Assisted Reproductive Technology (ART)
Obstetrics & Gynaecology · Reproductive Medicine · lean revision notes
Assisted Reproductive Technology (ART)
Assisted Reproductive Technology covers all techniques in which gametes (oocytes, sperm) or embryos are handled outside the body to achieve pregnancy. For NEET PG, the high-yield zones are precise indications (especially ICSI for severe male factor), the stepwise IVF cycle, embryo grading, luteal phase support, cryopreservation, and the statutory framework of the Indian ART (Regulation) Act 2021 and the Surrogacy (Regulation) Act 2021.
High-yield: "ART" by strict definition includes only techniques where the oocyte is handled in vitro (IVF, ICSI, GIFT, ZIFT, cryopreservation, donor oocyte/embryo). IUI is NOT technically ART because fertilisation occurs in vivo — a favourite distractor.
Definition & Classification
ART = procedures involving in-vitro handling of human oocytes and sperm, or embryos, for establishing a pregnancy. This excludes ovulation induction alone and intrauterine insemination (IUI), even though both are loosely called "infertility treatment."
| Procedure | Site of fertilisation | Gametes/embryo handled in lab | Counts as "true ART"? |
|---|---|---|---|
| Ovulation induction + timed intercourse | In vivo | None | No |
| IUI (intrauterine insemination) | In vivo (uterus/tube) | Sperm washed only | No (technically) |
| IVF | In vitro (dish) | Both gametes + embryo | Yes |
| ICSI | In vitro (single sperm injected) | Both + embryo | Yes |
| GIFT | In vivo (fallopian tube) | Gametes transferred to tube | Yes |
| ZIFT | In vitro → zygote to tube | Zygote | Yes |
| Cryopreservation / donor programmes | In vitro | Gametes/embryos | Yes |
High-yield: GIFT requires at least one patent fallopian tube and laparoscopy; fertilisation happens inside the tube. It is now largely obsolete (replaced by IVF) but remains examined.
Intrauterine Insemination (IUI)
Washed, motility-selected sperm are deposited directly into the uterine cavity around the time of ovulation, bypassing the cervix.
Indications: mild male factor, cervical factor (hostile mucus), unexplained infertility, ejaculatory/sexual dysfunction, mild endometriosis, donor sperm programmes.
Prerequisites for success:
- At least one patent fallopian tube (confirm by HSG/laparoscopy).
- Adequate total motile sperm count — generally >5–10 million post-wash; below ~1 million success is poor → move to IVF/ICSI.
- Reasonable ovarian reserve.
High-yield: IUI is usually combined with controlled ovarian stimulation (clomiphene/letrozole/gonadotrophins). Recommended limit is about 3–6 cycles; if unsuccessful → escalate to IVF. Per-cycle success is roughly 10–15%.
IVF — In Vitro Fertilisation
Classic IVF: retrieved oocytes and ~50,000–100,000 motile sperm are co-incubated in a dish; sperm fertilises the egg on its own. Louise Brown (1978, Steptoe & Edwards) was the first IVF baby; Kanupriya/Durga (1978, Dr Subhash Mukhopadhyay, Kolkata) was India's first test-tube baby.
Indications for IVF
- Tubal factor (blocked/absent tubes) — the original indication.
- Moderate–severe endometriosis.
- Unexplained infertility failing IUI.
- Anovulation unresponsive to ovulation induction.
- Moderate male factor (when IUI inadequate but ICSI not mandatory).
- Need for PGT (preimplantation genetic testing).
Stepwise IVF cycle (flow)
Controlled ovarian stimulation (gonadotrophins) → Pituitary suppression (GnRH agonist/antagonist to prevent premature LH surge) → Trigger (hCG or GnRH agonist) → Oocyte retrieval (transvaginal USG-guided, ~34–36 h post-trigger) → Insemination/fertilisation in lab → Embryo culture (Day 3 cleavage / Day 5 blastocyst) → Embryo transfer → Luteal phase support → β-hCG at ~14 days.
| Step | Drugs / detail | Exam point |
|---|---|---|
| Down-regulation | GnRH agonist (long protocol) or antagonist (short, flexible) | Antagonist protocol → lower OHSS risk |
| Stimulation | FSH ± LH (recombinant/HMG) | Monitor by follicle USG + serum estradiol |
| Final maturation trigger | hCG (mimics LH); GnRH agonist trigger if high OHSS risk | Agonist trigger nearly abolishes severe OHSS |
| Retrieval | Transvaginal, 34–36 h after trigger | Oocytes aspirated before ovulation |
| Transfer | Day 3 or Day 5 (blastocyst) | Trend toward single blastocyst transfer (eSET) |
High-yield: Oocyte retrieval is timed at 34–36 hours after hCG trigger — the single most repeated time interval in ART MCQs.
ICSI — Intracytoplasmic Sperm Injection
A single spermatozoon is injected directly into the oocyte cytoplasm using a micropipette. ICSI bypasses every natural barrier to fertilisation (zona binding, acrosome reaction, oolemma fusion).
Indications for ICSI (high-yield)
- Severe male factor — the classic, most-tested indication:
- Severe oligozoospermia / asthenozoospermia / teratozoospermia (OAT).
- Azoospermia with surgically retrieved sperm (TESA/PESA/TESE/MESA).
- Previous fertilisation failure with conventional IVF.
- Use of cryopreserved / very few sperm.
- Sperm with high DNA fragmentation or globozoospermia (round-headed).
- When PGT is planned (avoids contamination by extra sperm DNA).
High-yield: The single best answer for "treatment of choice in severe male-factor infertility / azoospermia with retrievable sperm" is ICSI, not IVF.
IVF vs ICSI — the comparison table
| Feature | Conventional IVF | ICSI |
|---|---|---|
| Fertilisation | Sperm penetrate egg on their own in dish | One sperm injected into oocyte |
| Main indication | Tubal/endometriosis/unexplained | Severe male factor, prior IVF fail |
| Sperm number needed | ~50,000–100,000 motile/oocyte | One viable sperm per oocyte |
| Bypasses zona/oolemma | No | Yes |
| Risk profile | Baseline | Slightly higher imprinting disorders, transmits male infertility genes |
High-yield: ICSI does not increase pregnancy rates in non-male-factor infertility; using it routinely ("ICSI for all") is not evidence-based — a conceptual MCQ trap.
Sperm Retrieval Techniques (for azoospermia → ICSI)
| Technique | Source | Typical azoospermia type |
|---|---|---|
| PESA (Percutaneous Epididymal Sperm Aspiration) | Epididymis | Obstructive |
| MESA (Microsurgical Epididymal Sperm Aspiration) | Epididymis (microsurgical) | Obstructive |
| TESA (Testicular Sperm Aspiration) | Testis (needle) | Obstructive/some non-obstructive |
| TESE / micro-TESE (Testicular Sperm Extraction) | Testis (open biopsy) | Non-obstructive (best yield with micro-TESE) |
Mnemonic — "PEM-TT": PESA & MESA take from Epididymis; TESA & TESE take from Testis.
Embryo Grading
Embryos are graded to select the best for transfer.
Cleavage-stage (Day 2–3): assessed by cell number (ideally 4 cells Day 2, 8 cells Day 3), evenness of blastomeres, and percentage fragmentation. Grade 1 = even blastomeres, no/minimal fragmentation; higher fragmentation = poorer grade.
Blastocyst (Day 5–6) — Gardner grading (most-tested system): a number + two letters.
- Number (1–6): degree of expansion of blastocoel (1 = early blastocyst, 4 = expanded, 5 = hatching, 6 = hatched).
- First letter (A–C): Inner Cell Mass (ICM) → becomes the fetus.
- Second letter (A–C): Trophectoderm (TE) → becomes the placenta.
- A = best (many tightly packed cells), C = poor.
High-yield: In Gardner grading a good blastocyst = e.g. "4AA" (expanded, excellent ICM and trophectoderm). ICM → fetus; trophectoderm → placenta is a classic one-liner.
Luteal Phase Support (LPS)
In stimulated ART cycles the corpus luteum function is impaired (GnRH analogue suppression of LH, aspiration of granulosa cells at retrieval), so the luteal phase is deficient and must be supported.
- Drug of choice: Progesterone — vaginal (gel/pessary), intramuscular, or oral micronised/dydrogesterone.
- Started around the day of/after oocyte retrieval and continued at least up to the positive β-hCG, often to 8–10 weeks of gestation (placental takeover).
- hCG can support the luteal phase but increases OHSS risk, so progesterone is preferred.
High-yield: Vaginal progesterone is the standard luteal support in IVF; hCG for LPS is avoided when OHSS risk is high.
Cryopreservation
Freezing and storing gametes/embryos for later use.
- Methods: slow programmable freezing (older) vs vitrification (ultra-rapid cooling → glass-like solidification, no ice-crystal formation). Vitrification is now preferred — superior survival for oocytes and blastocysts.
- What is frozen: embryos, oocytes (fertility preservation, e.g. before chemotherapy/"social freezing"), sperm, and ovarian/testicular tissue (experimental→established for prepubertal cancer patients).
- Freeze-all strategy: all embryos frozen, transferred in a later cycle — used to avoid OHSS and when endometrium is suboptimal or progesterone is prematurely elevated.
High-yield: Vitrification (cryoprotectant + ultra-rapid cooling, avoids ice crystals) has largely replaced slow freezing, especially for oocytes which are very water-rich and ice-sensitive.
Complications of ART
- Ovarian Hyperstimulation Syndrome (OHSS) — the most important.
- Pathophysiology: gonadotrophin stimulation → many follicles → VEGF-mediated increased capillary permeability → fluid shifts to third space (ascites, pleural effusion), haemoconcentration, hypovolaemia, risk of thromboembolism.
- Triggered/worsened by hCG (the trigger and endogenous hCG of pregnancy) → late OHSS in conception cycles.
- Risk factors: PCOS, young age, low BMI, high antral follicle count, high AMH, high estradiol.
- Prevention: antagonist protocol + GnRH agonist trigger, freeze-all, cabergoline (dopamine agonist reduces VEGF effect).
- Multiple pregnancy — main driver of ART morbidity → push for single embryo transfer (eSET).
- Ectopic / heterotopic pregnancy (higher than spontaneous, especially with tubal disease).
- Oocyte retrieval risks: bleeding, infection, injury to bowel/vessels.
- OHSS-associated thromboembolism, even arterial.
- Possible small increase in imprinting disorders (Beckwith–Wiedemann, Angelman) — more discussed with ICSI.
| OHSS severity | Features |
|---|---|
| Mild | Abdominal bloating, mild ovarian enlargement |
| Moderate | Nausea/vomiting, ascites on USG, ovaries 8–12 cm |
| Severe | Tense ascites, haemoconcentration (Hct >45%), oliguria, pleural effusion, thromboembolism |
| Critical | ARDS, renal failure, thrombosis, Hct >55% |
High-yield: OHSS is mediated by VEGF and triggered by hCG; the most effective near-complete prevention is a GnRH-agonist trigger with a freeze-all strategy in high-risk (PCOS) women.
Legal & Regulatory Framework (Indian ART Act & Surrogacy Act, 2021)
Two laws were enacted together and are increasingly examined.
ART (Regulation) Act, 2021
- Regulates all ART clinics and banks; mandates National & State ART Registries and a National ART and Surrogacy Board.
- Commercial sale of gametes/embryos prohibited; only altruistic donation through registered ART banks.
- Oocyte donor: must be an ever-married woman with at least one living child (≥3 years old), aged 23–35 years, and may donate oocytes only once in her life, with a maximum of seven oocytes retrieved.
- Age limits for commissioning couple: woman 21–50 years, man 21–55 years.
- Mandatory insurance for the oocyte donor, informed consent, and counselling.
Surrogacy (Regulation) Act, 2021
- Permits only altruistic surrogacy; commercial surrogacy is banned.
- Surrogate must be a willing, ever-married woman with a child of her own, aged 25–35 years, a close relative of the intending couple, and may act as surrogate only once.
- Eligible intending couple: legally married Indian couple, woman 23–50, man 26–55, with infertility certified and no surviving child (with exceptions for disabled/fatal-illness child).
- A certificate of essentiality and eligibility is required; sex selection is prohibited.
High-yield: Under the 2021 laws — commercial surrogacy banned, only altruistic with a close relative; oocyte donor 23–35 yrs, married with a living child, donates only once; commissioning woman 21–50 / man 21–55 for ART. These exact numbers are the examinable points.
High-yield: Pre-conception and Pre-Natal Diagnostic Techniques (PCPNDT) Act independently bans sex determination/selection — applies to ART/PGT too (PGT cannot be used for non-medical sex selection).
Key Differentials / "Which technique?" decision logic
- Blocked tubes, good sperm → IVF.
- Severe male factor / azoospermia with retrieved sperm → ICSI.
- Mild male factor, ≥1 patent tube, good sperm count → IUI first.
- Premature ovarian insufficiency / no oocytes → donor oocyte IVF.
- Recurrent genetic disease / aneuploidy risk → IVF/ICSI + PGT.
- High OHSS risk (PCOS, high AMH) → antagonist protocol + agonist trigger + freeze-all.
Recently asked / exam angle
- "Treatment of choice in severe oligospermia/azoospermia (with sperm retrieval)?" → ICSI.
- "Time of oocyte retrieval after hCG trigger?" → 34–36 hours.
- "Which is NOT a true ART?" → IUI.
- "In Gardner blastocyst grading, ICM gives rise to?" → fetus (trophectoderm → placenta).
- "Drug of choice for luteal phase support in IVF?" → progesterone (vaginal).
- "Mediator of OHSS?" → VEGF; "trigger of OHSS?" → hCG.
- "Preferred cryopreservation method for oocytes?" → vitrification.
- "Under Surrogacy Act 2021, surrogacy permitted is?" → altruistic only; surrogate must be a close relative, 25–35 yrs, married with own child, once only.
- "Procedure requiring patent fallopian tube?" → GIFT (and IUI).
- "First test-tube baby in the world / India?" → Louise Brown (1978) / India: Kanupriya by Dr Subhash Mukhopadhyay (1978).
Rapid revision
- IUI is not technically ART — fertilisation is in vivo; needs ≥1 patent tube and adequate motile sperm.
- IVF = sperm fertilises egg in a dish; main indication tubal factor.
- ICSI = single sperm injected into oocyte; treatment of choice for severe male factor/azoospermia.
- ICSI needs only one viable sperm; does not improve outcomes in non-male-factor cases.
- Oocyte retrieval = 34–36 h after hCG trigger.
- GnRH antagonist protocol + agonist trigger minimises OHSS; freeze-all for high risk.
- OHSS is VEGF-mediated, hCG-triggered; severe = haemoconcentration (Hct >45%), ascites, thrombosis risk; PCOS is the top risk factor.
- Gardner grading: number = expansion, first letter = ICM (→fetus), second = trophectoderm (→placenta); "4AA" is excellent.
- Luteal support = vaginal progesterone, continued to ~8–10 weeks.
- Vitrification (no ice crystals) is the preferred cryopreservation method, especially for oocytes.
- Sperm retrieval: PESA/MESA → epididymis (obstructive); TESA/TESE/micro-TESE → testis (non-obstructive).
- 2021 laws: commercial surrogacy banned (altruistic, close relative, 25–35 yrs); oocyte donor married with living child, 23–35 yrs, donates once; sex selection barred under PCPNDT.