The whole process of embryo transfer for surrogate mothers: scientific management, legal guarantees and keys to success

Scientific Preparation for Embryo Transfer

Medical Evaluation and Legal Compliance
The surrogate mother needs to pass hormone level test (FSH, LH, estradiol), endometrial tolerance assessment (thickness ≥8mm, triple line pattern) and psychological stability test to ensure that her physical and psychological status meets the requirements of pregnancy. The legal agreement should specify the ownership of the embryos, the payment of compensation in installments (30% for contracting, 30% for successful transfer, and 40% after delivery), and the division of medical responsibility.

Embryo quality optimization techniques

Ovulation promotion program: Microstimulation (daily injection of FSH 75-150IU + LH 75IU) is used to avoid overstimulation of the ovaries, the number of eggs obtained is controlled at 8-12 eggs/cycle, and the rate of mature eggs is increased to 85%.
Embryo screening:
Blastocyst culture: dynamic monitoring using Timelapse culture system (Timelapse), blastocyst formation rate 70%.
PGT-A Screening: Whole genome analysis of 23 pairs of chromosomes of embryos to exclude aneuploidy and 200+ single gene disorders, 99% accuracy of healthy embryo screening.
Cryopreservation: Vitrification (freezing) technology enables the survival rate of embryo resuscitation to exceed 95%, supporting cross-border transportation and long-term preservation.

Key steps in the embryo transfer operation

Endometrial preparation program

Hormone Replacement Therapy (HRT)
Estrogen phase: oral supplementation with Gamma (2mg/day) or transdermal patch for 10-14 days, targeting endometrial thickness ≥8mm.
Progesterone conversion: vaginal progesterone gel (90mg/day) or intramuscular progesterone oil (50mg/day) starting 5 days prior to transplantation to mimic the luteal function of the natural cycle.
Endothelial synchronization: endothelial morphology and blood flow signals are monitored by ultrasound (PI <3, RI <0.8) to ensure the optimal window for implantation.

Technical details of painless implantation

Pre-operative preparation: Oral diazepam (5mg) 1 hour prior to transfer to relieve anxiety, bladder moderately filled to optimize ultrasound view.
Embryo loading: The embryologist loads 1-2 good quality blastocysts using a Cook catheter (≤0.23mm internal diameter) to avoid mechanical damage.
Precise Positioning: Under ultrasound guidance, the embryos are placed in the mid-upper uterine cavity, 1-1.5 cm from the uterine fundus to minimize the risk of contractions. The whole operation takes ≤ 10 minutes, and you can leave the hospital after the operation with 30 minutes of bed observation.
Scientific management program after transfer

Early pregnancy monitoring system

Hormone dynamic tracking:
Detect serum β-HCG on the 10th day after transplantation, and the threshold value >50mIU/mL suggests successful implantation.
HCG doubling rate is monitored every 48 hours, and the growth rate <66% should be checked for ectopic pregnancy risk.
Ultrasound confirmation: Vaginal ultrasound is performed on the 28th day after implantation to confirm the location of the gestational sac, the length of the fetal buds (CRL ≥ 5mm) and the fetal heart rate (normal range 110-160 beats per minute).

Surrogate mother health management

Nutritional intervention:
Protein fortification: 120g of high-quality protein (fish, beans, low-fat dairy products) per day to prevent pregnancy anemia.
Glycemic control: adopt a low glycemic index diet (GI <55) with 40%-50% carbohydrates with dietary fiber (25-30g/day).
Complication prevention:
Blood pressure management: weekly monitoring of blood pressure (target <140/90 mmHg) and combination of calcium (1000 mg/day) with aspirin (81 mg/day) to reduce the risk of preeclampsia.
Multifetal interventions: selective fetal reduction for three or more pregnancies, preservation of 1-2 embryos, 40% reduction in preterm birth rate.

Psychological and social support

Psychological counseling: professional psychological counseling twice a month to relieve mother-infant separation anxiety and cognitive behavioral therapy (CBT) to adjust emotions.
Residence management: centralized residence in a medically supervised apartment with 24-hour nursing team, no smoking, alcohol consumption and high-risk activities.

Legal and Ethical Safeguards

Contractual Risk Control

Staged Payment: Compensation is paid in three stages: contracting, successful transplantation, and delivery. Default is subject to return of payments made and 20% liquidated damages.
Insurance coverage: The surrogate mother is entitled to commercial medical insurance with a coverage of $100,000, covering 26 pregnancy complications (e.g. placental abruption, postpartum hemorrhage).

Ethical Review Standards

Voluntariness: The surrogate mother is required to sign a statement witnessed by an independent attorney confirming that there is no coercion or inducement for gain.
Privacy protection: anonymized information management, prohibiting the disclosure of the surrogate mother’s identity and medical records.
Frequently Asked Questions and Professional Advice
Is post-transplant bleeding normal?
Slight spotting bleeding (<5mL/day) is usually due to implantation bleeding. Persistent bleeding or abdominal pain requires immediate medical attention to investigate the risk of miscarriage. Can I continue to work? It is recommended to rest at home for 3 days after transplantation, after which you can resume light activities (e.g., walking, paperwork), but no heavy lifting (>5kg) or prolonged standing is allowed.
How is medication compliance ensured?
With the use of smart pillboxes (e.g. Hero Health) to provide regular reminders and daily video confirmation of medication by nurses, the rate of missed doses has been reduced to less than 2%.

Conclusion

Embryo transfer is the most technically precise and management-intensive stage of the surrogacy process. From endometrial preparation to postoperative health management, every step of the process must follow evidence-based medical standards and ethics. Through scientific physical conditioning, professional medical support and sound legal protection, surrogate mothers can significantly increase the success rate of pregnancy and reduce physical and mental risks.