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PubMed This is a summary of 17 peer-reviewed journal articles Updated
Maternal-Fetal Medicine

Confirming the Diagnosis: Imaging and Testing

At a Glance

Iniencephaly is primarily diagnosed during pregnancy using prenatal ultrasound and fetal MRI. Doctors look for hallmark signs like a "stargazing" backward-tilted head, skull openings, and spinal defects. Genetic testing may also be offered to understand the underlying cause.

Confirming a diagnosis of iniencephaly involves specialized imaging that allows doctors to see the internal structures of your baby’s head and spine [1][2]. While the process can feel overwhelming, these tests provide the detailed information your medical team needs to understand the severity of the condition and help you prepare for what comes next [1][3].

Prenatal Ultrasound: The First Step

The first tool used to identify iniencephaly is usually a prenatal ultrasound [4][5]. This condition can sometimes be detected as early as the first trimester, around 13 weeks of gestation [5]. On an ultrasound, doctors look for three hallmark signs:

  • The “Stargazing” Posture: This is the most recognizable sign of iniencephaly [2][6]. Because the neck bones (cervical vertebrae) are malformed or fused, the baby’s head is pulled into a fixed position, tilted sharply backward as if looking at the stars [2][7].
  • Occipital Bone Defects: Doctors check the bone at the back of the skull (the occipital bone) for an opening or abnormality, particularly near the foramen magnum (the opening where the spinal cord passes) [1][2].
  • Spinal Dysraphism: This refers to gaps or abnormalities in the spine, especially in the neck and upper back area [1][8].

Fetal MRI: A Detailed View

If an ultrasound suggests iniencephaly, your doctor will likely recommend a fetal MRI [1][9]. While ultrasound is excellent for screening, an MRI provides a much clearer, high-resolution picture of the baby’s brain and spine [9][10].

An MRI is particularly helpful for:

  • Visualizing the posterior fossa (the area at the base of the brain) and the spinal cord in more detail [1][11].
  • Confirming whether the defect is apertus (open, often with a brain protrusion called an encephalocele) or clausus (closed and covered by skin) [12][13].
  • Identifying subtle anomalies that might be hard to see on an ultrasound due to the baby’s position or the mother’s body type [1][9].

Looking for Other Anomalies

Because iniencephaly is a complex condition, it is often accompanied by other structural issues. Your medical team will carefully scan other organs to see if they are affected [1][8]. Common associated findings include:

  • Brain anomalies: Such as anencephaly (absence of parts of the brain and skull) or holoprosencephaly (a condition where the brain doesn’t properly divide into two halves) [14][12].
  • Heart defects: Various cardiovascular malformations are common [8][1].
  • Other structural issues: These can include diaphragmatic hernia (an opening in the muscle between the chest and abdomen) or defects of the abdominal wall [1][8].

The Role of Genetic Testing

The cause of iniencephaly is typically multifactorial (a complex mix of genetic and environmental factors) rather than a single chromosomal abnormality [15][16]. However, your doctor may offer amniocentesis—a procedure to collect a small amount of amniotic fluid—to perform genetic testing [15][17].

Tests like chromosomal microarray (CMA) or whole exome sequencing (WES) can help rule out underlying genetic syndromes [15][17]. While these tests will not change the physical prognosis of the baby, they can provide important information for understanding why this happened and for planning future pregnancies [15][16].

Note: Genetic testing takes time. Be sure to ask your doctor how long the results will take and whether waiting for these results will impact any strict legal timelines in your state regarding your pregnancy options.

Common questions in this guide

How is iniencephaly diagnosed during pregnancy?
Iniencephaly is usually diagnosed using a prenatal ultrasound, which can sometimes detect the condition as early as the first trimester. If an ultrasound suggests the condition, a fetal MRI is typically used to get a much clearer, detailed picture of the baby's brain and spine.
What is the "stargazing" posture on an ultrasound?
The "stargazing" posture is a classic sign of iniencephaly visible on imaging where the baby's head is tilted sharply backward, as if looking up at the stars. This fixed position happens because the baby's neck bones are malformed or fused together.
Why might my doctor recommend a fetal MRI after an ultrasound?
While an ultrasound is an excellent initial screening tool, a fetal MRI provides a higher-resolution view of the baby's central nervous system. It helps doctors see subtle details, confirm whether the defect is open or closed, and accurately check for other structural anomalies.
What is the purpose of genetic testing for iniencephaly?
Your doctor may offer an amniocentesis to look for underlying chromosomal syndromes using microarray or whole exome sequencing. While it won't change the baby's physical diagnosis, the results can help you understand the potential cause and plan for future pregnancies.
Are there other conditions associated with iniencephaly?
Because iniencephaly is a complex condition, babies often have other structural issues. Your medical team will carefully scan for associated brain anomalies, heart defects, and conditions like diaphragmatic hernias or abdominal wall defects.

Questions to Ask Your Doctor

Curated prompts to bring to your next appointment.

  1. 1.What specific markers on the ultrasound or MRI led to the diagnosis of iniencephaly?
  2. 2.Can you show us the 'stargazing' posture or the spinal defects on the scan images?
  3. 3.Would an amniocentesis or genetic testing help us understand if this is part of a larger syndrome?
  4. 4.How long will genetic test results take, and how does that timeline align with legal limits for making pregnancy decisions?
  5. 5.How certain is the diagnosis based on the imaging we have so far?

Questions For You

Tap a prompt to share your answer — we'll use it plus this page's context to start a tailored conversation.

References

References (17)
  1. 1

    Iniencephaly: radiologic and pathomorphologic perinatal observation.

    Korostyshevskaya A, Gornostaeva A, Volkov R, Yarnykh V

    Radiology case reports 2021; (16(1)):201-204 doi:10.1016/j.radcr.2020.11.003.

    PMID: 33294089
  2. 2

    Surgical Outcome in an Iniencephaly Survivor: Case Report and Review of the Literature.

    Khatri D, Gosal JS, Joseph J, et al.

    World neurosurgery 2019; (129()):105-109 doi:10.1016/j.wneu.2019.05.202.

    PMID: 31150861
  3. 3

    Twin pregnancy complicated with congenital Hemivertebra: report of two cases and literature review.

    Xu T, Wang X, Yu H, Zhao F

    BMC pregnancy and childbirth 2020; (20(1)):479 doi:10.1186/s12884-020-03177-3.

    PMID: 32819302
  4. 4

    A Fetus with Iniencephaly Delivered at the Third Trimester.

    Tanriverdi EC, Delibas IB, Kamalak Z, et al.

    Case reports in medicine 2015; (2015()):520715 doi:10.1155/2015/520715.

    PMID: 26345271
  5. 5

    Iniencephaly: A Challenging Prenatal Diagnosis of a Neural Tube Defect.

    Mendonça L, Cerveira I, Santos F, et al.

    Cureus 2024; (16(12)):e75457 doi:10.7759/cureus.75457.

    PMID: 39791056
  6. 6

    Expanding the spectrum of congenital myopathies: prenatal onset with extreme hyperextension of the neck.

    Tiberi E, Costa S, De Rose DU, et al.

    Neurological sciences : official journal of the Italian Neurological Society and of the Italian Society of Clinical Neurophysiology 2021; (42(4)):1549-1553 doi:10.1007/s10072-020-04937-x.

    PMID: 33244741
  7. 7

    Ultrasonographic evidence of persistent hyperextension of the fetal neck: is it a true sign? A diagnostic and prognostic challenge.

    Pellegrino M, Lombisani A, Lanzone A, Visconti D

    The journal of maternal-fetal & neonatal medicine : the official journal of the European Association of Perinatal Medicine, the Federation of Asia and Oceania Perinatal Societies, the International Society of Perinatal Obstetricians 2022; (35(17)):3393-3399 doi:10.1080/14767058.2020.1818223.

    PMID: 32998589
  8. 8

    Iniencephaly: Case Report.

    Alvis-Miranda HR, Bula-Anichiarico DA, Calderón-Miranda WG, Moscote-Salazar LR

    Journal of pediatric neurosciences 2015; (10(2)):181-4 doi:10.4103/1817-1745.159211.

    PMID: 26167231
  9. 9

    Fetal MRI Neuroradiology: Indications.

    Powers AM, White C, Neuberger I, et al.

    Clinics in perinatology 2022; (49(3)):573-586 doi:10.1016/j.clp.2022.05.001.

    PMID: 36113923
  10. 10

    Multimodality Imaging Evaluation of Fetal Spine Anomalies with Postnatal Correlation.

    Aboughalia H, Noda S, Chapman T, et al.

    Radiographics : a review publication of the Radiological Society of North America, Inc 2021; (41(7)):2176-2192 doi:10.1148/rg.2021210066.

    PMID: 34723699
  11. 11

    What Not to Miss in Fetal Head and Neck MRI: A Pictorial Essay.

    Bucci AS, Siala S, DeFreitas MR, Guimaraes CV

    Seminars in ultrasound, CT, and MR 2025; (46(5)):375-388 doi:10.1053/j.sult.2025.09.001.

    PMID: 40930194
  12. 12

    Prenatal imaging diagnosis of iniencephaly apertus associated with heterotaxy syndrome, alobar holoprosencephaly and myelomeningocele: a case report.

    Minchola-Vega JL, Zamora-Mostacero VE, Lazarte-Rantes CI

    AJOG global reports 2025; (5(3)):100539 doi:10.1016/j.xagr.2025.100539.

    PMID: 40740247
  13. 13

    Iniencephaly Clausus: A New Case With Clinical and Imaging Findings.

    Khatami A, Hasanzadeh M, Norouzi H, et al.

    Iranian journal of radiology : a quarterly journal published by the Iranian Radiological Society 2015; (12(3)):e4790 doi:10.5812/iranjradiol.4790v2.

    PMID: 26528385
  14. 14

    Iniencephaly.

    Holmes LB, Toufaily MH, Westgate MN

    Birth defects research 2018; (110(2)):128-133 doi:10.1002/bdr2.1082.

    PMID: 29377645
  15. 15

    Fetal Exome Sequencing on the Horizon.

    Wou K, DeBie I, Carroll J, et al.

    Journal of obstetrics and gynaecology Canada : JOGC = Journal d'obstetrique et gynecologie du Canada : JOGC 2019; (41(1)):64-67 doi:10.1016/j.jogc.2018.06.016.

    PMID: 30580830
  16. 16

    Whole-exome sequencing on deceased fetuses with ultrasound anomalies: expanding our knowledge of genetic disease during fetal development.

    Yates CL, Monaghan KG, Copenheaver D, et al.

    Genetics in medicine : official journal of the American College of Medical Genetics 2017; (19(10)):1171-1178 doi:10.1038/gim.2017.31.

    PMID: 28425981
  17. 17

    Molecular cytogenetic characterization of a duplication of 15q24.2-q26.2 associated with anencephaly and neural tube defect.

    Chen CP, Chen CY, Chern SR, et al.

    Taiwanese journal of obstetrics & gynecology 2017; (56(4)):550-553 doi:10.1016/j.tjog.2017.06.003.

    PMID: 28805617

This page provides educational information about diagnosing iniencephaly through prenatal imaging and genetic testing. It is not intended to replace professional medical advice. Always discuss your scan results and testing options directly with your maternal-fetal medicine specialist or obstetrician.

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