Preimplantation Genetic Testing Medical Services in China

Preimplantation Genetic Testing (PGT) is a specialized laboratory procedure performed during in vitro fertilization (IVF) to analyze embryos for genetic abnormalities prior to uterine transfer. It is not a disease but a diagnostic and preventive reproductive technology used within reproductive medicine to enhance the likelihood of a healthy pregnancy and reduce the risk of transmitting inheritable genetic disorders. PGT encompasses three primary subtypes: PGT-A (aneuploidy screening), which detects abnormal chromosome numbers (e.g., trisomy 21); PGT-M (monogenic/single-gene disorders), which identifies specific pathogenic variants linked to conditions such as cystic fibrosis, spinal muscular atrophy, or Huntington’s disease; and PGT-SR (structural rearrangements), designed for carriers of balanced chromosomal translocations or inversions. Pathogenesis underlying the need for PGT lies in gametogenesis errors—especially maternal meiotic nondisjunction—and de novo or inherited germline mutations. These errors increase with advancing maternal age, particularly after 35, and are also associated with recurrent pregnancy loss, repeated IVF implantation failure, severe male factor infertility, and known familial monogenic disease carriers. Epidemiologically, aneuploidy affects ~30–60% of human blastocysts, rising sharply with maternal age; approximately 1 in 200 live births carries a clinically significant monogenic disorder, and ~0.5–1% of couples undergoing IVF have an indication for PGT-M or PGT-SR. Key risk factors include advanced maternal age (>35 years), parental balanced chromosomal rearrangements, prior child or pregnancy affected by a genetic condition, history of ≥2 unexplained miscarriages, and multiple failed IVF cycles. While PGT itself carries no direct physical symptoms or morbidity, its clinical context profoundly impacts quality of life: patients often experience significant emotional distress—including anxiety, grief, guilt, and decisional burden—related to fertility challenges, ethical dilemmas around embryo selection/discard, financial strain, and prolonged treatment timelines. Psychosocial support, genetic counseling, and shared decision-making are integral to mitigating these impacts. Importantly, PGT does not guarantee pregnancy or eliminate all genetic risks—it cannot detect polygenic disorders, mosaicism below detection thresholds, or de novo mutations occurring post-biopsy. Its success depends on IVF efficacy, embryology expertise, and comprehensive pretest genetic counseling to define appropriate indications, limitations, and alternatives.

Preimplantation Genetic Testing (PGT) is an advanced assisted reproductive technology (ART) performed during in vitro fertilization (IVF) to analyze embryonic genetic material prior to uterine transfer. PGT encompasses three primary modalities: PGT-A (aneuploidy screening), PGT-M (monogenic/single-gene disorder testing), and PGT-SR (structural rearrangements). It is indicated for couples with recurrent pregnancy loss, repeated IVF implantation failure, advanced maternal age (≥35 years), known carrier status for autosomal recessive or X-linked conditions, balanced chromosomal rearrangements, or a prior pregnancy affected by a genetic disorder. As a core service within the Department of Reproductive Medicine, PGT is not a standalone treatment but an integrated diagnostic enhancement to IVF—requiring coordinated multidisciplinary input from reproductive endocrinologists, clinical embryologists, molecular geneticists, and genetic counselors.

Conservative management precedes and supports PGT implementation. This includes comprehensive pre-cycle evaluation: karyotyping of both partners, carrier screening via expanded genomic panels (e.g., 500+ gene panels), ovarian reserve assessment (AMH, AFC, FSH), semen analysis with DNA fragmentation testing, and uterine cavity evaluation (saline infusion sonohysterography or hysteroscopy). Lifestyle optimization is emphasized—smoking cessation, alcohol abstinence, BMI normalization (18.5–24.9 kg/m²), folic acid (400–800 µg/day) and vitamin D supplementation, and stress reduction through cognitive behavioral therapy or mindfulness-based interventions. For patients with mild male factor infertility or borderline ovarian reserve, expectant management with timed intercourse or intrauterine insemination (IUI) may be trialed—but only if genetic risk is low and prognosis remains favorable; PGT is not deferred in high-risk scenarios due to unacceptable risks of transmitting serious monogenic disease or sustaining recurrent aneuploid losses.

Pharmacologic intervention centers on controlled ovarian stimulation (COS) protocols tailored to individual response profiles. Gonadotropin-releasing hormone (GnRH) antagonist regimens are preferred for most patients due to lower risk of premature luteinization and flexibility in trigger timing. Recombinant FSH (e.g., follitropin alfa/beta) ± low-dose LH is titrated based on serial transvaginal ultrasound and estradiol monitoring. Final oocyte maturation is induced with either a GnRH agonist (e.g., leuprolide acetate) in antagonist cycles or recombinant hCG (e.g., chorionic gonadotropin alfa) when appropriate. Luteal phase support includes vaginal micronized progesterone (600–800 mg/day) ± oral dydrogesterone, initiated on the day of oocyte retrieval and continued until pregnancy test confirmation—and extended through week 10 in PGT-conceived pregnancies given the higher baseline risk of luteal insufficiency in freeze-all cycles. Adjunctive medications such as low-dose aspirin (75–100 mg/day) or intravenous immunoglobulin (IVIG) are not evidence-based for routine PGT use and are reserved for research protocols or highly selected cases with documented immune dysregulation.

Surgical treatment is ancillary but critical for optimal PGT outcomes. Hysteroscopic resection of submucosal fibroids (>2 cm), endometrial polyps, or intrauterine adhesions is performed prior to embryo transfer to normalize endometrial receptivity. Laparoscopic evaluation and treatment of moderate-to-severe endometriosis (ASRM Stage III–IV) or hydrosalpinges—via salpingectomy or proximal tubal occlusion—is recommended before PGT-IVF, as these conditions impair implantation and increase miscarriage risk independent of embryo genetics. Varicocelectomy may be offered to men with clinical varicocele and elevated sperm DNA fragmentation (>30%), though its impact on PGT-derived euploid blastocyst rates remains under investigation. All surgical interventions follow strict perioperative antimicrobial prophylaxis and are scheduled to allow ≥3 months for endometrial recovery prior to COS initiation.

China offers distinct advantages in PGT delivery. First, regulatory oversight by the National Health Commission ensures standardized laboratory accreditation (e.g., CAP/CLIA-equivalent certification for >95% Tier-1 ART centers), rigorous validation of next-generation sequencing (NGS) platforms, and mandatory external quality assessment. Second, China’s large-scale patient volume enables rapid protocol refinement—leading to industry-leading blastocyst biopsy success rates (>98%) and concordance between trophectoderm and inner cell mass (>97%). Third, cost-effectiveness is notable: comprehensive PGT-A with NGS costs approximately USD $2,200–$3,500 per cycle (vs. $4,000–$7,000 in the US/EU), inclusive of biopsy, sequencing, bioinformatic analysis, and reporting—all without compromising analytical sensitivity (<10% mosaicism detection threshold). Fourth, integration with national electronic health records facilitates longitudinal tracking of PGT-conceived children, contributing robust real-world data on pediatric outcomes. Finally, China’s centralized ART registry enables timely epidemiological surveillance—supporting evidence-based updates to PGT indications and technical standards.

Post-PGT recovery focuses on physiological stabilization and psychological continuity. Patients undergoing freeze-all cycles (standard for PGT) require endometrial preparation with sequential estrogen priming (2–3 weeks) followed by progesterone initiation 5–6 days prior to euploid blastocyst transfer. Strict adherence to medication timing and vaginal administration technique is reinforced. Post-transfer, patients are advised to avoid heavy lifting (>10 kg), vigorous exercise, hot tubs, and intercourse for 10 days—but routine ambulation and desk-based work are encouraged. Psychological support is integral: structured counseling addresses anxiety related to mosaic result interpretation, decision-making regarding embryo disposition, and adjustment to prolonged treatment timelines. Nutritional guidance emphasizes anti-inflammatory foods (omega-3-rich fish, leafy greens, berries), adequate hydration (2–2.5 L/day), and avoidance of ultra-processed sugars. Follow-up includes serum β-hCG testing 10 days post-transfer, transvaginal ultrasound at 6–7 weeks to confirm viability and gestational age, and referral to maternal-fetal medicine for first-trimester aneuploidy screening (NIPT) and detailed anatomy scan at 18–22 weeks—even after PGT, given residual limitations in detecting low-level mosaicism, uniparental disomy, or de novo CNVs. Long-term follow-up includes pediatric developmental assessments at 12 and 24 months, coordinated through regional birth cohort programs. Ultimately, PGT represents not merely a technical procedure but a precision reproductive strategy—one that demands scientific rigor, ethical transparency, and compassionate continuity of care.