4.1 Disorders of Sex Development | Neonatology Academy

Bedside Action Box — Newborn with Suspected DSD / Ambiguous Genitalia

Treat as a medical emergency until CAH, adrenal crisis, hypoglycemia, and severe electrolyte disturbance are excluded

Call the attending neonatologist and pediatric endocrinology early.
Do not assign sex or use gendered language before expert evaluation. Use the baby's name or "your baby" — never "it."
Check: glucose, serum Na/K/bicarbonate, BP, hydration, weight trend, urine output, and perfusion. Repeat electrolytes — CAH salt-wasting may not appear until after the first day.
Before starting steroids in a sick infant, draw critical endocrine samples if this can be done without delaying resuscitation; then give stress-dose hydrocortisone when CAH/adrenal crisis is strongly suspected or the baby is unstable.
Order: urgent rapid sex-chromosome testing or karyotype per local lab pathway, plus pelvic/abdominal ultrasound by an experienced pediatric sonographer.
Assign one senior clinician as the single family-contact person and document exactly what was said, what remains uncertain, and the follow-up plan.

Quick Navigation

Section	What It Answers
1. Scope and definitions	What DSD means, why terminology matters, and when NICU evaluation is required
2. Recognition triggers	Which genital, prenatal, family, biochemical, and systemic findings should prompt evaluation
3. Emergency priorities	How to rule out CAH/adrenal crisis, hypoglycemia, salt-wasting, and hypopituitarism
4. Communication pathway	How to avoid harm from premature sex assignment or stigmatizing language
5. Diagnostic workup	History, examination, karyotype/rapid testing, hormonal tests, imaging, genetics, and consults
6. Differential diagnosis	How to organize 46,XX DSD, 46,XY DSD, and sex-chromosome DSD at the bedside
7. Treatment and discharge	Steroid replacement, stabilization, outpatient planning, and red flags before discharge
8. Source differences and references	Where Baylor, West Midlands, Belize, Endocrine Society, AAP, and Endotext guidance align or differ

1. Scope and Definitions

This chapter is written for newborns whose external genital appearance, prenatal sex-chromosome information, gonad position, hormone screen, or systemic findings raise concern for a disorder or difference of sex development (DSD). The NICU role is to stabilize the infant, protect the family experience, prevent premature labeling, and coordinate expert evaluation.

DSD describes congenital conditions in which chromosomal, gonadal, or anatomic sex development is atypical. The bedside classification starts with chromosomal pattern: 46,XX DSD, 46,XY DSD, and sex-chromosome DSD such as mosaic 45,X/46,XY or other chimeric/mosaic patterns. DSDs occur in roughly 1 in 4,500 live births (Baylor Ed. 33); minor variations are commoner than that.

Terminology note

Many families and affected individuals prefer "differences of sex development" rather than "disorders." For a clinical guideline, DSD is used because it remains common in medical literature and laboratory systems, but communication with families should be respectful, plain-language, and individualized.

Classification	Common Neonatal Examples	Immediate NICU Concern
46,XX DSD	21-hydroxylase CAH with virilization; maternal androgen exposure; disorders of ovarian development	Do not miss: salt-wasting CAH, cortisol deficiency, shock, hyperkalemia, hypoglycemia
46,XY DSD	Gonadal dysgenesis; defects of testosterone synthesis; 5α-reductase deficiency; androgen insensitivity; hypogonadotropic hypogonadism	Assess testes/gonads, undervirilization, micropenis, hypospadias, hypoglycemia, and pituitary-axis deficiency
Sex-chromosome DSD	45,X/46,XY mixed gonadal dysgenesis, mosaicism, chimerism, Turner/Klinefelter spectrum presentations	Consider associated anomalies, gonadal location, cardiac/renal screening needs, and malignancy-risk planning with specialists

2. Recognition Triggers: When to Start a DSD Workup

A DSD workup is not required for every minor variation in genital appearance. It is required when anatomy is ambiguous enough to affect sex assignment, appears discordant with prenatal testing, suggests serious endocrine disease, or is associated with other anomalies.

Finding	Why It Matters	First Bedside Response
Overt genital ambiguity or cloacal/exstrophy pattern	May represent complex urogenital anatomy requiring urgent surgical/urologic planning	Call consultant neonatologist, endocrinology, urology/surgery, genetics; avoid sex assignment
Apparent female genitalia with enlarged clitoral/genital tubercle, posterior labial fusion, or inguinal/labial mass	Can represent virilized 46,XX CAH or gonadal tissue in a 46,XY DSD	Check electrolytes/glucose/BP; evaluate for CAH; order pelvic ultrasound and karyotype/rapid sex-chromosome testing
Apparent male genitalia with bilateral nonpalpable testes	A phenotypic male without palpable gonads can represent 46,XX virilization, 46,XY gonadal disorder, or CAH risk	Urgent endocrine evaluation; do not reassure before labs and imaging
Perineal/penoscrotal hypospadias, micropenis, or hypospadias plus undescended testis	Suggests impaired androgen production/action or pituitary-gonadal axis disorder	Measure stretched phallic length; examine gonads; obtain endocrine/genetic pathway labs
Discordance between prenatal karyotype/NIPT and postnatal phenotype	May reflect DSD, mosaicism, lab limitations, vanishing twin, or incorrect assumptions from ultrasound	Do not rely on prenatal report alone; confirm with postnatal testing and specialist review
Hypoglycemia, cholestasis/prolonged jaundice, midline defect, micropenis, cryptorchidism	Raises concern for hypopituitarism with ACTH, TSH, GH, and gonadotropin deficiency	Check critical glucose/endocrine labs and treat adrenal crisis/hypoglycemia promptly
Hyponatremia, hyperkalemia, dehydration, shock, excessive weight loss, abnormal CAH newborn screen	Classic salt-wasting CAH may deteriorate after the first days of life — salt loss and cardiovascular collapse usually occur between day 4 and day 15, so a reassuring first 72 hours means nothing	Draw critical samples and give hydrocortisone if unstable or high suspicion; monitor electrolytes serially

3. Emergency Priorities in the First Hours

The two most dangerous early errors

Error 1: focusing on naming the genital anatomy while missing adrenal crisis or hypoglycemia.
Error 2: creating irreversible communication harm by prematurely assigning sex before the multidisciplinary team has enough information.

Priority	What to Check	Why It Matters
Cardiorespiratory stability	HR, perfusion, pulses, BP, SpO₂, acid-base status, lactate if ill	Shock from adrenal crisis, sepsis, cardiac disease, or dehydration can coexist with DSD
Glucose safety	Bedside glucose now; lab glucose with critical endocrine samples if hypoglycemic	Hypopituitarism, cortisol deficiency, GH deficiency, and illness can cause neonatal hypoglycemia
Electrolyte safety	Na, K, Cl, bicarbonate, BUN/creatinine, calcium as indicated; repeat serially	Salt-wasting CAH may show evolving hyponatremia, hyperkalemia, dehydration, acidosis, and shock
Adrenal safety	17-OHP, cortisol, ACTH, renin/aldosterone, adrenal steroid panel when available; draw before steroids if safe	CAH and adrenal insufficiency are treatable emergencies; do not delay hydrocortisone in unstable infants
Pituitary safety	Cortisol/ACTH, glucose, GH when hypoglycemic, TSH/free T4, prolactin, LH/FSH; assess midline defects	Micropenis/cryptorchidism with hypoglycemia may be the first sign of combined pituitary hormone deficiency
Urinary/genital anatomy	Document urine output and stream; assess for obstruction; pelvic/abdominal ultrasound	Some infants need urgent urologic or surgical assessment for urogenital sinus, exstrophy, or obstructive anomaly

CAH / Adrenal Crisis Safety Rule

If the infant is unstable, hypoglycemic, hypotensive, dehydrated, acidotic, or has concerning Na/K changes → treat as possible adrenal crisis while the workup continues.
Draw critical labs first only if doing so does not delay stabilization: glucose, electrolytes, cortisol, ACTH, 17-OHP/adrenal steroid panel, renin/aldosterone if available, blood gas if ill.
Give stress-dose hydrocortisone after samples in an unstable infant or when CAH/adrenal crisis is judged likely; follow local dosing/formulary.
Begin isotonic fluid resuscitation, glucose support, and hyperkalemia treatment as clinically indicated; add fludrocortisone and NaCl once classic CAH is confirmed or directed by endocrinology.
Baylor Ed. 33 states the stress dose: in a clinically unstable infant, or one with high clinical suspicion for CAH, give hydrocortisone 100 mg/m² IV after the sample is drawn, while results are pending. Confirm against your own formulary before use.

4. Family-Centered Communication Pathway

The communication plan is a treatment. Families often remember the first words used by clinicians. The team should communicate uncertainty honestly without shame, urgency without panic, and a clear plan without premature conclusions.

Do	Avoid
Use "your baby," the baby's name, "gonads," "genital folds," and "genital tubercle" until the family and expert team have a shared plan	Avoid "it," "abnormal," "malformed," "hermaphrodite," "pseudohermaphrodite," jokes, speculation, or contradictory hallway opinions
Explain that the immediate goal is to keep the baby medically safe while expert testing clarifies chromosomes, hormones, internal anatomy, and gonad function	Avoid saying "we do not know if this is a boy or girl" without a plan — this can sound frightening and careless
Assign one senior clinician as the primary communicator; document the agreed wording used with parents	Avoid multiple team members giving different interpretations or using gendered pronouns inconsistently
Encourage normal bonding: holding, feeding, skin-to-skin when medically safe, photos, naming if desired, and parental participation in care	Avoid unnecessary NICU separation if the baby is well and evaluation can occur safely without intensive care
Tell parents that some results are rapid and others take days to weeks; explain what is urgent today and what can wait for the DSD team	Avoid pressuring immediate birth registration or public announcement of sex when evaluation is incomplete

5. Diagnostic Workup

5.1 History

Prenatal: NIPT/karyotype/amniocentesis, fetal ultrasound genital findings, growth restriction, renal/urinary anomalies, adrenal or pelvic masses, congenital anomaly screen
Maternal: virilization during pregnancy, androgen/progestin exposure, fertility medications, aromatase-inhibiting drugs, phenytoin or other relevant exposures, endocrine tumors, diabetes, autoimmune disease
Family: consanguinity, neonatal deaths, salt-wasting crises, infertility/amenorrhea, delayed puberty, inguinal hernia in phenotypic females, DSD/CAH, unexplained sudden infant death, known genetic diagnoses
Infant: feeding, vomiting, weight loss, urine output, hypoglycemia, hypotension, hyperpigmentation, jaundice, shock, seizures, temperature instability, newborn-screen results

5.2 Physical Examination

Domain	What to Document	Why It Matters
General	GA, size, dysmorphic features, hydration, pigmentation, BP, perfusion, midline facial defects, clefting, jaundice	Guides differential: syndromic DSD, CAH, pituitary disease, renal/cardiac association, or systemic illness
Genital tubercle / phallic structure	Stretched length from pubic ramus to tip on dorsal surface; chordee; glans appearance	Micropenis or clitoromegaly definitions are gestation-dependent; measurement prevents subjective labeling
Genital folds	Fusion degree, rugosity, pigmentation, labioscrotal development, single vs. separate openings	Helps describe virilization without assigning sex
Degree of virilization — Prader staging	I slightly virilized female, perhaps only isolated clitoral hypertrophy · II narrow vestibule, at the end of which the vagina and urethra open · III a single perineal orifice giving access to a urogenital sinus, with the labia majora partially fused · IV phenotypic male with hypospadias and micropenis · V a cryptorchid boy	Gives a shared vocabulary for describing the same anatomy across teams and over time, without implying a sex assignment
Urethral/vaginal/perineal openings	Urethral meatus position, hypospadias severity, urogenital sinus, separate vaginal opening, urine stream	Important for urology, imaging, infection/obstruction risk, and future operative planning
Gonads	Palpable/nonpalpable; unilateral/bilateral; inguinal/labial/scrotal location; consistency; tenderness	Palpable gonad in a labioscrotal/inguinal fold often suggests testicular tissue — but imaging and labs are still needed
Anus/back/abdomen	Anorectal anomalies, spinal defects, abdominal wall/pelvic mass, bladder exstrophy/cloacal findings	Complex anomalies need surgical/urologic and genetic evaluation

5.3 First-Line Tests

Test Group	Recommended Tests	Bedside Interpretation / Caution
Immediate safety labs	Glucose; Na/K/Cl/HCO₃; BUN/creatinine; blood gas/lactate if ill; BP and weight trend	Repeat electrolytes — CAH salt-wasting may not be abnormal on day 0–1 and often emerges later
Rapid genetic sex testing	Karyotype plus rapid QF-PCR/FISH or local rapid sex-chromosome/SRY test	Karyotype guides differential; rapid testing helps communication but does not replace full evaluation
CAH/adrenal axis	17-OHP, cortisol, ACTH, androstenedione, DHEA-S, renin/aldosterone, adrenal steroid panel; ACTH stimulation if endocrinology recommends	Draw before steroids when safe; do not delay hydrocortisone in a clinically unstable baby. 17-OHP can be affected by prematurity and timing. If the level is non-diagnostic, or the infant must start steroids, do a high-dose ACTH stimulation test: Cosyntropin 250 mcg for infants over 3 kg, 125 mcg under 3 kg, with the CAH panel drawn at 60 minutes — this accentuates the block in the pathway. 21-hydroxylase deficiency accounts for about 90% of CAH. Adequate DHT by mass spectrometry rules out 5α-reductase deficiency.
Gonadal function	Testosterone, DHT, AMH, LH/FSH; inhibin B or hCG stimulation when indicated	AMH and testosterone/DHT help identify functional testicular tissue and androgen synthesis/action patterns
Pituitary screen	Glucose, cortisol/ACTH, TSH/free T4, GH during hypoglycemia, prolactin, LH/FSH; MRI brain/pituitary if indicated	Micropenis/cryptorchidism plus hypoglycemia or midline defects may signal multiple pituitary hormone deficiency
Imaging	Pelvic/abdominal ultrasound by experienced pediatric sonographer; evaluate uterus/Müllerian structures, gonads, kidneys, adrenals; MRI or genitography/cystoscopy/EUA if needed	Ultrasound helps identify internal genitalia and renal anomalies but may miss gonads or be operator-dependent
Advanced genetics	Chromosomal microarray (CMA), DSD gene panel, single-gene testing, or exome sequencing after specialist review	Useful when first-line testing does not explain phenotype, when syndromic features are present, or for family counseling

6. Differential Diagnosis: A Practical Bedside Frame

Presentation Pattern	High-Yield Possibilities	Clues That Help Separate Them
Virilized apparent female genitalia or 46,XX pattern	21-hydroxylase CAH; other CAH variants; maternal androgen exposure; placental aromatase deficiency; ovarian/testicular DSD variants	Uterus present, no palpable gonads, elevated 17-OHP/adrenal steroids, salt-wasting, maternal virilization or medication exposure
Undervirilized apparent male genitalia or 46,XY pattern	Androgen synthesis defects; 5α-reductase deficiency; partial androgen insensitivity; gonadal dysgenesis; hypogonadotropic hypogonadism	Palpable gonads, hypospadias/micropenis, testosterone–DHT pattern, AMH level, LH/FSH, response to hCG, family history
Micropenis with bilateral cryptorchidism and hypoglycemia	Congenital hypogonadotropic hypogonadism or combined pituitary hormone deficiency	Midline defects, recurrent hypoglycemia, low cortisol/GH/TSH axis abnormalities, low/normal gonadotropins
Labial/inguinal mass in apparent female	Testis in androgen insensitivity or other 46,XY DSD; hernia with gonad; ovotesticular DSD less commonly	Palpable gonad, absent uterus, AMH/testosterone pattern, karyotype/SRY
Overt complex genital/urogenital anomaly	Cloacal exstrophy, urogenital sinus, syndromic DSD, renal/genitourinary malformation	Single perineal opening, bladder/exstrophy findings, renal anomalies, anorectal/spinal anomalies; needs surgical imaging pathway

7. Treatment, Monitoring, and Discharge Planning

Clinical Situation	NICU Treatment Focus	Consultation / Follow-Up
Unstable infant or high suspicion for CAH/adrenal crisis	Stabilize ABCs; isotonic fluid and dextrose support; treat hyperkalemia; draw critical labs if safe; start stress hydrocortisone per local endocrine pathway	Pediatric endocrinology immediately; pharmacy verification; consider transfer to endocrine/urology-capable center
Stable infant with suspected DSD and no electrolyte/glucose abnormality	Avoid unnecessary intensive admission; complete evaluation safely; repeat electrolytes/glucose; support feeding/bonding	Endocrinology, genetics, urology/gynecology, psychology/social work; DSD clinic follow-up before discharge if possible
Micropenis/cryptorchidism with hypoglycemia or midline features	Treat hypoglycemia; evaluate cortisol/GH/thyroid axes; do not discharge until pituitary/adrenal safety is addressed	Endocrinology; consider brain/pituitary MRI and long-term hormone plan
Complex urogenital anatomy or obstructive concern	Ensure urine output, renal function, infection surveillance, and imaging	Urology/surgery urgently; radiology with pediatric expertise; transport if needed
Before discharge (all DSD infants)	Written plan for electrolytes/glucose follow-up, pending labs, emergency steroid plan if relevant, family contact person, specialty appointment dates	DSD multidisciplinary clinic; endocrinology; genetics counseling; urology/gynecology; psychology/support resources

Discharge Safety Checklist

Do not discharge until all of these are addressed

No unresolved hypoglycemia, shock, dehydration, significant electrolyte abnormality, or untreated suspected adrenal insufficiency
Family has one clear contact clinician/team and written instructions for urgent symptoms: poor feeding, vomiting, lethargy, dehydration, fever, weight loss, or reduced urine output
All pending tests are tracked with responsible clinician, expected result dates, and contact plan
Endocrinology appointment is arranged; urology/genetics/psychology/social work follow-up arranged as indicated
Sex assignment, naming, registration, and pronoun use are documented only after expert/family discussion — not by unilateral bedside assumption

8. Source Differences and Practical Reconciliation

Topic	How Sources Differ	Neonatology Academy Synthesis
Urgency	Baylor frames DSD evaluation as prompt and comprehensive, especially when CAH/hypopituitarism may be life-threatening. West Midlands states DSD is a medical emergency and calls for immediate consultant involvement.	Treat suspected DSD as urgent until CAH, adrenal crisis, hypoglycemia, and severe electrolyte disturbance are excluded; stable babies may not need NICU admission solely for DSD workup.
Terminology	Baylor emphasizes gender-neutral anatomic language and not assigning sex until diagnosis; West Midlands advises using "baby" and avoiding gendered pronouns or "it."	Use respectful neutral language, avoid stigmatizing terms, and assign one senior communicator to prevent inconsistent messages.
Size thresholds	Baylor uses term micropenis <2.5 cm and clitoromegaly >0.9 cm. West Midlands lists normal penis ≥1.9 cm, reflecting different local references and gestational assumptions.	Measure carefully, interpret by gestational age and local endocrine references, and never make a diagnosis from one size threshold alone.
17-OHP timing	Baylor supports adrenal steroid testing and ACTH stimulation when needed; West Midlands advises delaying 17-OHP until day 3 when possible because early maternal/neonatal effects may confound results.	Draw urgent labs before steroids if sick; in stable babies, time 17-OHP/adrenal panel with endocrinology guidance to improve interpretation.
Advanced testing	Baylor explicitly includes karyotype, FISH/SRY, CMA, WES, and single-gene testing as situation-dependent. West Midlands lists molecular genetics after specialist advice.	Start with rapid chromosomal testing and ultrasound, then escalate to DSD gene panel/CMA/exome under genetics/endocrinology guidance.

9. Teaching Points

Ambiguous genitalia is not only an anatomy problem — it may be the first sign of life-threatening CAH, adrenal insufficiency, hypoglycemia, or hypopituitarism.
Do not wait for severe hyponatremia/hyperkalemia before thinking about CAH — salt-wasting can evolve after the first days of life.
A palpable gonad is important because ovarian tissue is usually not palpable; however, karyotype, hormones, ultrasound, and specialist interpretation remain necessary.
Micropenis plus hypoglycemia or midline defects should trigger pituitary-axis evaluation.
A single "boy/girl" statement at the bedside can cause lasting family harm if later contradicted — use neutral language until the team and family agree on a plan.
Stable infants should bond and feed normally whenever possible — uncertainty about sex development alone is not a reason to separate parents and baby.
Document anatomy descriptively: genital tubercle length, urethral location, labioscrotal fusion, gonad palpability/location, urine stream, and associated anomalies.

10. References

Fernandes CJ, Pammi M, editors. Guidelines for Acute Care of the Neonate. Edition 33, 2025–2026. Baylor College of Medicine / Texas Children's Hospital. Section 4.1.
Bedside Clinical Guidelines Partnership and West Midlands Perinatal Network. Neonatal Guidelines 2025–2028. Disorders of Sexual Development; relevant endocrine/electrolyte sections.
Flück CE, Güran T. Ambiguous Genitalia in the Newborn. Endotext. Last update November 13, 2023. NCBI Bookshelf.
Speiser PW, Arlt W, Auchus RJ, et al. Congenital Adrenal Hyperplasia Due to Steroid 21-Hydroxylase Deficiency: An Endocrine Society Clinical Practice Guideline. J Clin Endocrinol Metab. 2018;103(11):4043–4088.
Lee BR, Strobel KM, Chu A. The Neonate with Ambiguous Genitalia. NeoReviews. 2021;22(4):e241–e249.
McCann-Crosby B, Sutton VR. Disorders of sexual development. Clin Perinatol. 2015;42(2):395–x.
White PC, Speiser PW. Congenital adrenal hyperplasia. N Engl J Med. 2003;349:776–788.
Local hospital formulary and pediatric endocrinology pathway for stress-dose hydrocortisone, fludrocortisone, NaCl, hyperkalemia, hypoglycemia, and ACTH-stimulation testing must be followed.

Approach to the Management of Disorders of Sex Development