm).

Note: Diagnostic findings should always be interpreted by a qualified healthcare professional together with the patient's symptoms, medical history, physical examination, laboratory investigations, previous imaging studies, and other relevant clinical information. Additional investigations or specialist consultation may be recommended depending on the findings.

Why Choose Dr. Essa Lab for U/S Anomaly (DAO)?

• Experienced Healthcare Professionals: Our scans are performed and interpreted by highly qualified female and male radiologists specializing in obstetric and fetal imaging.
• Patient-Focused Care: We prioritize maternal comfort, dignity, and clear communication, ensuring a supportive environment throughout the procedure.
• Quality Diagnostic Services: Dr. Essa Lab is a trusted name in Pakistan, known for maintaining rigorous quality control and diagnostic accuracy.
• Professional Reporting: Detailed, structured reports with high-resolution images are compiled in accordance with international obstetrical guidelines.
• Modern Diagnostic Approach: We utilize advanced, high-resolution ultrasound machines that provide superior tissue resolution and diagnostic clarity.
• Comfortable Environment: Our diagnostic centers are designed to offer a clean, hygienic, and relaxing atmosphere for expectant mothers and their families.
• Convenient Locations: With an extensive network of branches across Karachi and other major cities, accessing our diagnostic services is highly convenient.
• Commitment to Accurate Diagnosis: Since 1987, Dr. Essa Lab has remained dedicated to providing reliable, evidence-based diagnostic insights to support maternal and fetal health.