About 1.7 to 2 percent of Indian babies are born with a congenital anomaly, which translates into hundreds of thousands of affected newborns every year. The most common categories are structural heart defects (the single largest group), neural tube defects such as spina bifida and anencephaly, chromosomal conditions led by Down syndrome (trisomy 21) and the rarer trisomies 18 and 13, and inherited single-gene disorders led by thalassemia and sickle cell disease. Some are mild and compatible with a normal life with treatment, others require major surgery in the newborn period, and a small minority are incompatible with survival. The point of antenatal screening is not to find a reason to end pregnancies — it is to identify problems early enough that families can prepare, plan delivery at a hospital with the right paediatric and surgical support, arrange specialist neonatal care, or, in cases of severe anomalies confirmed before the legal cut-off, consider the difficult decision of termination with proper counselling and legal process.

Indian regional patterns matter. Thalassemia carrier rates run at about 3 to 4 percent nationally, with substantially higher prevalence in Sindhi, Gujarati, Punjabi and Bengali communities, where carrier rates can exceed 10 percent in some pockets — which is why high-performance liquid chromatography (HPLC) for hemoglobinopathy screening is recommended at the first antenatal visit for both partners, particularly in these communities. Sickle cell disease is concentrated in tribal populations of central India. Neural tube defect rates are higher where pre-conception folic acid uptake is poor. Knowing where you live, what your community background is, and what your family history holds shapes the screening pathway your OB-GYN will recommend.

Most Indian women now have access to at least the core screening pathway, either through the Pradhan Mantri Surakshit Matritva Abhiyan (PMSMA) which provides a free first-trimester check at government facilities on the ninth of every month, through Ayushman Bharat (PMJAY) for hospitalisation cover at empanelled tertiary centres, or through private hospitals and labs. The Rashtriya Bal Swasthya Karyakram (RBSK) extends screening into the postnatal period, picking up defects that were not caught antenatally. For a fuller understanding of how to read each scan and lab report along the way, see Understanding Scans, Labs & Reports: A Complete India Pregnancy Guide.

The screening schedule in India follows a fairly standard pattern across both government and private settings, with small variations in which optional tests are offered. The first scan, the dating scan, happens between 8 and 10 weeks. It confirms a viable intrauterine pregnancy, dates the pregnancy accurately from crown-rump length, and identifies twin or higher-order pregnancies. From 11 to 13 weeks plus 6 days, the NT scan measures the nuchal translucency at the back of the fetal neck, looks at the nasal bone, and assesses ductus venosus flow; combined with the double marker biochemistry (PAPP-A and free beta-hCG) drawn at the same time, this gives a risk estimate for trisomies 21, 18 and 13.

If the early-trimester screen is missed, a quadruple marker (AFP, hCG, unconjugated estriol, inhibin-A) between 15 and 20 weeks provides a second-trimester chromosomal screen and also screens for neural tube defects through the AFP component. NIPT, the non-invasive cell-free fetal DNA test, can be done from 10 weeks onwards and is the most accurate single chromosomal screen available, with about 99 percent detection for trisomy 21; it is increasingly chosen instead of or alongside the older serum markers, particularly for women with higher baseline risk.

The single most important scan of the whole pregnancy from a structural perspective is the level-2 anomaly scan, also called the targeted imaging for fetal anomalies or TIFFA scan, performed between 18 and 22 weeks. This is a detailed systematic examination of every fetal organ system — head, brain, face, spine, heart and great vessels, abdomen and kidneys, limbs, placenta and amniotic fluid. The FOGSI antenatal care guidelines treat this scan as mandatory in every pregnancy, and almost every structural anomaly the screen can detect is detected on this single scan. Costs in India range from around 500 rupees at a government facility to 5000 rupees at a premium private centre, with results available the same day in most cases.

The NT scan and double marker together form the standard first-trimester chromosomal screen in India. The NT measurement is taken between 11 weeks and 13 weeks plus 6 days, when the crown-rump length is between 45 and 84 mm; outside this window the measurement loses its predictive value. The nuchal translucency is the fluid-filled space at the back of the fetal neck, and a thickness above the 95th percentile for gestational age (often quoted as above 3.5 mm) raises the probability of a chromosomal condition or a major structural heart defect. The scan also looks at whether the nasal bone is present and at blood flow in the ductus venosus, both of which feed into the combined risk calculation.

The double marker is a simple maternal blood test drawn at the same visit, measuring two placental proteins: pregnancy-associated plasma protein A (PAPP-A) and the free beta subunit of human chorionic gonadotropin. Low PAPP-A combined with high free beta-hCG raises the risk for trisomy 21, while different patterns suggest trisomy 18 or 13. The lab software combines the biochemistry with the NT measurement, maternal age, gestational age and other factors to produce a single combined risk number, usually expressed as a ratio (for example 1 in 250 for trisomy 21). A result above the cut-off (commonly 1 in 250 or 1 in 270 depending on the lab) is reported as high-risk and triggers an offer of NIPT or directly of diagnostic confirmation, depending on how high the risk is and on parental preference.

Cost in India for the NT scan plus double marker combination ranges from around 500 rupees in government PMSMA facilities to 4000 rupees in private centres. Detection rate for trisomy 21 is about 80 to 85 percent, with a false-positive rate of around 5 percent. It is a useful and accessible first screen, but its accuracy is below NIPT for the conditions both tests cover; the choice between a double marker and an NIPT often comes down to cost and to whether early high accuracy matters enough to a family to justify the higher out-of-pocket spend on NIPT.

If you do nothing else in your pregnancy, do the anomaly scan. The level-2 anomaly scan, performed between 18 and 22 weeks, is the single most important structural screen of pregnancy and is treated as mandatory under the FOGSI antenatal care guidelines. A trained fetal medicine sonologist examines the fetal head and brain structures (lateral ventricles, cerebellum, posterior fossa), face and lip (looking for cleft lip), spine (full sweep for neural tube defects), heart and great vessels (a detailed four-chamber and outflow tract examination, which picks up most major structural heart defects), abdomen (stomach, kidneys, bladder, abdominal wall), limbs (long bone measurements and counting digits), placenta and amniotic fluid volume. The scan typically takes 30 to 45 minutes when done properly.

Most major structural anomalies — anencephaly, large encephaloceles, severe ventriculomegaly, cleft lip, major spina bifida, large congenital heart defects, gastroschisis, renal agenesis, limb reduction defects — are detected on this scan. Some subtle defects may be missed, particularly very small ventricular septal defects in the heart or very small spina bifida lesions, and some defects only become apparent later in pregnancy (such as growth restriction or progressive ventriculomegaly). The scan also picks up the soft markers discussed in detail later in this guide.

Cost in India ranges from around 500 rupees at government and PMSMA facilities to 5000 rupees at premium private fetal medicine centres. If a major anomaly is identified, the standard pathway is referral to a fetal medicine specialist for a detailed targeted review, a paediatric cardiology assessment for any cardiac finding, genetic counselling, and a discussion of prognosis and options. If the family chooses to consider termination based on a confirmed severe anomaly, the legal framework is the Medical Termination of Pregnancy Act, which allows termination up to 24 weeks of pregnancy on substantial fetal abnormality grounds with the approval of a Medical Board for pregnancies beyond 20 weeks.

NIPT is a maternal blood test that analyses cell-free fetal DNA fragments shed from the placenta into the mother's circulation. It can be done from 10 weeks of pregnancy onwards and gives a detection rate of about 99 percent for trisomy 21, around 97 percent for trisomy 18 and around 90 percent for trisomy 13, with very low false-positive rates. It also screens sex chromosome aneuploidies, and many panels add optional microdeletion screening, though accuracy for microdeletions is much lower and false-positive rates much higher.

Cost in Indian labs ranges from about 15,000 rupees for a basic trisomy-only panel to 35,000 rupees for a premium whole-chromosome panel with microdeletions. Major labs offering NIPT include Thyrocare, Metropolis, SRL Diagnostics and Dr Lal PathLabs, with international panels such as Verifi, PrenaTest, MaterniT21 and IriSure available through these networks. Insurance does not usually cover NIPT unless the pregnancy is documented as high-risk; most families pay out of pocket.

NIPT is most strongly indicated for advanced maternal age (35 or older), an abnormal NT scan or double marker, a previous pregnancy with a chromosomal abnormality, a family history of a genetic disorder, IVF pregnancies, and twin pregnancies. It is also an entirely reasonable elective choice for women with no specific risk factor who want the reassurance of an early high-accuracy screen. Critically, NIPT is a screening test, not a diagnostic one — a high-risk NIPT result always needs confirmation with CVS or amniocentesis before any major decision is made about the pregnancy. For a deeper look at NIPT, see NIPT in India: Cost, Accuracy, and What the Test Can and Cannot Tell You.

If a screening test (double marker, quadruple marker or NIPT) comes back high-risk, or if the anomaly scan shows a finding that strongly suggests a chromosomal condition, the next step is a diagnostic test. Diagnostic tests sample fetal cells directly and give a definitive yes or no answer, unlike screening tests which only give a probability. The two main diagnostic options are chorionic villus sampling (CVS) and amniocentesis.

CVS is performed between 10 and 13 weeks. Under continuous ultrasound guidance, a fine needle is used to take a small sample of placental tissue, either through the abdomen or through the cervix depending on placental position. The sample contains cells of the same chromosomal make-up as the baby, and results are available in about 7 to 14 days. The procedure-related miscarriage risk in experienced hands is about 0.2 percent. Cost in India ranges from 8,000 to 25,000 rupees depending on the centre, and CVS is offered at major fetal medicine units at AIIMS, KEM, CMC Vellore, JIPMER, Apollo, Fortis and Cloudnine, among others.

Amniocentesis is performed from 15 weeks onwards, most commonly between 16 and 20 weeks. A fine needle, again under continuous ultrasound guidance, is used to withdraw a small volume of amniotic fluid through the abdominal wall; the fluid contains fetal cells that can be cultured for chromosomal analysis. Results are available in about 7 to 14 days for chromosomal microarray and 2 to 3 weeks for full karyotype. The procedure-related miscarriage risk in experienced hands is about 0.1 percent, slightly lower than CVS. Cost in India ranges from 6,000 to 15,000 rupees. Both procedures require informed consent, are offered only after counselling, and are not done casually — they exist for situations where the screening result or scan finding makes definitive confirmation important enough to justify the small procedural risk.

Soft markers are ultrasound findings that are, in themselves, not abnormalities — they are anatomical variants that occur commonly in normal babies but that are also found slightly more often in babies with chromosomal conditions. The most frequently encountered soft markers on the anomaly scan are an echogenic intracardiac focus (a small bright spot in the heart muscle), a choroid plexus cyst (a small fluid-filled cyst in the choroid plexus of the brain), mild renal pyelectasis (slight dilatation of the kidney collecting system), echogenic bowel (bowel appearing brighter than usual on ultrasound), a slightly short femur or humerus, and a single umbilical artery (the cord normally has two arteries and one vein, occasionally only one artery).

An isolated soft marker — meaning the only finding on an otherwise normal scan — usually does not change the clinical picture meaningfully. Most babies with an isolated echogenic intracardiac focus or an isolated choroid plexus cyst are entirely normal, and the cysts in particular almost always resolve on their own by 24 to 28 weeks. The slight increase in chromosomal risk from a single soft marker is small, and many fetal medicine units do not even change their management plan for an isolated soft marker beyond noting it and reviewing later. Multiple soft markers together raise the prior probability more substantially, and in that situation an offer of NIPT or, depending on the combination, of amniocentesis becomes appropriate.

What soft markers are not is a diagnosis. They do not mean the baby has the condition; they raise or lower the prior probability of one. The right response to a soft marker on a scan is calm interpretation in context — what other findings are there, what does the screening biochemistry or NIPT say, what is the maternal age and baseline risk — followed by a clear plan, which may be simply continued routine care, a repeat scan in a few weeks, or an offer of further testing if the picture warrants it. A soft marker reported on a scan is not, in itself, a reason to panic, and it is not, in itself, a reason for any major decision about the pregnancy.

Genetic counselling is the structured conversation that helps a family understand what a high-risk screening result, an abnormal scan finding, a positive carrier test or a family history of a genetic disorder actually means in practical terms — the probability of the condition, the spectrum of severity, what diagnostic tests can do and cannot do, what management options exist after birth, and what the legal and personal options are during the pregnancy. It is not advice on what to do; it is a structured exploration of what the family wants to know and what choices are available so that decisions are made with full understanding.

In India, qualified genetic counsellors are available at major academic and tertiary centres including AIIMS Delhi and its newer satellite institutes, KEM Hospital Mumbai, Christian Medical College Vellore, Sanjay Gandhi Postgraduate Institute Lucknow, JIPMER Puducherry, Nizam's Institute of Medical Sciences Hyderabad, NIMHANS Bengaluru, and at several private chains including Apollo Hospitals, Fortis Healthcare, Cloudnine Hospitals and Cytecare. The cost per session typically ranges from 500 rupees at a public sector centre to 3000 rupees at a premium private one; many fetal medicine units now include genetic counselling as part of the package after a high-risk screening result.

A genetic counsellor will usually take a detailed three-generation family history (the pedigree), explain the specific finding in plain language, lay out the testing options and their detection rates, discuss what each possible result would mean for the pregnancy and beyond, and connect the family to any support groups or networks of families who have been through similar situations. This is particularly valuable for inherited conditions like thalassemia where both partners may be carriers — for the wider context, see thalassemia-carrier-screening-india-couples.

A high-risk screening result is not a diagnosis. The first thing to do after one is nothing major — no decision needs to be made on the day the result comes through, and the standard pathway specifically allows time and space for considered decisions. The recommended next step is a counselling visit with the OB-GYN and, where available, a genetic counsellor, to understand what the specific high-risk result actually means in terms of probability. From there, the family is offered diagnostic confirmation with CVS at 11 to 14 weeks or amniocentesis at 16 weeks onwards.

If a diagnostic test confirms a serious chromosomal abnormality or if the anomaly scan confirms a major structural defect, the family faces a deeply personal decision. The Indian legal framework for considering termination on fetal abnormality grounds is the Medical Termination of Pregnancy Act, as amended in 2021. It allows termination up to 20 weeks on the opinion of one registered medical practitioner, up to 24 weeks on the opinion of two practitioners for specified categories (including substantial fetal abnormality), and beyond 24 weeks only with the approval of a State or Union Territory Medical Board specifically for cases of substantial fetal abnormality. The framework exists to give families with confirmed serious anomalies a legal and medically supervised pathway, not to encourage termination based on screening results alone.

Whatever the decision, it is the family's to make, with full information, time to absorb it, access to counselling, and the support of clinicians who treat the situation with seriousness and care. Many families choose to continue pregnancies even after a confirmed serious diagnosis, planning delivery at a centre with the appropriate paediatric subspecialty care and preparing emotionally and practically for the journey ahead. Others choose, after careful consideration, to end the pregnancy within the legal framework. Both are valid choices, both deserve respect and support, and neither should be presented as the default.

A meaningful proportion of birth defects can be prevented or substantially reduced through care that begins before conception, not just during pregnancy. The single highest-yield intervention is folic acid supplementation: 400 to 800 micrograms daily, started at least 3 months before conception and continued through the first trimester, reduces the risk of neural tube defects by roughly 70 percent. For women with a previous pregnancy affected by a neural tube defect or with epilepsy on certain medications, the recommended dose is higher — often 4 to 5 mg daily — under medical supervision.

Other pre-conception steps with strong evidence include achieving good glycaemic control if diabetic before conception (poorly controlled diabetes substantially raises the risk of congenital heart defects, neural tube defects and other anomalies), controlling blood pressure and thyroid function, reviewing all chronic medications for teratogenic potential and switching where needed, ensuring immunity to rubella and varicella before pregnancy (vaccinating at least 1 month before trying), updating tetanus immunisation, and stopping smoking and alcohol well before conception. For overweight and obese women, even modest pre-conception weight loss reduces anomaly risk.

Thalassemia and other hemoglobinopathy carrier screening for both partners before pregnancy is particularly important in India, given the high carrier rates in several communities. If both partners are carriers, the couple can make informed reproductive decisions including pre-implantation genetic testing with IVF or early antenatal diagnosis with CVS in a natural pregnancy. For a wider pre-conception readiness framework, see Is My Body Ready to Conceive?. For week-by-week pregnancy context once you are pregnant, see What to Expect Week by Week During Pregnancy.